Study On The Relationship Between Selenium And Cadmium In Root-crop System

Edible selenium-enriched agricultural products are an effective way to supplement selenium in science and health.Selenium in the soil migrates to the human body through the food chain.The lack of selenium in agricultural products directly affects the daily selenium intake level of the human body.In China,51% of the land is low in selenium and selenium,and there is still a large gap in the daily health of selenium.With the discovery of more selenium-enriched areas in the nationwide land survey work,the development and utilization of selenium-enriched land and the production of green and healthy selenium-enriched products have gradually become the focus of attention.Selenium-enriched soil is affected by heavy metals and human pollution,which is a problem that must be faced in the development of selenium-enriched industries.In this paper,four crops,rice,wheat,corn and rapeseed,which are widely grown in Xiantao area,and their corresponding root soils were studied.The relationship between selenium and cadmium in the root-crop system of selenium-enriched areas was explored in order to produce selenium-rich crops.Get the following main conclusions:(1)Soil selenium enrichment and heavy metal high value distribution are similar,there is a distribution pattern of upper and lower high and low middle.The high value area is mainly distributed in the alluvial belt along the River.It is speculated that the main material source is caused by the weathering and erosion of the black rock series in the upper Hanjiang River.(2)The whole selenium-enriched level of the crops in Xiantao area is high.The selenium-enriched soil and the acid-stained selenium soil are beneficial to the enrichment of selenium in rice.The selenium-rich ability of rapeseed is concentrated,and the excess selenium in rapeseed is concentrated in the high-value area of alkaline selenium.In neutral and alkaline soils suitable for wheat and maize growth,soil selenium content is above the level of selenium,and wheat and corn can reach selenium-enriched crops.(3)The cadmium exceeding standard in the Xiantao area is mainly concentrated in the slightly acidic soil.The agricultural cadmium risk control limit value is near 0.4mg/kg,and the crop has the risk of heavy metal pollution in the soil environment near the limit.(4)Synergistic analysis of root soil-crop samples found:Selenium was positively correlated with cadmium in rice seeds,and cadmium and selenium in rice had obvious synergistic effects,which was related to the high content of selenium in alkaline soil.Wheat is a selenium sensitive cereal crop with a higher level of selenium enrichment and a weaker cadmium enrichment ability.In alkaline soil,Se can promote the enrichment of selenium in wheat and inhibit the absorption of cadmium by wheat.The alkaline environment is more conducive to planting selenium-enriched wheat.There was a negative correlation between cadmium and selenium in corn seed,and selenium and seed cadmium in acid soil and alkaline soil.However,selenium and cadmium in soil had synergistic effect on selenium and cadmium in seed,comprehensive seed and soil.The interaction found that organic-rich selenium-rich neutral soils may be the best soil for producing selenium-enriched corn.There was a negative correlation between selenium and cadmium in rapeseed,and it had obvious antagonistic effect.Planting rapeseed in neutral selenium-enriched soil could reduce the enrichment of Cd by rapeseed,while the acidity and alkalinity of high cadmium and selenium were high.In the soil,especially in high-cadmium and high-selenium alkaline soil,the rapeseed planted may be rich in selenium but has a higher risk of exceeding cadmium.