Preparation Of Highly Efficient Biogas Fertilizer And Study On Its Application In Greenhouse Tomato

At present, China is the first of biogas application and one of the largest vegetableproducers of the world. Based on the increasing demand of pollution-free vegetables andenvironment friendly essence of the Biogas’ fertilizer, in this study, a novel highly efficientbiogas fertilizer was prepared by using raw biogas slurry as the main raw material and otherchemical fertilizers, such as nitrogen, phosphorus and potassium were used as secondaryraw materials. Both the nutrition and safety standard achieved the requirements of"Water-soluble fertilizers containing nitrogen, phosphorus and potassium（NY1107-2010）" and "Water-Soluble Fertilizers Containing Micronutrients（NY1428-2007）". Also, the efficiency of product biogas fertilizer was evaluated by study itseffect on the growth of greenhouse tomato plants, yield and fruit quality. In order toestablish the optimized application method of this fertilizer,3different fertilizationmethodology namely: root irrigation, foliar spray and combination of this two wereevaluated. The aim of this study was to explore a new environmental friendly ways toenhance the efficiency of biogas utilization thus to provide a theoretical basis and technicalreference for scientific and rational fertilization of crops. The main conclusions of the studyare as follow:1. The preparation of the high efficient biogas fertilizer was conducted by using biogasslurry as main raw material, using commercial chemical fertilizers, such as nitrogen,phosphorus and potassium as secondary raw material, in accordance with “Water-solublefertilizers containing nitrogen, phosphorus and potassium （NY1107-2010）" and"Water-Soluble Fertilizers Containing Micronutrients （NY1428-2007）" requirements.Reasonable compatibility was established during the preparation. After investigation ofstability of the nutrient content, an optimal formula was selected, for abundant elements（count with N, P₂O₅, K₂O content）, for instance, with the total amount of fertilizer at502.3g/L, the nutrient content ratio: N: P₂O₅: K₂O=4.86:2.47:1, PH=7.48. When thetemperature is below7℃, the formula fertilizer will have needle-like crystals precipitated, crystals will be dissolved as temperature increases, and trace precipitation left will not affectthe efficiency of the fertilizer. Results of germination rate and mortality rate of ascaris eggs,fecal coliform and total number of bacteria and measurements of other indicators indicatesthat, the development of high efficient biogas fertilizer is environmentally safe.2. Under the same conditions of basal fertilizer amount and other farming operations,the biogas slurry efficient fertilizer is proved to significantly promote the growth ofgreenhouse tomato plants. In the early stage of plant growth, compared to CK, TR2showedthe most significant impact on plant height, with a growth rate at54.34%; TR2and TR4showed the highest stem diameter growth rate amongst the five groups:23.63%and20.45%,respectively. But TR2stem diameter was significantly higher than TR4.3. The highly efficient fertilizer can enhance the tomato yield significantly, amongthese5treatments, the yield of TR4reached93.39t/hm²and was the highest, which is25%higher than that of the CK （74.57t/hm²）. Among each group, the tomato showed smallerdifferences in early yield but significant differences in post-production. After using thebiogas slurry high efficient fertilizer, tomato fruit showed higher uniformity in fruit size,smoother surface and the number of deformed fruit was significantly reduced than CK.4. The highly efficient fertilizer can improve the fruit quality of greenhouse tomato. Vccontent of TR2and TR4treatment are1.83times and1.87times of CK, respectively, whichwere significantly higher than other treatments. Although, the application of highly efficientfertilizer did increase the nitrate content in tomato fruit slightly, in which the nitrate contentof TR4treatment was21.31mg/kg and was the highest among all the treatments, but it’salso lower than the nitrate content in vegetables standard in China （≤440mg/kg）.5. Based on evaluation of tomato fruit yield and fruit quality, the best fertilizationmethod was TR4（combination of root irrigation and foliar spray） and the optimum amountof fertilizer was5833kg/hm².