Soil acidification, as influenced by N-fertilizer, stubble management and crop rotations, was investigated using soil samples from a long-term rotation trial at Tarlee, South Australia.

用南澳大利亚Tarlee地区一个长期田间试验的土壤样品研究了轮作措施、氮肥施用和残茬管理对土壤酸化的影响。

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The defence ministry says that to sustain a long-term operation, with a proper rotation system, it ideally likes to have at its disposal three or four ships or aircraft, and up to five army units, for every one deployed at any given time.

ECONOMIST: The army

After his goalscoring exploits last season, Bellion has featured slightly less frequently this term, thanks to Blanc's squad-rotation system, but he is content with life on the Garonne river and feels his maturity off the pitch is reflected by his play on it.

BBC: How Bellion bounced back