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 resuhs 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 treat- ment 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.