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"Hemingway, Fitzgerald, and Mass-Market Magazines: Aspects of the Relationships between Writers and 'Magazinedom' (Jack London)"

Introduction

Both Hemingway and Fitzgerald were very much connected with "big," mass-market magazines. Maybe the two modernist writers most associated with big periodicals, they contributed to Esquire, Vanity Fair, Harper's, Scribner's, Collier's, Ladies Home Journal, Woman's Home Companion, McCall's, the Saturday Evening Post (the then largest weekly magazine in the world), and even Life, to name but a few, as well as The Smart Set, the transatlantic review, The Double Dealer, The Dial, transition and other small magazines. A lot of references to big magazines fuel their fiction and their nonfiction, in particular their correspondence. My goal here is to look at their discourse on big magazines, show their ambivalence, and reflect on what that ambivalence suggests about the interactions between writers, magazines, and the editing world, at a time when magazines had become a dominant medium.

The Presence of Magazines in Fitzgerald's and Hemingway's Fiction

It is a well-known fact that magazines and newspapers, in the first half of the 20th century, enjoyed a status they hadn't known so far, and haven't known afterwards. All the textbooks that retrace the history of the press, in the U.S. and in other countries as well, insist on the fact that the years 1910-1960 corresponded to a golden age for the magazines, after a period of strong growth and diversification of the market, with a shift to big business, between more or less the Reconstruction Era and WW1. Many facts reveal the strength of magazines, not only in the editing world, but also in the world at large, as some magazines went beyond their editing mission, launching philanthropic campaigns during the Progressive Era (such as The Delineator's Child-Rescue Campaign between 1907 and 1911), creating correspondence schools (Cosmopolitan launched one in 1897, Les Annales politiques et littéraires in France did the same ten years later), and even offering to intervene in the world's affairs: as Tebbel and Zuckerman recall in their history of the magazine in America, Cosmopolitan "sent a representative to the Spanish government offering to purchase Cuban independence for $100 million, offered a plan to save the nation from depression through a credit system, advocated a commission to establish an international language, and proposed a World Congress"1 .

That magazines were then a dominant, powerful medium emerges from many of Hemingway's and Fitzgerald's short stories and novels. Hemingway refers to magazines (and newspapers) to give local color to exotic scenes (in The Garden of Eden, "The patron was sitting at one of his tables on the terrace of the long house with a bottle of wine, a glass and an empty coffee cup reading the Eclaireur de Nice (…)" beg chap 10 Scribner 1995, p. 83). Both Hemingway and Fitzgerald use references to the press to shape specific atmospheres. In Across the River and Into the Trees, Colonel Cantwell and a young woman he has met engage in escapist dreams partly derived from the reading of Vogue:

"Where will we leave the Cadillac?" "Is it a Cadillac now?" "Yes. Unless you want to take the big Buick Roadmaster, with the Dynaflow drive. I've driven it all over Europe. It was in the last Vogue you sent me." (chap 37 Scribner 1998 p. 228).

In The Beautiful and Damned, the presence of Vanity Fair on a table helps build an atmosphere of luxury and sophistication: "A faint string of smoke was rising from a cigarettetraya number of Vanity Fair sat astraddle on the table." (Book 3, chap 1, Penguin Edition 2001 p. 290).

If the many references to newspapers and magazines we find in Hemingway's fiction tell a lot about the special relationship Hemingway had with the press, in particular through his work as a journalist, they also suggest that he thought he had those references in common with his readers. Otherwise, a sentence such as "She looks like anybody's mother in an illustration in 'The Ladies' Home Journal,' the Colonel thought" (Across the River chap 9 p. 78) would make no sense. Fitzgerald too seems to rely on his readers' knowledge of "magazinedom" as he refers to magazines and newspapers to contribute to characterization. In The Beautiful and Damned, the fact that "we've got to be very quiet. Mother sits up reading Snappy Stories" (Book 3, chap 1, Penguin Edition 2001 p. 267) is meant to ridicule the speaker, Dorothy. Pulp magazines are also used in To Have and Have Not to suggest the social gap between Richard Gordon, a writer, and a veteran he meets in a bar: "You haven't got a book with you?" asked the other Vet. "Pal, I'd like to read one. Did you ever write for Western Stories, or War Aces? I could read that War Aces every day." (chap 22, Charles Scribner's, McMillan, 1988, p. 210) Those examples suggest that Hemingway's and Fitzgerald's readers were familiar, to some extent at least, with the world of magazines, which reflects the domination of magazines in the media landscape of the time, and their influence on society at large. In fact, the social domination of magazines was both highlighted and criticized by Hemingway and Fitzgerald.

The Criticism of the Power of Magazines, Big, Small, and Otherwise, in Hemingway's and Fitzgerald's Fiction, with References to Martin Eden Social power and prestige, as well as decisive career benefits, could be obtained through associations with magazines, as young Amory, in Fitzgerald's largely autobiographical first novel This Side of Paradise, realizes: "Amory found that writing for the 'Nassau Literary Magazine' would get him nothing, but that being on the board of the 'Daily Princetonian' would get anyone a good deal." (Book 1 chap 2 Cambridge University Press ed. James L. W. West 1995 p. 49). Of course, the lexicon chosen by Fitzgerald ("get," "deal"), as well as the fact that Fitzgerald himself published his first texts in the Nassau Literary Magazinethe magazine that would get Amory nothingreveal the gap between Amory's and Fitzgerald's notions of the magazines.

But before Amory "is throughas far as ever being a power in college is concerned" (Book 1 chap 3 p. 96), his success is tightly associated to his future career in the Nassau Literary Magazine: "I want to pull strings, even for somebody else, or be 'Princetonian' chairman or Triangle president. I want to be admired, Kerry." (Book 1 chap 2 p. 51). And the professional prestige linked to Amory's association with the Princetonian has a price, or is supposed to have one, on the matrimonial market. As Amory flirts with Isabelle, "They had now reached a very definite stage. They had traded accounts of their progress since they had last met, and she had listened to much she had heard before. He was a sophomore, was on the 'Princetonian' board, hoped to be chairman in senior year." (Book 1 chap 2 p. 69). In the same way, in The Beautiful and Damned, Anthony, when dreaming of his future career, sees himself as "editor of a brilliant weekly of opinion, an American Mercure de France" (Book 2, chap 2, p. 185). (In reality, the American Mercury was founded two years after the publication of the novel, in 1924, but in 1922, Fitzgerald knew of Mencken's and Nathan's project).

Just as Fitzgerald highlights and puts into question the social importance of magazines through Amory's and Anthony's destinies in This Side of Paradise, and The Beautiful and Damned, Hemingway also mocks the social aura and educational mission of magazines in Torrents of Spring, a satirical novella the young writer published in 1926. In Torrents of Spring, writer Scripps O'Neill marries a waitress, Diana, before leaving her for another, younger waitress, Mandy. Distraught by her eviction, Mandy does everything she can to keep Scripps. Mostly, she reads magazines, as she's convinced that sharing her readings with Scripps will enable her to save her couple. But of course, if Amory can nourish some hope of seducing Isabelle by being on the 'Princetonian' board, there's little hope for Mandy to rescue her marriage by subscribing to magazines. Her helplessness pervades the end of the novella: Scripps was fascinated by Mandy. Diana admitted that to herself. But she might hold him. That was all that mattered now. To hold him. To hold him. Not to let him go. Make him stay. She looked into the mirror.

Diana subscribing for The Forum. Diana reading the Mentor. Diana reading William Lyon Phelps in Scribner's. Diana walking through the frozen streets of the silent Northern town to the Public Library, to read the Literary Digest 'Book Review.' Diana waiting for the postman to bring the Saturday Review of Literature. Diana, bareheaded now, standing in the mounting snowdrifts, waiting for the postman to bring her the New York Times 'Literary Section.' Was it doing any good ? Was it holding him ? At first it seemed to be. Diana learned editorials by John Farrar by heart. Scripps brightened. A little of the old light shining in Scripps's eyes now. Then it died. Some little mistake in the wording, some slip in her understanding of a phrase, some divergence in her attitude, made it all ring false. She would go on. She was not beaten. He was her man and she would hold him. She looked away from the window and slit open the covering of the magazine that lay on her Eventually, her failure to keep her husband is symbolized by her failure to keep a copy of The Century in her hand. "She felt she couldn't hold him. As she looked out of the window, a copy of The Century Magazine dropped from her nervous hand." (Chap 10, p. 44).

While those examples reveal an implicit criticism of the power of magazines, in other cases Hemingway and Fitzgerald are more straightforward. In his final novel, The Garden of Eden, Hemingway looks back on some of his own experience as a young writer through David's interactions with the editing world. As David reads a letter from his publisher congratulating him on his second novel, which "validated all the promise his first had shown," he feels a growing frustration with his submission to both his publisher and the magazine world: "(…) the hell with the promise he had validated. What promise to whom? To The Dial, to The Bookman, to The New Republic? No, he had shown it. Let me show you my promise that I'm going to validate it. What shit." (chap 7 p. 59) More humiliation is in store as, later in the novel, his wife Catherine, who has burned some of his manuscripts out of jealousy, wants to give him money for his loss. In order to set a price, she offers to have his stories appraised by "such people as the editor of the Atlantic Monthly, Harper's, La Nouvelle Revue Française" (chap 26 p. 226). David's cold anger comes, in part, from his incapacity to grant these magazines any power to assess the value of his fiction:

'Just what is it you propose to do?' 'I'll have their value determined and I'll have twice that paid into your bank.' 'Sounds very generous,' David said. 'You were always generous.' 'I want to be just, David, and it's possible that they were worth, financially, much more than they would be appraised at.' 'Who appraises these things?' 'There must be people who do. There are people who appraise everything.' 'What sort of people?' 'I wouldn't know, David. But I can imagine such people as the editor of the Atlantic Monthly, Harper's, La Nouvelle Revue Française.' 'I'm going out for a while,' David said. 'Do you feel all right?' (p. 226-7)

As we can see, the magazines Hemingway mentions in these two passages are not necessarily big magazines. The New Republic would be better described as a quality magazine, while The Dial is usually considered a little magazine. What Hemingway, through David's voice, denounces, is the power of magazines, which can derive either from their economic or their cultural capital. Fitzgerald's criticism develops in a similar way: it centers on magazines as places of power, and encompasses student magazines, as we saw earlier, and quality magazines such as The New Republic. In This Side of Paradise, Amory explains to his friend Tom, a critic on The New Democracy (probably an alias for The New Republic) that his work goes against ethical values: Look at you; you're on The New Democracy, considered the most brilliant weekly in the country, read by the men who do things and all that. What's your business? Why, to be as clever, as interesting, and as brilliantly cynical as possible about every man, doctrine, book, or policy that is assigned you to deal with. The more strong lights, the more spiritual scandal you can throw on the matter, the more money they pay you, the more the people buy the issue. (p. 212)

As for Anthony, in The Beautiful and Damned, he reflects on the difficulty to enter the magazine world at large: "It was palpably impossible to get on a magazine unless you had been on one before." (Book 2, chap 2, "Winter," p. 185).

