贵州山区坡耕地钾素输入与输出研究

Study on Input and Output of Potassium in Sloping Land of Guizhou Mountain

通过田间试验和分析测试,研究了5种水土保持措施和种植制度的钾素输入与输出规律。研究结果表明：坡耕地的钾素输入与输出与施肥、作物吸收有关,还与降水、地表径流和土壤侵蚀有密切的关系。坡耕地钾素循环体系中,钾素输入主要是降雨和施肥,共输入钾素93.12-180.26 kg/hm^2,输入的钾素全部为有效钾。钾素输出主要包括地表径流、土壤侵蚀、作物吸收3个方面,输出的钾为全钾、缓效钾、有效钾3种形态。共输出全钾658.13-1 590.01 kg/hm^2,输出有效钾19.28-32.45 kg/hm^2,输出缓效钾5.05-11.94 kg/hm^2,输出的总钾达687.34-1 634.40 kg/hm^2。坡耕地每年亏缺钾素507.08-1 541.37 kg/hm^2,各种水土保持措施和种植制度亏缺程度不一样,从高到低的排列为：农民习惯〉横坡种植〉条带种植2〉条带种植1〉工程梯化。改良的水土保持措施和种植制度由于降低了水土流失及合理施肥,减少了钾素亏缺,与农民习惯相比可减少钾素亏缺49%-67%。

The paper researched on five kinds of soil and water conservation and planting system about the input and output of potassium through field experiments and analysis. The results indicate： （1） The input and output of potassium in sloping land is related with absorption of crops and use of fertilization, furthermore, it＇s affected by precipitation, runoff and soil erosion closely. （2） In recycling system of potassium, the total input is 93.12-180.26 kg/hm^2 in virtue of rainfall and fertilization which are effective potassium. However, the output is 658. 13- 1 590.01 kg/hm^2 on account of runoff, soil erosion and absorption of crops, which contains the total potassium （687.3-1634.40 kg/hm^2）, slowly available potassium （5.05-11.94 kg/hm^2） and effective potassium （19.28-32.45 kg/hm^2）. （3） The loss of potassium in sloping land is 507.08- 1 541.37 kg/hm^2 yearly. While, deficiencies are influenced by different measures, especially, influenced by soil and water conservation and planting system. Then the order of force from high to low as follows, the habit of farmers, cross-slope cultivation, strip planting 2, strip planting 1, terrace project. The rate of preventing loss of potassium is up to 49%-67% compared five kinds of soil and water conservation and planting system with the habit of farmers.