宁夏石嘴山地区主要粮食作物铜含量特征及影响因素分析

为探讨石嘴山地区主要粮食作物中微量元素铜的含量特征及影响因素,以石嘴山地区土壤及主要粮食作物玉米、小麦和水稻为研究对象,分析不同农作物根系土壤中总Cu、有效Cu及作物Cu的含量。通过线性回归法分析了作物Cu吸收量与土壤中总Cu、有效Cu、pH、阳离子交换量(CEC)、有机质、有效Fe、碱解N、有效P、有效K、有效B、有效Se及有效Mo等环境因素之间的相关性。结果表明：石嘴山地区土壤介于pH 7.97~9.09之间,对应的玉米、小麦和水稻田块土壤酸碱度中位值在pH 8.47~8.53之间,为弱碱性或碱性土壤。研究区域的土壤总Cu含量介于11.70~30.40 mg/kg之间,对应的玉米、小麦和水稻田块土壤总Cu含量中位值在20.95~25.32 mg/kg之间,平均值在21.12~24.65 mg/kg之间,与全国土壤总Cu平均含量24 mg/kg相当。有效Cu含量介于0.74~7.51 mg/kg之间,对应的玉米、小麦和水稻田块土壤有效Cu含量中位值在1.65~2.99 mg/kg之间。研究区域的玉米、小麦和水稻田块土壤有效态Cu占总Cu比例介于6.32%~48.10%之间,总Cu及有效态Cu总量均不高,但有效态Cu占比相对较高。玉米、小麦和水稻等作物的Cu含量分别介于1.20~3.24、4.11~11.70、14.80~53.21 mg/kg之间,Cu含量中位值分别为1.66、5.95、27.80 mg/kg。作物Cu富集系数由大到小依次为水稻>小麦>玉米,其中水稻对Cu的富集能力远高于小麦和玉米。影响因素分析表明,土壤有效Cu含量与土壤总Cu含量显著相关,玉米吸收Cu含量与土壤总Cu含量显著相关,水稻吸收Cu含量与土壤有机质含量显著相关,而包含土壤pH、CEC、有效Fe、碱解N、有效P、有效K、有效B、有效Se及有效Mo等在内的环境因素,均与玉米、小麦和水稻对Cu的吸收不存在显著相关性。石嘴山地区水稻产品属于富含微量元素Cu的优质稻米,大力开发富Cu水稻,可为人们提供安全健康营养充足的富Cu食品。

Copper Content Characteristics of Main Grain Crops and Their Influencing Factors in Shizuishan of Ningxia

To investigate the content characteristics of trace element copper in main grain crops in Shizuishan and their influencing factors, the contents of total Cu and available Cu in soil and main grain crops such as maize, wheat and rice in the area were analyzed. Linear regression method was used to analyze the correlation between crop Cu uptake and soil environmental factors, such as total Cu, available Cu, pH, cation exchange capacity (CEC), organic matter, available Fe, alkali-hydrolyzed N, available P, available K, available B, available Se and available Mo. The results showed that Shizuishan had soil pH 7.97-9.09, and the median pH of soil in maize, wheat and rice fields was pH 8.47-8.53, indicating that the soil was weakly alkaline or alkaline. The total Cu content in soil of maize, wheat and rice fields ranged from 11.70 to 30.40 mg/kg, with a median value of 20.95 to 25.32 mg/kg; the average value was 21.12 to 24.65 mg/kg, which was equivalent to the average content of soil Cu of 24 mg/kg in China. The available Cu content ranged from 0.74 to 7.51 mg/kg, and the median available Cu content in maize, wheat and rice plots ranged from 1.65 to 2.99 mg/kg. The ratio of available Cu to total Cu in maize, wheat and rice plots ranged from 6.32%-48.10%. The content of total Cu and available Cu were not high, but the proportion of available Cu was relatively high. The Cu content in maize, wheat and rice ranged from 1.20 to 3.24g, 4.11 to 11.70 and 14.80 to 53.21 mg/kg, respectively, and the median Cu content was 1.66, 5.95 and 27.80 mg/kg, respectively. Cu enrichment coefficient of crops was in the order of rice > wheat > maize, and Cu enrichment capacity of rice was much higher than that of wheat and maize. Analysis of influencing factors showed that soil available Cu content was significantly correlated with soil total Cu content, maize Cu content was significantly correlated with soil total Cu content, and rice Cu content was significantly correlated with soil organic matter content. However, the environmental factors including soil pH, CEC, available Fe, alkali-hydrolyzed N, available P, available K, available B, available Se and available Mo had no significant correlation with Cu uptake in maize, wheat and rice. Rice products in Shizuishan belong to high-quality rice rich in trace element Cu, and vigorously developing Cu-rich rice could provide safe, healthy and nutritious Cu-rich food for consumers.