【作者】 颜雄；

【导师】 张杨珠； 彭新华；

【作者基本信息】 湖南农业大学 ， 土壤学， 2013， 博士

【摘要】 伴随着全球气候的变暖和现代农业的发展,生态环境的破坏和资源的日益稀缺等问题日益凸显,土壤质量的保育与土壤资源的可持续性利用已经成为当今农业科学与生态环境领域的热门研究课题。本研究以设立在江西省进贤红壤研究所内由第四纪红色粘土发育的红壤性水稻土和旱地红壤上的长期定位试验各施肥处理土壤作为研究对象,探讨不同施肥措施对土壤肥力质量、有机碳库的分布与周转和土壤团聚体的形成与稳定的影响,为指导农业生产,加强农田养分管理,实现土壤的可持续利用和农业可持续发展提供科学依据。本文研究结果如下：(1)长期施肥对红壤性水稻土和红壤旱地的肥力性质影响显著。与长期不施肥处理相比,施化学N肥处理的土壤pH值都有所降低,施用化学氮肥是导致红壤pH降低的主要原因之一,旱地红壤比水稻土酸化程度更为明显。有机无机肥配施处理(NPKOM)则较明显地抑制土壤酸化,显著提高了土壤肥力。与试验开始前相比,所有处理的有机C含量都有升高,说明土壤有机质的增加主要是来自作物根茬的返田或施用有机肥。因此,采用有机无机肥配施模式最有利于土壤肥力水平的提高和土壤的可持续利用。(2)应用Fuzzy综合评判法对各处理土壤的肥力质量进行数值化的综合评价表明,红壤性水稻土和旱地红壤的NPKOM处理土壤肥力质量均属于二级,水稻土其他施肥处理的土壤肥力质量均属于三级,旱地的NPK和2NPK处理的土壤肥力质量属于三级,其他处理属于四级。旱地的整体土壤肥力质量比水稻土低。两种土壤均是有机无机配施肥最有利于土壤肥力质量的提升,单施氮肥处理的土壤肥力质量都明显降低。(3)土地利用方式和长期施肥显著改变土壤有机碳库中颗粒有机碳的组成(cPOM、fPOM、iPOM_mM)。其中,水稻土微团聚体中的有机碳库占土壤总有机碳库的60%以上,旱地红壤矿物结合态有机C占绝大部分。通过室内59天的好气培养,C02-Ct累积量的高低顺序为微团聚体>原土>粉黏粒。旱地的土壤有机碳的半衰期基本都远远大于水稻土,周转速率比水稻土要慢。施用有机肥能提高土壤有机碳库的周转速率,促进土壤有机碳库的更新。在水田和旱地两个生态系统中,土壤固碳与有机碳投入均呈指数型增长关系,水稻土的固碳效率(ΔSOC/ΔC input)和土壤有机碳储量明显高于旱地。水淹状况下有机质的矿化速率比较低,说明在嫌气条件下,微生物活性比好气条件下要低。(4)对CK、NPK和NPKOM三种施肥模式的土壤团聚体进行不同方式(Water作为对照、Ammonium oxalate、DCB和H202)浸提处理后,通过分析比表面积、铁铝氧化物和有机质的关系,结果表明,水稻土0.053-0.25mm团聚体的胶结物质以游离氧化铁铝为主,其他粒级以有机质为主；早地红壤0.25-2.0mm团聚体的胶结物质以有机质为主,0.053-0.25mm团聚体以游离氧化铁铝胶结为主,铁铝氧化物为<0.053mm团聚体比表面积的主要影响因素。(5)不同施肥模式影响作物的生物产量和养分吸收量。籽粒产量占水稻总生物量的50%以上。与CK相比,一元施肥处理中单施P肥能够提高水稻籽粒产量,除N、K、NK处理低于CK外,其它各处理秸秆和根茬生物量都有所提高。说明磷肥在提高籽粒产量、秸秆和根茬生物量方面发挥了重要作用。NPKOM处理显著增加作物的生物量。玉米的秸秆生物量占50%左右,单施氮肥处理各器官的生物量均最低,说明单施氮肥处理导致了玉米大幅减产。SOC和土壤碱解N对水稻和玉米各器官生物量的影响均达到极显著水平。土壤全P和有效P对地上部生物产量的影响也是极显著的,土壤K养分对玉米生物量影响较小。水稻和玉米吸收的N、P养分都主要分布在籽粒中,而吸收的K主要分布在秸秆中。更多还原