Writing in the 1920s and later, Hemingway and Fitzgerald were not the first to put into question the intellectual legitimacy and the working methods of American magazines. Jack London, in the autobiographical 2 novel Martin Eden, written in 1906, famously developed a thorough criticism of "magazinedom," 3 as he writes, as a realm of stupidity and violence, in particular towards writers, and questioned the role of actors such as literary critics and editors. 4 His denunciation of the effects of an "inhuman editorial machine" (Martin Eden, p. 250 5 ) seems at times to foreshadow Pound's 1930 outburst against big magazines: "[Martin] was amazed at the immense amount of printed stuff that was dead. No light, no life, no color, was shot through it. (…) the magazine short stories seemed intent on glorifying the Mr Butlers, the sordid dollar-chasers, and the commonplace little love affairs of commonplace little men and women." 6 However, London's analysis of "magazinedom" is quite different from Pound's. He doesn't oppose small and big magazines, as Pound will later do, but magazines that pay and magazines that don't. As Martin remarks, the opposition between magazines that pay and magazines that don't pay is far from intuitive: The Transcontinental, a "staid, respectable," "high and lofty" 7 magazine, in other words, an established quality magazine, doesn't pay, while The White Mouse, which he had thought "a third-rater," "pay[s] 2 London wrote that he "narrated therein all [his] personal experiences from the very beginning of [his] attempt to kick into the writing game." (The Letters of Jack London, 2 April 1915, vol 3, p. 1437). 3 p. 344: Brissenden: "Love Beauty for its own sake (…) and leave the magazines alone. (…) You are cutting your throat every day you waste [in these cities] trying to prostitute beauty to the needs of magazinedom." 4 p. 251: Praps and Vanderwater as "the two foremost literary critics in the US. Every school teacher in the land looks up to Vanderwater as the Dean of American criticism." Idem for Praps. "Not a comma is out of place" and the tone is "lofty, so lofty". He is the best-paid critic in the US. / But he's not a critic at all. They do criticism better in England. But the point is, they sound the popular note… so beautifully and morally and contentedly. (…) They are the popular mouthpieces. They back up your professors of English, and your professors of English back them up." English professors described as "microscopic-minded parrots". p. 322: "The chief quality of 99% of all editors is failure. They have failed as writers. Don't think they prefer the drudgery of the desk and the slavery to their circulation and to the business manager to the joy of writing. They have tried to write, and they have failed. And right there is the cursed paradox of it. Every portal to success in lit is guarded by those watchdogs, the failures in literature." 5 p. 250: "the inhuman editorial machine ran smoothly as ever. (…) Surely there were no live, warm editors at the other end. It was all wheels and cogs and oil-cups -a clever mechanism operated by automatons." The same metaphor appears on p. 160. Such criticism is made explicit on p. 300: "Encouraged by his several small sales, Martin went back to hackwork. Perhaps there was a living in it, after all. Stored away under his tale were the twenty storiettes which had been rejected by the newspaper short-story syndicate. He read them over in order to find out how not to write newspaper storiettes, and so doing, reasoned out the perfect formula. He found that the newspaper storiette should never be tragic, should never end unhappily, and should never contain beauty of language, subtlety of thought, nor real delicacy of sentiment. Sentiment it must contain, plenty of it, pure and noble, of the sort that in his own early youth had brought his applause for "nigger heaven" -the "For God my country and the Czar" and "I may be poor but I am honest" brand of sentiment. (…) The formula consisted of three parts: 1) a pair of lovers are jarred apart; 2) by some deed or event they are reunited; 3) marriage bells. 6 p. 160: "He was amazed at the immense amount of printed stuff that was dead. No light, no life, no color, was shot through it. (…) He wanted to glorify the leaders of forlorn hopes, the mad lovers, the giants that fought under stress and strain, amid terror and tragedy, making life crackle with the strength of their endeavor. And yet the magazine short stories seemed intent on glorifying the Mr Butlers, the sordid dollar-chasers, and the commonplace little love affairs of commonplace little men and women. Was it because the editors of the magazines were commonplace? he demanded. Or were they afraid of life, these writers and editors and readers?" 7 p. 264: "Five dollars for 'The Ring of Bells,' five dollars for five thousand words! Instead of two cents a word, ten words for a cent! (…) And he would receive the check when the story was published [and not upon acceptance] (…) The Transcontinental sold for 25 cents, and its dignified and artistic cover proclaimed it as among the first-class magazines. It was a staid, respectable magazine, and it had been published continuously since long before he was born. (…) And the high and lofty, heaven-inspired Transcontinental paid five dollars for five thousand words!" on acceptance and two cents a word."8 The White Mouse, probably an alias for The Black Cat, a Boston literary magazine published between 1895 and 1922, and to which London contributed, defined itself as "a monthly magazine of original short stories". While definitely a smaller magazine than The Overland Monthly, the reputed San Francisco-based periodical disguised as The Transcontinental review in Martin Eden, The Black Cat was in no way a little magazine. Although Pound's article on "Small Magazines" and London's analysis of "magazinedom" and the editing world in Martin Eden do not compare, London's analysis being much more thorough and sociological, reading both side by side is an interesting experience which helps to take distance with the dominant opposition between little and big magazines. Indeed, such an opposition reflects the experience of some writersand probably the experience of those "expressing vociferously radical views upon all creation,"9 as London writes in Martin Eden, i.e. the avant-garde scene to which Pound himself belonged -, but probably not the experience of most writers, among whom London himself.

If Jack London is radical, not in his "views upon all creation," but certainly in his denunciation of the ills of the editing world, he was careful to find fictional aliases for the magazines he attacked. Martin Eden, after all, was first published in a magazine, the Pacific Monthly, which, "recognizing the thinly veiled attack" against the Overland Monthly, "published a substantially rewritten version of the chapter when it serialized the novel."10 Being cautious might have been a legal necessity, but it was probably as well a way of protecting his own interests. As the editors of The Letters of Jack London recall, "During the first decade of the twentieth century, scarcely a month passed without his contributions appearing in popular magazines like Century, Cosmopolitan, and the Saturday Evening Post. In less than twenty years he produced some five hundred nonfiction pieces, nearly two hundred short stories, and twenty novels (over fifty books in all)." 11 This leads me to the third and last part of this talk, about the mutual interests tying together writers and big magazines.

Beyond Conflicts: Mutual Interests and Circulations

Although Hemingway and Fitzgerald could be fierce in their criticism of magazines, and big ones in particular, they probably did not have the means, starting with the financial ones, to push their complaints too far. One obvious reason for publishing in big magazines was that they paid their contributors, when the little magazines usually did not, or paid very little. As Thomas Wolfe sarcastically wrote to Norman Pearson in 1938, "There's one thing to be said about getting published in the New Masses: you never have to bother about an income tax." [START_REF] Wolfe | The Letters of[END_REF] Just as David in Hemingway's Garden of Eden engages into complicated mathematical calculations, minutely detailed to the reader, as soon as he receives a letter from his publisher, 13 Fitzgerald is equally straightforward when writing to the Post fiction editor Adelaide Neall in 1937: "Thanks for your note and for scheduling the Trouble story. 1937 better be good -35' and 36' were one long doctor's bill." [START_REF] Nowell | Duggan with the assistance of Susan Walker[END_REF] Two years later, while seemingly delicate about "his price," as he writes to the fiction editor of Collier's, he is nonetheless quite blunt about it : "I don't know what my price isonly once did I get under $3000. from the Post and was in a year (1937) when they got only one story." [START_REF] Similarly | [END_REF] But obviously, selecting magazines for publication was not just a question of money, otherwise writers would have targeted big magazines only. Many modernist writers published in big and small magazines, because they developed different strategies at the same time, "making a respectable income while creating a public image," [START_REF] Hammill | Modernism and the Quality Magazines: Vanity Fair[END_REF] as Faye Hammill and Karen Leick wrote in their contribution to Brooker's and Thacker's encyclopedia on modernist magazines. Fitzgerald and Hemingway, as well as London, who "pioneered in the art of using the media to project the writer as public celebrity," 17 had a very good knowledge of, and interest in, "magazinedom," and both London's and Fitzgerald's correspondences use sociological notions, such as "field," "market," and "writing game," when referring to magazines, showing their willingness to produce a scientific analysis of the editing world. London was eager to give writers advice: "Magazines do not like horror-stories." "under no circumstances [study] Latin." "Instead, read the magazines and newly published novels, in short, study your market." 18 In 1907, London was able to list 12 magazines to be contacted successively for the publication of a short story. [START_REF] Thacker | [END_REF] In 1930, addressing his agent, Fitzgerald engaged in a similar exercise: "About Zelda's sketches, have you tried Century? They printed my little skit on Scotty. But better stillsend them to the New Republic, attention of Edmund Wilson, under the blanket title of Stories from a Swiss Clinique. Failing that I'll try This Quarter here in Paris. Unfortunately transition has quit." [START_REF] Fsf | [END_REF] It is interesting to notice that quality magazines such as Century and the New Republic were preferred to little magazines such as This Quarter and transition, probably for financial, and maybe circulation reasons. The same text could find its way into different magazines, but different strategies could also be used according to the type of text to be published. As Leick and Hammill show in their piece for Brooker and Thacker, "Modernist writers rarely placed experimental work in Esquire, but instead used the publication to promote their personal interests and concerns. (…) Many modernist writers appeared in the magazine, but they submitted pieces that were not experimental, and were instead instructive, reflective, or usually mainstream."21 All this points to complex authorial strategies, and complex negotiations for writers, but also for magazines themselves. Donal Harris opens On Company Time, American Modernism in the Big Magazines, on an analysis of "This is a Magazine," a satirical text on a popular magazine, probably the Saturday Evening Post, which Fitzgerald published in Vanity Fair in 1920. He shows Fitzgerald's "ambivalence toward the role of popular magazines," since the mass-market magazines he targeted "are the very ones that provided him with his foothold in the literary market." 22 But the publication of "This is a magazine" also allows us to pinpoint two converging strategies, Fitzgerald's and Vanity Fair's. By writing a satire on a SEP-like type of magazine, Fitzgerald made sure he was not associated with the most commercial big magazines only, and suggested that he did belong in more sophisticated big mags such as Vanity Fair. Making sure he was not seen exclusively as a "Post writer," even though he did "Post stories" was crucial, as he needed a plurality of outlets for his short stories. And indeed, the 11 short stories composing Tales of the Jazz Age, published by Scribner's in 1922, were first published in a wide range of periodicals: the Metropolitan, the SEP, the Smart Set, Collier's, the Chicago Sunday Tribune, and Vanity Fair. And if being published in Vanity Fair was interesting for Fitzgerald, it was equally interesting for Vanity Fair to define itself, through such publication, as not being like the Saturday Evening Post, as being more distinguished, more sophisticated.

