厢作免耕对稻田土壤呼吸与有机碳组分的影响

发布时间：2018-04-20 11:18

本文选题：厢作免耕 + 土壤呼吸　；参考：《华中农业大学》2015年硕士论文

【摘要】：研究厢作免耕稻田对土壤呼吸与有机组分的影响,为评估厢作免耕稻田土壤碳排放与有机碳累积提供科学参考,以及为稻田免耕技术推广提供技术支撑。基于华中地区油-稻(油菜-中稻)系统试验田,通过设计0.6 m(W1)、1.2 m(W2)、1.8 m(W3)与2.5 m(W4)四个不同厢宽的免耕稻田以及平作免耕(FNT)和平作翻耕(T)稻田,监测土壤呼吸及组分(总呼吸、异养呼吸)时空变化特征与土壤活性有机碳组分(微生物量碳、可溶性有机碳、易氧化态碳、总有机碳和团聚体碳)的变化特征。(1)各处理厢中心或厢边际积温与冠层透光率差异不显著;厢作免耕主要影响着积温、冠层透光率在空间上的分布,其中厢作免耕处理厢边际积温显著高于厢中心,厢边际水稻群体冠层中层与底层透光率显著高于厢中心。(2)对厢作免耕稻田土壤呼吸的日变化(分蘖盛期与齐穗期)特征分析表明,在两个主要生育期,土壤呼吸通量的日变化呈现不同的规律:在分蘖盛期各厢宽处理厢边际和厢中心CO2排放通量均在18:00达到高峰;在孕穗期各厢宽处理只有厢中心CO2排放速率在18:00形成高峰,厢边际未形成明显高峰,但白天土壤呼吸明显高于夜晚。进一步的研究提出,9:00-12:00是监测土壤呼吸日变化的最佳时间。(3)对厢作免耕稻田土壤呼吸与组分的季节性变化进行了研究,表明土壤呼吸与根呼吸具有明显的季节性变化特征,各处理厢中心或厢边际土壤呼吸与根呼吸均在分蘖盛期与齐穗期出现峰值。(4)对厢作免耕稻田土壤呼吸与组分的空间变化特征的分析指出,由于厢作免耕厢-沟的特殊配置,导致厢边际相对于厢中心肥料流失大,厢边际水稻对养分的吸收利用降低,水稻根生物量与地上部生物量显著降低,进而降低了土壤呼吸与组分,因此厢作免耕稻田厢边际土壤呼吸与组分显著低于厢中心。(5)对厢作免耕稻田土壤碳组分的分析表明,厢作处理边际可溶性有机碳含量均显著高于中心;厢宽处理边际的土壤微生物量碳与微生物熵均显著小于中心,其中1.8m厢宽处理土壤微生物量碳与微生物熵最小;四个厢作处理的土壤总有机碳含量显著高于平作免耕与平作翻耕,另边际土壤总有机碳含量小于中心;1.8m处理边际1-0.25 mm与0.25-0.053 mm组分以及中心2-1 mm与1-0.25 mm组分团聚体碳含量最大;四个厢宽处理的碳库管理指数著大于平作免耕与平作翻耕。(6)对厢作免耕处理稻季土壤CO2累积排放与产量的综合分析表明,相对于翻耕处理,厢作免耕与传统平作免耕处理显著降低了稻季土壤CO2累积排放;1.8 m厢宽处理稻季土壤CO2累积排放量最小,显著低于翻耕处理18.5%-35.2%。同时,产量分析表明,由于具有最高的有效穗,1.8 m厢宽处理具有最高的产量;综合产量与土壤CO2累积排放的分析指出,1.8 m厢宽处理具有最低的单位产量碳排放量,因此是一项土壤CO2排放低与水稻产量高的免耕稻作技术。
[Abstract]:The effects of box as no-tillage paddy field on soil respiration and organic components were studied to provide scientific reference for assessing soil carbon emission and organic carbon accumulation in no-tillage paddy field and to provide technical support for popularization of no-tillage technology in paddy field. Based on the oil-rice (rapese-medium rice) system test field in central China, four no-tillage paddy fields with different widths of 0.6 mW _ (1) and 2.5 m / W _ (4) were designed to monitor soil respiration and subgroup (total respiration). Spatial and temporal characteristics of heterotrophic respiration and soil active organic carbon components (microbial biomass carbon, soluble organic carbon, easily oxidized carbon), The variation characteristics of total organic carbon and aggregate carbon. (1) there was no significant difference between the accumulated temperature and canopy transmittance at the center or edge of each treatment, and the canopy no-tillage mainly affected the accumulated temperature and the spatial distribution of canopy transmittance. The marginal accumulated temperature of the box for no-tillage treatment was significantly higher than that in the center of the box. The diurnal changes of soil respiration (tillering peak stage and full heading stage) in the canopy layer and bottom layer of the marginal rice population were significantly higher than those in the center of the canopy. The results showed that the diurnal changes of soil respiration (tillering peak stage and full heading stage) were observed in the two main growth stages. The diurnal variation of soil respiration fluxes showed different patterns: at the peak of tiller, the CO2 fluxes reached the peak at 18:00 at the edge and center of the compartment width treatment, and only the CO2 emission rate in the center of the box reached the peak at 18:00 at booting stage. There was no obvious peak in the