宁夏农田土壤耕层养分含量的时空变化特征

根据土壤普查资料和实际采样测定结果,探讨了宁夏山区和灌区农田土壤耕层有机质和氮磷钾养分含量的时空变化特征。结果表明,在1970年、1985年和2000年3个时段内,土壤有机质、有效磷和碱解氮含量呈显著或较显著增长态势,土壤速效钾含量近15年在灌区明显下降,土壤氮磷钾全量养分在30年间没有明显变化。从两个地区比较来看,除土壤全磷量外,土壤有机质和其它养分含量都是灌区显著高于山区,而变异系数除土壤全钾外都是山区显著大于灌区。

Temporal and Spatial Variability of Soil Nutrients in Plough Layer of Farmland Soils in Ningxia Province

Based on the data of both soil survey previously and soil properties tested in 2000,the temporal and spatial variability of soil organic matter and nitrogen,phosphorus and potassium nutrients in the plough layer(0～20cm)of farmland soils in the mountain region and the irrigation region of Ningxia Province was studied by using traditional statistic method from 1970 to 2000.The results showed that the contents of soil organic matter,available phosphorus and alkali-hydrolyzable nitrogen had been increased gradually either significantly or slightly significantly over 30 years.The content of soil readily available potassium had no obviously change among the years in semiarid mountain region of south Ningxia.However,it decreased significantly in irrigation region of north Ningxia in the last 15 years.The contents of soil total nitrogen,phosphorus and potassium had no evidently change in the past 30 years.Compared with the two regions, the contents of both soil organic matter and soil nutrients in the irrigation region were higher than that in the mountain region except for soil total phosphorus.Whereas the variation coefficients of soil organic matter and soil nutrients except for soil total potassium in the semiarid mountain region of south Ningxia were obviously higher than that in the irrigation region of north Ningxia.