【作者】 赵建波；

【导师】 李增嘉；

【作者基本信息】 山东农业大学 ， 农业生态， 2008， 博士

【摘要】 本研究于2005年-2007年在山东农业大学农学实验站展开,试验以华北平原小麦-玉米两熟农作制下保护性耕作田为研究对象,探寻保护性耕作条件下农田土壤理化性状、微生物特性、土壤酶活性、土壤温室气体排放变化以及对作物发育动态的影响,以明确保护性耕作与各指标之间的关系,为实现低耗高效的耕作方式提供理论基础。主要研究结果如下:1.保护性耕作对土壤物理性质的影响秸秆还田提高0-30cm土壤水稳性团聚体含量。保护性耕作提高0-10cm土层水稳性团聚体含量。保护性耕作的土壤分散系数小于常规耕作。保护性耕作能显著提高土壤毛管孔隙度,秸秆还田有利于土壤孔隙度的增加。耕作因素是非毛管孔隙度的决定性因素。在秸秆还田条件下,深松处理的水分利用效率最大。在相同耕作措施时,秸秆还田处理的水分利用效率均高于无秸秆还田处理。2.保护性耕作对土壤化学性质的影响秸秆还田利于提高土壤有机质的含量,在0—10cm耕层,保护性耕作提高土壤有机质含量幅度大于常规耕作。少免耕0--10cm土层有机质含量大于10--20cm土层,常规耕作相反。无秸秆还田处理下,深松、耙耕模式有利于0-10cm土壤全氮含量的增加。秸秆还田处理下,旋耕、耙耕模式土壤全氮含量显著高于无秸秆还田处理。在全氮累积量中,深松模式下全氮累积量平均值高于常规耕作,而免耕、旋耕、耙耕均低于常规耕作。秸秆覆盖利于0-20cm土壤碱解氮、速效磷、速效钾含量的提高。少耕处理的碱解氮水平均高于常规处理。常规耕作秸秆还田在0-20cm土层提高速效磷幅度最大。免耕无秸秆处理在生育期中能增加土壤速效磷的含量。20--40cm土壤速效钾,总趋势是无秸秆还田大于秸秆还田。3.保护性耕作对土壤微生物特性的影响0--10cm土壤细菌(除无秸秆还田的常规耕作)、放线菌(除无秸秆还田的常规耕作)、真菌数量,均大于10--20cm土层。10--20cm土层土壤菌数量保护性耕作小于常规耕作。0--20cm土层,秸秆还田的常规耕作真菌量最高,免耕最低。保护性耕作0-10cm土层的微生物量碳、活跃微生物量、微生物活性均大于10-20cm土层。保护性耕作和秸秆还田利于土壤微生物量碳的提高。保护性耕作利于0-10cm土层活跃微生物量和微生物活性的提高。10--20cm土层的微生物活性,免耕最低。0--10cm,常规耕作呼吸强度大于保护性耕作,免耕最小。0-10cm土层的呼吸强度大于10-20cm,秸秆还田大于无秸秆还田。0-10cm土壤微生物商均高于10-20的微生物商。保护性耕作处理的微生物商高于常规耕作处理。4.保护性耕作对土壤酶活性的影响保护性耕作土壤0-10cm的脲酶活性高于10-20cm。常规耕作规律正好相反。秸秆覆盖利于0-10cm土层的蔗糖酶活性的提高。0--20cm土壤蔗糖酶活性,秸秆还田的常规耕作最高,免耕最低。0-10cm土层过氧化酶活性,保护性耕作(除深松)大于常规耕作。10-20cm土层,免耕酶活性降低,深松和常规处理的酶活性提高。秸秆利于土壤过氧化氢酶活性的提高。5.保护性耕作对小麦田温室气体(CH4、N2O、CO2)排放的影响麦田处理表现为CH4的吸收汇,保护性耕作CH4吸收量小于常规耕作;保护性耕作CH4吸收量与温度正相关,与水分负相关,常规耕作与两因素相关性不显著。各处理CH4吸收量与NH4+含量显著负相关。除免耕秸秆还田外,N2O排放通量保护性耕作与常规耕作差异显著。保护性耕作(除免耕)利于N2O的排放。温度是制约N2O排放的关键因素,随着温度的升高N2O表现出增加的趋势。N2O排放与水分、土壤无机氮含量无相关性。CO2排放通量常还最高的,免耕最低,秸秆覆盖利于CO2的排放。相关分析表明,CO2排放通量与气温、5cm地温之间呈显著正相关关系,与水分相关性不显著。玉米季土壤是CH4的吸收汇,苗期CH4的吸收通量最低,灌浆期最高。处理间相比,无秸秆还田的常规耕作>常还>松还>耙还>旋还>免耕。N2O排放通量在苗期和大口期出现排放峰值,收获期出现最低值,少免耕处理的N2O排放通量大于常规耕作。苗期CO2排放通量最小的,大口期CO2的排放通量达到最大值。常规耕作CO2排放通量大于保护性耕作。常规耕作温室总效应均大于保护性耕作,免耕最小,常规耕作秸秆覆盖最大。玉米季的温室效应大于小麦季。N2O和CO2是温室正效应, CH4是负效应,温室效应主要表现为CO2的效应。6.保护性耕作对作物发育动态及产量的影响免耕处理基本苗均极显著低于常规无秸秆还田。小麦冬前最大分蘖耙还、常还高于常无,免无、松无、免还、松还显著低于常无,耙无处理与对照无显著差异。小麦春季最大分蘖松无、耙还PH与常无无显著差异,免耕处理显著低于AC。小麦,秸秆还田条件下,常规耕作的穗数最高。无秸秆还田条件下,深松、免耕和旋耕的穗数显著低于常规耕作,免耕和旋耕的穗粒数极显著低于常规耕作。深松的籽粒产量均显著高于常规耕作,免耕和旋耕均极显著低于常规耕作。玉米,在秸秆还田条件下,深松的千粒重高于常规耕作,免耕和旋耕则极显著低于常规耕作。深松与耙耕行粒数高于常规耕作,免耕与旋耕极显著显著低于常规耕作。深松与耙耕的籽粒产量高于常规耕作,免耕和旋耕比常规耕作低。相同耕作措施下,秸秆还田的籽粒产量均高于无秸秆还田。更多还原

【Abstract】 This research was conducted in the field in Shandong Agricultural University in 2005-2008, which was to explore the changes of nutrition in soil and the response of crops to conservation tillage. Two crop species, wheat and maize, were planted every year in this farming system. Some parameters including physical and chemical characters, microbial properties, and enzyme activities, greenhouse gas of the soil and development of crop growth were examined at different season of each year, and the effects of conservation tillage on these parameters were analyzed. These results can give some suggestions for the application of different tillage patterns in the sysytem of high efficiency and low expending agriculture.The major results were as follows.1.The effects of conservation tillage on soil physical charactersStraw returning could increase the content of water-steadied coacervate in the soil layer between 0-30cm upright levels. Conservation tillage could increase the content of water-steadied coacervate in the soil layer 0-10 cm upright level. The soil decentralization coefficient of the conservation tillage was less than that of conventional tillage. Conservation tillage significantly increased soil capillary hole linear measure, straw returning was propitious to increase soil hole linear measure, but tillage modal decided the non-capillary hole linear measure.When straw was returned to the soil, the using efficiency in PS was the highest. And when same tillage technique was used, the using efficiency was higher in straw returning treatment than no straw returning.2. The effects of conservation tillage on soil chemical charactersStraw returning was helpful to improve organic matter content, and the increase of organic matter conten was greater in conservation tillage than conventional tillage in 0-10cm soil layer. In few and no tillage modals, organic matter content in 0-10 cm soil layer was more in10-20 cm, but it was reverse in conventional