Distribution characteristics of soil Selenium and exogenous Selenium fertilizer enrich Selenium on soybean seeds in Nenjiang City

Abstract To study the background value selenium (Se) content in soil and the effect of exogenous Se application on increasing Se content of soybean seeds, 124 soil samples of different soil types were collected in Nenjiang city, Heilongjiang province, which is the primary soybean-producing area of China. The results showed that the soil Se content in Nenjiang city exhibited a range from 0.032 to 0.519 mg/kg, with an average of 0.206 mg/kg, which was lower than the average national Se content of 0.290 mg/kg. It indicated that the soil Se content in Nenjiang city belonged to low Se or Se deficiency level. Further more, the different soil types also showed different results on soil Se content, such as the meadow black soil was the lowest one (0.186 mg/kg) in Nenjiang City. To enhance the Se content of crop by spraying inorganic Se and organic Se fertilizers on leaves at different growth stages of soybean, the best effect on Se-rich soybean seed was spraying Se fertilizer at flowering stage, and the Se content in soybean seeds reached 0.260 mg/kg. It also promoted the yield by the range 2.4%-15.0%. Se-rich by exogenous application was the important way to increase Se content in soybean seeds, which provided theoretical support for the priority development of Se-rich soybean industry and special soybean planting in Nenjiang City.