【作者】 田慎重；

【导师】 李增嘉； 宁堂原；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2010， 硕士

【摘要】 本实验于2007²009年在山东农业大学农学试验站进行,利用静态箱-气相色谱法分析了耕作措施及其转变后麦玉两熟农田CH₄和N₂O季节排放规律和日变化规律并系统分析了其温室效应,结合土壤固碳量、作物产量,利用多指标综合评价法对5种耕作措施进行综合评价,探讨出在较优的产量基础上,具有较好的温室气体减排潜力和土壤固碳潜力,以期为该地区温室气体排放量估算、土壤固碳量提供数据支持,并为该地区制定符合农业可持续发展的合理耕作模式提供理论依据。主要研究结果如下:1耕作措施及其转变对麦玉两熟农田土壤CH₄和N₂O排放的影响不同耕作措施下土壤CH₄和N₂O有明显的季节变化和日变化,不同时期各处理均表现为CH₄的吸收汇和N₂O的排放源,CH₄、N₂O通量都呈现冬季底、夏季高的季节排放趋势。通过相关性分析表明,不同耕作措施下,土壤CH₄吸收通量与土壤5cm地温和地表温度呈正相关关系,与土壤0²0cm水分含量呈负相关关系; N₂O排放通量与土壤水分和土壤硝态氮含量呈正相关关系。不同耕作措施下,各处理CH₄、N₂O通量具有明显的差异。CH₄总吸收通量旋耕≈耙耕>常规耕作>深松耕>免耕,N₂O总排放通量免耕>耙耕>深松耕≈旋耕>常规耕作,旋耕的CH₄吸收通量最高且N₂O排放通量较低。耙耕、旋耕、免耕在原有耕作模式基础上进行深松后,CH₄吸收通量明显的增加而N₂O排放通量略有增加,说明保护性耕作+深松模式虽然会略微增加土壤N₂O的排放,但是其会大幅度增加土壤对CH₄的吸收。不同耕作方式其农田CH₄和N₂O的温室效应具有明显的差异,小麦季总温室效应:免耕>耙耕≈深松>旋耕>常规耕作;而玉米季总温室效应:常规≈旋耕>免耕>耙耕>深松。总温室效应:免耕>耙耕>旋耕>深松耕>常规耕作。2不同耕作措施及秸秆还田对麦田土壤有机碳含量的影响不同耕作措施下,秸秆还田各处理0²0cm有机碳含量显著比无秸秆还田处理高,说明秸秆还田能显著增加土壤表层有机碳含量,在秸秆还田条件下,保护性耕作各处理0¹0cm土层有机碳含量显著高于0²0cm,而常规翻耕处理表现出相反的趋势。多因素方差分析表明:耕作因素、秸秆因素和两者交互效应在不同生育期对0²0 cm土层的有机碳含量都有显著影响。在秸秆还田条件下,根据两年有机碳含量的变化,计算出0²0cm土层土壤固碳量:深松耕>旋耕>常规耕作>耙耕>免耕,说明深松和旋耕模式具有较好的固碳潜力。3耕作措施及其转变对作物产量的影响秸秆还田条件下,不同耕作措施各处理小麦产量具有明显的差异,旋耕>常规>耙耕>深松>免耕,而深松后,各处理小麦显著增产,增产幅度免耕>耙耕>旋耕,说明采用保护性耕作2～3年后深松1次的耕作模式,结合秸秆还田技术,能促进作物生长,提高作物产量。4耕作措施综合评价通过多指标综合评价法中的RSR值综合评价法对5种耕作措施进行综合评价表明,旋耕措施在较优的产量基础上具有较好固碳潜力、温室气体减排潜力,是适应生态农业条件下较为合理的耕作模式。耙耕和深松处理次之,常规耕作较差,免耕最差。旋耕+深松措施虽然会略微增加温室效应,但却具有较好的增产效果和固碳效果。结合本课题组6年的保护性耕作定位试验,旋耕措施在实行一定年数后会有减产趋势,增加深松后,有利于打破犁底层,促进作物根系生长,增产效果和固碳效果非常明显,因此,2+1、3+1 （2、3年旋耕后深松一次）模式是实现作物产量、土壤固碳和温室气体减排三者协调统一的合理模式。更多还原

