闽西北烟-稻轮作系统地表氮、磷流失特征研究

为了明确福建省高温多雨气候条件下烟-稻轮作系统中地表氮、磷流失情况,在连续3a定位试验条件下研究了不同施肥措施对烟-稻轮作系统中地表氮、磷流失的影响。研究结果表明,福建省烟-稻轮作系统中氮、磷流失主要集中在上半年(烟季),而且氮、磷流失总量主要受降水量的影响,与产流降雨量呈显著或极显著相关关系。当地习惯施肥条件下,烟-稻轮作系统中氮、磷的流失量分别为4.71～14.86kg·hm-·2a-1和0.93～2.20kg·hm-·2a-1,流失系数分别为0.76%～1.27%和0.47%～1.71%。与习惯施肥相比,优化施肥处理氮、磷的流失量分别减少了1.25%～13.82%和8.82%～14.99%,流失系数分别为0.76%～1.43%和0.41%～1.54%。增施50%氮肥和增施50%磷肥的氮和磷流失量分别比优化施肥处理提高7.6%～37.6%和21.5%～27.4%。此外,同等施肥量条件下,稻草还田的氮、磷流失量分别提高6.4%～16.4%和-3.4%～14.0%,流失系数分别达到0.86%～1.91%和0.36%～2.00%。综上所述,优化施肥处理可以减少氮、磷的流失量,而增量施肥明显增加肥料流失量,稻草还田也提高了氮、磷流失的风险。

Nitrogen and Phosphorus Losses from Surface Runoff in Tobacco-rice Rotation System in Northwest of Fujian Province, China

To investigate the losses of nitrogen(N) and phosphorus(P) from surface runoff in the tobacco-rice rotation system in Fujian Province,a located field experiment was conducted to study the effect of different fertilization measures on the losses.The results indicated that the N & P losses mainly occurred in tobacco growing season,and the loss amounts were significantly correlated with the rainfall which conducted runoff.With conventional fertilization,the loss amounts of N and P were 4.71～14.86 kg·hm-2·a-1 and 0.93～2.20 kg·hm-2·a-1,whose loss coefficients were 0.76%～1.27% and 0.47%～1.71%,respectively.Compared to conventional fertilization,the loss amounts in optimized fertilization treatment decreased 1.25%～13.82% for N and 8.82%～14.99% for P,whose loss coefficients were 0.76%～1.43% and 0.41%～1.54%,respectively.And the N & P losses with the treatment that increasing 50% nitrogen and phosphorus fertilizer applied would bring about increase of 7.6%～37.6% and 21.5%～27.4% than that with optimized fertilization.Compared to optimized fertilization,the treatment that rice straw returning increased the N & P runoff losses of 6.4%～16.4% and-3.4%～14.0%,whose loss coefficients reached 0.86%～1.91% and 0.36%～2.00%,respectively.Based on the analysis results it was considered that the optimized fertilization could reduce N & P runoff losses amount,more application of N & P increased the losses,and the rice straw returning also increased the risk of N & P runoff losses.