Studies On Release Dynamics Of Available Nutrients From Fertilizers

Nitrogen, Phosphorus and Potassium are important for growth of crops. They cannot only increase yield of crops, but also ameliorate their qualities. They are importantto evaluate environmental pollution and yield of crops on using fertilizers. At thesame time, they can bring a lot of environmental problems, and they aredisadvantageous to growth of crops. If release characteristics of available nutrientswere very good, they could advance growth of crops, reduce environmental pollution,and bring many environmental benefit and social influence. Release characteristics ofavailable nutrients from fertilizers are important to judge release capabilities offertilizers, so determination of the fertilizer release curves can help us not only to geta better understanding of the characteristics of fertilizers, to match the releaseorderliness of fertilizers and requirement of crops, but also to optimize the relevantmanufacture process of fertilizers and further improve the quality of products.In this thesis, this is on the device of release characteristics of available nutrientsfrom fertilizers manufactured by myself. A comparative study of the releasecharacteristics of available nutrients from some fertilizers, such as chemical fertilizers(compound fertilizers, (NH4)2HPO3, CO(NH2)2, KCl), organic slow release fertilizersproduced by myself, biologic compound fertilizers produced by myself, organicenveloping fertilizers produced by myself was performed using a method of therelease of available nutrients at constant solution flow of 58±1mL·d-1 and ofdetermining the contents of N, P, K in pouring liquid. At the same time, releasedynamics was simulated and analyzed by two different simulating methods. Thecontent of N in pouring liquid was performed using distillation and titration of GB/T8572-2001, and the content of P, K in pouring liquid was performed using ICP-AES.The obtained experimental results indicated that chemical fertilizers, Nitrogenand Phosphorus release of compound fertilizers, Potassium release of KCl are verygood, they are all in the first stage, release characteristics of available nutrients arevery fast, and they are slow and persistent time is long;Release effects of organicslow release fertilizers are better than chemical fertilizers, their release time is long, itis propitious to advance the absorbability and growth of crops;Release curves oforganic enveloping fertilizers are smoothness and slowness, moreover the releaseeffect of wrapping CuSO4 fertilizers is better than wrapping S fertilizers and wrappingPolyvinyl Alcohol fertilizers. At the same time, simulation and analysis of releasedynamics are from two different aspects. But they are current, in other words, it isaccordant of release velocity on a certain time. The typical dynamics equation:dynamics equation of release characteristics of available nutrients from biologiccompound fertilizers.1.Dynamics equation of NBeeline equation: lnCN(mmol/L)+0.38t=6.58 (t≤12d)lnCN(mmol/L)+0.20t=4.38 (12d