Effects Of Cadmium Content And EM On The Safety And Quality Of Spinach

Cadmium (Cd) has a strong migration and toxicity in soil environment. Spinach which is one of the common green vegetables with rich nutrients is widely planted for its growth period is short and can be cultivated in four seasons. But spinach has a strong ability to absorb Cd and it is easy to be contaminated by cadmium. EM species is a group of bacteria, which is composed of a variety of microorganisms. It has a powerful function to decompose soil organic matter, and it also has the function of oxidizing and curing the heavy metal. Therefore, in this paper, a pot experiment was conducted to study the effects of different cadmium levels on the growth, chlorophyll, cadmium content and nutrients of spinach from the perspective of food safety. At the same time, the characteristics of Cd ions in the soil of EM were studied, which could provide scientific suggestion for improving the hygienic quality of agricultural products and food habits in high pollution area.(1) The results of the study about the level of different cadmium concentrations on spinach growth affects:with the increase of cadmium concentration, there is a trend which spinach shoot and root fresh weight, dry weight was gradually decreasing; and when the Cd concentration up to 15 mg/kg, indicators of various biomass decreased significantly and reached significant level; also with the increasing concentration of CD, spinach plants in total chlorophyll content continued to decline; there is a slight increase and a decrease when the concentration of cadmium reached in 1?10mg/kg. The overall root cap ratio is not obvious, but control comparison showed a significant downward trend;when the Cd concentration in 15mg/kg, root shoot ratio decreased significantly; spinach part and underground part of the cadmium content in constantly increased significantly, and the underground part of the root of Cd content were higher than that of spinach in Soil. The content of active Cd in spinach was also significantly increased, and the enrichment ability of the ground and the roots of the spinach was gradually weakened. The enrichment ability of the root of spinach was greater than aboveground parts of the spinach, and the transfer coefficient of the upper part was greater than the root; the effect of low concentration on a large number of nutrients is small. but the effect of high concentration is relatively large; The content of Fe and vitamin C was inhibited by it, but the effect of Zn was promoted.(2) The results of EM on the release of cadmium from spinach experiment:The effect of EM on the release of Cd in soil was obvious. The higher the concentration of EM, the less Cd content in spinach plants, when the concentration of EM reached 2%, the content of the plant reached the lowest; when the cadmium concentration is15mg/kg, the addition of EM can decrease the content of Cd in the plants, but the content of Cd in spinach plants increased significantly when 50mg/kg; The content of Cd was the lowest when spinach was add to EM in every stage; Finally, the orthogonal test results show that:the inhibition of Cd on the absorption of Cd by EM was the best in the whole period of EM.When the concentration of Cd in the soil was at the low concentration of lmg/kg, the amount of the spinach plants was low regardless of the concentration of EM or the time of the application. When the concentration of Cd in soil reached 10mg/kg or 15mg/kg, no matter how high the concentration of EM and whatever the application period is, the adsorption capacity of spinach plants was relatively high.