白银市平川区土壤与农产品硒含量特征及成因分析

为探明白银市平川区土壤硒分布规律和影响土壤中硒含量的因素，为保护和开发富硒土壤资源提供理论依据。我们在白银市平川区共采集土壤样本59个、农作物可食部分样品36个，通过检测分析土样全硒含量、土壤化学性状(铅、汞、镉、pH、有机质、有效硅、有效硼、有效铜、有效锌、有效铁、有效锰)与农作物可食部分全硒含量，研究了白银市平川区土壤与农作物全硒含量特征及其影响因素。结果表明:平川区土壤全硒平均含量为0.29 mg/kg，高出甘肃省土壤全硒平均含量45.0%，且富硒土壤母质均为冲洪积物。土壤全硒含量与土壤有机质(R2=0.32*)、有效硅(R2=0.35**)呈显著或极显著正相关。平川区各农产品全硒含量大小依次为胡麻、枸杞、藜麦、菊芋、玉米、马铃薯。平川区土壤硒含量有区域差异，西北部高于东南部，且灌区高于旱作区。土壤母质、有机质含量、有效硅含量是决定土壤富硒的主要因子，富集系数是各农产品全硒平均含量产生较大差异的主要原因。

Analysis on the Characteristics and Genesis of Selenium Contents in Soil and Agricultural Products in Pingchuan District, Baiyin

To understand the distribution pattern of soil selenium content in Pingchuan District, Baiyin, and to explore the influencing factors of selenium content in soil, a total of 59 soil samples and 36 edible crop samples in Pingchuan District, Baiyin were collected. Through testing and analyzing the total selenium content and soil chemical properties (lead, mercury, cadmium, pH, organic matter, available silicon, available boron, available copper, available zinc, available iron, and available manganese), and the total selenium content of edible parts in crops, the characteristics and influencing factors of total selenium contents in soil and crops in Pingchuan District, Baiyin were studied. The results indicated that the average soil total selenium in Pingchuan was 0.29 mg/kg which was 45.0% higher than the average soil total selenium content in Gansu Province. Moreover, the parent material of selenium rich soil was alluvial and proluvial deposits. Soil total selenium content had significant positive relationship with soil organic matter(R2 = 0.32*) and available silicon content(R2 = 0.35**). The total selenium contents of various agricultural products in Pingchuan District was in the order of sesame> goji berries > quinoa > Jerusalem artichoke > corn > potato. There were regional differences in soil selenium content in Pingchuan District with higher levels in the northwest than that in the southeast, and higher levels in irrigated areas than that in arid areas. The soil parent material, organic matter content, and available silicon content were the main factors determining soil selenium enrichment, and the enrichment coefficient was the main reason for significant differences in the average total selenium content of various agricultural products.