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首页> 外文期刊>Plant and Soil >Interactions between white clover and ryegrass under contrasting nitrogen availability: N2 fixation, N fertilizer recovery, N transfer and water use efficiency.
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Interactions between white clover and ryegrass under contrasting nitrogen availability: N2 fixation, N fertilizer recovery, N transfer and water use efficiency.

机译：白三叶草和黑麦草之间的氮素交互作用不同：固氮，氮肥回收，氮素转移和水分利用效率。

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摘要

Seasonal variation in N2 fixation, N transfer from clover (Trifolium repens) cv. Milkanova to ryegrass (Lolium perenne) cv. Sisu, Merlinda, Borvi and Tivoli, and N uptake by white clover-ryegrass swards were investigated under field conditions in 1994-96 near Copenhagen, Denmark. The plots were established with sowing ratios of clover and ryegrass of 0:20, 1:20, 6:20, 12:20 and 12:0, and were given 3, 24, 48 or 72 kg N ha-1 year-1 as urea. The clover content of the sward was decreased by 72 kg N but not by smaller N dressings. The total amount of atmospherically derived N in clover growing in mixture with ryegrass, averaged over the three years, was 83, 71, 68 and 60 kg ha-1 with application of 3, 24, 48 and 72 kg N, respectively. The proportion of atmospherically derived N declined with increasing N application, but never became smaller than 80% of total clover N. The proportion of atmospherically derived N in a pure stand of white clover amounted to 60-80% of the total N content, equivalent to109, 110, 103 and 90 kg N with application of 3, 24, 48 and 72 kg N, respectively. Only small amounts of atmospherically derived N were transferred to the associated ryegrass during the first production year, while in each of the following years up to 21kg ha-1 was transferred. The average amount of N transferred from clover to ryegrass was equivalent to 3, 16 and 31% of the N accumulated in ryegrass in the first, second and third production year, respectively. Expressed relative to the total amount offixed N2 in the clover-ryegrass mixture, the transfer amounted to 3, 17 and 22% in the first, second and third production year, respectively. Thus transfer of atmospherically derived N from clover contributed significantly to the N economy of the associated ryegrass. Uptake of soil-derived N by the clover-ryegrass mixture was consistently higher than in the pure stands of the two species. Only 11% of the total accumulated fertilizer N and soil-derived N in the mixture was contained within the clover component. Lower water use efficiencies for the plants grown in mixture compared with pure stands were mainly related to the increased N uptake in the mixture, with the subsequent increase in growth compared with the pure stands. It is concluded that positive interactions between clover and ryegrass growing in mixture ensure a more efficient fixation of atmospheric N2 and uptake of fertilizer N and soil-derived N than in pure stands of the same species.
机译：N2固定的季节性变化，三叶草（Trifolium repens）cv的N传递。 Milkanova转黑麦草（Lolium perenne）简历。 Sisu，Merlinda，Borvi和Tivoli，以及1994-96年在丹麦哥本哈根附近的田间条件下研究了白三叶草-黑麦草草对氮的吸收。以三叶草和黑麦草的播种比例为0：20、1：20、6：20、12：20和12：0的地块建立样地，并给予3、24、48或72 kg N ha-1 year-1作为尿素。草皮的三叶草含量减少了72 kg N，但较小的N敷料并未减少。与黑麦草混合生长的三叶草中，大气中衍生的氮的总量在三年中平均为83、71、68和60 kg ha-1，分别施用3、24、48和72 kgN。大气中氮的含量随氮肥施用量的增加而下降，但从未低于三叶草总氮的80％。纯白三叶草中，大气中氮的比例占氮总含量的60-80％，当量分别施加3、24、48和72 kg N到109、110、103和90 kgN。在生产的第一年中，仅少量的大气中衍生的N被转移到相关的黑麦草中，而在随后的每一年中，最多转移了21kg ha-1。从三叶草转移到黑麦草的氮的平均含量分别相当于第一，第二和第三生产年黑麦草中积累的氮的3％，16％和31％。相对于三叶草-黑麦草混合物中固定氮的总量表示，第一，第二和第三生产年的转移量分别为3％，17％和22％。因此，来自三叶草的大气中氮的转移显着促进了相关黑麦草的氮经济。三叶草-黑麦草混合物对土壤中氮的吸收一直高于两个物种的纯林。三叶草成分中仅占混合物中累积的肥料氮和土壤氮总量的11％。与纯林相比，在混合物中生长的植物的水分利用效率较低，主要与混合物中氮的吸收增加有关，与纯林相比，随后的生长增加。结论是，与纯种林分相比，三叶草和黑麦草在混合物中生长的正向相互作用确保了对大气中氮的固定以及对氮和土壤氮的吸收。

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