【Abstract】 A field experiment was carried out at experimental plot of Shandong Agriculture University in 2007²009 to study the effects of tillage measures and conversion on the seasonal and diurnal variation emission of soil CH₄&N₂O in wheat-maize farmland was using the Static-Chamber&the Gas Chromatography（GC） method and systematically analyzed its GWPs. Comprehensive evaluation five tillage measures using the Multi-index comprehensive evaluation method combined with soil carbon sequestration potential and crop yield. The objective is to carry out better with greenhouse gas reduction exhaust potential and soil carbon sequestration potential on basis of better yield. Provide data supportion to estimation of greenhouse gas emission and soil carbon sequestration amount. At the same time, provide theoretical basis to making reasonable tillage measure accord with agricultural sustainable development in this area. The main result was as follows:1 Effects of tillage measures and conversion on the emission of soil CH₄&N₂O in wheat-maize farmlandCH₄&N₂O flux had obvious seasonal and diurnal variation under different tillage measures. All treatments were the sink of CH₄ absorption and emission source of N₂O in different growth periods, CH₄&N₂O flux present seasonal variation trend of lower in winter and higher in summer. By correlation analysis showed that, there was positive correlation between CH₄ uptake flux and soil temperature of 5cm depth, and negative correlation with soil water content of 0²0cm depth; in the same time, there was positive correlation between N₂O emission flux and soil water content of 0²0cm and ammonium N of 0¹0cm depth. Comparison of CH₄&N₂O flux among different treatments indicated that CH₄ uptake flux under PR≈PH>PC>PS>PZ and N₂O emission flux under PZ>PH>PS≈PR>PC. PR has the highest of CH₄ uptake flux and the lowest of N₂O emission flux. PH, PR and PZ was subsoil tillage after basing on original tillage measure manifested as its will increase CH₄ uptake and N₂O emission flux, this phomenon showed that althought increased to N₂O emission appreciably, but CH₄ uptake flux was improved greatly. GWPs of CH₄&N₂O have an obvious difference under different tillage measures, total GWPs of wheat seasonal was PZ>PH≈PS>PR>PC; total GWPs of maize seasonal was PC≈PR>PZ>PH>PS. Total GWPs of wheat- maize farmland was PZ>PH>PR>PS >PC.2 Effects of different tillage measures and returning straw on soil organic carbon content in wheat fieldThe results showed that, all treatments of straw returning had higher values than treatments with no straw returning, and that of conservation tillage was higher than conversional tillage. The soil organic carbon content in 0-10 cm soil layer of all treatments was higher than that in 10-20cm soil layer except conversional tillage treatments. Multi factor variance analysis showed that tillage measures, straw returning and their interaction significantly affected the organic carbon content in 0-20cm soil layer at various growth stages of wheat. Under the condition of straw returning and according of SOC content variation of two year, we calculated soil carbon sequestration amount in 0²0cm layer that PS>PR>PC>PH>PZ, it showed that PS and PR has good carbon sequestration potential3 Effects of tillage measures and conversion on crop yield in wheat-maize farmlandAll treatments yield of wheat has an obvious difference under different tillage measures with straw returning that PR>PC>PH>PS>PZ. After subsoil tillage measures, all treatments yield of wheat was significantly increased that PZ>PH>PR, it showed that must be subsoil tillage after two or three years with conservation tillage, and with strew returning could promote crop growth and increasing yield.4 Comprehensive evaluations of different tillage measuresComprehensive evaluations five tillage measures using the RSR value mothed of Multi-index comprehensive evaluation methods showed that, PR was a potential measure of greenhouse gas reduction exhause and soil carbon sequestration meanwhile has a basis on better yield, PH and PS took the second place, PC was poor and PZ was the poorest.Combined with the results of a 10-years located experiment of our team shows that it has trend of yield reduction carried to PR with several years, but after subsoil tillage, it will beneficial to breaking plough pans, promote to growth of crop roots, and has abvious effect on yield-increasing and carbon sequestration, therefore, measure of 2+1, 3+1 is a reasonable measures in coordination and unification of crop yield, soil carbon sequestration and greenhouse gas reduction exhaust.更多还原