Abstract:

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.

Key words: Shizuishan, main grain crops, copper, absorption, influencing factors