Study On The Making Of Fly Ash Slow Release Fertilizer And Its Effects On Crop Growth

There are the low fertilizer use efficiency and environmental problems in agricultural. Carrying out of slow/controlled release fertilizer is becoming a hot topic in academic research. On the one hand, slow/controlled release fertilizer can be made by hydrophobic low permeability of the membrane covering up the fertilizer; on the other hand, it can be made by adding the inhibitor to improve nutrient utilization and crop production. In this experiment, we used the method of indoor simulation combining field experiments. We made homemade slow release fertilizer by using four kinds of inorganic mineral material and nitrification inhibitor dicyandiamide. And the physical and chemical properties of fertilizer, nutrient release characteristics and biological effects were studied. The main results are as follows:1. Several kinds of fertilizers were made by using four types of another inorganic mineral material and organic binder by an open disc granulation process. The results showed that the best material was flying ash and particle size less than 90μm particle content 36.8% by laser particle size analysis. The performance was flying ash> talc> kaolin> diatomaceous earth of fertilizer through determing and analyzing the grain rate, compressive strength, wear resistance, cracking and rate of fertilizer membrane shell 800-time and 1200-time magnification image scanning.2. Fly ash as the best performance coating materials was selected. In soil column leaching experiment, the nutrients release characteristics of three kinds of slow-release fertilizers with coating thickness, which were 15%, 20% and 25% were studied. The results showed that after 28 days, the EC, NH4 +-N, NO3 - -N in leaching solution of fly ash coated fertilizer was higher than ordinary fertilizer treatment. The homemade coated fertilizer can reduce nitrogen, phosphorus and potassium leaching rate. In addition, the nitrogen, phosphorus and potassium leaching curves a quadratic equation.3. A field experiment was conducted to study effects of the coated controlled release fertilizers on physiological characteristics, yield and quality of the Chinese cabbage growing in the field. Results show that the fertilizers increased chlorophyll content, photosynthetic rate, transpiration rate and stomatal conductance and decreased stomatal limitation (Ls) in the leaves of the plant during its late growth stage, and improved the plant parameter characteristics, and biomass per head by 0.10～0.33 kg, yied by 9.72%～33.1%. In addition, the coated controlled release fertilizers decreased NO3--N significantly and organic acid contents by a certain extent in the functional leaves of the plant, and improved sugar-acid ratio and soluble sugar and Vc contents of the head of the plant at the harvest stage.4. New dual-release coated slow release fertilizer was made through adding the nitrification inhibitor to fly ash, and further studies on soil nutrient content and its enzyme activity. The results showed that the homemade coated slow release fertilizer with the addition of nitrification inhibitors, which were 1%, 2% and 4% improved soil pH, and increased soil EC, NH4+-N, available P and K content, and decreased NO3--N content at maize growth stage. The three kinds of homemade slow release fertilizer also enhanced urease activity and acid phosphatase activity by a certain extent, but there was no significant difference in catalase activity among the six treatments. In the summary, the treatment by adding 4% nitrification inhibitors improved the soil nutrient content and activity best.5. We further studied the effect of the homemade coated slow release fertilizer on the growth effect of maize in the field. The results showed: compared with ordinary compound fertilizer, the three kinds of fertilizer significantly improved the performance of maize photosynthesis and chlorophyll fluorescence; improved maize SOD, POD and CAT activity and soluble protein content; significantly improved the agronomic traits of maize, increased maize starch, protein and vitamin C content at late stage. In addition, compared with ordinary fertilizer, the three kinds of homemade slow release fertilizer increased maize grain yields by 24.0%, 31.4% and 35.8%, biomass increased by 57.2%, 64.6% and 74.4%; nitrogen utilization of the season increased by 1.24%～19.02%, P increased by 7.35% ~ 11.23%, K increased by 15.77% ~ 23.84%.