Effects Of Biochar, Organic Fertilizer Under Different Treatments On Growth And Rhizosphere Environment Of Grape Seedlings

The objectives of this experiment were to study the effect of biochar and organic fertilizer under different treatments on growth and rhizosphere environment of grape seedlings.The experiment was done by taking 1-year old V.vinifera cv.Flame Seedless grape seedlings as test material,According to the biochar different application patterns and different soil biochar contents(2.5% and 5%),five treatments were setted,all plants were cultivated in the pots.The objectives of this experiment were to study the effect of different application patterns and amounts of biochar on grape seedling nutrient uptake,root morphology and nutrient,enzyme activities,microbial diversity of rhizosphere soil.The another experiment included 4 treatments,which were no organic fertilizer(CK),single application of chicken manure(B),single application of oil residue(C),combined application of chicken manure with oil residue(D),According to soil fertilizer contents(2.5%),organic fertilizer was applied with hole pattern.The objectives of this experiment were to investigate the effect of different application modes of organic fertilizer on grape seedling growth and nutrient,enzyme activities,microbial diversity of rhizosphere soil.The results were as follows:1.Under the mixed treatment,HB treatment(mixed application of 5% biochar)significantly increased the plant biomass(dry weight of upper ground,dry weight of under ground),the index of root growth(root length,surface area,average diameter,number of root tips,root vitality)and TK(total potassium)content of the roots and leaves of the plants,but HA treatment(mixed application of 2.5% biochar)only significantly increased the root vitality and root TK content of the plants.The hole(JA,JB)treatment had no promotion on plant biomass,root growth index and TK content of the plants(except for TK content of leaves in JA treatment).Mixed and hole treatments had no or little effects on the stem diameter,plant height,root to crown ratio,root volume,TN(total nitrogen),TP(total phosphorus)content of the plants.Under the same amount of biochar,the plant biomass,root growth index and TK content of the plants in HB treatment were significantly higher than JB(hole application of 5% biochar)treatment.2.Compared with CK,biochar mixed(HA,HB)and hole application(JA,JB)patterns increased the content of rhizosphere soil organic matter,available phosphorus,available potassium and invertase,catalase activities,but soil bulk density and pH were decreased slightly.Under the same application pattern,the content of rhizosphere soil alkali hydrolysis nitrogen,available potassium and invertase,catalase activities increased with the increased of the application amount of biochar;under the same application amount,the content of rhizosphere soil organic matter,available nutrient(alkali hydrolysis nitrogen,olsen phosphorus,available potassium)and invertase,catalase activities in mixed application pattern was higher than that of hole application pattern,and among the HB treatment(mixed application of 5% biochar),the extent of increasing was the largest in the content of rhizosphere soil organic matter,available nutrient and invertase,catalase activities,which were 73.7%,19.2%,42.3%,20.8%,10.5%,8.6% higher with HB treatment than that CK.Alpha diversity analysis of soil bacteria showed that HB treatment could improve the abundance of bacterial community.However,the effect of HB treatment on bacterial community diversity was little.The number of Nitrospira in hole application pattern was higher than that of mixed application pattern,however,the number of Arthrobacter and Pseudomonas in mixed application pattern was higher than that of hole application pattern.At the phylum level,compared to control,biochar mixed application(HA,HB)pattern increased relative abundances of some bacteria such as Proteobacteria,Chloroflexi,Planctomycetes,Bacteroidetes,Saccharibacteria,among them,the relative abundances of Proteobacteria,Chloroflexi,Saccharibacteria increased with the increased of the application amount of biochar,but hole application(JA,JB)pattern only increased relative abundances of Proteobacteria and Nitrospirae.At the class level,biochar mixed application(HA,HB)pattern increased the relative abundance of the Alphaproteobacteria,Betaproteobacteria and Deltaproteobacteria,their relative abundances increased with the increased of the application amount of biochar,while in the hole application pattern,only JB treatment increased the relative abundance of those dominant class.Under the same amount of biochar,the relative abundance of the Alphaproteobacteria,Betaproteobacteria and Deltaproteobacteria in mixed application pattern was higher than that of hole application pattern.Under the mixed application treatment,the dominant bacterial population obviously increased at the Class,order,family,and genus level.Bacteria OTUs distribution and UPGMA clustering indicated that mixed application pattern induced large change of bacterial community composition and structure of rhizosphere soil.Redundancy analysis(RDA)further indicated that alkali hydrolysis nitrogen,organic matter,available potassium and pH were key environment factors affecting soil bacterial community structure.3.The plant growth of C treatment(single application of oil residue)was better than that of other fertilization treatments and the control(CK).The TK content of leaf,soil organic matter,alkali hydrolysis nitrogen,olsen phosphorus and urease,invertase,catalase activities in C,D(combined application of chicken manure with oil residue)treatments were higher than that of B(single application of chicken manure)treatment and CK,among them,the C treatment has the best effect,followed by the D treatment.At the class level,Alphaproteobacteria,Gammaproteobacteria,Betaproteobacteria were predominant bacterial communities,and their relative abundances in C,D treatments were also higher than that of B treatment and CK,among them,the C treatment has the best effect,followed by the D treatment.At the phylum level,the C treatment could increase the relative abundance of Proteobacteria and Bacteroidetes.Analysis of bacteria related to nitrogen,phosphorus and potassium metabolism revealed that the B,D treatment could promote the number of Sphingomonas and Pseudomonas,but the effect of D treatment was higher than that of B.For each organic fertilizer treatment,there was difference in bacterial community composition,and their representative species were also different.Principal component analysis revealed that soil bacterial community structure changed after applying organic fertilizer.The heatmap further analysis indicated that the effect of CK treatment was similar to B treatment,and the effect of C treatment was similar to D treatment.The Redundancy analysis(RDA)indicated that alkali hydrolysis nitrogen was key nutrient factor changing soil bacterial community structure.In summary,our results indicated that biochar mixed application pattern was better than hole application pattern in effect of rhizosphere soil nutrient,enzyme activities and microbial diversity,among them,HB treatment was better.Meanwhile,this treatment also promote the nutrient absorption and root growth of grape seedlings.After applying organic fertilizer,C treatment was the best in effect of grape seedling growth,nutrient,enzyme activities and microbial diversity of rhizosphere soil,followed by the D treatment.In grape production,it is not suitable to choose single application of chicken manure or biochar hole application pattern,we should choose single application of oil residue or combined application of chicken manure with oil residue about organic fertilizer,for biochar,we should choose mixed application pattern.