Study On Effects Of Irrigation And Fertilization Treatments On Quality, Soil Water And Nitrogen Use Of Two Vegetables

In this experiment, the effects of 5 water and nitrogen treatments (W1N1, W2N2, W3N3, W3N1, W3N2) on vegetable yields, quality .water and nitrogen use were studied in cauliflower and spinach grown in open land. The water flux and N leaching in 90cm soil , soil water use efficiency and soil nitrogen use efficiency were calculated. In addition, different treatments were evaluated multi-objectively and comprehensively by Grey Relativity Analysis. The main results are as follows:1. Except W IN 1 treatment of cauliflower got much less yields, the yields of all other treatments had no distinct difference.2. The shortness and excessiveness of water and nitrogenous fertilizer would reduce the content of water and total soluble solid, increase the content of acid within vegetable tissue products. The effects of nitrogenous fertilizer on the change of the content of VC, protein and nitrate in vegetable tissue product were greater than those of water. And increasing the supply of nitrogenous fertilizer would increase the protein and nitrate content of vegetables. Besides these, the soluble sugar and acid content of vegetables were influenced greatly by the interaction between water and nitrogen.3. The results of Grey Relativity Analysis on vegetable quality showed that the nitrogen was the most important affecting factor on quality and the proper irrigation would optimize vegetable quality. Taking into account of quality, W3N2 was the best in all of the 5 irrigation and fertilization treatments.4. The water store, the accumulated water flux of 90cm soil and the water consumption were positively effected mainly by irrigation and precipitation, and soil water use efficiency was correlated with water supply in reverse, while the effects of nitrate treatments were not distinct.5. Under a certain water and nitrate treatments, soil nitrate in open-land vegetable field would move down below 180cm soil.6. Big nitrogen supply would lead to low soil nitrogen consumption, soil nitrogen leaching andsoil nitrogen use efficiency. And nitrogen was the main affecting factor compared to water, but proper irrigation would reduce nitrate leaching and increase soil nitrogen use efficiency.7. Among the five treatments of W1N1, W2N2, W3N1, W3N2 and W3N3, W2N3 had the best economic and environmental benefits based on the results of Grey Relativity Analysis considering vegetable quality.