Effect Of Combination Of Rice Husk Biochar And Organic Fertilizers On Soil Organic Carbon Fractions And Soil Microbial Community Of Apple Orchard

In order to improve soil quality in apple orchards in the Loess Plateau and improve fruit quality and yield, this study tried to explore the effect of rice husk biochar and organic fertilizers on soil organic carbon fractions, soil microbial community, growth and yield of apple trees in the orchards of Weibei dryland. The experiment consists of four treatments: CK(control), B(rice husk biochar alone), OF(organic fertilizers alone) and B+OF(rice husk biochar + organic fertilizers). Three years orchard experiments were carried out in Qianxian county, Shaanxi province, and soil samples were taken from 0-100 cm soil layers to study the effects of different treatments on various soil organic carbon fractions and soil microbial community. The main results are as follows:(1) B(rice husk carbon alone) and B+OF(rice husk biochar + organic fertilizers)treatments significantly increased contents of total soil organic carbon, particulate organic carbon, light fraction organic carbon, microbial biomass carbon, readily oxidizable organic carbon and dissolved organic carbon in 0-40 cm soil lavers compared with the control. In the0-20 cm soil layers, content of readily oxidizable organic carbon in B and B+OF treatments were significantly increased by 35% and 58% compared with CK, content of particulate organic carbon in 0-20 cm soil layers under B+OF, B and OF treatments increased by 0.44,0.24 and 0.138 g/kg, respectively compared with CK, content of soil total organic carbon under 0-20 cm soil layers in B+OF, B and OF treatments increased by 60.1%, 38% and 6.5%,respectively compared with CK.(2) After the application of rice husk biochar and organic fertilizer, the AWCD, Shannon index(H) and Richness index(S) in all the addition treatments was higher than the CK. the AWCD under B, OF and B+OF treatments were 1.3, 1.2 and 1.9 times more than CK,respectively. Shannon index(H) of B, OF and B+OF plots was 46, 46 and 85% greater than the control(CK), respectively. Application of rice husk biochar increased soil pH from7.49(CK) to 7.89(B) and 7.79(B+OF).(3) Plant height, stem diameter and annual shoots length of all rice husk biochar applied treatments were significantly higher than those of CK which plant height under B+OF, B andOF 26.4%, 19.4% and 15.7% were higher than that of CK, respectively; stem diameter under B+OF, B and OF was increased by 49.5%, 12.9% and 5%, respectively. B and B+OF were conducive to apple flower formation compared with Control, number of flower buds of B+OF was the highest. Yield of per apple tree of treatments B+OF, OF and B was increased by43.3%, 33.6% and 20.4%, respectively compared with CK.Application of rice husk biochar and organic fertilizers could improve content of soil organic carbon fractions and increase the diversities of soil microbial community, the utilization rate of carbon source, richness of soil microbial community and soil pH, as well as growth and yield of apple tree. Combination of rice husk biochar and organic fertilizers was the most effective agricultural method in the apple orchards in the Loess Plateau.