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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。
In this study, Qiyang County of Hunan Province was used as an example to investigate the temporal and spatial variations of soil nutrient contents and the distribution of soil profile under different land use patterns in the hilly areas of South China. Compared with the soil nutrients of the second soil survey (1980) . The results showed that the average contents of organic matter, total nitrogen, available nitrogen and available phosphorus in paddy soil were higher than those in dry land, while the content of available potassium in paddy soil was lower than that in dry land. Compared with the second soil survey, the content of total nitrogen, available nitrogen and available phosphorus in paddy soil and dry land increased obviously, while that in paddy soil increased more than that in dry land. However, the available potassium content decreased to some extent, Paddy soil decreased less than dry land. The contents of soil organic matter and total nitrogen in all profiles of paddy soil were much higher than those in dryland soil. The content of total phosphorus in the soil layers was slightly higher than that in dry land, while the content of total potassium was slightly lower than that in dry land. Fertilization level and fertilization structure, farming system and field management under different land use patterns may be the main reason for the changes of soil nutrient content in the farmland in the study area.