中国农业科学 ›› 2016, Vol. 49 ›› Issue (5): 906-915.doi: 10.3864/j.issn.0578-1752.2016.05.010

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

稻田优化施肥效果与氮、磷环境效益评价

 智1,2,李小坤1,2,丛日环1,2,任 涛1,2,黄铁平3,鲁艳红4

 
  

  1. 1华中农业大学资源与环境学院,武汉 430070
    2农业部长江中下游耕地保育重点实验室,武汉 430070
    3湖南省土壤肥料工作站,长沙 410005;4湖南省土壤肥料研究所,长沙 410125
  • 收稿日期:2015-08-07 出版日期:2016-03-01 发布日期:2016-03-01
  • 通讯作者: 丛日环,Tel:027-87288589;E-mail:congrh@mail.hzau.edu.cn
  • 作者简介:张智,Tel:027-87288589;E-mail:zz2012@webmail.hzau.edu.cn
  • 基金资助:
    国家公益性行业(农业)科研专项(201303103)、中央高校基本科研业务费专项(2013PY113)、国家测土配方施肥技术项目资助

Optimized Fertilization Effects and Environmental Benefits Evaluation of Nitrogen and Phosphorus in the Paddy Soil

ZHANG Zhi1, 2, LI Xiao-kun1, 2, CONG Ri-huan1, 2, REN Tao1, 2, HUANG Tie-ping3, LU Yan-hong4   

  1. 1College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070
    2Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Wuhan 430070
    3Soil and Fertilizer Station   of Hunan Province, Changsha 410005; 4Hunan Soil and Fertilizer Institute, Changsha 410125
  • Received:2015-08-07 Online:2016-03-01 Published:2016-03-01

摘要: 【目的】针对稻田氮磷钾肥施用不合理引起环境问题较为严重的现象,从粮食高产高效和环境效益的角度分析稻田化肥的合理施用与管理策略。【方法】选用测土配方施肥项目2005—2010年在湖南省间布置的735个早、中、晚稻肥料田间试验,选取不施肥(CK)、农民习惯施肥(FP)和优化施肥(OPT)3个处理,对比分析了早、中、晚稻OPT较FP处理的增产效果与氮、磷、钾肥偏生产力的优势;通过筛选OPT处理产量或/和氮肥偏生产力前25%的试验点,建立高产、高效和高产高效3种方案,结合氮肥用量与氮素损失(N2O的排放、N的径流与淋失、NH3挥发)之间的经验模型,评估稻田节氮减排潜力;通过计算早、中、晚稻磷素表观平衡,分析稻田磷素残留状况;并引入湖南省早、中、晚稻种植面积,估算区域稻田氮、磷的环境效益。【结果】多年多点田间试验研究表明,与CK处理相比,FP和OPT处理分别可增产41.9%和52.0%(早、中、晚稻的平均值);与FP处理相比,OPT处理早、中、晚稻可增产7.0%—8.3%,氮、磷肥偏生产力分别提高16.8%—19.6%和5.5%—37.3%,而OPT处理钾肥用量的提高对钾肥偏生产力的负效应较小(早、中、晚稻平均降幅为6.4%)。节氮减排评估结果表明,高产组产量高而氮肥用量相对较高,高效组氮肥偏生产力高而产量相对较低,用高产高效组表征产量和氮肥偏生产力的潜力更可靠;高产高效组早、中、晚稻每年可节省氮肥用量共81 kg·hm-2(其中晚稻最多,为32 kg N·hm-2),减少氮素损失15.5 kg N·hm-2,温室气体N2O减排约20%。湖南省稻田节氮总潜力为12.5×104 t,减少氮素损失2.35×104 t,主要对象为早稻和晚稻。优化施肥可提水稻的磷素总吸收量,早、中、晚稻从FP处理的59—66 kg P2O5·hm-2增加到OPT处理的63—71 kg P2O5·hm-2。磷肥用量与水稻磷素吸收量之间的关系显示,两者并不能达到显著的正向相关关系,说明当磷肥投入总量满足作物需求后,多余的磷素对当季作物磷素吸收无效,从而残留在土壤中;早、中、晚稻分别有46%、44%和15%的样本出现磷残留现象,通过筛选并分析磷残留样本得出,早、中、晚稻OPT处理磷残留比例明显低于FP处理,且磷残留量分别可降低到1.36—5.30 kg P2O5·hm-2,较FP处理下降了33.7%—48.5%;从全省范围来看,磷残留总量可减少18.14×103、3.59×103和5.30×103 t;另一方面,农民习惯施肥中,仍有不施磷肥的现象,这对土壤养分的耗竭影响较大,应重视平衡施肥。【结论】稻田优化施肥是产量和环境安全的重要保障,氮肥减量施用可提高氮肥利用率,减少氮素损失和温室气体的排放,控制磷肥总量可有效地避免土壤磷素残留带来的污染风险。

