| Banana were planted widely in tropical area and subtropical area as a commercial crop, in Guangdong、Guangxi、Fujian and other areas of southern China, farmers got a great economic benefit from banana industry. Traditional planting pattern of banana use a quantity of chemical fertilizer for higher yield of banana and higher economic benefit, but use ratio of fertilizer is low in these extensive way, a lot of problem happened in banana plantation soil like soil acidification, structural damaged, soil hardening, organic matter content decreased, damage of soil microbial communities and so on. Meanwhile, superfluous chemical fertilizer flowed into underground water through rainfall and irrigation, which made a pollution of underground water. So a effectively and environment friendly soil amendment is needed to improve soil nutrition and banana’s grow. Biochar is a carbon rich material which made from biomass pyrolysis without oxygen, crop straw, branches and leaves of wood, excrement of animals, and other biomass could be biochar’s raw materials. Add biochar into field could promote organic matter and inorganic nutrition in soil, regulation acid soil pH, increase soil water holding capacity, repair soil microbial communities and so on. So biochar could be a ideal amendment for acidification soil. In this study, the influence of biochar on soil, seeding of banana and soil microbial communities were analyzed so as to provide some basic theory for biochar’s development and utilization. The main results in this study were as following:1.Physicochemical properties had a outstanding change between banana caulo biochar and banana caulo. When banana caulo was turned into biochar, smooth surface structure disppeared obviously voids appeared. pH of biochar is 10.30 appeared strongly alkaline. Fixed carbon, ash content, volatiles were 43.26%,37.25%, 9.49% respectively. Biochar have a good adsorbability by its poriferous structure, iodine sorption value reach 159.61 mg/g. The content of C、N、S、P in biochar were 16.58 mg/g, 5.91 mg/g, 5.93 mg/g. And content of metallic element K,Ca, Mg, Fe, Cu, Zn, Mn were 38.68 mg/g, 15.23 mg/g, 10.68 mg/g, 6.78 mg/g, 2.76mg/g, 5.05 mg/g, 1.05 mg/g. All these element content were promoted obviously compared with banana caulo.2. Banana caulo biochar had a positive effect on the growth of banana seedlings.Original soil(CK) and biochar mix with soil by 1%(C1)、2%(C2)、3%(C3)were used for banana seedlings’ planting in pot experiment. Biochar was found could accelerate banana seedlings’ growing. Biochar treatments banana seedling plant height, stem girth, number of leafiness, length and wide of biggest leaf were had a better value compare to CK. Root, banana caulo and leaves’ biomass were highest in C2 treatment, and increased 62.7%, 87.2%, 29.2%, 59.0% compared with CK.3. The content of C, N, K, P in banana seedlings leaf were higher than CK, the most content of C was 388.93 mg/g appeared in C3 treatment, increased by 7.5%compared with CK. The most content of N was 14.71 mg/g appeared in C1 treatment, increased by 13.2% compared with CK. The most content of K was 94.46mg/g appeared in C2 treatment, increased by 220.0% compared with CK. The most content of P was 5.02 mg/g appeared in C3 treatment, increased by 83.2% compared with CK.4. The pH of acid soil was clearly increased with biochar added. pH in C1, C2, C3 treatments was promoted into 7.13, 7.70, 7.90 from 6.68 in CK. And cation exchange capacitiy(CEC) was increased apparently, from 7.57 cmol/Kg in CK increased to 25.46 cmol/Kg, 31.99 cmol/Kg, 20.87 cmol/Kg. The content of available phosphorus, available potassium and organic matter got higher with more and more biochar added, the most value increased by 273.8%, 156.2%, 171.6%respectively compared with CK. The content of available nitrous reduced with biochar addition.5. Addition of biochar had a good influence on soil enzyme activity. Catalase activity get higher with biochar addition from 0.62 U/g in CK