不同水氮管理对氮素利用与平衡的影响

在宁夏引黄灌区露地菜田条件下,选择有代表性的春小麦白菜、芹菜白菜2种轮作体系,通过田间试验与室内分析的方法,以空白和单施有机肥为对照,研究了2种轮作体系下,不同水氮措施对春小麦白菜、芹菜白菜轮作体系中氮素利用与平衡的影响。试验结果表明:节水灌溉的推荐施氮处理(W2N3)对春小麦、芹菜、白菜的产量、吸氮量与传统灌溉的差异不大。节水灌溉的推荐施氮处理(W2N3)处理与传统灌溉的习惯施氮处理(W1N3)的处理相比,春小麦的产量提高6.7%,芹菜的产量提高12.2%,麦后复种白菜和芹菜复种白菜产量分别高5.9%、22.4%;在氮素平衡方面,氮素输入项中,施氮量和生育期内氮素矿化量占主要比例,氮素输出项中,作物吸收和氮素表观损失占很大比例,春小麦白菜轮作中,推荐施氮处理(N3)氮素损失比传统施氮损失分别低53 kg/hm2(传统灌溉)、47 kg/hm2(节水灌溉),节水条件下的推荐施氮处理(W2N3)比传统灌水的习惯施氮处理的无机氮(Nmin)残留减少了13 kg/hm2,芹菜白菜轮作体中,推荐施氮处理氮素损失比传统施氮损失分别低77 kg/hm2(传统灌溉)、83 kg/hm2(节水灌溉),节水条件下的推荐施氮处理(W2N3)比传统灌水的习惯施氮处理的无机氮(Nmin)残留减少了3 kg/hm2。不同轮作条件下节水的推荐施氮处理和习惯施氮处理均比传统灌溉的土壤残留硝态氮高,而且主要分布在0～60 cm表层。春小麦白菜土壤残留硝态氮均比芹菜白菜低,而且分布规律不一致,尤其是在底层180 cm处土壤残留硝态氮含量芹菜明显高于春小麦。

Effect of Different Water and Nitrogen Measure on N Utilization and Balance of Different Rotate System

The spring wheat-Chinese cabbage and celery-Chinese cabbage are two types rotate system in irrigation areas by diverting from yellow river in Ningxia.The paper aimed to determine and compared the effect on N utilization and balance of different rotate systems,based on nitrogen and water for optimum management.Compared with CK and organic fertilizer,the effects of different application nitrogen treatment were studied on the nitrogen balance,nitrate accumulation with different rotate system in Ningxia yellow river irrigated area.The data show that saving recommend nitrogen fertilization(W2N3) and convention irrigation fertilization(W1N3) treatment were little different in crop yield and uptake N.The yield of W2N3 were increased 6.7%(spring wheat),12.2%(celery) and 5.9%(wheat after planting Chinese cabbage),22.4%(vegetable after planting Chinese cabbage).The application nitrogen and nitrogen net mineralization were main place in nitrogen input,crop uptake and the nitrogen apparent loss were main place input of nitrogen balance principle.The result show in apparent nitrogen loss of recommend nitrogen fertilization(W2N3) were 53 kg/hm2(W1),47 kg/hm2(W2),residual Nmin of W2N3 decreased by 13 kg/hm2 of W1N3 in spring wheat-Chinese cabbage rotate.In celery-Chinese cabbage rotate,nitrogen loss of recommend nitrogen fertilization decreased 77 kg/hm2(W1),30 kg/hm2(W2) respective,residual Nmin of W2N3 decreased by 3 kg/hm2 of W1N3. 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 W1N3 treatment.There were mainly in 0~60 cm surface layer.The decrease of residual NO3—N of W2N3 in 0~60 cm surface layer was 0.21 times as much as with W1N3 in spring wheat-Chinese cabbage rotate.The decrease of residual NO3—N of W2N3 in 0~60 cm layer was 0.15 times as much as with W1N3 in cerely-Chinese cabbage rotate.The characteristic soil NO3—N of different layer were different significantly between spring wheat-Chinese cabbage rotate and celery-Chinese cabbage rotate.