Less frequently, differentiation, one of the keys to survival for a magazine, meant less distinction, less sophistication, as Carol Ingalls Johnston narrates about the publication of "An Angel on the Porch," a short story by Thomas Wolfe: "Perkins chose to publish the story for the same reason Wolfe had been willing to sacrifice it: the coarseness and unconventionality of the subject matter. (…) Scribners, with its long background of religious and academic publications was particularly conservative, but by 1928 the firm had reached a turning point. Perkins and some of the younger staff members at Scribners had come to feel that Scribner's Magazine and the publishing house it represented were in a rut. To rectify this, Perkins had, in early 28, approached Hemingway about serializing his next novel in the magazine." 23 In any case, magazines, just like writers, were dependent on their reputations, and the most knowledgeable writers, such as Fitzgerald, knew how to use the competition they were engaged in in order to advance their own interests. In a 1934 letter to the same Perkins, Fitzgerald alluded to the possibility, for Scribner's, to differentiate itself from the SEP, in order to push two stories slightly outside of the magazine's usual framework: "PS: if you do not like 'The Night before Chancellorsville' please tell me frankly. My idea is that this and 'The Fiend' would give people less chance to say they are all standardized Saturday Evening Post stories, because, whatever can be said about them, they are not that." 24 In order to sell more widely, writers adapted their discourses to suit a variety of magazines, which had in turn to differentiate themselves from one another in an ever-developing and increasingly competitive field. Most big magazines did not rely exclusively on the aggressiveness of their economic model, but tried to find their own balance between economic profitability and cultural distinction, generally trying to appear smart but not lofty. By integrating some aspects of modernism in order to look culturally attractive, in a context of a growing belief in the virtues of education and self-education, big magazines thus participated in the mainstreaming of modernism, which in turn made the integration of modernism into middlebrow magazines easier. All this suggests that the life of "magazinedom" was based on circulations. Writers, but also editors (such as Crichton and Kerfoot in the first Life magazine) easily moved between different types of magazines, and magazines kept evolving in order to survive in a constantly changing field. Readers themselves were also malleable to a certain degree: among other examples, the parody of a wide range of magazines in the 1928 Burlesque number of Life magazine suggests that Life readers were familiar, to some extent at least, with magazines such as Poetry and New Masses. The study of magazines reveals ongoing conversations between constantly moving actors, with some decisive encounters, such as Fitzgerald and Lorimer's, or Fitzgerald and Perkins's, across the categories of big or small magazines. To give but one example, in a 1930 letter, Fitzgerald, who was then in Paris, sent Perkins a list of writers from the little magazine sphere, whom Perkins could be interested in publishing, and mentioned participation to transition magazine as evidence of qualitythus showing once more that the opposition between small and big magazines underlying Pound's article published the same year was in many ways more rhetorical than real. 25

Conclusion

The study of the relationships between writers such as Fitzgerald and Hemingway on the one hand, and magazines on the other hand, point to the close intertwining of various types of ties, such as: -Fitzgerald's and Hemingway's acknowledgement of magazines' influence on society and on themselves -Their antagonism towards magazines exerting their power over them (magazines with economic or cultural capital were concerned, not just big magazines) -self-promoting authorial strategies emphasizing antagonism in order for H and F not to appear too closely associated with big mags, and therefore less distinguished. -mutual interests: many big magazines were interested in publishing writers such as Fitzgerald and Hemingway to look culturally upscale, while F and H needed big magazines for the money involved but also to "creat[e] a public image," as Faye

Hammill and Karen Leick wrote (Modernism is the Literature of Celebrity, to use the title of a book by Jonathan Goldman, and refer to Leick's pioneering work entitled Gertrude Stein and the Making of an American Celebrity) -respect, friendship, and professional collaborations involving the circulation of authors between writers like Fitzgerald and some big mags editors like Lorimer Of course, not all writers whose work was not primarily targeted to big magazines were in a position to develop all of these links with big magazines. But many did share some of them. Flux appears as one of the most important characteristics of the relationships between writers and magazinedom; for strategic reasons, writers and magazines constantly repositioned themselves, and an important number of writers and editors exchanged information and circulated across publishing venues.

  table. It was Harper's Magazine. Harper's Magazine in a new format. Harper's Magazine completely changed and revised. Perhaps that would do the trick. She wondered. (Scribner's 1987, end of chap 9, p. 42-43)

John Tebbel and Mary Ellen Zuckerman, The Magazine in America 1741-1990, Oxford, Oxford University Press, 1991, 77.

p. 271: "Pay on acceptance and two cents a word (…) And he had thought the White Mouse a third-rater! It was evident that he did not know the magazines. He had deemed the Transcontinental a first-rater, and it paid a cent for ten words."

p. 290: "Sometimes I am fairly sure I am out of water, and that I should belong in Paris, in Grub Street, in a hermit's cave, or in some sadly wild Bohemian crowd, drinking claretdago-red, they call it in San Francisco,dining in cheap restaurants in the Latin Quarter, and expressing vociferously radical views upon all creation."

 10 Joseph R. McElrath Jr, "Jack London's Martin Eden, The Multiple Dimensions of a Literary Masterpiece," in Jack London, One Hundred Years a Writer, edited by Sara S. Hodson and Jeanne Campbell Reesman, San Marino (Calif.): Huntington Library, 2002, p.

90. 11 "Introduction," The Letters of Jack London, Volume One: 1896-1905, edited by Earle Labor, Robert C. Leitz III, and I. Milo Shepard, p. XV.

"Modernism and the Quality Magazines," p. 193.

Donal Harris, On Company Time, American Modernism in the Big Magazines, New York, Columbia University Press, 2016, p. 4. Such ambivalence is comically illustrated by Hemingway in Torrents of Spring. If Scripps is quite happy with the $450 he got for a story he published in the SEP, he nonetheless expresses his despise for the magazine. Torrents of Spring, p. 14: "He turned and walked into the silent, deserted Northern town. Luckily, he had four hundred and fifty dollars in his pocket. He had sold a story to George Horace Lorimer just before he had started out with his old woman on that drinking trip." / p. 16-17 : A propos de Brown's Beanery : "Ah, these big beanery owners were wise fellows. They knew how to get the customers. No ads in The SEP for them. THE BEST BY TEST. That was the stuff. He went in."

Carol Ingalls Johnston, Of Time and the Artist, Thomas Wolfe, His Novels, and the Critics, Columbia, S. C., Camden House, 1996, 36.

Correspondence of F. Scott Fitzgerald, edited by Matthew J. Bruccoli and Margaret M. Duggan with the assistance of Susan Walker, NY, Random House, 1980, p. 396.


Julien Tissot

Alexander Schlacher

Christopher Gray

Air density normalisation using remote weather data for SCADA based performance analysis

Electrotechnical Commission (IEC). Power Performance Measurements of Electricity Producing Wind

 Turbines;IEC 61400-12-1 Ed. 2;International Electrotechnical Commission: Geneva, Switzerland, 2017 2. Electrotechnical Commission (IEC). Power performance of electricity-producing wind turbines based on nacelle anemometry; IEC 61400-12-2;International Electrotechnical Commission: Geneva, Switzerland, 2013 Following the recommendations from IEC 61400-12-1 [1], "the wind speed signal shall be normalized to a reference air density", generally being 1.225 kg/m 3 . "The air density shall be determined from measured air temperature, air pressure and relative humidity" according to:

𝜌 10𝑚𝑖𝑛 = 1 𝑇 10𝑚𝑖𝑛 𝐵 10𝑚𝑖𝑛 𝑅 0 -Φ𝑃 𝑤 1 𝑅 0 - 1 𝑅 𝑤
For modern WTGs, the normalisation is applied to the wind speed following:

𝑉 𝑛 = 𝑉 10𝑚𝑖𝑛 𝜌 10𝑚𝑖𝑛 𝜌 0 1/3
However, pressure and humidity are commonly missing from the OEM SCADA 10min database. Furthermore, the available air temperature, can be affected by the sensor's position on the nacelle, sometimes over-estimating the outside temperature. These limitations often inhibit the full application of the normalisation method using SCADA data.

It is undisputable that air density has an influence on wind turbine (WTG) performance. This needs to be accounted for when conducting performance analysis following the industry best practices.

Unfortunately, in most SCADA analysis, this normalisation is either partially performed, using only temperature, or completely excluded. It is typically due to the absence of one or more of the required signals, namely pressure, temperature, and humidity (PTH) in the studied dataset.

Interconnection of databases (DB) using Application Programming Interfaces (API) is now easier than it ever was, and a multitude of web services have emerged enabling direct and automated access to various historical weather datasets.

In this study, we explored the validity of using such weather data in the context of air density normalisation of WTG SCADA data.

Abstract

Assessing the effect on the Power Curve Fundamentals: Air Density Normalisation

Cost and Requirements

Enlarge SCADA data with Historical Weather APIs

The cost of most weather web service can be considered negligeable for recurring largescale fleet analysis. Additional computational power for the API requests, data correction, resynchronization and filtering and its additional cost can also be considered almost negligeable, if implemented properly.

The sea-level pressure provided by the API should be corrected to hub height. To do so we used the hypsometric equation in combination with the WTG altitude and hub height. The altitude of a WTG, if unknown, can be retrieved automatically using the SRTM database. Therefore, the only input required for the implementation of the process are the coordinates of the WTG and its hub height.

When analysing the PCs over a year, the Power_Sdv is slightly but consistently reduced (-4.85% in the analysis above). When deploying that metric on whole portfolio, we found an average reduction of the binned Power_Sdv of about -4%. -𝜌 10𝑚𝑖𝑛 is the derived 10 min air density -𝑇 10𝑚𝑖𝑛 is the 10 min air temperature -𝐵 10𝑚𝑖𝑛 is the corrected 10 min pressure -Φ is the relative humidity -𝑉 𝑛 is the normalised wind speed -𝑉 10𝑚𝑖𝑛 is the 10 min wind speed -𝜌 0 is the reference air density -𝑅 0 , 𝑅 𝑤 , 𝑃 𝑤 are constants [1] Given a set of geo-coordinates, most weather-data providers can now deliver worldwide sub-hourly historical dataset, geographically interpolated from all nearby weather stations within a predefined radius.

To sample the quality of these services, we conducted several comparisons with local observations. In the assessment below, we studied 5 years of data from a local met mast under management against the same period extracted from the selected weather service interpolated at this met mast location.

The graphs below show the correlations obtained for temperature and humidity measurement from both datasets as well as a sample of temporal comparison.

The main expected effect of the normalisation on the dataset is obviously to correct wind speeds the a value equivalent to the reference air density, 𝜌 0 . Since met masts are not available for all WTGs in our portfolio, we cannot automatically check the quality of weather data for each location.

However, an additional benefit of the normalisation is also the reduction of the scatter of the power curve (PC) when observed across a period where air density had varied. In our case, this is an effective method to check whether the process had a positive impact. If that scatter remains the same or increases, it implies that the method had either no effect or a negative one on the dataset. On the other hand, any significant reduction on the scatter would indicate that the normalisation reduces uncertainty.

