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为提高枣棉间作模式氮肥施用水平,设计N0、N10、N20、N30、N40、N50 6个氮肥处理,在棉花关键生育时期,调查棉花农艺性状和产量情况,测定土壤硝态氮的时空差异性。结果表明:施氮可增加单株结铃数,使棉花增产;增产效果随着氮肥用量的增加而增大,但超过一定范围后则有下降的趋势。施氮能够明显提高土壤硝态氮含量,中量施氮肥(450 kg/hm2)既可稳定产量又能减少土壤硝态氮残留。过量施氮造成了养分的累积及向下层淋洗。枣棉间作根系存在养分竞争,在距枣树50~100 cm区域氮肥竞争强,花期之后竞争开始增大,盛铃期达到最大,但随着与枣树距离加大竞争减弱。
In order to improve the level of nitrogen fertilizer application in intercropped Ziziphus jujuba cultivars, six N 0, N 10, N 20, N 30, N 40 and N 50 nitrogen fertilizers were designed to investigate the cotton agronomic traits and yield at the critical growth stage of cotton and the spatial and temporal variability of soil nitrate N . The results showed that nitrogen application could increase boll number per plant and increase yield of cotton. Yield increasing effect increased with the increase of nitrogen fertilizer dosage, but decreased after exceeding a certain range. Nitrogen application can significantly increase soil nitrate nitrogen content. Medium amount of nitrogen fertilizer (450 kg / hm2) can both stabilize yield and reduce nitrate residue in soil. Excess nitrogen fertilization caused accumulation of nutrients and leaching to the lower layer. Jujube plays an important role in the competition of root system. In the field of 50-100 cm from jujube tree, the competition of nitrogen fertilizer is strong, the competition begins to increase after florescence, and reaches the peak at full rhizome. However, competition with jujube tree decreases.