农田硝态氮淋溶规律对不同水氮运筹模式的响应

发布时间：2018-07-29 19:05

【摘要】：为探明不同水氮运筹对淋溶水中NO_3~--N时空分布特征以及施氮量和灌水定额对NO_3~--N淋失量的影响,进而制定安全有效的水氮运筹模式。试验采用裂区设计,主区为灌水定额,设置3个水平,分别为525(W1),750(W2),975(W3)m~3/hm~2。副区为施氮量,设置5个水平,分别为0(N0),80(N1),160(N2),240(N3),320(N4)kg/hm~2。每个灌水定额下有5种施氮量处理,共15个处理。并于2014—2015年连续2年进行田间试验。采用多孔PVC法和土钻法采集水样和土样,测定淋溶水中NO_3~--N浓度并计算NO_3~--N淋失量。结果表明,0—40cm埋深内,对比第1次灌水前后NO_3~--N浓度发现,随着施氮量的增加,W1水平下NO_3~--N浓度2年的平均增幅远低于W2和W3水平下NO_3~--N浓度2年的平均增幅。随着灌水定额的增加,N1、N2水平下的NO_3~--N浓度平均增幅远低于N3、N4水平下的NO_3~--N浓度平均增幅。NO_3~--N浓度平均增幅最大的为52.5%的W3N3。NO_3~--N浓度平均值最高的为8.29mg/L的W3N4。与0—40cm埋深内的各处理相比,40—80cm埋深的各处理NO_3~--N浓度整体下降,但整个生育期内淋溶水中NO_3~--N浓度的变化趋势与0—40cm埋深内相一致。80—120cm埋深内,施氮量、灌水定额以及两者的交互作用对NO_3~--N淋失量的影响呈极显著。当灌水定额一定时,2014年、2015年2年的NO_3~--N淋失量随着施氮量增加而递增,淋失率随着施氮量的增加而减少;当施氮量一定时,NO_3~--N淋失量及淋失率均随着灌水定额的增加而递增。鉴于根层内需要充足的NO_3~--N以被作物吸收,并保证NO_3~--N淋失量对地下水的污染在可控安全范围内,故推荐W2N3为适用于当地的水氮运筹模式。
[Abstract]:In order to find out the spatial and temporal distribution characteristics of NO_3~--N in leaching water and the effects of nitrogen application rate and irrigation quota on NO_3~--N leaching, a safe and effective water nitrogen operation model was established. The design of split area was adopted, the main area was irrigation quota, and three levels were set up, which were 525 (W1) -750m (W2) -975 (W3) MN 3 / hmmng ~ (2). There were 5 levels of nitrogen application in the secondary area, which were 0 (N0) 80 (N1), 160 (N2), 240 (N3), 320 (N4) kg / hmmc20 (N4), respectively. Under each irrigation quota, there were 5 kinds of nitrogen application treatments, 15 treatments. Field trials were carried out in 2014-2015 for 2 years. Water and soil samples were collected by porous PVC method and soil drill method. The concentration of NO_3~--N in leaching water was determined and the amount of NO_3~--N leaching was calculated. The results showed that the average increase of NO_3~--N concentration in two years under W1 level was much lower than that in W2 and W3 levels with the increase of nitrogen application rate, compared with the NO_3~--N concentration before and after the first irrigation. With the increase of irrigation quota, the average increase of NO_3~--N concentration at N _ 1N _ 2 level was much lower than that at N _ 3N _ 4 level. Compared with the treatments with 0-40cm buried depth, the NO_3~--N concentration of each treatment with 40-80cm depth decreased as a whole, but the variation trend of NO_3~--N concentration in leaching water during the whole growth period was consistent with that in the 0-40cm buried depth of .80-120cm, and the amount of nitrogen applied was the same. The effect of irrigation quota and their interaction on NO_3~--N leaching was very significant. When the irrigation quota was fixed, the leaching loss of NO_3~--N in 2014 and 2015 increased with the increase of nitrogen application rate, and the leaching loss rate decreased with the increase of nitrogen application rate, and the N leaching loss and leaching loss rate increased with the increase of irrigation quota. In view of the need for sufficient NO_3~--N in the root layer to be absorbed by crops, and to ensure that the pollution of groundwater caused by NO_3~--N leaching is within a controllable and safe range, W2N3 is recommended as a suitable model for local water and nitrogen operation.
【作者单位】：内蒙古农业大学水利与土木建筑工程学院;
【基金】：国家“十二五”科技支撑计划项目“内蒙古河套灌区粮油作物节水技术集成与示范”(2011BAD29B03)
【分类号】：S274;S143.1

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