tillage treatment.Under no straw returning, subsoiling tillage and harrow tillage modals were benefited to the improvement of total N in surface layer of 0-10cm. But under straw returning treatment, the total N content in rotary tillage and harrow tillage was significantly higher than no straw returning.The total N accumulation of deep scarification treatement was higher than conventional tillage, but those of no tillage, rotary tillage and harrow tillage treatmwnt were lower than conventional tillage.Straw returning avail to increase AN content , available P , available K in the soil. The AN content in few tillage was higher than conventional tillage. The increase of available P conten was the gretest in conventional tillage and straw returning treatement in 0-20cm cultivating soil layer. No tillage with no straw returning could increase available P content in sampling date. In 20-40cm tillage layer, in all cultivating treatment, the highest available K content was found in the harvest season in the process of crop development, and on regularity was found in other seasons.3. Effects of conservation tillage on soil microorganismsThe average numbers of bacteria(except conventional tillage with no straw returning), set bacteria(except conventional tillage with no straw returning) , epiphyte in 0-10 tillage layer were more than 10-20cm . In 10-20cm tillage layer, the numbers of bacteria in conservation tillage were less than conventional tillage. The average numbers of set bacteria in 0-20cm tillage in layer in conventional tillage with straw returning were highest, no tillage were the lowest . The soil microbial biomass C,active microbial biomass,microbial activity and mirobial quotient in 0-10cm in conservation tillage were bigger than in 10-20cm. conservation tillage and straw returning was helpful to improve soil microbial biomass C. conservation tillage conservation was helpful to improve active microbial biomass and microbial activity in 0-10cm.The microbial activity in 10-20 soil layer in no tillage was the lowest. the catalase activity of conservation tillage treatment was higher than conventional tillage,no tillage was the lowest,straw returning than no straw returning. Mirobial quotient in conservation tillage was higher conventional tillage. 4. The effects of conservation tillage on soil enzyme activitiesIn conservation tillage, the urease activity in 0-10cm soil layer was higher than in 10-20cm, but that was reverse in conventional tillage. Straw covertion was benefit to sucrase activity in 10-20cm soil layer. Sucrase activity in conventional tillage with straw returning was highest, and no tillage was lowest . In 0-10cm soil layer, the catalase activity of conservation tillage treatment (except PS) was higher than conventional tillage. In 10-20cm soil layer, soil enzyme activities in PZ was depressed, and soil enzyme activities was improved in PS and C treatment. Straw returning was benefit to improve soil enzyme activities.5. Effects of conservation tillage on greenhouse emission in the fieldThe fields of conservation tillage were the sink of CH4 absorption. Comparing with the field of conventional tillage, CH4 absorption fluxes of conservation tillage field were reduced. A positive correlation was found between CH4 absorption fluxes and temperature in conservation tillage field, and a negative correlation was found that with soil water content. The temperature and soil water content were not related to CH4 absorption fluxes in conventional tillage. A significant negative correlation was existed between CH4 absorption fluxes and NH4+ content in different treatments. The difference of N2O fluxes between conservation tillage field and conventional tillage was significant except no tillage with Straw returning treatment. Comparing with conventional tillage, N2O fluxes of conservation tillage (except NS) were increased significantly. The temperature was the primary factor that influencing N2O emission, N2O emission was enhanced with the increase of temperature.Water content and mineralized N of soil were not related to N2O emission. The CO2 emission fluxes was the highest in PA, and that was the smallest in PZ treatment.Straw returning was availe