Effects Of Biogas Slurry And Bamboo Char On Dynamic Changes Of Soil Fertility, Rice Yield And Nutrient Uptake By Rice Plants

A field experiment was conducted to study effects of biogas slurry and bamboo charon soil fertility, dynamic changes of soil nutrient content during rice growth as well as riceyield and nutrient uptake by rice plants.Results showed that:（1） The proper amount of biogas slurry improved soil physical and chemicalproperties. Soil organic carbon content was increased, soil available nitrogen andphosphorus were improved too. Based on equal rate of nitrogen application, similar ricegrain yield was achieved between the conventional fertilization （chemical fertilizer）treatment and the treatments of basal fertilizers applied with halved chemical fertilizercombined with another half nitrogen supplied by biogas slurry, or total nitrogen solelysupplied with biogas slurry applied as basal fertilizer for rice growth. It was proved thatchemical fertilizers could be substituted in the relatively fertile soil with biogas slurryfertilizer, so that to reduce the cost while soil fertility was improved. Consequently,environmental pollution risk was decreased and carbon emission was reduced bydecreasing application of chemical fertilizers. Bamboo char could improve soil organiccarbon content, and soil available nutrients of nitrogen, phosphorus and potassiumsignificantly. Therefore, the application of biogas slurry and bamboo char to rice fieldcould be a positive way to develop low-carbon and organic agriculture.（2） There was a large number of the total microbial population in the soil regardlessdifferent treatments, and the microbial community structure under different fertilizationsystems had a higher degree of similarity. However, it showed that there was also differentbands among the treatments, indicating that there was certain impact on soil microbialcommunity structure and diversity under the different fertilizer treatments. Under thebiogas slurry treatment, microbial diversity and evenness was high, and this was littleaffected by application rate of biogas slurry. Treatment of （CF+C3）, which was chemicalfertilizers with applying high rate of bamboo char (6750kg·hm^-2) had the highest soilmicrobial diversity compared with other treatments.（3） When basal fertilizers solely supplied with biogas slurry, the higher rate wasfavorable to increase nitrogen in brown rice Yet too much of biogas slurry (12529kg·hm^-2)would result in decrease of nitrogen in brown rice. Effect of bamboo char varied with itsapplication method. Concentration of nitrogen in brown rice was decreased by applicationof bamboo char mixed with chemical fertilizers. By contrast, treatment of mixed bamboochar, biogas slurry, and chemical fertilizers increased nitrogen in brown rice.