The graphs below compares the standards deviation of the power signal (Power_Sdv) binned using the raw wind speed and the normalized wind speed, i.e. using the Weather API data for one of the WTG in the portfolio.

Thanks to the very high temporal and spatial inertia of the signals needed for air density normalisation, we see a good correlations between local observations and the geographically interpolated data from the weather API. As seen in the first graph, daily variation at the tested location are covered with sufficient accuracy.

Conclusions

• Although the use of a local and controlled PTH sensor is industry standards, the use of remote weather data is preferable to the current status-quo, i.e. when no PTH information are available, the normalisation is performed partially or ignored.

• Obtaining weather data via APIs is a pragmatic solution to enhances the quality of predominantly SCADA-based analysis. For the case of air density normalisation, it avoids falsely diagnosed under-performance or perceived seasonal effects which in fact may originate from air density variations.

• Given the results of this pragmatic approach, it was deemed suitable for immediate deployment and used for regular, automated analysis of the performance of over 3000 WTGs. The adoption of this method enables asset managers, often bound to SCADA datasets, to refer to more accurate power curves which comply more closely with industry best practices.

Air density normalisation using remote weather data for SCADA based performance analysis Julien TISSOT, Alexander SCHLACHER, Christopher GRAY

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Arbuscular mycorrhizal fungi and sewage sludge enhance growth and adaptation of Metrosideros laurifolia on ultramafic soil in New Caledonia: A field experiment

Keywords: Serpentine soil, AMF, sewage sludge, field experiment, plant nutrition, heavy metals

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A C C E P T E D

M A N U S C R I P T

Introduction

New Caledonian ultramafic ecosystems, which cover one third of the main island, are characterized by poor and toxic soils, with very low concentrations of P, K and N, a low Ca/Mg ratio, along with high levels of heavy metals particularly Ni, Co, Cr and Mn (Jaffré and L'Huillier, 2010a;[START_REF] Proctor | Vegetation and soil and plant chemistry on ultramafic rocks in the tropical Far East[END_REF]. Most of these soils are occupied by ultramafic maquis (a shrub heathland) subject to large fluctuations of water availability ranging from waterlogging to drought (Jaffré andL'Huillier, 2010a, 2010b). The adaptive traits of the plants to these constraints (low growth rate, xenomorphic foliage, etc.) are termed "serpentine syndrome" [START_REF] Bini | The « serpentine syndrome » (H. Jenny, 1980): a proxy for soil remediation[END_REF][START_REF] Jenny | The soil resource. Origin and behaviour[END_REF].

Due to these extreme conditions (but also to insularity), about 89% of the vascular plants of New Caledonian maquis are endemic [START_REF] Jaffré | Composition et caractérisation de la flore indigène de Nouvelle-Calédonie[END_REF] and have developed different specific mechanisms to cope with these constraints [START_REF] Baker | Accumulators and excluders-strategies in the response of plants to heavy metals[END_REF][START_REF] Bini | The « serpentine syndrome » (H. Jenny, 1980): a proxy for soil remediation[END_REF]. Metrosideros laurifolia (Myrtaceae) is an endemic shrub (sometimes becomes a tree), with coriaceous leaves, that is considered often a pioneer species in these extreme ultramafic soils and frequently used for ecological restoration of mining-degraded areas [START_REF] Wulff | Espèces indigènes utilisables en revégétalisation[END_REF].

Arbuscular mycorrhizal fungi (AMF) are known to be involved in plant mineral nutrition by increasing the soil volume explored by the roots [START_REF] Smith | Roles of arbuscular mycorrhizas in plant nutrition and growth: new paradigms from cellular to ecosystems scales[END_REF].

They are also involved in plant adaptation to water stress [START_REF] Augé | Water relations, drought and vesicular-arbuscular mycorrhizal symbiosis[END_REF][START_REF] Smith | Plant performance in stressful environments: interpreting new and established knowledge of the roles of arbuscular mycorrhizas[END_REF] and to heavy metal toxicity in metal polluted soils [START_REF] Amir | Role of mycorrhizal fungi on the alleviation of heavy metal toxicity on plant[END_REF][START_REF] Ferrol | The heavy metal paradox in arbuscular mycorrhizas: from mechanisms ti biotechnological applications[END_REF]Khade and Adoleya, 2007;[START_REF] Wang | Occurrence of arbuscular mycorrhizal fungi in mining-impacted sites and their contribution to ecological restoration: Mechanisms and applications[END_REF]. AMF are abundant in New Caledonian ultramafic soils [START_REF] Amir | Les bactéries et les champignons du sol sur roches ultramafiques[END_REF][START_REF] Perrier | Occurrence of mycorrhizal symbioses in the metalrich lateritic soils of the Koniambo Massif, New Caledonia[END_REF] and contribute to plant adaptation to ultramafic conditions, particularly by improving P

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4 absorption and increasing plant metal tolerance [START_REF] Amir | Arbuscular mycorrhizal fungi, from New Caledonian ultramafic soils, improve tolerance to nickel of endemic plant species[END_REF][START_REF] Lagrange | New insights into the mycorrhizal status of Cyperaceae from ultramafic soils in New Caledonia[END_REF].

In New Caledonian ultramafic maquis, the soils are generally poor in organic matter (Jaffré and L'Huillier, 2010a). Sewage sludge is one of the amendments used to enrich the topsoil (or the lateritic subsoil, when there is no topsoil available) before the revegetation of degraded areas after mining (L 'Huillier et al., 2010). It is known to improve soil fertility, especially in forest soils (Henri and Cole, 1986) and degraded areas [START_REF] Delschen | Impact of long term application of organic fertilizers on soil quality parameters in reclaimed loess soils of the Rhineland lignite mining area[END_REF][START_REF] Petersen | Recycling of sewage sludge and household compost to arable land: fate and effects of organic contaminants, and impact on soil fertility[END_REF]. Different positive effects of this sludge have been reported: improvement of soil structure and soil stabilization [START_REF] Mata-Gonzalez | Physiological impact of biosolids application in desert grasses[END_REF][START_REF] Ojeda | Differences in aggregate stability due to various sewage sludge treatments on a Mediterranean calcareous soil[END_REF], soil enrichment with phosphorus and other elements [START_REF] Garcia | The influence of composting on the fertilizing value of an aerobic sewage sludge[END_REF], stimulation of microbial activity [START_REF] Petersen | Recycling of sewage sludge and household compost to arable land: fate and effects of organic contaminants, and impact on soil fertility[END_REF][START_REF] Selivanovskaya | Effects of composted sewage sludge on microbial biomass, activity and pine seedlings in nursery forest[END_REF], inducing clear increase of plant growth (Shen et al., 2007;[START_REF] Wang | Environmental and nutritional responses of Pinus radiata plantation to biosolids application[END_REF] and stimulating plant recolonization of former mine sites [START_REF] Rate | Application of biosolids in mineral sands mine rehabilitation: use of stockpiled topsoil decreases trace element uptake by plants[END_REF].

Only few field experiments have been reported on ultramafic soils. Some concerned the effects of soil fertilization on plant growth and species dynamics [START_REF] Chiarucci | Long-term effects of climate and phosphorus fertilization on serpentine vegetation[END_REF]. As far as we know, the only field experiment on mycorrhizal symbiosis [START_REF] Lagrange | Mycorrhizal status of Cyperaceae from New Caledonian ultramafic soils: effects of phosphorus availability on arbuscular mycorrhizal colonisation of Costularia comosa in field conditions[END_REF] was about the effects of P fertilisation on mycorrhizal status of Costularia comosa (Cyperaceae). The field experiment presented here was the first using AMF inoculation.

Different experiments combining AMF inoculation and sewage sludge in nonultramafic soils have been reported. Some of them showed complementary effects between this organic input and AMF inoculation on plant growth and nutrition in greenhouse [START_REF] Arriagada | Improvement of growth of Eucalyptus globulus and soil biological parameters by amendment with sewage sludge and inoculation with arbuscular mycorrhizal and saprobe fungi[END_REF]Mackay et al., 2017), or in field conditions (Algacil , 2004). Another experiment recorded an inhibition effect of sewage sludge on AMF root colonization (Jacquot et al., 2000).

We inoculated M. Laurifolia seedlings with AMF in a nursery and then transferred them to a test site consisting of a degraded laydown platform area that had been covered with a stored topsoil layer ready for revegetation (the topsoil is frequently stored during mining activities until revegetation space available). A combination of AMF inoculation and sewage sludge amendment was also tested. The aims of the experiment were : i) to test the effects of AMF on growth and adaptation parameters in field conditions; ii) to assess the effects of this inoculation on natural AMF diversity;

iii) to test the influence of sewage sludge on mycorrhizal symbiosis and plant growth in these conditions.

Materials and methods

Experimental site description.

New Caledonia is located in the South Pacific, approximately 1,500 km east of Australia and 1,800 km north of New Zealand (Fig. S1). The climate is subtropical to tropical, with a rainy season from December to May and a dry season from September to November that can vary in duration and severity.

The experimental site is located in Goro, in the south of the main land, inside the VALE New Caledonia mining company area (22°19'13.2"S 166°54'16.0"E) (Fig. S1). The Platform used for the test was cleared of vegetation and topsoil, and the degraded topsoil, stored for 4 years, was then spread on the area as a 20 cm thick layer before the experiment, with grader and frond end loader to reduce soil compaction. The use of a degraded topsoil has two advantages: i) topsoil storage by mining companies is a frequent practice and AMF inoculation is then particularly useful, because of the strong reduction of natural AMF populations in these conditions [START_REF] Bordez | Stratégies de revégétalisation des maquis miniers nickelifères de Nouvelle-Calédonie: étude sur les potentiels biologiques des topsoils et leur gestion en vue de leur utilisation pour la restauration écologique des milieux degradés. PhD thesis[END_REF] ; ii) the stored topsoil has then a low density of AMF spores, so that the difference between the non-inoculated plots (control) and the inoculated ones was sufficient to highlight the effects of the mycorrhization. Preliminary analyses before the experiment showed that this topsoil contained only 22 AMF spores per 100 g, whereas the soil collected in the non-perturbed maquis close to experimental field showed 4489 spores per 100 g.

The topsoil was a ferralsol [START_REF] Becquer | Mineralogical, chemical and charge properties of Geric Ferralsols from New Caledonia[END_REF]; its main physico-chemical characteristics are as follow : organic carbon (%): Al 2 O 3 (%): 5.37 ; total Mn (g kg -1 ): 4.74 ; total Ni (g kg -1 ): 5.62 ; total Co (g kg -1 ): 0.47 ;

total Cr (g kg -1 ): 32.25 ; DTPA extractable Mn (mg kg -1 ): 282.9 ; DTPA extractable Ni (mg kg -1 ): 19.73; DTPA extractable Co (mg kg -1 ): 79 ; DTPA extractable Cr (mg kg -1 ): 0.6.

