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2008年,对黑河中游临泽县1982年第二次土壤普查时有详细取样记录的287个样点进行了取样,测定了耕层土壤(0-20cm)中碱解氮、速效磷和速效钾含量,分析20多年来土壤速效养分的时空变化。比较2个时期土壤养分含量,碱解氮、速效磷和速效钾平均含量分别增加了5.5、22.4和42.0mg·kg-1;配对样本T-检验结果表明,2008年土壤速效养分含量比1982年有显著提高,尤其是速效磷增加了225.6%,土壤缺磷已不再是临泽农业生产中的主要限制因子。两个时期速效养分的Kriging插值图叠加结果表明,3种速效养分的空间分布特征发生了不同程度的变化,具有明显的地域性特点。速效磷和速效钾的空间异质性显著增加,变程分别从1982年的21.96km和80.34km减小到2008年的2.46km和2.13km。人为活动对土壤性质的影响不断提高,使得土壤的空间异质性增加。研究结果可为临泽县以及黑河中游绿洲农田土壤质量的综合研究和管理决策提供依据。
In 2008, 287 samples with detailed sampling records from the 1982 second soil census of Linze County in the middle reaches of Heihe River were sampled. The contents of available nitrogen, available phosphorus and available potassium in topsoil (0-20 cm) Content, analysis of spatio-temporal changes of soil available nutrients over the past 20 years. Comparing the soil nutrient contents, the average contents of available nitrogen, available phosphorus and available potassium increased 5.5, 22.4 and 42.0 mg · kg-1 respectively in the two periods. The results of paired samples T-test showed that the available soil nutrient content in 2008 was higher than that in 1982 Significantly increased, especially available phosphorus increased by 225.6%, soil phosphorus is no longer a major limiting factor in Linze agricultural production. The superposition of Kriging interpolation results of available nutrients in two periods showed that the spatial distribution of three available nutrients changed in different degrees and had obvious regional characteristics. The spatial heterogeneities of available P and available K increased significantly, ranging from 21.96km and 80.34km in 1982 to 2.46km and 2.13km in 2008 respectively. The impact of human activities on the nature of the soil continues to increase, making the spatial heterogeneity of the soil increased. The results can provide a basis for comprehensive study and management decision-making of farmland soil quality in Linze County and oasis in middle reaches of Heihe River.