关键词: 早中晚稻, 优化施肥, 产量, 氮损失, 磷残留

Abstract: 【Objective】 Environmental issue caused by unreasonable fertilization has been widely noticed in the paddy field. Yield increase potential and nutrient surface balance in the plant-soil system were analyzed, aiming to achieve scientific fertilizer principle and management strategy from the view of yield productivity and environmental benefit. 【Method】 A total of 735 site-year fertilization experiments were conducted on early rice, middle rice and late rice in Hunan province under the Project of Soil Testing and Fertilizer Recommendation during the period of 2005-2010. Three treatments were selected, control (i.e., CK), farmer’s practice (i.e., FP), and optimum fertilization (i.e., OPT). The yield increment and partial factor productivity (PFP) of nitrogen (N), phosphorus (P) and potassium (K) between the OPT and FP treatments for early, middle and late rice were analyzed. Three groups (i.e. high-yield, high-efficiency and high-yield & efficiency) were divided through screening the 75-100th percent of the yield and/or PFPN for the OPT treatment. Evaluation of N saving and emission reduction in the paddy soil were combined the empirical model between N rates and N losses (i.e., nitrous oxide emission, N leaching and runoff, and ammonia volatilization). Apparent balance of P for early, middle and late rice were calculated to analyze the P residuals. In addition, the planting areas of early, middle and late rice in Hunan province were applied to assess the regional environmental benefit of N and P. 【Result】 Compared with the CK treatment, rice (average of early, middle and late rice) yield increment of FP and OPT treatments were 41.9% and 52.0%, respectively. And yield increase rate reached 7.0%-8.3% for the OPT treatment as compared with FP treatment for early, middle and late rice. Compared with the FP treatment, the optimum fertilization improved the PFP of N and P fertilizers by 16.8%-19.6% and 5.5%-37.3%, respectively, and slightly decreased (6.4%) in PFPK since K rates were increased in the OPT treatment. In general, the high-yield group had high yield but also high N rate, and the high- efficiency group got low N rate but also low yield. The high-yield & efficiency group was proper to estimate the potential of yield and efficiency. Under the group of high-yield & efficiency, N fertilizers would be saved by 81 kg N·hm-2 annually (32 kg N·hm-2 for late rice), nitrogen loss decreased by 15 kg N·hm-2, and nitrous oxide emission reduced by 20%. Total N saving potential would be 12.5×104 t, mainly contributing by early rice and late rice, with the emission reduction potential of 2.35×104 t. Optimum fertilization improved the total P uptake of rice from 59-66 kg·hm-2 (FP treatment) to 63-71 kg·hm-2 (OPT treatment). However, total P uptake of rice was not improved by increasing P rate. Clearly, when phosphorus rate meets the requirement of rice, surplus P would be residual in soil. There were 46%, 44% and 15% of the samples appeared to P residual for early, middle and late rice, respectively. The ratio of P residual for OPT treatment was obviously lower than that of the FP treatment. Phosphorus residual amounts of early, middle, and late rice for OPT treatment can be dropped to 1.36-5.30 kg P2O5·hm-2, which were 33.7%-48.5% lower than the FP treatment. For the whole province, the total phosphorus residual of early, middle, and late rice would be decreased by 18.14×103, 3.59×103 and 5.30×103 t. In the other hand, no P application was still exist in the farmer practice. Balance fertilization is very important for crop growth and soil nutrient maintaining. 【Conclusion】 Optimized fertilization is an important guarantee for food and environment security. Applying lower nitrogen fertilizer would improve nitrogen use efficiency, decrease nitrogen loss and produce less greenhouse gases. Controlling total phosphorus fertilization rate would reduce the pollution risk of soil phosphorus residual.

Key words: early, middle and late rice, optimized fertilization, yield, nitrogen loss, phosphorus residual