绿洲滴灌棉田土壤碳氮相互作用研究

发布时间：2018-06-10 01:09

本文选题：滴灌 + 棉花秸秆　；参考：《石河子大学》2017年硕士论文

【摘要】：【目的】土壤有机碳和氮直接影响土壤肥力和作物产量,对土壤生产力和可持续利用具有重要作用。研究农田管理措施(灌溉、施肥、秸秆还田等)对土壤有机碳、氮组分及含量的影响,明确滴灌棉田土壤有机碳和氮的变化规律,阐明土壤碳氮相互作用机制,提出土壤“增碳保氮”调控途径,为绿洲滴灌农田土壤可持续利用提供理论依据。【方法】采取野外调查和田间试验相结合,采集石河子垦区土壤样品200个,应用地统计学方法分析土壤有机质和全氮空间分布特征。田间小区试验包括水氮试验和碳氮试验。水氮试验采用水氮2因素3水平试验设计,灌溉定额设三个水平:360、480、600 mm(分别以W360、W480、W600表示);施氮量为:0、300、450 kg N hm~(-2)(分别以N0、N300、N450表示)。碳氮试验采用碳氮2因素3水平设计,设对照(CK)、棉花秸秆(ST)、生物碳(BC)三个施碳处理和0、300、450 kg N hm~(-2)三个施氮水平。【主要结果】(1)20世纪60~80年代,石河子垦区土壤有机质和全氮含量稳步增加;90年代以后有机质维持稳定,全氮含量持续增加,碳氮比降低。目前,垦区农田土壤有机质平均含量10.8 g kg-1,全氮平均含量0.68 g kg-1。有机质含量处于缺乏和很缺乏的面积占92%;全氮含量处于极缺乏的面积占28%,缺乏和很缺乏的占60%。土壤有机质和全氮的空间分布相似,总体呈现南高北低。(2)增加灌水量会降低土壤总有机碳、易氧化有机碳、水溶性有机碳含量以及土壤全氮和无机氮含量,提高有机物料降解率,土壤碳氮比无明显变化。增加施氮量显著降低土壤总有机碳、易氧化有机碳含量和全氮含量,提高土壤水溶性有机碳、微生物量碳含量和无机氮含量,加速有机物料分解,降低土壤碳氮比。(3)增加灌水和施氮显著提高土壤脲酶、β-葡萄糖苷酶(BG)和N-乙酰基-β-D-氨基葡萄糖苷酶(NAG)活性。不施氮(N0)和中氮(N300)条件下,土壤酶活性随灌水量增加(360~600 mm)而增加;而高氮(N450)条件下,中等灌水量处理(W480)土壤酶活性最高。棉花干物质重和氮素吸收量随灌水量和施氮量的增加显著增加。不施氮(N0)条件下,W600处理棉花籽棉产量显著高于W480和W360;施氮肥(N300和N450)条件下,W480处理棉花籽棉产量最高。(4)不施氮(N0)条件下,施用秸秆(ST)和生物碳(BC)土壤全氮含量变化不大或降低;施氮(N300和N450)条件下,ST和BC处理土壤全氮含量较CK分别提高39.2%和18.6%。不同施氮条件下,土壤总有机碳、易氧化有机碳和微生物量碳含量均表现为BCSTCK。N0条件下,ST和BC处理土壤碳氮比显著高于CK;N300和N450条件下,ST处理土壤碳氮比较CK降低15.7%,BC处理土壤碳氮比较CK增加23.3%。(5)ST处理土壤基础呼吸、β-葡萄糖苷酶(BG)和N-乙酰基-β-D-氨基葡萄糖苷酶(NAG)活性较CK分别提高16.5%、43.1%和71.8%;BC处理土壤基础呼吸较CK提高14.6%,BG和NAG活性影响不显著。不施氮(N0)条件下,秸秆(ST)和生物碳(BC)对棉花产量影响不显著;中氮(N300)条件下,ST和BC处理棉花产量分别较CK提高17.9%和24.8%;高氮(N450)条件下,秸秆对棉花产量影响不显著,生物碳显著提高棉花产量和氮肥表观利用率。【结论】石河子垦区滴灌农田土壤有机质和全氮含量总体偏低,且土壤碳氮比呈降低趋势。过量灌溉和施氮肥均会导致土壤有机碳和全氮含量显著降低。棉花秸秆还田配施氮肥可以提高土壤碳氮含量,但土壤碳氮比降低。生物碳和氮肥配施既可提高土壤碳氮含量,又能增加碳氮比,提高棉花产量和氮肥利用率,是滴灌农田土壤“增碳保氮”的有效措施。
[Abstract]:[Objective] soil organic carbon and nitrogen have a direct effect on soil fertility and crop yield, which play an important role in soil productivity and sustainable utilization. The effects of farmland management measures (irrigation, fertilization, straw returning and so on) on soil organic carbon, nitrogen components and content are studied, and the changes of soil organic carbon and nitrogen in the soil are clarified and the soil is clarified. The mechanism of carbon nitrogen interaction was proposed, and the regulation of soil "carbon and nitrogen conservation" was put forward to provide a theoretical basis for the sustainable utilization of soil in Oasis drip irrigation field. [method] 200 soil samples were collected in Shihezi reclamation area by field investigation and field test, and the spatial distribution characteristics of soil organic matter and total nitrogen were analyzed by the method of geostatistics. Field experiment includes water nitrogen test and carbon nitrogen test. Water nitrogen test uses 2 factors and 3 levels of water and nitrogen test design, irrigation quota is set up three levels: 360480600 mm (W360, W480, W600, respectively); nitrogen application is 0300450 kg N hm~ (-2) (N0, N300, N450, respectively). Carbon nitrogen 2 factor 3 level design and control (CK) ), cotton straw (ST), carbon (BC) three carbon application treatment and 0300450 kg N hm~ (-2) nitrogen application level. [main results] (1) in twentieth Century 60~80 years, the soil organic matter and total nitrogen content in Shihezi reclamation area increased steadily; after 90s, the organic matter remained stable, the total nitrogen content continued to increase, the carbon and nitrogen ratio decreased. The average content of the organic matter was 10.8 g kg-1, the average total nitrogen content was 0.68 g kg-1. in the lack and the very lack of area accounted for 92%; the total nitrogen content was in the extremely deficient area 28%. The spatial distribution of organic matter and total nitrogen in the soil was similar to the lack and lack of 60%., and the