The Study On Nitrate Accumulation Control Measurements In Leaf Vegetables In Facilities

Leaf vegetables easy-enriched nitrate,81.2%nitrate intake in the human body come from vegetables.Nitrate is the precondition of carcinogenic nitrosamines, long-term intake will affect people’s health. Therefore, this study take garden chrysanthemum, Spinach, Chinese cabbage and celery as test materials, through the regulation of light, water, sowing date and other factors and increasing phosphate fertilizer, potash fertilizer, organic fertilizer and inorganic feilizer means to study the mechanism of nitrate accumulation and methods of control for leaf vegetables safe and stable to provide a theoretical basis.Through the test we can draw the following conclusions:(1Illumination,water and seedtime have influence on nitrate accumulation in leafy vegetables, performance in high light intensity is beneficial to reduce the nitrate content of chrysanthemum, spinach and Chinese cabbage, but celery is less affected by the illumination. More moisture content is beneficial to reduce the nitrate content of chrysanthemum, spinach, celery in the body, and spinach’s nitrate content is the minimum in the case of60～70%water content. Sowing in June chrysanthemum, spinach, Chinese cabbage’s nitrate accumulation significantly more,while less sowing in March. Therefore,the reasonable control of the external environment condition is pay attention to the control of light intensity, soil moisture, reasonable arrangement of seeding time, it has a very important role in the quality and yield increase of leaf vegetables.(2) The phosphorus and potash fertilization can significantly reduce nitrate accumulation in leafy vegetables. The application of P effectively reduce the nitrate accumulation, the accumulation of nitrate is the lowest when fertilizer P2O56g/m2.A suitable amount of k fertilizer for lower leaf vegetables nitrate content is application of K2O11.25g/m2. When combined application of NPK, the most suitable proportion of NPK is N9.2g/m2, P2O56g/m2, K2O15g/m2for chrysanthemum and celery, while the most suitable proportion of NPK is N9.2g/m2, P2O56g/m2, K2O11.25g/m2for spinach and Chinese cabbage. Concentration using rational fertilization, combined application of NPK fertilizer and other measures to help improve the quality and yield of leafy vegetables,and the excess will be counterproductive.(3) To some extent, suitable amount of organic fertilizer applied can reduce nitrate accumulation in leafy vegetables.Chrysanthemum and Chinese cabbage’s nitrate content is the lowest in the case of organic fertilizer and inorganic fertilizer1:1ratio,while spinach and celery are shown as the more proportion of organic fertilizer the less nitrate content they have. Comprehensive consideration the equal total amount of nitrogen, appropriate increase organic fertilizer can reduce nitrate accumulation, but the proportion of organic fertilizer will reduce leaf production exceeds70%,we can take organic fertilizer and inorganic fertilizer proportion of1:1to use for production.(4) Suitable amount of bacterial manure application can effectively reduce the nitrate content of leaf vegetables. Under the application of bacterial manure fertilizerl.5g/m2,the nitrate accumulation of spinach is the least, while2g/m2for chrysanthemum, Chinese cabbage, celeryis the best. Suitable amount of bacterial manure application can improve the GS activity, soluble protein content,root activity and yield, etc., so the production of bacterial manure fertilizer application should be appropriate, to improve the yield and quality of leaf vegetables have certain effect.Above all, light, moisture, sowing date, phosphorus,potash,organic fertilizer and bacterial manure all have a certain influence on nitrate accumulation in leafy vegetables.We can infer the nitrate accumulation mode of regulation through that. When production, by increasing light intensity, improve the soil moisture content, select suitable sowing date, plant avoid high temperature to reduce the leaf vegetables nitrate accumulation in the body. In the application of fertilizer, through NPK fertilizer combined application, organic fertilizer and bacterial manure fertilizer application, right amount increasing researches can effectively reduce the leaf vegetables nitrate content, improve the yield and quality of leaf vegetables, achieve a high yield production.