不同土地利用方式对农田土壤养分含量的影响

Effect of Different Land Use on Farmland Soil Nutrients

本研究以湖南省祁阳县为例,探讨了南方丘陵区不同土地利用方式下农田土壤养分含量的时空变化及剖面含量分布,并与第二次土壤普查时(1980年)的土壤养分状况相比较。结果表明,水稻土有机质、全氮、碱解氮及速效磷平均含量高于旱地,而速效钾含量低于旱地土壤。与第二次土壤普查时相比,水稻土和旱地的全氮、碱解氮和速效磷含量都明显增加,水稻土的增加幅度要高于旱地土壤;而速效钾含量有不同程度的下降,水稻土下降程度小于旱地。水稻土各剖面层土壤有机质和全氮含量均远高于旱地土层,各土层全磷含量略高于旱地,而全钾含量则略低于旱地土壤。不同土地利用方式下施肥水平与施肥结构、耕作制度、田间管理等可能是造成研究区域农田土壤养分含量变化的主要原因。

The study investigated the effect of land use on farmland soil organic matter and nutrients and their temporal-spatial variability in Qiyang County,Hunan Province.The results showed that,the paddy soil organic matter,total nitrogen,alkali-hydrolysable nitrogen and available phosphorus contents were higher than upland field,while available potassium contents were lower than it.Compared with the results of the Second Soil Census,total nitrogen,available nitrogen and available phosphorus contents both in paddy field and in upland field were significantly increased,with higher increased rates in paddy field,while available K content declined at different degrees in paddy field and upland field.Soil organic matter,total nitrogen and total phosphorus contents in paddy soil profile were higher than upland soil profile,and the total potassium content were slightly lower than upland field.Fertilizer levels,fertilizer structure,farming system and field management in different land use patterns may be the main factors to the change of soil nutrients.