title: [Effects of nitrogen management on maize nitrogen utilization and residual nitrate nitrogen in soil under maize/soybean and maize/sweet potato relay strip intercropping systems].
abstract: A large amount of nitrogen (N) fertilizers poured into the fields severely pollute the environment. Reasonable application of N fertilizer has always been the research hotpot. The effects of N management on maize N utilization and residual nitrate N in soil under maize/soybean and maize/ sweet potato relay strip intercropping systems were reported in a field experiment in southwest China. It was found that maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato with an increase of 22.6% for maize yield after sustainable growing of maize/soybean intercropping system. Nitrate N accumulation in the 0-60 cm soil layer was 12.9% higher under maize/soybean intercropping than under maize/sweet potato intercropping. However, nitrate N concentration in the 60-120 cm soil layer when intercropped with soybean decreased by 10.3% than when intercropped with sweet potato, indicating a decrease of N leaching loss. Increasing of N application rate enhanced N accumulation of maize and decreased N use efficiency and significantly increased nitrate concentration in the soil profile except in the 60-100 cm soil layer, where no significant difference was observed with nitrogen application rate at 0 to 270 kg · hm(-2). Further application of N fertilizer significantly enhanced nitrate leaching loss. Postponing N application increased nitrate accumulation in the 60-100 cm soil layer. The results suggested that N application rates and ratio of base to top dressing had different influences on maize N concentration and nitrate N between maize/soybean and maize/sweet potato intercropping. Maize N concentration in the late growing stage, N harvest index and N use efficiency under maize/soybean intercropping increased (with N application rate at 180-270 kg · hm(-2) and ratio of base to top dressing = 3:2:5) and decreased nitrate leaching loss with yield reaching 7757 kg · hm(-2) on average. However, for maize/sweet potato, N concentration and use efficiency and maize yield increased significantly with N application rate at 180 kg · hm(-2) and ratio of base to top dressing = 5:5 than that under other treatments with yield reaching 6572 kg · hm(-2). Under these circumstances, it would be possible to realize maize high yield, high efficiency and safety of N man- agement under maize/soybean and maize/sweet potato relay strip intercropping systems.
authors: Xiao-Chun
authors: XC
authors: Wang
authors: Wen-Yu
authors: WY
authors: Yang
authors: Xiao-Yan
authors: XY
authors: Deng
authors: Qun
authors: Q
authors: Zhang
authors: Tai-Wen
authors: TW
authors: Yong
authors: Wei-Guo
authors: WG
authors: Liu
authors: Feng
authors: F
authors: Yang
authors: Shu-Ming
authors: SM
authors: Mao
mesh_terms: D000383:Agriculture / Q000379:methods; D002681:China; D005308:Fertilizers; D027723:Ipomoea batatas / Q000254:growth & development; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D013025:Glycine max / Q000254:growth & development; D003313:Zea mays / Q000254:growth & development / Q000378:metabolism*
chemical_list: D005308:Fertilizers; D009566:Nitrates; D012987:Soil; D009584:Nitrogen