Plant production in nursery

Metrosideros laurifolia is an endemic Myrtaceae. Seeds were surface-disinfected by soaking in hot water (80°C for 5 minutes) before being sown on sterilised substrate

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constituted with a mix of equal volumes of compost and vermiculite. After 3 months, the seedlings were transferred on 750 mL plastic bags with a sterilised mix of equal volumes of sand, compost and vermiculite. At this stage, the stem of the seedlings was only 2-3 cm height.

Plant inoculation with AMF in nursery

Two hundred seedlings were inoculated with AMF three months after germination, during the transfer to the plastic bags. We used a mix of three selected isolates from ultramafic soils, previously tested in greenhouse conditions and described [START_REF] Gensous | Les champignons mycorhiziens à arbuscules des sols ultramafiques de Nouvelle-Calédonie[END_REF]. They were isolated from soil taken under plants in ultramafic maquis in the south of Grande Terre (Demazures), by trap culture with sorghum. They were selected for their tolerance to Ni, their spore production and their effect on sorghum growth. These isolates have been characterized by a sequence analysis of a part of the SSU rDNA: PSB1 (98% of similarity with Claroideoglomus etunicatum), PSO1 and RARC (the two showed 98% of similarity with Acaulospora rugosa). The accession numbers are as follow: PSB1: Gb_MH424515 ; PSO1:

Gb_MH424516; RARC: Gb_MH424517. Their morphological characteristics confirmed this identification. The plants were inoculated with a mix of spore suspensions of the three isolates at the following proportions (in relation to the spore production of each isolate): PSB1: 60%; PSO1: 20%; RARC: 20%. Spores of the AMF isolates were produced on a sorghum culture grown for 5 months, on a non-ultramafic soil (sorghum does not grow correctly in ultramafic soil), autoclaved three times at 120°C for 1 hour, with an interval of 24h. The spores were isolated by wet sieving (50 µm) and centrifugation using a 50% sucrose solution and thoroughly rinsed with water. For each plant, two mL

A C C E P T E D M A N U S C R I P T 8
of suspension containing 100 spores were applied on the root system. For the two hundred non-inoculated plants, the same treatment was assessed but the spore suspension was autoclaved 30 min at 120°C before the application on root system. All the plants were then grown for 15 months in the nursery to reach a sufficient size to resist environmental stresses: plants of New Caledonian ultramafic maquis have a low growth rate and small plants could be killed by the water stress.

Field experiment

The total surface of the experimental field was about 450 m 2 . Four treatments were assessed: non-inoculated plants growing in non-amended topsoil (control); plants inoculated with AMF growing in non-amended topsoil; non-inoculated plants growing in a topsoil amended with sewage sludge; and combined treatment: inoculated plants, in topsoil amended with sewage sludge. For each treatment, four plots of 16 m² representing experimental units were planted with 25 plants separated each from other by 80 cm to reduce contamination. Two-meter bands separated adjacent plots and allowed for easier evaluation of plants while at the same time reducing contamination. To avoid any substrate influences between adjacent plots of different treatments, we chose to place the plots of each treatment on a line following the direction of the slight slope. As the topsoil was carefully homogenised before being spread on the site, a randomized block was not necessary here and would create more difficulties to control the influences between adjacent plots of different treatments.

The plantation was performed in May 2012. At this stage, the height of the plant stems varied from 6 to 18 cm. Holes of 25 cm diameter and 30 cm depth were prepared for the plantation. About 100 g of a water retention agent (biopolymer of A C C E P T E D M A N U S C R I P T 9 hyaluronic acid) were mixed with soil in the bottom of the hole to ensure greater moisture availability during post seedling plantation acclimatization. For the treatments without sewage sludge, each plant was deposited inside base of the hole which was then mixed with surrounding topsoil. For the amended treatments, 158 g of sewage sludge were carefully mixed with the topsoil inside the hole. This amount of sludge corresponds globally to about 1.5 t DW.ha -1 , but the content inside each hole is a lot higher (about 20 t DW. ha -1 ). The characteristics of the sludge are as follow:

dryness: 57.3%; mineral matter: 87.2%; organic matter: 12.8%; pH: 6.2; total N: 22.73 mg.g -1 ; total P: 4.44 mg.g -1 ; total Cu: 90 mg.kg -1 ; total Zn: 960 mg.kg -1 ; total Cd: < 0.5 mg.kg -1 ; total Hg: 0.7 mg.kg -1 ; total Pb: 23 mg.kg -1 .

Plant growth evaluation

After plantation, plant height was measured each 3 to 5 months during 23 months and a final measure was performed after 41 month to check the persistence of the observed effects. After 17.3 months (528 days), 12 plants randomly selected inside the 4 plots were removed for each treatment. The fresh and dry weight (at 45°C) of the shoot biomass was also determined. The roots were not included because at this stage, the root system was large and very difficult to remove totally.

Mycorrhizal colonization

Mycorrhizal colonization was estimated 528 days after plantation. For each treatment, fine roots of 6 randomly sampled plants were taken for mycorrhizal colonization assessment (for each plant, the roots were collected from different parts

A C C E P T E D M A N U S C R I P T
10 of the root system). The roots were stained with Trypan blue [START_REF] Koske | A modified procedure for staining roots to detect VA Mycorrhizas[END_REF].

Root fragments were placed in a 10% KOH bath at 90°C for 90 minutes. A few drops of hydrogen peroxide (H 2 0 2 ) were added after one hour to lighten the brown colour. The roots were then rinsed in distilled water and stained with Trypan blue (15 minutes at 90°C). For each plant, at least 25 root segments of 1-2 cm length were mounted on glass slides in 10% glycerol and observed under an optical microscope. A root segment was considered to be mycorrhized when arbuscules, vesicules or intracellular hyphal coils were clearly identified. The intensity of arbuscular mycorrhizal colonization, i.e.

mycorrhizal density (M%), was determined according to [START_REF] Trouvelot | Mesure du taux de mycorhization VA d'un système radiculaire. Recherche de méthodes d'estimation ayant une signification fonctionnelle[END_REF].

M (%) =  95n5 + 70n4 + 30n3 + 5n2 + n1
total number of root fragments where n5 is the number of root fragments with more than 90% infection, n4 between 90% and 50% infection, n3 between 50% and 10% infection, n2 between 10% and 1% infection, n1 less than 1% infection.

Chemical analyses

To assess the plant mineral nutrition, for each treatment, five samples of washed roots, stems and leaves were dried and ground. The roots (only fine) were cleaned thoroughly with water in a small colander and checked meticulously to avoid any soil particles. The ground samples were then used to determine total P, total N, K, Ca and Mg contents, after digestion in microwave with potassium persulfate (K 2 S 2 O 8 ) and H 2 SO 4 and analysed by ICP-OES and by CHN, mass spectrometry using an Integra2 spectrometer (Sercon Instruments, www.sercongroup.com) linked to a Sercon elemental analyzer. These analyses were performed by the Laboratoire des Moyens Analytiques (LAMA, IRD-Noumea). Ca/Mg ratio was then calculated. Metal contents (Fe, Mn, Co,

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Ni, Cr) in roots, stems and leaves were also determined after microwave acidic mineralization in aqua regia (means of 4 samples) and analysis with an atomic absorption spectrometer (Perkin Elmer Analyst 800).

DNA extraction, PCR and sequencing.

Root samples of M. laurifolia were collected 335 days after plantation. Three plants of each treatment were sampled. For each plant, fine root tips collected on two sides of the root system, were gathered and grinded in liquid nitrogen with a mortar and a pestle. The resulting powder was used to extract genomic DNA using the Ultraclean Plant DNA extraction kit (MoBio -ref # 13000-250) according to the manufacturer's instructions.

A 550 bp partial fragment of SSU rDNA was produced using a nested PCR approach in order to avoid cross amplification of non-AMF DNA. First PCR was performed using the AML1 and AML2 primers (Lee et al., 2008), in a 25 µl reaction containing 1X AmpliTaq® 360 PCR buffer (ABI), 2.5 mM MgCl 2 , 200 µM dNTP, 0.4 µM of each primer and 0.5 U AmpliTaq® 360 DNA polymerase. Reaction conditions were as follow: one initial denaturation step at 95 °C for 3 min; 30 cycles of: 94 °C for 45s, 50 °C for 45s, 72 °C for 45 s; 72°C for 10min. One microliter of the PCR product was used to perform the second PCR amplification with primer pair AM1 [START_REF] Helgason | Ploughing up the wood-wide web? Nature 394: 431. treatment and utilization of municipal and industrial wastes[END_REF] and NS31 [START_REF] Simon | Specific amplification of 18S fungal ribosomal genes from vesicular arbuscular endomycorrhizal fungi colonising roots[END_REF]. The PCR was performed in the same conditions except the annealing temperature that was set to 55°C.

The PCR products were cloned into the pGEM-T vector (Promega) following the manufacturer's instructions. Ligated plasmids were transformed into CaCl 2 competent E. coli DH5α cells using a heat-shock approach. The transformed bacteria were plated

Sequence analyses and construction of phylogenetic tree

DNA sequences were proofread and trimmed to remove primer sequences before being aligned using MAFFTv7 [START_REF] Katoh | MAFFT multiple sequence alignment software version 7: improvements in performance and usability[END_REF] and grouped into Operational Taxonomic Units (OTUs) using the average-neighbour algorithm of the MOTHUR program with a 97% sequence similarity cut off [START_REF] Schloss | Introducing mothur: open-source, platform-independent, community-supported software for describing and comparing microbial communities[END_REF]. A representative sequence for each OTU, reference sequences isolated from the MaarjAM database (Öpik et al., 2010) and consensus sequences as determined by [START_REF] Krüger | Phylogenetic reference data for systematics and phylotaxonomy of arbuscular mycorrhizal fungi from phylum to species level[END_REF] were subsequently aligned as described above. The alignment was used to construct a neighbour-joining tree with MEGA6 using a Kimura 2-parameter sequence evolution model. Statistical confidence of branching was determined based on 1000 bootstrap resamplings [START_REF] Felsenstein | Confidence Limits on Phylogenies: An Approach Using the Bootstrap[END_REF].

The representative rDNA sequences for each OTU were submitted to GenBank and can be retrieved under the accession numbers MH150839 -MH150870.

Statistical treatments

Data were expressed as means with standard errors. The data were compared by ANOVA using the statistical software R, with a post-hoc Bonferroni corrected Mann-

A C C E P T E D M A N U S C R I P T 13
Withney test. Total correlation test was also used to analyse the correlations between mycorrhizal colonization parameters and plant growth.

Results

Plant growth

At the beginning of the field experiment, plants of M. laurifolia that have been inoculated with AMF in nursery were significantly bigger than non-inoculated ones (Fig. 1). This difference remained constant all along the experiment period, while the plants height increased progressively. After 41 months, the mean values of plant height reached 14.3 cm and 29.7 cm respectively for non-inoculated and inoculated plants. In soil amended with sewage sludge, the plants grew faster than the others and finally caught up with the height of the inoculated plants. The combination "AMF + sludge" showed the better effect, with plant height being 2.6 times higher than the control after 528 days and 3.1 higher after 41 months. The visual differences between the tested treatments are very clear (Figure S2).

