华北山前平原农田土壤肥力演变与养分管理对策

Change in farmland soil fertility and nutrient management strategy in the piedmont of Mount Taihang, North China Plain

  • 摘要: 通过对2000 年、2008 年栾城县农田土壤养分与1979 年土壤普查资料的比较, 分析了养分肥力指标的变化程度, 研究了30 年间该县农田土壤养分演变趋势及其原因, 提出了养分资源管理的相应对策。研究结果表明, 2008 年土壤肥力状况较2000 年和1979 年发生了明显变化, 土壤有机质、碱解氮、有效磷和速效钾含量均有显著提高(P<0.01), 碱解氮含量增加尤为显著。土壤碱解氮平均含量由1979 年的56.7 mg·kg-1 增加到2000 年的80.0 mg·kg-1 和2008 年的109.1 mg·kg-1, 1979~2000 年间土壤碱解氮以每年1.1 mg·kg-1 的平均速度增长, 年均增长率1.9%, 增幅41.1%; 进入21 世纪后, 增长速度明显加快, 2000~2008 年间以每年3.6 mg·kg-1的平均速度增长, 年均增长率4.5%, 增幅为36.4%。土壤有机质由1979 年的11.6 g·kg-1 增加到2008 年的18.8g·kg-1, 平均每年以0.24 g·kg-1 的速度增长, 年均增长率为2.1%, 增幅为62.1%。30 年间土壤有效磷含量由17.5mg·kg-1 增加到24.7 mg·kg-1, 增加幅度为41.1%。由于受到"北方石灰性土壤不缺钾"的观点影响, 20 世纪该区域农民很少施用钾肥, 1979~2000 年间土壤速效钾含量呈下降趋势, 由140.6 mg·kg-1 下降到111.4 mg·kg-1, 下降幅度20.8%; 进入21 世纪, 由于秸秆还田措施的实施和含钾肥料的施用, 至2008 年全县土壤速效钾平均含量又回升到149.5 mg·kg-1。栾城县农田土壤肥力水平较高, 生产潜力大, 该区域农田养分管理应以氮素的精确管理为核心, 以实现作物持续高产稳产与环境保护相协调为目标, 氮肥管理推行实时诊断与推荐施肥技术,磷钾肥实施恒量监控储备施用技术, 推广秸秆直接还田, 实行有机无机相结合的培肥措施。

     

    Abstract: The trend, degree and mechanism of change in soil nutrient/fertility in farmlands of Luancheng, Hebei Province was analyzed using soil survey data for 2008, 2000 and 1979, from which a sustainable strategy for agricultural nutrient resource management was put forward. The results indicated a significant change in soil fertility for 1979 through 2008. There was a significant increase (P<0.01) in soil organic matter, Olsen-P, available K, and especially in available N. Average available N increased from 56.7 mg·kg-1 in 1979 to 80.0 mg·kg-1 in 2000, and to 109.1 mg·kg-1 in 2008. This represented an annual increment of 1.1 mg·kg-1 and 3.6 mg·kg-1 in 1979~2000 and 2000~2008, respectively. Available N increased by 1.9% and 4.5% annually for 1979~2000 and 2000~2008 and with a total corresponding increase of 41.1% and 36.4%, respectively. The rate of increase in 2000~2008 was higher than in 1979~2000. Soil organic matter content increased from 11.6 g·kg-1 in 1979 to 11.6 g·kg-1 in 2008, which represented an annual increment of 0.24 g·kg-1. Soil organic matter increased by 2.1% annually and by 62.1% in total for 1979~2008. Soil Olsen-P content increased from 17.5 mg·kg-1 to 24.7 mg·kg-1 in the 30-year period, represented a total increase of 41.1%. It was then evident that no shortage existed in soil potassium due to the calcareous nature of soils in North China coupled with occasional potassium fertilizer application in the past century. This resulted in a decrease in available K from 140.6 mg·kg-1 to 111.4 mg·kg-1 in 1979~2000, representing 20.8% decrease over the period. Available K increased to 149.5 mg·kg-1 in 2008 as a result of incorporating straw into the soil and increasing potassium fertilizer application in the current century. Soil fertility in the farmlands of Luancheng was high with a high potential for agricultural production. While the key to nutrient management in the region lied with nitrogen, the overall objective of nutrient management was sustainable high crop yield and sound environment. While nitrogen management should include real-time soil nutrient deficiency diagnosis and dosage, phosphorus and potassium management should based on constant soil nutrient monitoring and conservative phosphorus/potassium application. Fertilizer management practices that incorporate straw into the soil and combine the application of organic and inorganic fertilizers should be implemented in the study area.

     

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