不同水氮措施对农田氮素流失和动态变化规律

【目的】 研究不同水氮措施对农田氮淋失的影响。【方法】 以宁夏黄灌区玉米为供试材料,采用田间试验、取样、室内分析与生物统计的方法,设CON(常规处理)、RN(减施氮肥)、SRN(减氮节水)、SMN(节水增施有机肥)和CRF(控释肥配施)共5个处理,研究不同水氮措施对农田氮素流失和动态变化规律。【结果】 土壤含水量是影响淋溶量的因素之一,而灌溉量是影响淋溶量的主要因素,节水控灌处理(SRN、SMN)所产生的淋溶水量均低于常规灌溉处理(CON、RN、CRF),节水控灌处理淋溶水量比常规灌溉处理淋溶水量减少14.6%~18.4%;土壤淋溶水总氮、可溶性总氮、硝态氮浓度年内变化呈降低趋势,均在基施肥或第1次追施氮肥后出现峰值,是控制氮素流失的关键时期,施氮量是影响淋溶水氮素浓度的主要因素;2016~2018年总氮淋失量大小顺序均为CON(常规处理)＞RN(减施氮肥)＞SRN(减氮节水)＞SMN(节水增施)＞CRF(控释肥配施),CRF总氮淋失量较CON减少21.4~43.0 kg/hm²。【结论】 CRF处理降低氮素淋失的效果最佳,与CON处理相比总氮淋失量降低比例为68.4%~74.7%。

Preliminary Study on Nitrogen Loss and Dynamic Change of Farmland under Different Water and Nitrogen Measures

【Objective】 In view of the serious problem of nitrogen loss caused by improper management of corn water and fertilizer, the effects of different water and nitrogen measures on nitrogen leaching loss in farmland was studied with corn in Yellow Irrigation Area of Ningxia as the test material. 【Method】 Using the methods of field experiment, sampling, indoor analysis and biostatistics, five treatments were set up CON (conventional treatment), RN(nitrogen reduction), SRN(nitrogen reduction and water saving), SMN(water saving and increasing organic fertilizer application) and CRF(controlled-release fertilizer application). 【Result】 Soil water content was one of the factors affecting leaching capacity, while irrigation volume was the main factor affecting leaching capacity. Water-saving and controlled irrigation treatment (SRN and SMN) produced less leaching water than conventional irrigation treatment (CON, RN and CRF), and compared with conventional irrigation, the water amount of water leaching in water-saving controlled irrigation treatment decreased by 14.6%-18.4%; Total nitrogen, soluble total nitrogen and nitrate nitrogen concentrations in soil leached water showed a decreasing trend during the year, all of which showed peaks after base fertilization or the first topdressing of nitrogen fertilizer. It was the key period to control nitrogen loss, and it also showed that nitrogen application was the main factor affecting the nitrogen concentration in leaching water. From 2016 to 2018, the order of total nitrogen spray loss was CON> RN > SRN > SMM > CRF, and the total nitrogen spray loss of CRF decreased by 21.4-43.0 kg/hm² compared with CON. 【Conclusion】 CRF treatment in this test has the best effect on reducing nitrogen leaching loss. Compared with CON treatment, the reduction ratio of total nitrogen leaching loss is 68.4%-74.7%.