The dry weight of the shoots, measured 528 days after plantation, attained a mean of 15.4 g for the control plots (Fig. 2). The control was significantly different from the other treatments (P = 0.002). The weight was four times greater for AMF inoculated plants. The mean value in plots amended with sludge was 3.1 times greater than the control. The combination "AMF + sludge" was significantly different from the two separate corresponding treatments (P = 0.018 and 0.005). It showed mean values of shoot biomass 7.7 times greater than the control (119.4 g).

Mycorrhizal colonization

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Mycorrhizal colonization (M) expresses the percentage of root cortex occupied by AMF. After 528 days the mean value of M for non-inoculated plants was relatively weak (3.3% for the control) (Fig. 2). Preliminary analyses before the experiment showed that the stockpiled topsoil of the experimental field contained few viable spores before plantation (22 AMF spores per 100 g). Even if sewage sludge treatment with non-inoculated plants showed M value higher than the control (10.9%), the difference was not significant (P = 0.103). AMF inoculation significantly enhanced mycorrhizal colonization, in comparison with control (P = 0.009), but the values stayed moderate (12.4%). The values of mycorrhizal colonization were higher for the combination "AMF + sludge" (22.8%), but non-significantly different from AMF treatment, because of the high variability of the mycorrhization in sewage sludge amended plots.

A significant positive correlation between shoot biomass and mycorrhizal colonization was detected (r = 0.378; p<0.05).

Mycorrhizal frequency values (F), expressing the percentage of root fragments containing AMF, were: 35.6 ± 12.7% (control), 47.2 ± 14.1% (sludge), 72.2 ± 5.6%

(AMF) and 85.0 ± 9.8% (AMF+ sludge). The values of F for the two treatments with inoculated plants were significantly different from the non-inoculated ones (P < 0.05),

but not different from each other. Microscopic aspects of the mycorrhizal colonization are showed in Figure S3.

Mineral nutrition

Contents of the main mineral elements in M. laurifolia leaves 528 days after plantation were relatively low (Table 1). P content of leaves was significantly enhanced

A C C E P T E D M A N U S C R I P T

by sludge amendment (P<0.05). AMF inoculation did not increase this value; but the combination of sludge and AMF inoculation showed the best effect on this element (1.8 times higher than the control; (P<0.01). P content of the stems was significantly higher than the control for the three tested treatments (P<0.05; P<0.01 for "AMF+sludge"). Values of P total uptake per plant were a lot higher than the control for the three treatments, in relation to the biomass increase (P<0.01). For example, inoculated plants in plots amended with sludge showed values of P per plant 14 times higher than control plants.

Contents of N, K, and Ca in leaves of M. laurifolia plants were not enhanced by the three tested treatments. However the quantities of these elements absorbed for each plant (total uptake per plant) were clearly higher than those of the control (P<0.01).

Unlike leaves, content of K in stems and roots was higher for inoculated plants (P<0.05). Ca content was enhanced in roots by sludge amendment and AMF inoculation (P<0.05).

The results also indicated that the three treatments did not influence significantly the water content of the plants (Fig. S4).

Ca/Mg ratio

Ca/Mg ratio in leaves was 3.5 ± 0.3 for control plants (Fig. 3). Sludge amendment significantly reduced this ratio even in inoculated plants (P<0.05), while AMF inoculation without amendment increased it (P<0.05).

Ca/Mg ratio in roots of control plants was 5.2 ± 0.5. Sludge amendment and AMF inoculation significantly enhanced this ratio (P<0.05), whereas their combination reduced it (P<0.01).

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M A N U S C R I P T 16

Metal contents in plant parts

Except for Co, no significant differences between the treatments were noted for the tested metal contents in leaves (Table 2). Co content was reduced in this part of the plant by sludge amendment and AMF inoculation (P<0.05). No significant differences were found in stems for all metals. In roots, large differences were noted between the treatments, but standard errors were very high. However Fe and Mn contents of inoculated plants were significantly higher than the control plants (P<0.05).

Root Ni content was also increased by AMF inoculation (P<0.05).

Metal translocation factor (leave/root contents) for Mn and Co was significantly lower for the three treatments in comparison with control (respectively P<0.05 and P<0.01). For Fe and Ni, the values of this factor were significantly lower only for AMF inoculated plants (respectively P<0.05 and P<0.01). Cr translocation was not influenced by the three treatments DTPA-extractable concentrations of each metal in soil under plants were not significantly different (Table 2), except for Fe and Ni values in AMF inoculated plots which were significantly lower than the control (p<0.05).

AMF diversity in roots

The neighbour-joining tree (Fig. S5) allowed us to identify the phylogenetic relationships between the OTUs obtained in plant roots and the three AMF isolates used for plant inoculation. Strikingly, only two OTUs out of the 32 identified (6.25%)

were similar to those of the inoculum. AMF diversity in roots of M. laurifolia 335 days after plantation showed the presence of several taxa. The total amount of obtained

A C C E P T E D M A N U S C R I P T

17 DNA sequences was 157; these sequences have been clustered in 32 different OTUs (Table 3). Nine OTUs have been found in control plants, for a total amount of 37 sequences. 8 OTUs were found in plants amended with sewage sludge (31 sequences), whereas AMF-inoculated plants showed 25 OTUs for 58 sequences. Inoculated plants showed higher AMF diversity within roots as indicated by the clear increase of the amount of identified OTUs and the Shannon Index. However, this positive effect of inoculation on AMF diversity did not occur in plants amended with sewage sludge.

Eight different genera (Diversispora, Redeckera, Scutellospora, Acaulospora, Claroideoglomus, Rhizophagus, Glomus and Sclerocystis), corresponding to five families were detected for the entire experimental field, six genera in roots of control plants and in AMF-inoculated plants, and four genera in sludge amended plots (Fig. 4).

Glomeraceae were the most frequent taxa, with 118 sequences out of 157 (75%).

Inoculation with AMF has induced changes in the structure of AMF populations inside the roots (Fig. 4). Two genera present in control plants (Diversispora and Redeckera) were note detected in inoculated plants. Claroideoglomus was abundant in control plants (27% of the identified sequences) and seemed to be marginalized in inoculated plants (1.7%). Conversely, Scutellospora and Glomus were present in inoculated plants but not found in control ones. In sewage sludge amended plots, Diversispora and Redeckera were also absent in the roots.

Discussion

Effects of the treatments on plant growth and mycorrhizal colonization

Only few studies have been reported on the effects of AMF inoculation on growth and adaptation of endemic plants to ultramafic soils in New Caledonia (Amir et al.,

A C C E P T E D M A N U S C R I P T

18 2013; [START_REF] Lagrange | New insights into the mycorrhizal status of Cyperaceae from ultramafic soils in New Caledonia[END_REF]. Some native AMF isolates highly tolerant to Ni [START_REF] Amir | Tolerance and induction of tolerance to Ni of arbuscular mycorrhizal fungi from New Caledonian ultramafic soils[END_REF], tested in greenhouse conditions, showed positive effects on growth and tolerance to Ni of endemic plants species [START_REF] Amir | Arbuscular mycorrhizal fungi, from New Caledonian ultramafic soils, improve tolerance to nickel of endemic plant species[END_REF]. However, the effects of AMF inoculation on ultramafic plant species in field conditions have not been reported

until now, even in other countries.

The mixture of the three AMF isolates studied here has been tested in greenhouse conditions with the same plant species [START_REF] Gensous | Les champignons mycorhiziens à arbuscules des sols ultramafiques de Nouvelle-Calédonie[END_REF]. The results obtained here confirm their highly positive effect on plant growth, in field conditions: the shoot dry weight, 528 days after plantation, was 4.1 times higher than the control. These results are similar to those obtained in greenhouse despite the presence of AMF viable spores in the field topsoil before the experiment (as revealed also by mycorrhizal colonization and AMF diversity analyses). In comparison, [START_REF] Emam | Local soil, but not commercial AMF inoculum, increases native and non-native grass growth at a mine restoration site[END_REF], working in mercury mine restoration site in field conditions, compared the effects of inoculation of Stipa pulchra with commercial AMF or topsoil. Commercial inoculum was inefficient, whereas topsoil inoculation induced a biomass increase of about 230%. In a review article, [START_REF] Berruti | Arbuscular Mycorrhizal Fungi as Natural Biofertilizers: Let's Benefit from Past Successes[END_REF] reported field effects of AMF on growth of different plants. The values of biomass increase were 70% to 90%. Studies on agricultural crops in field conditions showed that yields of AMF-inoculated plants were about two times higher for cucumber [START_REF] Ortas | Effect of mycorrhiza application on plant growth and nutrient uptake in cucumber production under field conditions[END_REF] and soy bean [START_REF] Cely | Inoculant of Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) Increase Yield of Soybean and Cotton under Field Conditions[END_REF]. [START_REF] Saia | Soil inoculation with symbiotic microorganisms promotes plant growth and nutrient transporter genes expression in durum wheat[END_REF] reported an increase of 20-30% of wheat growth inoculated with AMF. The mixed AMF isolates tested here showed then a great influence on M. laurilolia growth, in mine restoration conditions.

The evaluation of the mycorrhizal colonization showed that control plants were colonized at a low level (M: 3.3%); but the mycorrhizal colonization of AMF-inoculated

A C C E P T E D M A N U S C R I P T

19 plant was also moderate (M: 12.4% for AMF inoculated plants; M: 22.8% for inoculated plants in amended plots). Low levels of mycorrhization are frequent in New Caledonian ultramafic soils [START_REF] Perrier | Occurrence of mycorrhizal symbioses in the metalrich lateritic soils of the Koniambo Massif, New Caledonia[END_REF]) and this seems to not limit the positive effects of the symbiosis [START_REF] Lagrange | New insights into the mycorrhizal status of Cyperaceae from ultramafic soils in New Caledonia[END_REF]. This limitation of mycorrhizal colonization is partly related to the low level of plant productivity in ultramafic maquis and to soil nutrient deficiency, especially P [START_REF] Koide | Density-dependant response to mycorrhizal infection in Abutilon theophrasti Medic[END_REF][START_REF] Smith | Fresh perspectives of the roles of arbuscular mycorrhizal fungi in plant nutrition and growth[END_REF]. Nevertheless a significant positive correlation between shoot dry weight and mycorrhizal colonization was detected.

