| The polymeric slow-release fertilizer containing iron-manganese-copper-zinc wasprepared with urea, formaldehyde and the dihydrogen phosphate of these four elements as rawmaterial. The structure of the fertilizer was characterized by the Fourier transform infraredspectroscopy (FT-IR), and the weight and molecular weight distribution of it were determinedby gel permeation chromatography (GPC). Through orthogonal and optimization experiments,the optimum reaction condition for synthesis of polymeric slow-release fertilizer containingiron-manganese-copper-zinc was obtained as follows: the ratio of urea and formaldehyde (U/F)was1.6, temperature of addition reaction was30℃, time of addition reaction was80min,temperature of condensation reaction was50℃, time of condensation reaction was30min,gel temperature was70℃, drying temperature was80℃, under this condition, the cold andthe hot water solubility of the polymeric slow-release fertilizer containingiron-manganese-copper-zinc was24.4%and77.2%, respectively.The polymeric slow-release fertilizer containing boron was prepared with urea,formaldehyde, boric and potassium hydroxide as raw material. The structure of the fertilizerwas characterized by the Fourier transform infrared spectroscopy (FT-IR), and the weight andmolecular weight distribution of it were determined by gel permeation chromatography (CPC).Through optimization experiments, the optimum reaction condition for synthesis of polymericslow-release fertilizer containing boron was obtained as follows: the ratio of urea andformaldehyde (U/F) was1.25, temperature of addition reaction was30℃, time of additionreaction was80min, temperature of condensation reaction was60℃, time of condensationreaction was40min, gel temperature was70℃, drying temperature was80℃, under thiscondition, the cold water solubility and the hot water solubility of the polymeric slow-releasefertilizer containing boron was23.8%and76.9%, respectively.Water incubation was adopted to research the nutrient release characteristics of thepolymeric slow-release fertilizer containing trace elements, and the nutrient release dynamic was analyzed. The results indicated that the nutrient release curves and the weight loss ratechanging curve were reverse “L” pattern for polymeric slow-release fertilizer containingiron-manganese-copper-zinc, the cumulative release rate of N, P and weight loss rate were49.0%,100%and62.8%after120days, Fe, Mn, Cu and Zn released completely after30days.The release curves of N, B and the weight loss rate changing curve of polymeric slow-releasefertilizer containing boron were reverse “L” pattern, the cumulative release rate of N and Breached49.2%and43.1%after120days, and weight loss rate were42.0%, K releasedcompletely after10days. The Elovich equation can well describe the nutrient release patternsof polymeric slow-release fertilizer containing trace elements.Soil incubation were adopted to research the nutrient release characteristics ofpolymeric slow-release fertilizer containing iron-manganese-copper-zinc under different soilmoisture, and the nutrient release dynamic was analyzed. The results were summarized asfollows:(1) With the time prolonging, the content of NH4+-N in the soil showed the trend ofincrease-decrease-increase-decrease, while the content of NO3-N, available phosphorus, iron,manganese, copper and zinc were increase gradually, the cumulative release rate of everynutrient elements increased gradually, Fe, Mn, Cu and Zn released completely after90days.(2) With the increase of soil moisture, the content of available phosphorus, iron, manganese,copper, zinc were all increased, the soil moisture of80%and60%were more conductive tothe accumulation of NH4+-N and NO3-N, the accumulation release rate of P, Fe, Mn, Cu andZn increased with the increase of soil moisture, and the order of N accumulation release ratewas60%>80%>40%, the order of weight loss rate was the same as N.(3) The polymericslow-release fertilizer containing iron-manganese-copper-zinc has little effect on the soilpH.(4) The Parabola equation, first-order kinetics equation and Elovich equation could welldescribe the nutrient release patterns of polymeric slow-release fertilizer containingiron-manganese-copper-zinc in the soil with the moisture contents of40%,60%and80%.Pot experient of cole were adopted to study the fertilizer efficiency of polymericslow-release fertilizer containing iron-manganese-copper-zinc. The results showed that theheight, yield and nutrient absorption of cole under different treatment were all had an order as:common compound fertilizer mixed with trace element (CCFW)> common compoundfertilizer (CCF)≈polymeric slow-release fertilizer containing iron-manganese-copper-zinc(SRMF)> blank control (CK), the content of nitrogen, phosphorus and potassium in the soil of pot experient were all had an order as: SRMF>CCF>CCFW>CK, while the order of thecontent of iron, manganese, copper and zinc were as the follow: SRMF>CCFW>CK>CCF.,these can be seen that the addition of trace elements could promote the growth anddevelopment of cole, and increase the soil fertility at the same time. |
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