增氧联合施用有机肥对设施土壤氮素转化及微生物学机制研究

Reasonable increase the application of organic fertilizer is the future of facility agriculture. Oxygation technique is a new irrigation method for facility agriculture. However, the effect of the combination of application organic fertilizer and oxygation on soil nutrient and soil microbial community are still not known. Based on preliminary tests, in this study, the appropriate oxygation concentration of crop rhizosphere soil was determined through pot experiment under the condition of organic fertilizer application. In this project, MiSeq sequencing technique will be used to analyze the specific microbial community and structure. Real-Time PCR technique will be used to detect the number of microbes. Subsequently, 15N tracing experiment and full process-based N cycle models was used to quantify simultaneously occurring gross N transformations in soil. In addition, structure and function of microbial community associated with nitrification and denitrification were detect by RNA transcription sequencing technique and Real-Time PCR technique. This project will find out the mechanism involved in rhizosphere microflora response to oxygation and organic fertilizer application. And the mechanism involved in soil N transfomation caused by the change of microbial community structure and function.

合理增施有机肥是设施农业发展的趋势，而增氧滴灌技术是设施农业新兴的灌溉技术，两者的结合对土壤养分含量的影响及相关土壤微生物作用机制亟待研究。本项目在前期工作基础上，采用盆栽试验方法，筛选施用有机肥条件下作物根际合适的增氧浓度。利用MiSeq高通量测序技术分析土壤微生物具体类群，辅以Real-Time PCR技术测定微生物数量，结合土壤酶活性的测定，探明根际微生物区系群落结构及功能。利用15N示踪技术，辅以RNA转录分析测序技术，探明土壤氮素初级转化速率与氮素转化相关功能微生物群落活性的关联性。以期阐明土壤微生物区系响应增氧与施用有机肥的特征及其代谢功能的改变对土壤氮素转化作用机制，最终为设施蔬菜栽培提供理论依据。

合理增施有机肥是设施农业发展的趋势，而增氧滴灌技术是设施农业新兴的灌溉技术，两者的结合对土壤养分含量的影响及相关土壤微生物作用机制亟待研究。本项目以番茄为指示植物，通过盆栽实验，研究不同增氧灌溉方式（传统曝气增氧(AW)、微纳米气泡增氧(NB)以及界面微纳米气泡增氧(Z^O2)）结合施用有机肥对番茄生长的影响。研究结果表明，三种增氧灌溉处理均能提高番茄生物量和产量。在番茄移栽30天后，番茄植株生长促生效果最为明显。与单施有机肥处理相比，AW、NB和Z^O2增氧灌溉处理的株高分别提高了12.84%、10.30%和6.67%，茎粗分别提高了23.0%、30.2%和3.11%，产量分别提高了17.2%、22.4%和24.3%，但三种增氧灌溉处理之间，番茄产量无显著差异。土壤培养试验研究结果表明，增氧灌溉结合有机肥施用提高了土壤养分矿化速率、提高了土壤酶活和土壤微生物代谢活性的影响。在土壤培养28天时，AW处理和NB处理与对照相比，速效氮含量分别提高了13.18%和28.96%，土壤速效磷含量分别提高了12.69%和35.42%。增氧处理，与C，N和P循环相关的酚氧化酶, 过氧化物酶，β-1,4-木糖酶，α-1,4-葡糖苷酶，β-1,4-N-乙酰氨基葡萄糖苷酶和磷酸酶酶活性均显著提高。与对照相比，AW和NB处理酶活性分别提高了48.07%和29.66%, 17.73%和18.50%, 28.44%和8.57%, 13.6%和13.7%。与N循环相关的β-1,4-N-acetyl-glucosaminidase酶活性分别提高了9.66%和27.11%。与P循环相关的phosphomonoesterase酶活性分别提高了20.49%和42.58%。增氧处理的土壤微生物均能够很好的利用不同类别的碳源物质，表明增氧处理促进了土壤微生物的碳代谢活性，提高了土壤的活力。其中，AW和NB处理土壤样品对Cabohydrate和Amino acids的代谢活性显著高于对照处理。