Adsorption Characteristics Of Diatomite And Modified Sepiolite To N,P,K And Effects Of The Compound Fertilizer On Growth Of Maize

In order to improve the using efficiency of N, P, K compound fertilizer, and obtain the optimum proportion of diatomite, modified sepiolite and N, P, K in compound fertilizer, the diatomite, modified sepiolite were conducted as adsorption agent and slow-release agent in this experiment. The adsorption characteristics of diatomite and modified sepiolite to N, P, K and effects of the compound fertilizer on growth of maize were measured in the meantime. The results are showed as follows.(1) Adsorption time and initial concentration of nitrogen, phosphorus and potassium had important influence on adsorption characteristics of diatomite and modified sepiolite. When the oscillation continued for 4 hours at 25? under the initial concentration of NH4CI and KCl of 60 mg·L-1, the adsorption rates of diatomite to N and K reached the maximum of 12.80% and 17.26%, the adsorption rates of modified sepiolite to N and K reached the maximum of 19.22% and 14.75%. When the oscillation continued for 6 hours under the initial concentration of Ca(H2PO4)2 of 60 mg·L-1, the adsorption rates of diatomite and modified sepiolite to P reached the maximum of 35.42% and 13.42%.(2) Diatomite and modified sepiolite slow-release fertilizer could effectively improve available N, P and K content in soil. Among all the treatments, the proportion of diatomite: modified sepiolite:urea:calcium superphosphate:potassium chloride with 3:3:17.3:9.3:9.6 in compound fertilizer had the best slow-release effect. Compared with the control, the available N, P and K content in soil increased 35.68%,92.17% and 17.12% respectively.(3) Diatomite and modified sepiolite slow-release fertilizer could effectively improve net photosynthetic rate, chlorophyll content and N, P, K content of maize leaves. The maximum net photosynthetic rate increased 10.52%, the maximum chlorophyll content increased 81.34% and the maximum N, P, K contents in leaves increased 94.79%,36.36% and 34.51% respectively.(4) Diatomite and modified sepiolite slow-release fertilizer could effectively improve the yield and dry matter weight of maize. The maximum yield and dry matter weight of maize increased 34.13% and 11.46% respectively.