半干旱区玉米水肥空间耦合效应Ⅰ.氮素的吸收和残留及其环境效应

通过田间试验研究了半干旱地区不同灌水量和水肥空间耦合方式下玉米对N素的吸收及玉米收获后N素在1.0m土体中的残留。结果表明,与常规施肥灌水方式(均匀施肥均匀灌水、全生育期灌水量为2500 m3/hm2)相比,在全生育期灌水量为1125 m3/hm2和600 m3/hm2的水平下,均匀施肥交替灌水、水肥同区交替灌水、水肥异区交替灌水3种不同水肥空间耦合方式在玉米植株吸收N略有下降的情况下,增加了肥料N在60cm以上土壤中的残留量,从而减小了N向下层土壤淋溶的可能;相同灌水量下,60cm以上层次土壤N素残留量大小顺序为:水肥异区交替灌水处理>水肥同区交替灌水处理>均匀施肥交替灌水处理。

EFFECT OF DIFFERENT WATER-FERTILIZER SPATIAL COUPLINGS ON CORN IN SEMIARID AREA I.N UPTAKE, N RESIDUE AND ITS ENVIRONMENTAL EFFECT

Field experiments were conducted to study effect of irrigation and water-fertilizer spatial coupling on corn N uptake and N residue in the solum (1.0m) after corn was harvested in the semi-arid region. The results show that in comparison with the conventional pattern of fertilization and irrigation (even fertilizer application and even irrigation at a rate of 2500m3/hm2 during the entire growing period), at the irrigation rate of 1125m3/hm2 and 600m3/hm2, three different patterns of water-fertilizer spatial coupling, i.e. even fertilization and alternate irrigation, fertilization and alternate irrigation in the same field, and fertilization and alternate irrigation in different fields, slightly decreased N uptake by corn, but increased fertilizer N residue in the soil (060 cm in depth), thus reducing the possibility of N leaching down to the deeper layers; when the irrigation rates were kept the same, the three treatments were in a decreasing order of even fertilization and alternate irrigation> fertilization and alternate irrigation in the same field>fertilization and alternate irrigation in different fields.