施氮对南疆干旱荒漠绿洲枣棉间作土壤硝态氮时空分布的影响

Effects of Nitrogen Fertilizer on Spatial and Temporal Distribution of Soil Nitrate under Red Date and Cotton Intercropping System in Southern Xinjiang Arid Desert Oasis

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。

A field experiment of six treatments was conducted to improve fertilizer management in red date andcotton intercropping system. The six fertilization treatments of N0, N10, N20, N30, N40, N50 were designed.The cotton agronomic traits and yield and spatial and temporal variation of soil nitrate-N were studied indifferent growth and development stages of cotton. The results showed that： the number of bolls per plant andcotton production could be increased by using nitrogen. The yield would be increased with increasing amountof nitrogen, but there was a downward trend when the amount of nitrogen was more than a certain range. Thecontent of nitrate nitrogen could be significantly improved by using nitrogen fertilizer in soil. The applicationamount of nitrogen of 450 kg/hm2 could not only reduce the residual nitrate-N in soil but also stabilize theyield. But the excess application of nitrogen would cause the accumulation of nutrients and their leachingdownward. There was nutrient competition of the roots in red date and cotton intercropping system. There wasstrong nitrogen competition in the region that was 50 to 100 cm from the red date trees, the nitrogen competition increased after flowering stage, and achieved the maximum in the boll period, but the nitrogen competitionwould be weakened with the distance increase between the red date trees.