Effect Of Application Of New Kinds Of Organic-inorganic Mixed Fertilizers On Growth Of Spinach And Pakchoi And Soil Nitrogen Supply

The ratio of nutrient input to the field supplied by traditional organic fertilizer was dramatically decreasing owing to the limits of it in recent years. At the same time the improper application of chemical fertilizer causes some serious problems, such as environmental pollution, global warming, et al.. Therefore new kinds of organic fertilizers or organic-inorganic mixed fertilizers (commercial organic manure) are needed to make to overcome the shortcomings of the traditional one. Three pot experiments were conducted to study the effect of application of the organic-inorganic mixed fertilizers newly made by our research group on growth, yields of spinach and pakchoi and soil nitrogen supply.The organic fertilizers, organic-inorganic mixed fertilizers and urea were applied at a rate of 60 mg N kg-1 soil and no fertilizer was applied in CK. Fresh weight and nitrogen uptake of spinach and pakchoi, nitrate and Vc content of spinach, soil mineral N and soil microbial biomass N were determined during the growth of the two vegetables. The results obtained are showed as follows.1 The fresh weights of spinach and pakchoi were increased by112% and 178% respectively in the application of the organic fertilizers and organic-inorganic mixed fertilizers compared with CK and they were also increased by 0.77 and 1.03 times of those in the treatments with urea alone respectively, demonstrating that the organic-inorganic mixed fertilizers newly made have the same effect on the growth of vegetables as chemical fertilizer (urea).2 The nitrogen taken up by two vegetables in the application of these new kinds of organic fertilizers and organic-inorganic mixed fertilizers were 91% and 149 % higher than those of CK respectively, and 92% and 114% of those of the treatments with urea alone respectively.3 The soil mineral N of the treatments applied with these new kinds of organic fertilizers and organic-inorganic mixed fertilizers were 89.8% and 78.9% higher than thoseof CK during the whole growth period of the two vegetables respectively, 202% and 220% higher than those of original soil samples used in the experiments respectively. And the changing range of soil mineral N in the application of these new kinds of organic fertilizers and organic-inorganic mixed fertilizers were 57.1% and 38.8% lower than those of the treatments with urea alone respectively. To sum up, the application of these new kinds of organic-inorganic mixed fertilizers could maintain a good model of soil mineral nitrogen for the requirement by the vegetables.4 The changing range of soil microbial biomass N in the application of these new kinds of organic fertilizers and organic-inorganic mixed fertilizers were 223% and 149% larger than those of the treatments with urea alone respectively. This means the higher nitrogen buffering capacity of the soil could be obtained with the application of organic fertilizers and organic-inorganic mixed ferilizers. Hence, the application of these new kinds of organic fertilizers and organic-inorganic mixed fertilizers synchronized the soil nitrogen supply with the requirement by spinach and pakchoi and thus, greatly improved the soil nitrogen supply.5 The application of new kinds of organic fertilizers and organic-inorganic mixed fertilizers decreased the nitrate content of the vegetables by 10.1% and 16.2% compared with the application of urea alone. And the Vc content of the treatments applied with new kinds of organic fertilizers and organic-inorganic mixed fertilizers were slightly lower than those of CK and the treatments with urea alone.To conclude, the application of new kinds of organic-inorganic mixed fertilizers could improve the soil nitrogen supplying characteristics and synchronize the soil nitrogen supplying process with the requirement by spinach and pakchoi. Almost the same yields of spinach and pakchoi could be obtained in the application of these new kinds of organic-inorganic mixed fertilizers as those in urea application alone. And better spinach quality could be got in the application of these new kinds of org...