total nitrogen was low in the south. (2) increasing the amount of irrigation would reduce the total soil organic matter. Carbon, easy to oxidize organic carbon, water soluble organic carbon content and soil total nitrogen and inorganic nitrogen content, improve organic material degradation rate, soil carbon and nitrogen ratio no obvious change. Increase nitrogen fertilizer significantly reduce soil total organic carbon, oxidizing organic carbon content and total nitrogen content, improve soil water soluble organic carbon, microbial biomass carbon content and inorganic nitrogen content To accelerate organic material decomposition and reduce soil carbon and nitrogen ratio. (3) increase soil urease, beta glucosidase (BG) and N- acetyl - beta -D- glucosidase (NAG) activity. Under the condition of nitrogen (N0) and medium nitrogen (N300), soil enzyme activity increases with irrigation water increase (360~600 mm); while high nitrogen (N450), medium irrigation The soil enzyme activity was the highest in water treatment (W480). The dry matter weight and nitrogen absorption of cotton increased significantly with the increase of irrigation and nitrogen application. Under the condition of non nitrogen application (N0), the yield of cotton seed cotton was significantly higher than that of W480 and W360; under the condition of nitrogen application (N300 and N450), the yield of cotton seed cotton was the highest. (4) the application of straw under the condition of no nitrogen application (N0). The total nitrogen content in soil ST and BC soil changed little or decreased. Under the condition of nitrogen application (N300 and N450), the total nitrogen content of soil in ST and BC treatment increased by 39.2% and 18.6%. in different nitrogen application conditions, the total soil organic carbon, oxidizing organic carbon and microbial biomass carbon content were all under BCSTCK.N0 conditions, and ST and BC treated soil carbon and nitrogen ratio. Under the conditions of higher than CK, N300 and N450, ST treatment of soil carbon and nitrogen was reduced by 15.7%. BC treatment of soil carbon and nitrogen was increased by 23.3%. (5) ST treatment soil basal respiration, and the activity of beta glucosidase (BG) and N- acetyl beta glucosidase increased by 16.5%, 43.1% and 71.8%, respectively. And the effect of NAG activity was not significant. Under the condition of nitrogen (N0), the effect of straw (ST) and bio carbon (BC) on cotton yield was not significant. Under the condition of medium nitrogen (N300), the yield of cotton with ST and BC increased by 17.9% and 24.8%, respectively. Under the condition of high nitrogen (N450), the effect of straw on the yield of cotton was not significant, and the biological carbon significantly increased the yield of cotton and the apparent utilization of nitrogen fertilizer. [Conclusion] the content of organic matter and total nitrogen in soil of drip irrigation farmland in Shihezi reclamation area was generally low, and the soil carbon and nitrogen ratio decreased. Both excessive irrigation and nitrogen fertilizer could lead to a significant decrease in soil organic carbon and total nitrogen content. The amount of carbon and nitrogen in soil could be increased by the application of nitrogen fertilizer with cotton straw, but the soil carbon and nitrogen ratio decreased. The application of nitrogen fertilizer can not only increase the content of soil carbon and nitrogen, but also increase the ratio of carbon and nitrogen, increase the yield of cotton and the utilization rate of nitrogen fertilizer. It is an effective measure of "increasing carbon and nitrogen conservation" in the soil of drip irrigation farmland.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S562;S153

【参考文献】