School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China.
Sci Total Environ. 2013 Apr 15;450-451:129-39. doi: 10.1016/j.scitotenv.2013.02.016. Epub 2013 Mar 5.
There are two kinds of land policies, the smallholding land policy (SLP) and the farmland policy (FLP) in China. The farmland nutrient dynamics under the two land policies were analysed with the soil system budget method. The averaged nitrogen (N) input of the SLP and the FLP over sixteen years increased about 23.9% and 33.3%, respectively and the phosphorus (P) input climbed about 39.1% and 42.3%, respectively. The statistical analysis showed that the land policies had significant impacts on N and P input from fertilizer and manure, but did not obviously affect the N input from seeds and biological N fixation. The efficiency percentage of N of the SLP and the FLP climbed about 54.5% and 59.4%, respectively, and the P efficiency improved by 52.7% and 82.6%, respectively. About the nutrient output, the F-test analysis indicated that the land polices had remarkable impacts on N output by crop uptake, ammonia volatilisation, denitrification, leaching and runoff, and P output by uptake, runoff, and leach. The balance showed that the absolute loss of N from land deceased about 43.6% and 46.0%, respectively, in the SLP and the FLP, and P discharge reduced about 34.2% and 75.2%, respectively. The F-test analysis of N and P efficiency and balance of between two polices both indicated that the FLP had significant impact on nutrient dynamic. With the Mitscherlich model, the correlations between nutrient input and crop uptake, usage efficiency and loss were analysed and showed that was a threshold value for the optimal nutrient input with the highest efficiency rate. For the optimal nutrient efficiency, the space for extra P addition was bigger than the N input. The FLP have more advantage than the SLP on the crop yield, nutrient efficiency and environmental discharge.
中国存在两种土地政策，即小农地政策（SLP）和农田政策（FLP）。本文采用土壤系统预算法分析了这两种土地政策下农田养分动态。16 年来，SLP 和 FLP 的平均氮（N）投入分别增加了约 23.9%和 33.3%，磷（P）投入分别增加了约 39.1%和 42.3%。统计分析表明，土地政策对化肥和厩肥的 N 和 P 投入有显著影响，但对种子和生物固氮的 N 投入没有明显影响。SLP 和 FLP 的 N 效率分别提高了约 54.5%和 59.4%，P 效率分别提高了 52.7%和 82.6%。就养分输出而言，F 检验分析表明，土地政策对作物吸收、氨挥发、反硝化、淋溶和径流的 N 输出以及吸收、径流和淋溶的 P 输出有显著影响。平衡表明，SLP 和 FLP 中农田 N 的绝对损失分别减少了约 43.6%和 46.0%，P 的排放量分别减少了约 34.2%和 75.2%。对两种政策下 N 和 P 效率和平衡的 F 检验分析均表明，FLP 对养分动态有显著影响。通过米切尔利希模型，分析了养分投入与作物吸收、利用率和损失之间的相关性，表明存在一个最佳养分投入的阈值，具有最高的效率。对于最佳养分效率，P 的额外添加空间大于 N 输入。FLP 在作物产量、养分效率和环境排放方面比 SLP 更具优势。