【Abstract】 Along with the global warming and the development of modern agriculture, the problems of environmental degradation and resource scarcity have been more prominent, in order to keeping the quality of soil conservation and the sustainable use of soil resources the study of soil fertility quality, soil organic carbon pools and soil structure has become an important research field. In this study, paddy and upland red soils which derived from quaternary red clay had been chosen as the research materials. Affected by different patterns of fertilization, long-term fertilization plots are located in Jiangxi Provincial Red Soil Research Institute, the soil fertility quality, soil organic carbon pools distribution and turnover rates, stability of soil aggregates and the effects on soil aggregate stability were investigated. Thereby, it is meaningful to guide the agricultural production, strengthen the farmland nutrient management and finally realize the sustainable development of agriculture.The main results are showed as follows:(1) The long-term fertilization treatments significantly affected the properties of soil. The long-term application of N fertilizer may lead to soil acidification. In upland soil the soil pH values were significantly lower than in paddy soil. Only the NPKOM treatment effectively inhibited the soil acidification and significantly improved soil fertility quality. The SOC content of all treatments increased as a result of stubble and organic fertilizer remaining in the fields since the beginning of the experiment. Therefore, the combined application of inorganic and organic fertilizer is benefited for enriching soil nutrients and the sustainable development of agriculture.(2) The results of evaluating on the soil fertility quality by use of the Fuzzy comprehensive assessment showed:The NPKOM treatment in paddy soil and upland soil belonged to2grade and others were in the3grade. The upland soil under NPK,2NPK treatment belonged to3grade, and others were in the4grade. However, the fertility quality of upland soil was lower than paddy soil. The results described above illustrated that the application of chemical fertilizer plus organic manure will enhance the soil fertility quality in two soils. The quality of single application of N fertilizer had a decreasing trend on both soils.(3) The land use and long-term fertilization significantly changed the composition of POM associated C pools (cPOM、fPOM and iPOM_mM). The C conten of mM accounted for60%in paddy soil whereas the mineral associated C was mainly in upland soil. Through59days laboratory aerobic incubation, the cumulation of CO2-Ct followed the order of microaggregate, original soil and silt clay. The half-life of upland soil was larger than paddy soil, however, soil organic carbon pool turnover rate is slower. Therefore, the application of organic fertilizer can increase soil organic carbon pool turnover rate, and promote to update soil organic carbon pool. In the two ecosystems, the results showed a growing exponentially positive correlation between soil carbon sequestration and SOC input. The higher carbon sequestration efficiency (ΔSOC/ΔC input) and SOC pools in paddy soil explained that organic matter mineralization rate is relatively low under flooded. Apparently, microbial activity in anaerobic conditions is lower than in aerobic conditions.(4) In this paper, we chosed three long-term fertilizer treatments (CK, NPK and NPKOM) of the paddy soil and upland soil to study the formation mechanism of soil aggregates. After extracting from four treatments (Water treatment, Oxalate treatment, DCB treatment and H2O2treatment), throgh discussing the contents of organic carbon, iron and aluminum oxides and specific surface area, the results showed:at0.053-0.25mm level, free iron and aluminum oxides instead of organic matter acted as the main cementing substance of soil aggregates in paddy soil. Unlike paddy soil, in upland soil the main cementing substance was organic matter at0.25～2mm level or iron and aluminum oxides at0.053～0.25mm level.At<0.053mm level, iron and aluminum oxides were the main factors of specific surface area.(5) The biomass of different organs of rice and maize were affected by different fertilization patterns. Overall, The grain yield of rice biomass accounted for more than50%. Compared with CK, only single application of P fertilizer could improve rice grain yield among one-factor fertilization. The results revealed that P fertilizer has played an important role in raising grain yield and biomass of straw and stubble. NPKOM treatment significantly improved crop biomass and promoted system productivity. Maize straw biomass of total biomass accounted for about50%. The maize biomass is the lowest under the application of N fertilizer, indicating that the application of N fertilizer may decline the production of maize.The SOC and alkalized N reached extremely significant level with all organs of maize. Total P and available P has a significantly impaction on aboveground biomass. From the point of nutrient uptake of crops, N and P uptake of rice and maize were mainly absorbed in grains, and K nutrient was in straw.更多还原