Effects Of Applying Rice Hull Biochar On Soil Amelioration And Fruit Quality Of Nanfeng Tangerine

Nanfeng tangerine(Citrus reticulita Blanco cv.Kinokuni)cultivated in Nanfeng County,Jiangxi province,is China's Citrus varieties.However in recent years,Nanfeng tangerine appears a bad phenomenon of soil acidification,which seriously influenced the quality of Nanfeng tangerine fruit,decreased its economic value and will not be good to the further development of Nanfeng tangerine industry.In order to improve the soil quality of Nanfeng tangerine orchard and the quality of Nanfeng tangerine,this study mainly discussed the effects of applying biochar on Nanfeng tangerine orchard soil microbes,soil fertility and heavy metal element content,leaf mineral nutrition and its growth,as well as the growth and fruit quality of Nanfeng tangerine.This study has four treatments: CK,B,OF and B+OF.The results are as follows:(1)B,OF and B+OF have significantly increased the number of bacteria and fungi in the soil.B and OF suppressed the growth of actinomycetes,while B+OF remarkably promoted the growth of actinomycetes.(2)B,OF and B+OF increased the p H of the soil,therefore the effect of B is better than the other two treatments.B,OF and B+OF improved the soil hydrolysis N,effective phosphorus,available potassium,organic matter,exchangeable Ca,exchangeable Mg,effective B,effective Cu,effective Zn,effective Fe and effective Mn content.In terms of comprehensive,the effect of B+OF on soil nutrient was better than other treatments.(3)B,OF and B+OF reduced the amount of mercury,lead,chromium and cadmium in the soil,the effect of B and B+OF were both very significant.(4)B,OF and B+OF significantly improved the length and roughness of leaves,leaf area,blade length and width,fresh and dry weight of leaf blade,the effect of B+OF was better than other treatments.B,OF and B+OF also significantly improved the contents of N,P,K,Cu,Zn,Fe,Mn,Ca,Mg and B in the leaves,and the effect of B+OF was superior to other treatments.Biochar had no significant effect on the actual photosynthetic efficiency,electron transfer rate,the photochemical quenching coefficient,photochemical quenching,photochemical quenching coefficient,maximum photosynthetic efficiency,photochemical quenching.(5)B,OF and B+OF could promote the growth and development of Nanfeng tangerine and improve fruit quality.The weight of single fruit of B+OF was significantly higher than B,OF,CK during the growth and development of Nanfeng tangerine.B and B+OF significantly increased the brightness of the fruit.Compared with CK,B?OF and B+OF significantly reduced the shear force of fruit and improved fruit pulp mastication characteristics.Compared with CK,B could significantly improve content of vitamin C,soluble sugar and soluble solids in Nanfeng tangerine.B+OF significantly reduced titratable acid and citric acid content,and increased fructose,glucose and sucrose content in fruit.The ratio of sugar/acid and TSS/TA was significantly higher than other three treatments.There was no significant difference among the content of malic acid and quinic acid in each treatments.Effect of B+OF on fruit quality was better than other treatments.In summary,B improved p H of soil and color of fruit,decreased contents of heavy metal.B+OF improved growth of spring shoot and leaves and quality of fruit through increasing amount of microorganism,soil fertility,mineral nutrients of leaves and it was the optimum treatment.