margin of the compartment, but the respiration of soil was obviously higher during the day than at night. It was suggested that 9: 00-12: 00 was the best time to monitor the diurnal variation of soil respiration. The seasonal changes of soil respiration and components in no-tillage paddy field were studied. The results showed that soil respiration and root respiration had obvious seasonal variation characteristics. The spatial variation characteristics of soil respiration and components in no-tillage paddy field were analyzed at the peak value of soil respiration and root respiration at the peak tillering stage and full heading stage. It was pointed out that due to the special configuration of no-tillage box and ditch, the soil respiration and root respiration at the center or edge of each compartment were analyzed. The nutrient uptake and utilization of rice decreased, the root biomass and aboveground biomass decreased significantly, and the soil respiration and composition decreased. Therefore, the soil respiration and composition in the compartment of no-tillage paddy field were significantly lower than those in the center of the box. The analysis of soil carbon components in the box used as no-tillage paddy field showed that the content of the marginal soluble organic carbon in the box treatment was significantly higher than that in the center. Soil microbial biomass carbon and microbial entropy were significantly smaller than those of the center, and the soil microbial biomass carbon and microbial entropy were the smallest in the 1.8 m box width treatment. The soil total organic carbon content of the four compartment treatments was significantly higher than that of no tillage and tillage, while the marginal soil total organic carbon content was lower than that of the central 1.8m treatment with 1-0.25 mm and 0.25-0.053 mm fractions and the highest carbon content in the central 2-1 mm and 1-0.25 mm aggregate fractions. The carbon pool management index of four hatchback width treatments was higher than that of non-tillage and no-tillage treatments. The comprehensive analysis of soil CO2 cumulative emissions and yield under no-tillage treatment showed that compared with tillage treatment, the total soil CO2 emission and yield were higher than those under no-tillage treatment. Non-tillage treatment and conventional no-tillage treatment significantly reduced soil CO2 accumulative emissions in rice season, and the accumulative CO2 emission of rice season was significantly lower than that of tillage treatment (18.5-35.2g), and the cumulative CO2 emission of rice season was significantly lower than that of non-tillage treatment (1.8m box width). At the same time, the yield analysis showed that the highest yield was obtained from the treatment with the highest effective panicle width of 1.8m, and the analysis of the integrated yield and soil CO2 accumulative emission indicated that the 1.8m box width treatment had the lowest carbon emissions per unit yield. Therefore, it is a no-tillage rice cultivation technique with low soil CO2 emission and high rice yield.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154;S511

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