江淮丘陵季节性干旱区灌溉与施氮量对土壤肥力和水稻水分利用效率的影响

Effects of irrigation and nitrogen fertilization on soil fertility and water use efficiency of rice

采用防雨棚池栽试验,研究灌溉模式和施氮量对水稻土壤肥力和水分利用效率的影响。结果表明,灌溉模式与施氮量对土壤化学特性、土壤微生物学特性、产量及水分利用效率有着显著影响。与常规灌溉相比,控制灌溉条件土壤有机质含量、全氮含量、全钾含量、速效磷含量、速效钾含量、细菌数量、真菌数量和水分利用效率增加,碱解氮含量和放线菌数量降低。随着施氮量增加,土壤有机质含量、全氮含量、碱解氮含量、放线菌和真菌数量增加,而全磷含量、全钾含量、速效磷和速效钾含量降低,产量和水分利用效率呈现先增加后降低的趋势。在本研究条件下,以控制灌溉模式,施氮量180 kg.hm-2,产量达到11 495 kg.hm-2,节本增效效应最佳。

The effects of irrigation and nitrogen （N） fertilization on soil fertility and water use efficiency （WUE） of rice were studied in an experiment of pool culture within rain-proof shelter. Samples were collected from treatments under control and conventional irrigation receiving N application of 90 kg＂ hm-2, 180 kg＂ hm-2 and 270 kg＂ hm-2. The results showed that irrigation and nitrogen fertilization significantly influenced chemical and microbiological characteristics of soil, and yield and water use efficiency of rice. Compared with conventional irrigation, organic matter, total N, total P, total K, available P, available K, WUE, quantity of bacterium and quantity of fungus increased while available N and quantity ot＇ actinomycete decreased under control irrigation. With the increment of N application rates, organic matter, total N, available N, quantity of fungus, quantity of actinomycete increased, while total P, total K, available P, avail- able K, quantity of bacterium decreased. However, yield and water use efficiency ot＂ rice reached the highest at 180 kg＂ hm-2 of N applied. It was concluded that control irrigation combined with suitable N application rate （180 kg＂ hm-2） could benefit rice production by reducing cost and gaining high yield.