喀斯特生态重建果园土壤养分季节变化研究

A Study of Seasonal Changes in Soil Nutrients of Ecological Restoration Orchards in Karst

在喀斯特生态重建示范区李果园、黄皮果园、火龙果园内设置样地,对其土壤中氮磷钾土壤养分含量和相关性分析研究,结果表明:果园中氮、磷、钾养分元素含量随着果树生长周期对营养吸收量不同而呈现季节性变化,土壤中氮磷钾含量空间垂直变化性变化明显,从土壤表层向下逐渐减少;在相关性方面,全氮和水解性氮相关性显著,全磷与有效磷相关性显著,全钾与有效钾不相关。9月示范区果园土壤氮的含量丰富,磷的含量处于相对平衡状态,而钾的含量严重不足。喀斯特石漠化区土层薄,水土保持能力差,养分不足、季节性差异大的环境特点制约了生态重建工作。根研究结果,建议在喀斯特石漠化区开展生态重建时,应对其土壤环境进行调查,针对不同立地类型实施土壤改良,选择适宜的物种栽植,遵循生态恢复规律,循序渐进地开展。

For sampling plots of plum,Chinese wampee and dagon orchards in the demonstration areas of Karst ecological restoration,soil nitrogen,phosphorus,potassium and their relationships with these plots were analyzed.Results showed that there were seasonal variations in the contents of soil nitrogen,phosphorus,potassium in orchards,depending on the difference in the nutrient uptakes during the growth,and that those nutrients exhibit obviously vertical changes in space,being decreased with increasing soil depth.The significant correlationship could be found between the contents of total nitrogen and hydrolyzed nitrogen,as also is the case with total phosphorous and available phosphorus.However,total K and available K are not related.In September,orchard demonstration areas have rich soil nitrogen content,relatively balanced phosphorus content,but are very short of potassium.In the Karst,the projects of ecological restoration are constrained by environmental characteristics of Karst rocky desertification area including thin soil layer,poor water-holding capacity,nutrient deficiencies and seasonal fluctuations.It is suggested that soil status must be surveyed during the ecological restoration in the Karst,associated with different soil improvement according to the standing types and that suitable plant species should be chosen,in a progressive way,followed by those principles of ecological restoration.