Study On Soil And Crop Effects Of Biochar And Organic Fertilizer Made By Brewery-Waste

Chemical fertilizers play an important role in improving the growth,development,yield,and quality of crops.The application of chemical fertilizers in large quantities is quite common in agriculture.However,long-term and massive use of chemical fertilizers negatively influences the physical,chemical,and biological properties of soils,reduces soil fertility,and is unconducive to maintaining the stable and high yield of crops.In addition,the entrance of nutrients into rivers and lakes leads to eutrophication due to the leaching following chemical fertilization in soils.Thus,the Ministry of Agriculture and Rural Work of China has proposed the zero growth action of chemical fertilizers by advocating the use of organic and new fertilizers instead of chemical fertilizers.China is the largest country for producing and consuming liquor in the world.Of this,Luzhou flavor Baijiu amounts to more than 70% of the total liquor.For brewing each ton of Baijiu,3-3.5 tons of distiller grains are produced.Thus,40 million tons of distiller grains are produced every year in China.In the distiller grains of Luzhou flavor Baijiu,the proportion of chaff accounts for 70-75%,which is tightly combined with starch and protein and difficult to separate.Due to the low nutritional value for animals,poor palatability,and damage to the digestive systems of livestock,these solids can only be used as auxiliary feed for addition in a small amount.The distiller wastes are rich in water,low in p H,easy to deteriorate,and thus need drying when used as auxiliary feed.The economic benefits of drying the distiller wastes for auxiliary feed can’t make ends meet.Currently,factories that produce Luzhou flavor Baijiu have to incinerate and bury the distiller grains,wasting nutrients and organic matter resources.Given this,the Ministry of Science and Technology of China financially supported and issued the research project "thermochemical energization and recycling technology of distillery waste" in 2018 to produce biochar and organic fertilizer from distiller grains.In the current experiment,both of them were prepared from these solid wastes in Luzhou Laojiao Co.,Ltd.A 2-year field experiment was carried out to evaluate their impact on the soil as well as crop yield and quality in the rape-sorghum rotation system.The chief objective is to provide a scientific basis for the application of biochar and organic fertilizer in agriculture.The main findings are as follows:(1)When the distiller grains were pyrolyzed at different temperatures,biochar cracked at 480 ℃had the best porous structure on the surface,p H 10.1,larger cation exchange(33.41 cmol/kg),and more carbon and nutrients(nitrogen,phosphorus,and potassium)retained.Thus,480 ℃-pyrolyzed biochar had excellent physical and chemical properties in terms of agricultural use.(2)Compared with chemical fertilization alone,chemical fertilizers combined with biochar significantly increased carbon,microbial biomass carbon and nitrogen,as well as the activities of sucrase and phosphatase in the soil.Available nitrogen,phosphorus,and potassium were higher or similar to those of chemical fertilization alone.These results indicated that some carbon in the biochar could be used by microorganisms,promoting their growth and reproduction,enhancing soil enzyme activity,and improving nutrient bioavailability in the soil.(3)Compared with only chemical fertilizers,applying chemical fertilizers together with biochar increased the yield of rape by 9.3% and sorghum by 9.5% in the first year.However,there was no significant difference between them in the second year.(4)In the treatment of organic fertilizer plus chemical fertilizers,soil organic matter and available nutrients(nitrogen,phosphorus,and potassium)were higher or similar to those of chemical fertilizers alone and only organic fertilizer.Compared with chemical fertilizer alone,however,organic fertilizer plus chemical fertilizers remarkably increased the microbial biomass carbon and nitrogen as well as the activities of enzymes(including phosphatase,urease,and sucrose)in the soil.Thus,soil microorganisms may be positively sensitive to organic fertilizers,promoting their growth and propagation by the improvement of the soil ecosystems,which is beneficial to improving soil nutrient bioavailability.(5)Compared with only organic fertilizer,rape yield was increased by 14.6% in the first and 23.0%in the second years,respectively,by organic fertilizer in combination with chemical fertilizers(organic N: inorganic N=1:1).Organic fertilizer plus chemical fertilizer also enhanced the yield of sorghum by55.8% in the first and rape by 4.7% in the second year,respectively.On the other hand,the crop yields changed little,if any at all,between chemical fertilization alone and organic fertilizer plus chemical fertilizer for the two consecutive years.