稻鸭共作系统的稻田氮素渗漏和径流特征

通过田间试验，分析了稻鸭共作（MRD）、常规栽培(MR)和淹灌单作（CK）3种稻作方式的稻田氮素渗漏和径流特征.结果表明：与MR处理相比，稻鸭共作系统稻田渗漏液氮素浓度尤其是NO₃^--N浓度显著减少，与CK处理相比，稻鸭共作稻田渗漏液氮素浓度有增加趋势；MRD处理在施肥7～9 d后，田面水中的NH₄⁺-N和NO₃^--N浓度高于MR处理，由于MRD处理不用搁田且田埂较高，田间排水量显著减少，氮素径流损失反而显著少于MR处理；与MR处理相比，MRD处理增加了鸭粪的氮素投入,减少了氮素渗漏和径流损失,减少了化学氮肥用量,增加了水稻地上部吸氮量;MRD系统的氮素输入总量和氮素输出总量均减少，且减少量基本相等.

Characteristics of paddy field nitrogen leakage and runoff in rice-duck farming system.

A field experiment was conducted to study the characteristics of paddy field nitrogen (N) leakage and runoff under rice-duck farming (MRD), conventio nal farming (MR), and conventional farming with flooding (CK). Comparing with th at under MR, the paddy field under MRD had a notable decrease of N (especially N O3--N) concentration in its leaked liquid; but this concentration was tended to be increased, compared with that under CK. After 7〖KG-*2〗-〖KG-*7〗9 days o f fertilization, the NH4+-N and NO3--N concentrations in paddy field su rface water were higher under MRD than under MR. However, owing to the no draini ng and the higher band, the paddy field under MRD had a notable reduction of drainage, resulting in a marked decr ease of N runoff than that under MR. Comparing with MR, the paddy field under MR D had an addition of nitrogen supply from duck dung, a reduction of N leakage an d runoff, a lesser application of chemical nitrogen fertilizer, and more nitroge n uptake by rice plant. Both the reduction of N input and that of N output in ri ce-duck farming system were nearly equal in quantity.