稻鸭共作对稻田氮素变化及土壤微生物的影响

通过田间试验研究稻鸭共作生态系统中土壤与田面水全N、无机N的动态变化及水稻吸N的规律和土壤微生物数量的变化规律.结果表明,(1)与常规稻作相比,稻鸭共作稻田土壤、田面水全N含量略有提高,土壤、田面水NH 4含量和水稻含N量显著提高,而土壤、田面水NO-3含量无明显变化;(2)稻鸭共作极显著提高了水稻总吸N量,高于常规稻作17.8%;相关分析显示,水稻吸N量与NH 4含量呈一元二次方程式关系,达到显著或极显著相关.(3)与常规稻作相比,稻鸭共作能显著提高土壤微生物数量,其中细菌数最多,放线菌次之,真菌最少.

The N variations of paddy fields and amounts of soil microorganisms in rice-duck complex ecosystems

Research on N variations in field surface water and soils, rules of N uptakes of rice and amounts of soil microorganisms in rice-duck ecosystem was conducted by field experiments. The results showed: (1)Compared with conventional paddy fields, total nitrogen content in surface water and soils increased appreciably in rice-duck complex ecosystem, and NH+4 content in the field surface water and soils and N uptake of rice increased significantly in rice-duck complex ecosystem, meanwhile NO-3 content in the field surface water and soils scarcely any changed; (2) Rice-duck complex ecosystem boosted significantly total N uptake of rice and 17.8% higher than that of conventional paddy fields. Correlation analysis revealed that the relation between N uptake of rice and NH+4 content was fitted with by a unitary quadratic equation; (3) Rice-duck complex ecosystem could increase significantly soil microorganisms amount, in which bacteria amount were largest, actinomyces amount took second and the fungi amount were least.