The content of sewage sludge amendment used here is about 10 times lower than that used by [START_REF] Pitchel | Comparison of amendments and management practices for long term reclamation of abandoned mine lands[END_REF] for an abandoned mine land, and similar to that used by [START_REF] Rate | Application of biosolids in mineral sands mine rehabilitation: use of stockpiled topsoil decreases trace element uptake by plants[END_REF] for mine rehabilitation with stockpiled topsoil. The effect of this amendment on plant growth was clearly positive and similar to that observed for AMF inoculated plants, whether considering plant height progression or plant weight 528 days after plantation. The positive effects of sewage sludge on plant growth have been reported by many studies concerning forest trees and shrubs (Bramryd, 2002;[START_REF] Velayoudon | Sewage sludge application for spontaneous plant restoration of a New Caledonian ferralsol[END_REF] or herbaceous plants [START_REF] Sabey | Effects of municipal sewage sludge application on growth of two reclamation shrub species in copper mine spoils[END_REF][START_REF] Velayoudon | Sewage sludge application for spontaneous plant restoration of a New Caledonian ferralsol[END_REF], in relation to different soil characteristics improvements: soil structure and stabilization [START_REF] Mata-Gonzalez | Physiological impact of biosolids application in desert grasses[END_REF][START_REF] Ojeda | Differences in aggregate stability due to various sewage sludge treatments on a Mediterranean calcareous soil[END_REF] microbial activity [START_REF] Petersen | Recycling of sewage sludge and household compost to arable land: fate and effects of organic contaminants, and impact on soil fertility[END_REF][START_REF] Selivanovskaya | Effects of composted sewage sludge on microbial biomass, activity and pine seedlings in nursery forest[END_REF] and mineral composition [START_REF] Garcia | The influence of composting on the fertilizing value of an aerobic sewage sludge[END_REF]. But few studies have been reported on the combination effects of sewage sludge and AMF. [START_REF] Alguacil | Establishment of Retama sphaerocarpa L. seedlings on a degraded semiarid soil as influenced by mycorrhizal inoculation and sewage-sludge amendment[END_REF], working with Retama sphaerocarpa in field experiment with semiarid soil, observed about 15% more shoot dry weight for the combined treatment (AMF plus sewage sludge) in comparison with AMF in absence of sludge. [START_REF] Arriagada | Improvement of growth of Eucalyptus globulus and soil biological parameters by amendment with sewage sludge and inoculation with arbuscular mycorrhizal and saprobe fungi[END_REF], testing these two treatments in greenhouse condition

A C C E P T E D M A N U S C R I P T 20

with Eucalyptus globulus, showed an increase of 45% of shoot dry weight in plants inoculated with Glomus deserticola, whereas this increase reached 285% when AMF inoculation was combined with sewage sludge amendment. These results are consistent with ours; however, contrary to our findings, the mycorrhizal colonization was reduced by the sludge amendment. Field experiment testing combining AMF inoculation with other organic amendment has been reported by [START_REF] Caravaca | Assessing the effectiveness of mycorrhizal inoculation and soil compost addition for enhancing reafforestation with Olea europea subsp. sylvestris through changes in soil biological and physical parameters[END_REF]. These authors did not obtain differences on growth and mycorrhizal colonization of Olea europea plants, between AMF inoculation and a combination of AMF and a compost of solid municipal waste.

Effects of AMF inoculation and sewage sludge on plant mineral nutrition

The increase in growth of inoculated plants was coupled with a better mineral nutrition, especially for phosphorus. P is rare and weakly available in ultramafic soils, as it is strongly adsorbed to iron oxides, particularly in New Caledonia [START_REF] Dubus | Phosphorus sorption and desorption in oxide-rich ferrasols of New Caledonia[END_REF]Jaffré and L'Huillier, 2010a). The role of mycorrhiza can be important in these conditions, particularly in field conditions with large fluctuations of environmental variables in comparison with greenhouse conditions. The soil water content was generally sufficient, because there is a high rainfall level in Goro area (see site description), but there are large fluctuations with frequent saturations and soil surface drying and the temperatures are more variable than in greenhouse (12°C-34°C). The effect of AMF inoculation was not very clear when we consider only the element contents in plant organs, even if differences for stem or root contents were significant for P and K. As stressed by [START_REF] Smith | How useful is the mutualism-parasitism continuum of arbuscular mycorrhizal functioning?[END_REF], there is "a highly significant role for the fungi, not only in P uptake via the AM pathway but also in

A C C E P T E D M A N U S C R I P T 21
reducing the contribution of the direct pathway" (by root hairs) inducing an energy gain. Nevertheless, when we consider the total uptake of each AMF-inoculated plant, the absorption of major elements (i.e. P, N, K and Ca) was clearly stimulated by mycorrhizal symbiosis, in relation to the high biomass increase. The effect of sewage sludge on major elements absorption is similar to the AMF effect.

Ca/Mg ratio was higher in leaves and roots of AMF inoculated plants. As Ca is rare and Mg abundant in ultramafic soils (Ca/Mg low), this increase is an important contribution of AMF symbiosis to plant adaptation to ultramafic soils. Indeed, this low ratio is a limiting factor in these soils because of the competition between Mg and Ca (Jaffré and L'Huillier, 2010a;Proctor and Nagy, 1992). [START_REF] Doubkova | Arbuscular mycorrhizal symbiosis on serpentine soils : the effect of native fungal communities on different Knautia arvensis ecotypes[END_REF] reported a significant positive correlation between mycorrhizal colonization and Ca/Mg ratio of Knautia arvensis plants in different ultramafic and non-ultramafic areas.

Sewage sludge showed a negative effect on Ca/Mg ratio, particularly for leaves. It is possible that this organic matter has induced a complexation of Ca ions or/and microbial immobilization of Ca by the microorganisms in the rhizosphere.

Effects of AMF inoculation and sewage sludge on heavy metal translocation

Metal contents in leaves were not significantly reduced by the three treatments.

In fact, the values obtained here for leaves were lower than those generally observed for M. laurifolia in natural or greenhouse conditions (Crossay et al., submitted;Wulff et al., 2010), which means that this species is not inhibited by these amounts of metals in its leaves.

By contrast, the translocation factors for Fe, Mn, Co and Ni were all significantly lower in AMF inoculated plants in comparison with control ones. As heavy metal

A C C E P T E D M A N U S C R I P T

22 contents in mycorrhizal roots are generally higher than in control ones, it seems clear that the mycorrhizal root system retained a large part of the entering heavy metals.

These results in field conditions confirm those reported by [START_REF] Amir | Arbuscular mycorrhizal fungi, from New Caledonian ultramafic soils, improve tolerance to nickel of endemic plant species[END_REF] in greenhouse conditions for Ni and confirm the important role of AMF in the alleviation of heavy metal toxicity in plants in ultramafic soils. Different studies reported a lower translocation of heavy metals by plants inoculated with AMF in metal polluted soils [START_REF] Hildebrandt | Arbuscular mycorrhiza and heavy metal tolerance[END_REF][START_REF] Amir | Role of mycorrhizal fungi on the alleviation of heavy metal toxicity on plant[END_REF]; but very few concerned ultramafic soils [START_REF] Orlowska | The effect of mycorrhiza on the growth and elemental composition of Nihyperaccumulating plant Berkheya coddii Roessler[END_REF]Doubkova and Sudova, 2014).

Sewage sludge reduced the translocation of Mn and Co but not Fe, Ni and Cr. [START_REF] Velayoudon | Sewage sludge application for spontaneous plant restoration of a New Caledonian ferralsol[END_REF] have reported a reduction effect of sewage sludge on Mn, Co and Cr contents in pines planted in a New Caledonian ultramafic soil.

Effects of AMF inoculation on plant water content

AMF have frequently a positive effect on plant water content in relation to the increase of the absorbing surface [START_REF] Augé | Water relations, drought and vesicular-arbuscular mycorrhizal symbiosis[END_REF][START_REF] Smith | Plant performance in stressful environments: interpreting new and established knowledge of the roles of arbuscular mycorrhizas[END_REF]. In our experiment no effect of AMF inoculation on plant water content was observed 528 days after plantation. The climate in the experimental zone (Goro) is very humid and the soil was frequently saturated. The drought stress is therefore negligible, which can explain the absence of differences between inoculated and control plants for water content.

Gensous (2014), working with the same plant species in more fluctuating conditions of water availability, reported a clear increase of water content of AMF inoculated plants in relation to their tolerance to drought stress. Similar conclusion has been reported by [START_REF] Doubkova | Arbuscular mycorrhizal symbiosis alleviates drought stress imposed on Knautia arvensis plants in serpentine soil[END_REF] for Knautia arvensis in ultramafic soil. the most probable mechanism explaining the positive effect of AMF inoculation is that the higher growth rate of AMF-inoculated plants, at the beginning, induced more sugar photosynthesis and then more carbon allocated to symbiosis. This promoted AMF diversity in roots which again stimulated plant growth. Similar results were obtained by [START_REF] Alguacil | Plant type differently promotes the arbuscular mycorrhizal fungi biodiversity in their rhizospheres after revegetation of a degraded, semiarid land[END_REF]. These authors observed that plant inoculation with AMF stimulated AMF diversity and this stimulation was higher when plants were inoculated with two isolates in comparison with one.

Inoculation with AMF has also induced changes in the structure of AMF populations in the roots. The techniques used (DNA sequencing after nested PCR) are not adapted to quantify the abundance of each taxa. However the changes, considered globally, are sufficiently clear to be taken into account. These changes concerned 22 OTUs as seen in the phylogenetic tree (Fig. S5); two genera present in the roots of control plants were absent in inoculated plants and two other genera found in inoculated plants were not found in control plants (Fig. 4). Very few studies have been reported on the effects of AMF inoculation on AMF population structure. [START_REF] Janoušková | Effects of Inoculum Additions in the Presence of a Preestablished Arbuscular Mycorrhizal Fungal Community[END_REF], using a clayey spoil mixed with sand, have reported the competition between initial AMF community and inoculated isolates, inducing reduction of the latter abundance in roots. [START_REF] Cano | Competition and substrate colonization strategies of three polyxenically grown arbuscular mycorrhizal fungi[END_REF], using Ri T-DNA transformed carrot roots in vitro, reported a strong competition between AMF species for root colonization. Werner and Kiers (2014) tested the competition between two AMF species (Glomus aggregattum and Rhizophagus irregularis) in roots of Medicago truncatula, in glasshouse conditions, with pots filled with sand dune. When the roots were colonized by one of the two species, the inoculation of the second species induced a reduction of the abundance of the first species.

In our experiment, sewage sludge has significantly stimulated mycorrhizal colonization after 528 days, both in non-inoculated plants and inoculated ones.

Different studies reported the effects of sewage sludge on AMF. [START_REF] Weissenhorn | Arbuscular mycorrhizal contribution to heavy metal uptake by maize (Zea mays L.) in pot culture with contaminated soil[END_REF] found that this amendment stimulated mycorrhizal colonization of maize, but reduced spore abundance. Other studies reported negative effects on spore abundance only [START_REF] Val | Diversity of Arbuscular Mycorrhizal Fungus Populations in Heavy-Metal-Contaminated Soils[END_REF][START_REF] Moreira | Symbioses of plants with Rhizobia and mycorrhizal fungi in heavy metal contaminated tropical soils[END_REF]. We also observed that AMF diversity was reduced by sewage sludge after 335 days, especially in the roots of inoculated plants (8 OTUs instead of 25). [START_REF] Moreira | Symbioses of plants with Rhizobia and mycorrhizal fungi in heavy metal contaminated tropical soils[END_REF] reported equally a reduction of AMF diversity by this amendment, but this reduction was linked to the

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  rainfall level is high: average of 3490 mm/year. Mean monthly temperature in the area of Goro is highest in February with 25.0°C and lowest in August with 19.2°C. The area was situated at an altitude of 180 m and was an ultramafic maquis before the soil andA C C E P T E DM A N U S C R I P T 6 vegetation were stripped. The experimental field was plane and homogeneous, with a slight slope (2%).

