水肥对土壤盐分影响及增产效应

Effects of water and fertilizer on soil salinity and yield increase

为了内蒙古河套灌区盐渍化土壤的肥料高效利用,采用田间试验的方法,将不同种类肥料和灌溉定额进行组合,研究其对土壤盐分的动态影响及增产效应.结果表明:小麦收获后,除尿素处理外,有机肥、控释肥和缓释肥处理在常规及节水灌溉条件下耕层和剖面土壤电导率(EC)均值较试验初都有不同程度的降低.有机肥处理在常规灌水条件下(灌水定额为1 005 m3/hm2),控盐效果略显优势;缓释、控释肥在节水灌溉条件下(灌水定额为750 m3/hm2),控盐效果更明显,剖面土壤EC均值较试验前分别下降16.4%,14.3%;尿素处理在常规灌水条件下,耕层及剖面土壤EC均值较播前分别增加3.6%,2.7%,积盐程度略高于节水处理.4种肥料处理的小麦产量较对照处理增产效果显著;缓释肥处理在常规及节水灌溉条件下均表现出显著的增产优势.综合考虑节水、增产、土壤脱盐等效应,获得优化灌水施肥模式为:缓释肥配二铵基施,生育期内不进行追肥,缓释肥为800.4 kg/hm2,二铵为350.6 kg/hm2,灌水定额为750 m3/hm2,产量为8 374.5 kg/hm2,较当地农民习惯灌水施肥处理可增产2.14%、节水25%,作物耕层EC值和剖面土壤EC均值较播前分别下降18.6%,16.4%.

In order to achieve an efficient use of fertilizer in saline soil in Inner Mongolia Hetao Irrigation District,several different combinations between type of fertilizer and irrigation quota were made, and then their dynamic impacts on soil salinity and yield increase were studied by using field trials. It was shown that except the urea treatment all the means of soil EC( electrical conductivity) in topsoil and soil profiles under the organic fertilizer,controlled and slow-release fertilizer treatments and usual water-saving irrigation condition are decreased in some degree compared with their initial values after wheat being harvested. The organic fertilizer treatment exhibits an advantage in salt control under the conventional irrigation condition( irrigation quota = 1 005 m3/ hm2). Both the slow-release and controlled fertilizers have an even better salt control under the water-saving irrigation condition( irrigation quota = 750 m3/ hm2); as a result,the means of EC in topsoil are decreased by 16. 4% and 14. 3%,respectively. For the urea treatment,however,the means of EC in topsoil and soil profile are increased respectively by 3. 6% and 2. 7% under the conventional irrigation condition,and the salinity is slightly higher than that under the water-saving irrigation condition. Although the wheat yield is increased significantly after the four kinds of fertilizer treatments are applied,the slow-release fertilizer can result in a remarked yield increase under the routine and water-saving irrigation conditions. After the water-saving,soil salinity and wheat yield increase are considered comprehensively,the optimized irrigation and fertilization module should be: slow-release fertilizer and diammonium as the basal fertilization,no topdressing during growth period,slow-release fertilizer is 800. 4 kg / hm2,diammonium is 350. 6 kg/ hm2,irrigation amount is 750 m3/ hm2. This module leads to a wheat yield as high as 374. 5 kg / hm2, which is increased by 2. 14% than in the conventional irrigation and fertilizer module. Furthermore, the irrigation water is saved by 25%,and the means of EC in topsoil and soil profiles have been decreased by 18. 6% and 16. 4%,respectively.