稻田根际微生物生物量碳与水分、氮素影响效应分析

Effects of nitrogen supply levels and water schemes on rice rhizosphere microbial biomass carbon in rice development stage at paddy field.

结合大田3种氮素水平试验及网室3种施氮水平(不施氮、中氮、高氮)和3种水分模式(控水模式、干湿交替模式、浅水层连续灌溉模式)盆栽试验,对水稻不同生育期氮素及水分状况对根际微生物生物量碳的影响效应进行研究;并运用统计分析手段,在水稻生长关键期(分蘖期、孕穗期和灌浆期)进行氮素、水分因子和水、氮互作对根际微生物生物量碳效应的显著性分析.结果表明,不同时期水稻根际土壤微生物生物量碳,不仅受到水分状况和施氮的影响,还受到水分和施氮因素的交叉互作效应影响.不同处理的根际土壤微生物生物量碳基本上都在移栽期达最大值,成熟期最小,而移栽期与分蘖期之间变化不大.同一时期,施氮会影响水稻根际土壤的微生物生物量碳,微生物生物量碳变化顺序为:高氮>中氮>不施氮,大田微生物量碳最大值为4.743 mg?kg-1.3种水分模式下,浅水层连续灌溉模式下的微生物量碳普遍最小,控水模式和干湿交替模式下微生物量碳最大可达到3.500 mg?kg-1左右.水分和氮素互作因子在灌浆期对根际土壤微生物碳含量影响最为显著,这一时期3种水分模式及3种氮素水平影响下的根际微生物碳之间差异最显著.研究表明稻田根际微生物生物量碳可以作为根际生态功能指标并具有代表性.

The experiment of three nitrogen supply levels at field and three nitrogen and soil moisture regimes in pot plot was conducted in 2006 to study their mutual effects of nitrogen and water schemes on the microbial biomass carbon of rhizosphere during the rice development stage. Statistics was also used to analyze the significance of nitrogen and soil water regimes and their interaction on the microbial biomass carbon （MBC） of rice rhizosphere. The results indicate that MBC was not only influenced by the nitrogen and water condition at the rice development stage, but also affected by their interactions at the rice growth period. The maximum MBC was found at the transplanting stage and the minimum value at the maturity stage of rice. There was no difference for MBC between the transplanting and tillering stage of rice. The sequence of MBC at the same rice growth stage with different nitrogen rates was high N〉 medium N〉no N input. The maximum MBC at field experiment was 4, 743 mg·kg^-1. The maximum MBC around 3. 500 mg·kg^-1 happened in the drying and wetting water controlling treatment, while the minimum MBC was found in continuous water layer maintaining module in pot experiment with three soil moisture regimes. Soil moisture and nitrogen interaction produced significant effect on the MBC at the rice booting stage, and there existed the greatest significant difference among the nitrogen, water schemes and their interaction at this stage. The experiment results indicated that the MBC could be used as an indicator for rice rhizosphere ecosystem research.