不同水氮措施对芹菜-白菜轮作体系中氮素利用与土壤NO_3~--N残留的影响

在宁夏引黄灌区灌淤土设置田间试验,研究不同水氮措施对芹菜-白菜轮作体系中的氮素利用与平衡的影响,结果表明:节水灌溉的W2N3(推荐施氮)处理与传统灌溉(W1N3)(推荐施氮)的处理相比,芹菜的产量、吸氮量分别高12.2%、14.7%,白菜的产量、吸氮量分别高22.4%、4.4%。在氮素平衡方面,推荐施氮处理氮素损失比传统施氮损失分别低53kghm-2(传统灌溉)、30kghm-2(节水灌溉)。节水条件下推荐施氮处理的土壤剖面上的无机氮残留浓度,减少量分别达到3～13kghm-2。节水灌溉下与传统灌溉相比,节水灌溉的土壤残留硝态氮的含量均比传统灌溉低,而且主要分布在0～60cm表层,推荐施氮量的土壤残留硝态氮的含量又比习惯施氮量低。

Effect of Different Water and Nitrogen Measure on N Uptake and Balance in Celery-Chinese Cabbage Rotate System

The Celery-Chinese cabbage was a type of rotate system in Irrigation Areas by diverting from Yellow River of Ningxia in north-west China. Different rotate systems could cause different N utilization efficiency and leaching of any nitrate left in the profile. However,Nitrogen testing and water for optimum management has been rarely paid attention during crop growth. The paper aimed to determine and compared the effect on N utilization and balance of Celery-Chinese cabbage rotate system based on nitrogen and water for optimum management. The results showed that saving recommend nitrogen fertilization (W2N3) was higher than convention irrigation fertilization (W1N3) treatment in crop yield and uptake N. and were different significantly. Yield and uptake N were increased 12.2%,14.7%(celery) 22.4% and 4.4%(vegetable after planting Chinese cabbage) of W1N3,respectively. The account for decreasing irrigation and nitrogen application treatment were increased yield and uptake N because of local higher application nitrogen convention for a long time. Nitrogen loss of recommend nitrogen fertilization were higher 53kg hm-2(W1),30kg hm-2(W2),residual Nmin of W2N3 decreased by 3-13kg hm-2 of W1N3 The further account for recommend nitrogen fertilization in saving irrigation that was practical to consider nitrogen balance,nitrogen nutrition resources efficiency and environmental factors. At the layer of 0-180 cm depth after different crop harvest,the characteristic soil NO3--N in different layer were different significantly. The soil NO3--N content of W2N3 in different rotate were lower than W1N2 and W1N3treatment. There were mainly in 0-60 cm surface layer. The decrease of residual NO3--N of W2N3 in 0-60 cm surface layer was 0.15 times as much as with W1N3 in cerely-Chinese cabbage rotate.