increased to 1.05 U/g,1.45 U/g, 1.78 U/g in biochar treatment. Urease activity added from 3.16 U/g in CK increased to 3.58 U/g, 4.86 U/g, 5.13 U/g in biochar treatment. Dehydrogenase activity was undetected in CK and appeared 1.09 U/g, 0.91 U/g, 0.30 U/g respectively in biochar treatments. Acid phosphatase activity added from 0.49 U/g inCK increased to 1.50 U/g, 0.43 U/g, 0.37 U/g in biochar treatment. Neutral phosphatase activity added from 1.28 U/g in CK increased to 2.05 U/g, 1.61 U/g,1.94 U/g in biochar treatment.6. Biomass carbon of soil microbe was promoted with biochar addition. And microbial population were influenced distinct with biochar. Bacterial quantity appeared trend that CK < C1 < C2 < C3 and there was a significant difference between treatments. Fungus quantity appeared trend that CK < C3 < C2 < C1.Actinomycetes quantity appeared trend that CK < C2 < C1 < C3. Azotobacter quantity appeared trend that CK<C1<C2<C3. Ammonofying bacteria quantity appeared trend that CK<C1<C2<C3.7. With Biolog analysis we found that at same time the value of AWCD was appeared C3>C2>C1>CK, means that addition of biochar could enhance carbon source use ability of microbial communities in banana seedling rhizosphere. And shannon index, evenness index, substrate richness were added by 8.1% ~ 9.8%,0.8% ~ 1.8%, 10.0% ~ 18.7% respectively compared with CK. Biochar had a good influence on microbial communities use ability with compound, carbohydrate,carboxylic acids, amino acids, phenols and amine, especially with high biochar addition, the ability of soil microbial communities to use phenols and amine were promoted obviously. In all, with biochar addition banana seedling rhizosphere soil microbial communities metabolic capability was promoted and structure of microbial communities was optimized.8. After analysed with banana seedling rhizosphere soil microbial communities fatty acid of phosphoric acid(PLFAs), we found total PLFAs in biochar treatments were higher than CK and appeared a significant difference., all treatments tend to trend of C2>C1>C3>CK. Compared with CK, total PLFAs in biochar treatments added 48.2%, 55.1%, 15.5% respectively. Different microbe has a positive response with biochar addition: PLFAs of bacteria appeared trend for CK<C1<C2<C3, and significant difference was found between different treatments. PLFAs of gram-positive bacterium appeared trend for CK<C1<C2<C3, PLFAs in C1 and C2 were significantly higher than other treatments. PLFAs of gram-negative bacterium appeared trend for CK<C1<C2<C3. The PLFAs in fungus, arbuscularmycorrhizal fungus and actinomycetes were higher in C1 and C2 than other treatments, and has a significant difference.9. We analysed banana seedling rhizosphere soil bacterial communities 16 s DNA by high-throughput sequencing, biochar influence on different bacterial has a different phenomenon. At the phyla level, Proteobacteria, followed by Actinobacteria, Bacteroidetes, Acidobacteria,Verrucomicrobia and Chloroflexi were the top 6 in proportion across all sample, Proteobacteria and Actinobacteria in account were the man composition of the bacterial communities(60%--67%), so they were contributed to the mainly difference in consist of bacterial communities in different samples. Addition had a positive effect on Proteobacteria, Verrucomicrobia and Chloroflexi and so on. but had a negative effect on some bacteria like Acidobacteria, Actinobacteria. At genus level, biochar addition could promote abundance of Thermomonas, Steroidobacter, Arthrobacter, Nitrospira, Devosia,Candidatus-Nitrososphaera and so on, some bacterial abundance like Amycolatopsis,Phenylobacterium, Aquicella showed decreased when biochar appeared. As a whole,addition of biochar would made a significant difference on banana seedling rhizosphere soil bacterial communities, and among the biochar treatments bacterial communities structure in C1 and C2 had a higher similarity. |
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