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为研究黄土高原南部冬小麦田NH3挥发对垄作的响应,揭示其释放机制及污染风险,于2011—2013年冬小麦生长季,按照随机裂区试验设计布置田间试验,采用通气式田间原位酸吸收方法测定NH3挥发.主区为常规栽培及3种垄作,副区为2种施N(氮)处理——未施N(0 kg/hm2,以N计)和施N(180 kg/hm2).结果表明:不同施N处理下,各耕作模式NH3挥发通量在施肥后10 d均达到峰值,在施肥后30 d稳定在较低水平.垄作单季NH3累积挥发量(以N计)平均值为5.748 kg/hm2,比常规栽培降低4.9%;施N处理下NH3累积挥发量平均值为6.512 kg/hm2,比未施N处理提高26.8%.氮肥NH3挥发损失率为0.47%~1.38%,其中垄作平均损失率比常规栽培降低60.1%.不同施N处理下,各耕作模式NH3挥发通量与土壤w(NH4+)、含水量呈正相关;与25 cm深度处土壤温度、p H在冬前(施肥播种至土壤结冰阶段)呈正相关,而在冬后(土壤解冻至小麦收获阶段)则呈负相关.土壤w(NH4+)和土壤温度是控制NH3挥发的两大主要因素.冬前垄作降低NH3挥发通量主要是由于垄作集中深施肥会增加NH3挥发扩散阻力所致.可见,旱作冬小麦种植区采用垄作可降低NH3挥发风险.
In order to study the response of NH3 volatilization to the ridge in the winter wheat field in southern Loess Plateau, the mechanism of release and the risk of pollution were revealed. During the winter wheat growing season from 2011 to 2013, field experiments were conducted according to random split plot design. The NH3 volatilization was determined by conventional cultivation and three kinds of ridge planting in the main area, and two kinds of N (nitrogen) treatment in the secondary area - N (0 kg / hm2, N) and N (180 kg / hm2) The results showed that the NH3 volatilization flux reached the peak value on the 10th day after fertilization, and stabilized at the lower level at 30 days after fertilization.Under the condition of single ridge, NH3 cumulative volatilization (calculated by N) Was 5.748 kg / hm2, which was 4.9% lower than that of conventional cultivation.The average NH3 cumulative volatilization was 6.512 kg / hm2, which was 26.8% higher than that of no N treatment.The volatilization loss of NH3 was 0.47% -1.38% The average loss rate of ridge was lower by 60.1% than that of conventional cultivation.The NH3 volatilization flux of each tillage mode was positively correlated with soil NH4 + and water content under different treatments of N, (Fertilization sowing to the stage of soil icing) was positive, while in the winter (soil thawing to the stage of wheat harvest) was negative .The soil w (NH4 +) and soil temperature are the two main factors that control the volatilization of NH3.The reduction of NH3 volatilization flux is mainly caused by the concentration of deep fertilization in the ridge furrow, which will increase the resistance of NH3 to volatilization.It can be seen that the dryland winter wheat planting Ridge area can reduce the risk of NH3 volatilization.