覆盖栽培雷竹林土壤钾养分变化特征

摘要

以浙江省奉化市覆盖栽培的雷竹林为研究对象,运用定位研究方法揭示在相似气候和土壤质地条件下,不同覆盖年限下雷竹林土壤土壤钾素的养分变化特征。研究结果表明,不同覆盖年限的林地土壤全钾和速效钾存在显著差异。试验林地全钾含量变幅是12.5~34.24g/kg,速效钾是37.55~492.34mg/kg,速效钾的变异十分显著而全钾相对较小。全钾含量在覆盖栽培10年之前逐步递增,速效钾含量在覆盖3次或超过6年后增加尤为明显。值得关注的是全钾含量在10年后又趋下降,速效钾含量在覆盖栽培8年后开始下降,全钾含量变化幅度小于速效钾主要是由于二者养分来源和利用状态不同所致,矿物态的难溶性和缓效性钾是全钾主体,相对稳定,覆盖物料的残留分解释放引起速效钾养分增加显著。因而,从土壤肥力因子钾素养分来说,覆盖年限不宜超过10年,连续覆盖的次数或频率应少于3或4次,以稳定或提高雷竹林土壤钾素养分状况。%This paper dealt with a study on the effects of mulched Phyllostachys praecox stands on the potassium nutrient state in soils in Fenghua County, Zhejiang Province, in China, in the condition of intensive management and by adopting the principle of fixed monitoring in different cultivated manner, especially in mulching years, in similar climate and soil texture. The results showed that there existed obvious variations of the total potassium and available potassium in soils of cultivated Ph. praecox stands. The variation range of the contents of total potassium was 12.5~34.24 g/kg, while the variation range of available potassium content was 37.55~492.34 mg/kg, It appeared that there existed a wild variation of available potassium, whereas the change about total potassium was smaller. The contents of total potassium increased with mulching years by the end of ten years; in comparison, the available potassium increased very obviously after three-time mulching or six years later.It was very interesting that the content of the total potassium declined in the soil of the stands ten years later, while available potassium in the mulched stands declined only after eight years compared to those non-mulched ones. The smaller variation of the content of total potassium may result from converting or changing the physical and chemical environment and the process of the mineral of organic matter of mulching materials and soil components. From the point of variation trends of potassium nutrients in soil fertility, the years of mulching cultivation was limited, approximately more than ten years. Under the condition of mulching frequency, when it was three or four times, the number should be reduced or the frequency should be better measured, so as to maintain stability and improve potassium nutrients condition in the soil of Ph. Praecox stands.