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农业土壤是自然土壤开垦种植后,在自然因素和人为活动双重影响下长期形成的。所以农业土壤中各种元素的含量既与自然土壤有关联,而又与自然土壤有一些差异。采集东北地区中部近70个土壤剖面200个样品,用原子吸收法、阳极溶出伏安法和萤光光度法等分别测定了镉、铜、铁、汞、锰、镍、铅、锯、锌、硒等元素的含量。通动表土与心土对比法,4 d法和(?)+2s法剔除异常值,采取直方图法、概率纸法、Vistelius置信带法、Kolmogorov,Smirnov法和偏度、峰度法进行检验,综合判定元素概率分布类型。分别以表层土壤的(?)±S和M/D-M·D表示耕种暗棕壤、耕种黑土,耕种暗色草甸土和水稻土的元素背景值。 随着农业土壤腐殖质层的变薄和耕作层有机质含量的下降,许多元素的含量随之降低,尤以汞、锰、硒、锶为明显。
Agricultural soil is a long-term formation of natural soil cultivated and cultivated under the dual influence of natural factors and human activities. Therefore, the content of various elements in agricultural soil is related to both natural soil and natural soil. 200 samples from nearly 70 soil profiles in the central part of Northeast China were collected. The contents of cadmium, copper, iron, mercury, manganese, nickel, lead, saw, zinc, Selenium and other elements of the content. Through the method of contrasting topsoil and soil and earth, 4 d method and (?) + 2s method were used to eliminate the abnormal values and tested by histogram method, probability paper method, Vistelius confidence band method, Kolmogorov, Smirnov method and skewness and kurtosis method , Comprehensively determine the type of element probability distribution. The elemental background values of dark brown soil, cultivated black soil, cultivated dark meadow soil and paddy soil were expressed as (±) S and M / D-M · D of surface soils respectively. With the thinning of humus layer and the decrease of organic matter content in farming layer, the contents of many elements decreased, especially mercury, manganese, selenium and strontium.