Study On The Coated Compound Fertilizer In Tobacco Production

The application of compound fertilizer in tobacco production has become one of the best approaches to increase the efficiency of fertilizers and save the resources. However, most of the areas in Yunnan and Guizhou provinces, which are the two main districts of tobacco production,still use single fertilizer cooperately in fertilization and the effect of fertilizers used in this way is low and can bring serious pollution to the environment.This paper produced ammonium nitrate-based and urea-based compound fertilizers with different nutrient ratio by using agglomerated granulating method in rotary pan;a series of coated compound fertilizers with different coating rates were prepared in the rotary coating drum by using tung oil from natural product as major film-forming material;the slow release properties of the obtained (coated) compound fertilizers were evaluated by determining the rate of released nutrients in distilled water through the methods of weight and conductivity;the surface and section morphology of (coated) compound fertilizer granules were studied by scanning electron microscope(SEM);soil incubation and small scale of field experiments were conducted to study the effect of non-coated and coated compound fertilizers;the biodegradation behavior of the coated material was studied in the activated sludge and garden soil as two inoculums;the biodegradable degree was determined quantitatively by weight loss and CO₂ release test and studied qualitatively by scanning electron microscope.The results obtained in this study are as follows: wrapped compound fertilizer granules obtained in rotary pan , whose diameters are between 2 to 5mm, exceed 90% and this can meet the demands of GB and the experiment satisfactorily;the coating thickness of tung oil-coated compound fertilizer is up to 40¹80μm;the main factor which influences the nutrients release of the coated slow released fertilizer is the coating ratio;application of the ammonium nitrate-based compound fertilizers are better than urea-basedcompound fertilizers in the growth and yield whether coated or non-coated;taking coated ammonium nitrate-based and coated commercial tobacco compound fertilizer with N:P205:k20 are up to 1:1.90:2.17 and 1:1.13:2.61 respectively , the coating ratio are 9.37% and 8.63% for examples, the fertilization level are all 1. 2gN/basin, tobacco biological characteristics of the former is higher than the latter, whi le the difference of tobacco dried weight is not significant.The results in this paper show that after 12 weeks, the mass loss percentage of tung oil coated fertilizer capsule (global f i lm) can reach 31. 82% (providing oxygen) and 16. 24%( providing oxygen) in activated sludge with 1% concentration and 10²(w/v) garden soil solution inoculums;by the method of determining the amount of released C02, the biodegradation degree of tung oil coated fertilizer capsule is up to 3. 21% (providing oxygen periodically) and 1. 32%(not providing oxygen) in the two above inoculums after 148 days;this indicates that tung oil coated fertilizer capsule has good biodegradability and it is expected to be environment-friendly;the application of this kind of tung-oil coated compound fertilizers in tobacco production can provide good reference for how to improve the effect of fertilizers and fertilize scientifically and reduce the pollution which due to the excessive fertilization to the environment as well.