to emission of CO2 from soil. A positive correlation was found between CO2 emission fluxes and temperature in conservation tillage, and a negative correlation in soil water content. The soil water content was not related to CO2 emission in conventional tillage.The fields of conservation tillage were the sink of CH4 absorption in maize season. The lowest CH4 absorption fluxes were found in seedling stage and the highest was in grouting stage of maize. The order of CH4 absorption fluxes among different tillage models were: conventional tillage with no straw returning (AC) > conventional tillage with straw returning (PC) > subsoiling tillage with straw returning (PS)>harrow tillage with straw returning(PH)>rotary tillage with straw returning (PR)> zero tillage with no straw returning (PZ) The apex value of the N2O emission fluxes was found in seedling period and big-gob period, and the lowest apex value was in gain period. The N2O emission fluxes in conservation tillage were bigger than in conventional tillage. CO2 emission fluxes were the lowest in seedling stage, and the highest level of it was in big-gob stage. CO2 emission fluxes were bigger in conventional tillage than in conservation tillage.The general greenhouse effect was bigger in conventional tillage than in conservation tillage, zero tillage was the lowest in all treatment, and the biggest level of it was found in conventional tillage with straw returning treatment. Greenhouse effect was bigger in corn growth season than in wheat growth season. N2O and CO2 increased greenhouse effect, but CH4 decreased greenhouse effect. CO2 emission is the major factor in greenhouse effect.6. Effects of conservation tillage on the plant development and yieldThe basic seedling of wheat was lower significantly in zero tillage than in conventional tillage.The max winter tillering was slightly different with basic seedling of wheat. Harrow tillage with straw returning and harrow tillage with no straw returning were higher than conventional tillage with no straw returning, zero tillage with no straw returning, subsoil tillage with no straw returning, zero tillage with straw returning and subsoil tillage with straw returning were lower significantly than conventional tillage with no straw returning, but that of harrow tillage with no straw returning was no different with CK. In max spring tillering, no significant difference was found among AS, PH and AC, but that of zero tillage with no straw returning and zero tillage with straw returning were lower significantly than conventional tillage with no straw returning.In wheat growth season, in straw returning treatment, the numberof spike per hm2 was highest in conventional tillage; the weight per 1000 kernels was higher significantly in subsoil tillage than in conventional tillage, and that of zero tillage treatment was lower significantly than in conventional tillage; the grain yield was higher in subsoil tillage than in conventional tillage, and that of zero tillage and rotary tillage treatment was lower than conventional tillage treatment. In no straw returning treatment, the numbers of spike per hm2 was lower significantly in subsoil tillage, zero tillage and rotary tillage than in conventional tillage, and kernel numbers per spike was lower significantly in zero tillage and rotary tillage than in conventional tillage. Weight of per 1000 kernels was higher significnatly in subsoil tillage than in conventional tillage. Grain yield was higher in subsoil tillage than in conventional tillage, and that was lower in zero tillage and rotary tillage than in conventional tillage. In corn growth season, in straw returning treatment, the effects of conservation tillage on corn spike and spike row were significant. Weight of per 1000 kernels was higher in subsoil tillage than in conventional tillage, and that of zero tillage and rotary tillage was lower significantly than conventional tillage. Grain yield were higher in subsoil tillage and harrow tillage treatment than in conventional tillage, and that of zero tillage and rotary tillage were lower than conventional tillage. In same tillage treatment, grain yield were higher in straw returning than in no straw returning.更多还原