Preparation And Evaluation Of Organic-inorganic Complex Materials Felted And Coated Slow/Controlled Release Fertilizers

Developing better quality/price, simple preparation techniques and environmental friendly felted and coated slow/controlled release fertilizer is one of types for future fertilizers. The thesis prepared four kinds of organic-inorganic complex felted and coated slow/controlled release fertilizers which were environmental friendly and different quality/price and whose performance was appraised in lab and farm. Through leaching experiment in different mediums, we chose out two kinds of mediums in which nutrient dissolved ratio of fertilizers could be measured and provided new way and basic data for establishing measure method of slow/controlled release fertilizer trades and enterprises. In this paper, the main results and conclusions were as follows:1. Preparation and test of organic-inorganic complex material felted and coated fertilizersThe thesis prepared four kinds of organic-inorganic complex felted and coated materials that were environmental friendly and different quality/price with chemical reaction, micro-emulsification and high speed cut techniques, making organic polymer dissolve into water, choosing and matching different coated materials. Using these materials, the thesis adopted disk-sprayer making granule techniques to developed organic-inorganic complex material felted and coated fertilizers: acrylate(B2),dumped plastic(PS),unsaturated polyester(F2),humic acid(F2F). The performance was B2>PS>F2>F2F through analyzing their making granule rate, compression strength, abradability, water absorbency, and membrane.2. Nutrient dissolved ratio of fertilizers under different leaching mediumsCompared to NPK treatment, the differences of dissolved ratio of nitrogen, phosphorus and potassium in same sand column were significant for B2,PS,F2,F2F. The slow release performance was B2>PS>F2>F2F. For same felted and coated fertilizer, the shape of nutrient dissolved curves were similar in different sand column but dissolved ratios were not. The accumulated dissolved ratios of nitrogen were obvious negatively correlation to sand size(r: -0.8630～-0.9717), and incorrelate to potassium. The dissolved and accumulated dissolved ratios of phosphorus were all incorrelate. The accumulated dissolved ratios were N>K>P.The dissolved curves of nitrogen and potassium of B2,PS,F2,F2F in same soil column were similar to that of in sand column, and difference was only dissolved time. The peak time of phosphorus was later than that of nitrogen and potassium. The differences among B2,PS,F2,F2F in same soil column were same to that of in sand column. To same felted and coated fertilizer, nutrient dissolved ratios were different in three soils. The accumulated dissolved ratios for nitrogen and potassium were red soil>drab soil>black soil, for phosphorus it was drab soil>red soil≈black soil.3. Choosing out two kinds of appreciation medium of measuring nutrient dissolved ratios fast and rationally for organic-inorganic complex material felted and coated fertilizers. Then forecasting equations were established.Nutrient dissolved ratios were similar both in 0.25mm～1mm diameter sand column and in drab soil and black soil column(R²: 0.5224**～0.9710**), so was in 0.16mm～0.25mm diameter sand column and in red soil column(R²: 0.4502*～0.9720**). With accumulated dissolved ratios in sand column and its corresponding soil column, we established nutrient dissolved forecasting equation in soil column.4. Nutrient dissolved ratios of organic-inorganic complex materials felted and coated fertilizers in different soils and their effects on soil available nutrition.Compared to NPK treatment, the differences of dissolved ratio of nitrogen, phosphorus and potassium in soils and available nutrition were significant for B2> PS> F2> F2F. The shape of dissolved curves of nitrogen, phosphorus and potassium of B2, PS, F2, F2F in same soil were similar to that of in same sand column, but differences were only dissolved time and ratios. The peak time of B2 was in 50d and PS,F2,F2F in 35d.The slow release performance was B2>PS>F2>F2F. The peak time of nutrient dissolved ratios for same coated fertilizer was same in three soils, but nutrient dissolved ratios were different before and after peak. The accumulated dissolved ratios of nitrogen were in red soil>in drab soil>in black soil; in black soil >in drab soil> in red soil for potassium, but the differences were little; in red soil>in drab soil>in black soil for phosphorus, but the differences were little in drab soil and black soil.The change of soil available nitrogen and phosphorus appeared that slow dissolved initially, peaked mid and descended after peak, their peak time was later than that of nitrogen and phosphorus of coated fertilizers. Available nitrogen and phosphorus of B2 was in 65d, PS,F2 and F2F in 50d. The peak time was same in three soils for same coated fertilizer. Before peak, available nitrogen was in red soil> in drab soil and black soil; after peak, it was opposite gradually; the peak of available nitrogen was in red soil< in drab soil and black soil. The change of available nitrogen in black soil was reverse to that of in red soil, and available nitrogen content in drab soil was between red soil and black soil. Available phosphorus content initially was in black soil >in drab soil> in red soil before peak and after peak it was the same. The peak of available phosphorus content in red soil was the highest, but it was not obvious in black soil and drab soil.5. The effects of felted and coated fertilizers on crops and their economic benefits analysis.Compared to NPK treatment, B2,PS,F2,F2F increased yield(4.9%～19.84%) and nutrient recovery(2.08～24.27 percentage point), and reduced leaching amount of NO₃^- -N(3.98～9.64 percentage point), and enhanced nutrition and process quality of wheat and corn. The leaching amount of nitrogen, phosphorus and potassium in drab soil column was obvious negative correlation to yield and their recoveries(r: - 0.8632～-0.9593), however, the recovery of nitrogen, phosphorus and potassium was obvious positive correlation to yield(r: +0.9815～+0.9995). The correlate content of nitrogen, phosphorus and potassium was different. Net benefits all increased for fertilizer treatments compared to blank. Net benefits of B2,PS,F2,F2F were higher than that of NPK treatment, but increasing content was different(573～1736 yuan/hm²). Only input/output ratios of B2 and PS were higher than that of NPK treatment.Generally speaking, B2,PS,F2,F2F had different slow release performance and quality/price, increased nutrient recovery, crop yield, and quality and alleviated environment pollution.