Long-term (1980-2010) changes in cropland phosphorus budgets, use efficiency and legacy pools across townships in the Yongan watershed, eastern China
Long-term (1980-2010) changes in cropland phosphorus budgets, use efficiency and legacy pools across townships in the Yongan watershed, eastern China
复制标题
中国东部永安流域各乡镇农田磷收支、利用效率和遗留池的长期（1980-2010）变化
DOI：
10.1016/j.agee.2016.12.003
复制
发表时间：
2017-01-02
影响因子：
6.6
通讯作者：
Dahlgren, Randy A.
中科院分区：
文献类型：
--
作者：
Chen, Dingjiang;Hu, Mingpeng;Dahlgren, Randy A.
关于小城镇范围内农田磷流动的定量信息对于在小农耕作制度下制定可持续的磷管理措施至关重要。研究了1980-2010年中国东部永安流域21个乡镇农田土壤表层磷收支(即P投入和作物产出的净额)、利用效率(作物P吸收与总P投入的比率)和遗留P库的变化。整个流域的总磷输入(98%来自化肥和农家肥)、作物吸收和预算从1980年的50.4、17.3和33.1 kg P ha(-1)年(-1)增加到1995年的74.6、20.5和55.1 kg P ha(-1)年，然后急剧下降到2010年的39.6、11.4和28.2 kg P ha(-1)年(-1)。估计的磷利用效率从1980年的34%下降到1999年的26%，然后在2010年略有上升到28%。虽然这21个乡镇在1980-2010年期间有类似的时间变化，但在给定的年份内，各乡镇之间的P预算和利用效率表现出2-3倍的空间差异。磷素收支和利用效率的时空变化主要与磷肥施用量和模式(即所施合成肥料磷与农家肥磷的比例)和农田类型的变化有关。1984-2009年间，20个有土壤数据的乡镇农田表层土壤Olsen-P和全P含量分别增加了87-720%和113-395%。1984年至2009年间土壤总磷水平的增加表明，超过53%-79%的累积磷收支积累为农田土壤中的遗留磷库。根据回归分析，土壤遗留磷对作物年吸磷量的贡献从1980年的0.47 kg·ha(-1)·yr(-1)(3%)增加到2010年的3.45 kg·ha(-1)·yr(-1)(31%)，其中52%~80%来自化肥，2%~46%来自农家肥。为了最大限度地减少磷的输入和减少非点源磷污染负荷，必须提高土壤遗留磷库用于作物生产的利用率和磷的利用效率。在制定小农制度下的磷管理策略时，应考虑各乡镇磷预算和利用效率的高度空间异质性，以及长期过度使用后遗留下来的相当大的土壤磷库。(C)2016爱思唯尔B.V.保留所有权利。
Quantitative information on cropland phosphorus (P) flows at the township scale is critical for developing sustainable P management measures under the smallholder farming system. This study addressed changes in cropland soil surface P budgets (i.e., net of P inputs and crop outputs), use efficiencies (i.e., the ratio between crop P uptake and total P input) and legacy P pools across 21 townships in the Yongan watershed of eastern China in 1980-2010. For the entire watershed, total P input (>98% from synthetic fertilizer and farmyard manure), crop uptake and budgets per cropland area increased from 50.4, 17.3 and 33.1 kg P ha(-1) yr(-1) in 1980 to 74.6, 20.5 and 55.1 kg P ha(-1) yr(-1) in 1995, and then sharply declined to 39.6, 11.4 and 28.2 kg P ha(-1) yr(-1) in 2010, respectively. Estimated P use efficiency decreased from 34% in 1980 to 26% in 1999 before slightly increasing to 28% in 2010. Although the 21 townships had similar temporal variations over the 1980-2010 period, P budgets and use efficiency showed 2-3-fold spatial variability among townships within a given year. Spatio-temporal variations in the P budget and use efficiency were mainly related to changes in P fertilization rates and patterns (i.e., ratio of applied synthetic fertilizer P and farmyard manure P) and cropland types. The 20 townships having soil data had 87-720% and 113-395% increases of Olsen-P and total P contents in the upper 20 cm of cropland soils between 1984 and 2009, respectively. Increased soil TP level between 1984 and 2009 suggested that more than 53-79% of the cumulative P budget accumulated as legacy P pools in cropland soils. Based on regression analyses, legacy soil P contribution to annual crop P uptake was estimated to increase from 0.47 kg P ha(-1) yr(-1) (3%) in 1980 to 3.45 kg P ha(-1) yr(-1) (31%) in 2010, with 52-80% from synthetic fertilizer and 2-46% from farmyard manure. Improved utilization of soil legacy P pools for crop production and increasing P use efficiency are necessary to minimize P inputs and reduce nonpoint source P pollution load. The high spatial heterogeneity in P budgets and use efficiencies across townships, as well as considerable legacy soil P pools after long-term over-application, should be considered in developing P management strategies under smallholder farm systems. (C) 2016 Elsevier B.V. All rights reserved.