  A C C E P T E D M A N U S C R I P T 12 into Luria-Bertani (LB) solid medium containing ampicillin (50 µg mL -1 ) and grown overnight at 37°C. A PCR using the universal M13F and M13R primers was performed directly on bacterial colonies to screen for positive clones. Clones that exhibited fragments with the expected size were Sanger sequenced on an Applied Biosystems 3730xl capillary sequencer with the BigDye® Terminator v3.1 Cycle Sequencing Kit (Applied Biosystems) with PCR amplicons obtained from positive clones.

  Relationships with AMF diversityDespite the positive effect of AMF inoculation on the growth of plants in field, we found that the inoculated AMF isolates were under represented in roots of M. laurifolia 335 days after plantation, compared to the other identified taxa. Indeed the OTUs corresponding to the genera of the three isolates represented at most 9% of the detected OTUs in the roots of inoculated plants. As plant biomass was measured more than 6 months later (after 528 days), the inoculated isolates were probably less abundant at this time. How then can we explain the large differences of growth, persisting for 41 months after plantation, between inoculated and non-inoculated plants? It is important to first point out that AMF inoculation was assessed in a nursery 18 months before plantation in the field. Differences between inoculated and control plants were then clearly visible when AMF inoculated isolates were alone to colonize the roots. After plantation, autochthon AMF progressively replaced inoculated isolates; but we could clearly observe that AMF inoculation stimulated AMF diversity in roots: 25 OTU were detected for inoculated plants and only 9 OTU for control plants. Thus

Fig. 1 .Fig. 2 .

 12 Figures and tables

Fig. 3 .

 3 Fig. 3. Influence of AMF inoculation, sewage sludge and their combination on Ca/Mg ratio

Fig. 4 .

 4 Fig. 4. Distribution of AMF genera identified in the roots of Metrosideros laurifolia 335

  Figure1

Figure 4

 4 Figure4

Table 1

 1 Influence of AMF inoculation, sewage sludge and their combination, on mineral nutrition of Metrosideros laurifolia plants, 528 days after plantation (means values with standard error). For each parameter, values followed by the same letters are nonsignificantly different (post-hoc Bonferroni corrected Mann-Withney test). Only the aerial parts are considered because the roots were difficult to collect completely at this stage; /: value not available.

		Leaves	Stem	Total uptake	Roots (mg/g)
		(mg/g)	(mg/g)	for aerial parts
				(mg/ plant)*
	P
	Control	0.17 ± 0.01 a	0.12 ± 0.03 a	4.47 ± 0.62 a	/
	+Sludge	0.23 ± 0.02 b	0.18 ± 0.03 b	19.71 ± 2.40 b	/
	+AMF	0.15 ± 0.02 a	0.20 ± 0.01 b	22.37 ± 1.92 b	/
	+AMF+Sludge	0.31 ± 0.03 c	0.53 ± 0.11 c	100.57 ± 16.76 c	/
	N
	Control	4.1 ± 0.7 a	1.7 ± 0.4 a	90.1 ± 17.2 a	/
	+Sludge	4.9 ± 1.3 a	2.8 ± 0.7 b	366.8 ± 93.7 b	/
	+AMF	3.5 ± 0.9 a	2.7 ± 0.7 a	395.7 ± 107.4 b	/
	+AMF+Sludge	3.5 ± 1.3 a	2. 8 ± 0.8 a	750.7 ± 249.0 c	/
	K
	Control	1.6 ± 0.5 a	1.0 ± 0.2 a	40.0 ± 10.8 a	0.5 ± 0.2 a
	+Sludge	2.7 ± 1.2 a	1.5 ± 0.2 b	201.9 ± 67.3 b	1.3 ± 0.7 ab
	+AMF	2.2 ± 1.0 a	1.7 ± 0.5 b	249.3 ± 95.9 b	1.1 ± 0.3 b
	+AMF+Sludge	2.5 ± 2.0 a	2.9 ± 1.0 c	646.5 ± 359.2 b	2.0 ± 1.3 b
	Ca
	Control	12.8 ± 5.5 a	12.9 ± 4.1 a	395.8 ± 147.8 a	3.0 ± 0.1 a
	+Sludge	9.9 ± 5.2 a	11.7 ± 2.7 a	1038.3 ± 379.7 b	6.7 ± 3.2 b
	+AMF	12.2 ± 6.7 a	13.2 ± 4.4 a	1623.8 ± 709.6 bc	5.5 ± 2.0 b
	+AMF+Sludge	8.3 ± 2.2 a	12.3 ± 3.1 a	2466.4 ± 643.6 c	3.7 ± 2.0 ab

*:

Table 2

 2 Influence of AMF inoculation, sewage sludge and their combination, on metal contents in Metrosideros laurifolia organs and in soil under plants, 528 days after plantation (means values with standard error). Values followed by the same letters are non-significantly different (post-hoc Bonferroni corrected Mann-Withney test).

		Leaves (L)	Stem	Roots (R)	Translocation factor (L/R)	Soil*
	Fe (µg/g)
	Control	232.3 ± 112.9 a 493.1 ± 187.7 a	331.1 ± 66.7 a	0.70 ± 0.38 a	8.0 ± 1.8 a
	+Sludge	210.8 ± 72.7 a	846.1 ± 624.4 a	596.2 ± 297.6 a	0.35 ± 0.21 a	7.4 ± 2.1 ab
	+AMF	172.6 ± 98.04 a 251.1 ± 99.0 a 2169.8 ± 1668.1 b 0.08 ± 0.06 b	4.7 ± 1.2 b
	+AMF+Sludge	202.5 ± 64.9 a 340.7 ± 173.3 a 4785.0 ± 4179.2 b 0.04 ± 0.03 b	6.9 ± 2.2 ab
	Mn (µg/g)
	Control	497.0 ± 178.8 a 255.9 ± 67.5 a	62.2 ± 26.3 a	7.99 ± 3.34 a	24.2 ± 3.2 a
	+Sludge	390.4 ± 183.7 a	256.3 ± 60.8 a	138.4 ± 91.4 ab	2.82 ± 0.98 b	26.1 ± 7.0 a
	+AMF	397.3 ± 114.4 a 269.2 ± 56.1 a	121.9± 26.0 b	3.26 ± 0.77 b	18.6 ± 6.3 a
	+AMF+Sludge	487.9 ± 186.9 a 332.8 ± 134.0 a	247.1 ± 164.0 b	1.97 ± 1.23 b	20.2 ± 4.8 a
	Co (µg/g)
	Control	1.1 ± 0.4 b	1.1 ± 0.4 a	1.3 ± 0.2 a	0.85 ± 0.29 a	3.0 ± 0.9 a
	+Sludge	0.3 ± 0.1 a	1.0 ± 0.7 a	1.6 ± 0.6 a	0.19 ± 0.09 b	3.1 ± 1.2 a
	+AMF	0.4 ± 0.2 a	0.8 ± 0.2 a	4.2 ± 3.0 a	0.09 ± 0.06 b	1.9 ± 0.6 a
	+AMF+Sludge	0.6 ± 0.3 ab	0.9 ± 0.2 a	17.9 ± 16.0 a	0.03 ± 0.03 b	2.8 ± 0.9 a
	Ni (µg/g)
	Control	8.7 ± 3.1 a	8.1 ± 1.5 a	9.0 ± 4.0 a	0.97 ± 0.33 a	5.1 ± 1.3 a
	+Sludge	7.6 ± 2.7 a	9.8 ± 1.2 a	9.6 ± 3.8 a	0.79 ± 0.30 a	4.3 ± 1.3 ab
	+AMF	6.5 ± 2.3 a	12.4 ± 6.5 a	19.9 ± 4.5 b	0.32 ± 0.13 b	3.2 ± 0.7 b
	+AMF+Sludge	9.8 ± 4.0 a	10.3 ± 4.4 a	83.7 ± 80.2 ab	0.11 ± 0.09 b	4.5 ± 1.7 ab
	Cr (µg/g)
	Control	12.8 ± 4.1 a	8.1 ± 4.5 a	13.6 ± 4.5 a	0.94 ± 0.48 a	15.0 ± 5.2 a
	+Sludge	15.2 ± 4.1 a	8.9 ± 0.5 a	17.7 ± 3.0 a	0.86 ± 0.35 a	17.7 ± 3.9 a
	+AMF	15.4 ± 2.2 a	13.2 ± 5.6 a	24.2 ± 15.1 a	0.64 ± 0.31 a	15.3 ± 3.8 a
	+AMF+Sludge	12.0 ± 3.9 a	9.6 ± 3.5 a	21.0 ± 5.6 a	0.57 ± 0.29 a	15.9 ±3.8 a

* DTPA-extractable metals in soil sampled under plants, between roots; DTPA: Dimethylene triaminopentaacetic acid.

Table 3

 3 AMF diversity associated with roots of Metrosideros laurifolia, 335 days after plantation.

					Treatments
		Control	Sludge AMF AMF + Sludge	Total
	Number of sequences	37	31	58	31	157
	Number of OTUs	9	8	25	8	32
	Sequences / OTUs	4.11	3.88	2.32	3.88	4.91
	Shannon index	1.46	1.14	2.42	1.15

Proctor J, Nagy L. 1992. Ultramafic rocks and their vegetation: an overview, In: Baker

Acknowledgments

The authors gratefully acknowledge CNRT "Nickel et son Environnement" for providing the financial support. The results reported in this publication are gathered from the CNRT report "Ecomine BioTop".

A C C E P T E D

M A N U S C R I P T 25 increase in heavy metal concentrations. In our case, the reduction of AMF diversity could not be explained by heavy metal toxicity as their extractable concentration in soil was not increased by sludge amendment (Table 2). The differences between measurement periods between AMF diversity (335 days) and mycorrhizal colonization (528 days) make interpretation more difficult; however a probable explanation is that the soil enriched with sewage sludge promoted few taxa more competitive in these conditions for root colonization, which induced the elimination (or rarefaction) of others.

In conclusion, the field experiment, assessed in mine restoration conditions in south New Caledonia, clearly demonstrated the importance of AMF functions in an ultramafic soil. Growth of Metrosideros Laurifolia plants was greatly increased by AMF symbiosis and the combination of AMF with sewage sludge showed complementary effects with a higher growth rate. Plant adaptation to ultramafic constraints has been also enhanced, with a higher Ca/Mg ratio and a reduction of heavy metal translocation. Application of these results to ecological restoration of ultramafic degraded areas is now under consideration.

Supplementary data

Supplementary data associated with this article can be found online at: doi…