鸭稻共作对土壤微生物数量及其功能多样性的影响

Effects of Integrated Rice-Duck Farming on Soil Microbial Quantity and Functional Diversity

鸭稻共作起源于我国传统的稻田养鸭,作为一种环境友好型的生态农业技术,许多研究表明该模式具有良好的生态效应。为了进一步探讨鸭稻共作对稻田土壤微生物群落的影响,于2005年在华南农业大学增城教学科研基地进行了田间试验,共设计鸭稻区、浑水区、清水区和常规区4个处理,采用平板培养法和BIOLOG技术研究了其对稻田土壤微生物群落动态及功能多样性的影响效应。结果表明,鸭稻共作能够增加水稻生长中后期稻田土壤可培养的微生物总数以及细菌、放线菌和真菌数量;与常规区相比,土壤微生物总数、细菌、放线菌在抽穗期、成熟期的差异显著,真菌数量在乳熟期、成熟期的差异显著。BIOLOG分析显示,与清水区相比,稻田放鸭能够提高土壤微生物群落的碳源利用能力和整体代谢活性,显著增加水稻抽穗期的微生物功能多样性。说明鸭稻共作系统对稻田土壤微生物群落数量、代谢活性和功能多样性的提高均具有积极作用。

Integrated rice-duck farming system （IRDFS）, an environmentally friendly eco-agricultural technique, was developed from the Chinese traditional farming method of raising ducks in paddy fields. Many studies have reported that the farming system has positive ecological effects on paddy ecosystems. In order to further understand the effects of rice-duck farming on population dynamics and functional diversity of microbial flora in paddy soil, we conducted field experiments with four treatments including rice-duck farming, turbid water, clear water, and conventional rice farming in Zengcheng Research and Education Station in 2005. We then investigated changes in soil microbial communities using agar plate bioassay and BIOLOG techniques. The study results showed that under rice-duck farming, the quantities of culturable bacteria, actinomycetes, fungi and microbial community of paddy soil increased in the middle-latter stage of rice growth. As compared to conventional rice farming, bacteria, actinomycetes and microbial community were significantly increased in the heading stage and ripening stage, and fungi significantly increased in the milk stage and ripening stage. BIOLOG analysis showed that rice-duck farming increased carbon utilization ability and total metabolic activity of soil microbial communities compared to the clear water plot, and significantly improved functional diversity in the heading stage. This study indicated that integrated rice-duck farming systems had positive effects on improvement of quantity, activity and functional diversity of soil microbial community in paddy fields.