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首页> 美国政府科技报告 >Nitrogen Fixation by Forage Legumes Grown in Pure Stands and in Mixtures with Cereals. Final Report for the Period February 1982 - November 1987.
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Nitrogen Fixation by Forage Legumes Grown in Pure Stands and in Mixtures with Cereals. Final Report for the Period February 1982 - November 1987.

机译：纯饲料和与谷物混合饲料生长的饲料豆类固氮。 1982年2月至1987年11月期间的最终报告。

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Nitrogen fertilizers labelled with (sup 15)N were used to estimate N(sub 2) fixed in Vetch (Vicia sativa), Peas (Pisum sativum), Chickpeas (Cicer arietinum), medic (Medicago truncatula), ochrus vetch (Lathyrus ochrus), bitter vetch (Vicia ervilia), tick bean (Vicia faba), woolly pod vetch (Vicia dacycarpa), and faba bean (Vicia faba) in Cyprus between 1982 and 1987. The proportions of N derived from N(sub 2) fixation were as follows: Vetch, 70-80%; peas, 30-70%; medic, 50-70%; ochrus vetch, 47-79%; bitter vetch, 33-70%; faba bean, 49-80%; tick bean, 84% (for only one year); woolly pod vetch, 79% (for one year) and chickpea, 41% (for one year). Large seasonal variations in N(sub 2) fixation were noticed, and high inorganic N was found to depress N(sub 2) fixation. Both the A-value and (sup 15)N isotope dilution approaches gave statistically similar estimates of N(sub 2) fixed. Cereals grown in mixture with legumes contained lower (sup 15)N enrichments than the pure cereal crop, which might indicate the transfer of fixed N(sub 2) from the legume to the associated cereal. However, the N uptake profiles of the sole versus mixed cereal crops were often dissimilar. It is therefore uncertain if the discrepancy in (sup 15)N enrichments is largely attributable to N transfer or to the mismatched N uptake at different periods. Preliminary data from studies in which (sup 15)N-labelled plant tissues were incorporated into soil as a source of a relatively low-fluctuating (sup 15)N/(sup 14)N ratio in soil indicated that this may be a more reliable approach for studying N transfer between plants, since differences in N uptake patterns in the different cropping systems is of reduced effect in the final results. (Atomindex citation 19:076434)

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