水旱轮作体系的磷平衡与土壤磷有效化过程研究

发布时间：2018-03-07 00:06

  本文选题：磷平衡　切入点：水旱轮作　出处：《中国农业大学》2016年博士论文　论文类型：学位论文

【摘要】：水旱轮作是一种非常重要的提高作物产量、保障粮食安全的种植体系,其季节性的土壤干湿交替过程,以及不同类型作物(特别是根际过程差异较大的作物)参与轮作,使得水旱轮作体系成为研究土壤过程与植物根际过程产生剧烈交互作用的理想模式,其内在的养分平衡与转化机制并不清楚,理解根系介导的水旱轮作体系的养分平衡及有效化机制,对于优化这一传统体系,提高土壤磷的利用效率,具有重要的科学和实践意义。本研究针对以土壤干湿交替为特点的水旱轮作体系中的磷为研究对象,通过对大量数据的系统收集与综合分析,重点探讨我国长江流域中磷的表观平衡及演变规律,定量评价长江流域水旱轮作体系对该区域粮食生产、资源投入的历史贡献,通过对长江流域作物生产现状的综合分析,明确该系统中磷平衡存在的问题及可能的对策：同时,采用田间定位试验作为对上述关键科学问题的实证研究,通过田间(结合盆栽)试验综合评价了水旱轮作、水田连作、早地轮作三种不同轮作体系的作物生产力与磷平衡状况,并对土壤中磷的运移进行动态监测,综合分析了具有不同类型根际过程的作物对土壤磷利用方式的差异,揭示了干湿交替与不同根际过程对土壤磷平衡及有效化过程的影响,并探讨了内在的互作机制。为通过基于根际原理的作物-土壤系统的优化管理,提高土壤磷的利用效率实现可持续作物生产提供科学依据。本研究的主要结论和进展如下：(1)系统揭示了以水早轮作为典型农业种植体系的长江流域中磷的表观平衡及损失途径。长江流域的磷输入主要以化学肥料投入为主,长江流域磷输出的主要方式是通过水体带走的方式流失,而其中泥沙中所携带的颗粒磷占主导地位。长江流域磷表观平衡表现为以积累为主,从1971年开始出现盈余,随后年盈余量逐年递增,2010年达到180万吨每年,相当于当年全球磷肥总消费量的1/10。通过与其他流域历史变化对比,预测长江流域未来存在巨大的磷损失风险,因此提高区域内磷的循环再利用,挖掘土壤磷自身利用潜力,是避免磷环境风险的重要途径。(2)揭示了水旱轮作体系对区域粮食生产的贡献、磷肥的产量效应和演变规律。水旱轮作一直是长江流域农业生产中重要的种植体系,其水稻生产量占整个长江流域的80%,水旱轮作对于水稻产量的提高在1970年前养分投入较少的情况下,能够提升水稻总产达到1200万吨以上,占当时长江流域水稻产量的20%。水旱轮作体系中磷肥的肥料效应低于双季稻或旱地作物,表明水旱轮作体系能显著提高土壤自身磷的有效性。(3)明确了三种种植体系的产量效应、磷的平衡和损失途径,揭示了水旱轮作体系“土壤磷有效性高、但施肥不造成大量积累”的内在原因和机制。与水田连作和早地轮作体系相比,水旱轮作体系的总生物量和磷带出量最大,表明水旱轮作体系具有较高的生产力。发现盈余的磷下移到深层土壤(50-60 cm)的速率,三种体系具有显著差异,下移速率最快的是水旱轮作体系,每100kg Phm-2的盈余能够使下层土壤有效磷的浓度提高0.95 mg P kg-1,而旱地轮作为0.48 mgP kg-1,水田连作体系磷的下移趋势不明显,表明水旱轮作体系加剧了磷在土壤剖面中的下移,这可能促进了旱季深根作物小麦对下层磷的利用,小麦根系产生的土壤生物孔隙又进一步促进了水稻根系的生长和分布,这是水旱轮作体系中磷高效利用的一种重要机制。(4)证明了不同旱地作物高效获取磷的根际过程存在显著差异,据此可对磷利用方式进行功能分组。本研究首次应用主成分分析方法定量评价了根系形态与生理反应对磷吸收的贡献,结果表明以细根为主的作物(玉米、小麦和油菜)主要依靠根系形态的可塑性改变提高土壤磷的空间有效性,从而增强作物对磷的吸收。而以粗根为主的直根系作物(白羽扇豆和鹰嘴豆)主要是通过释放根分泌物(有机酸与酸性磷酸酶)增强土壤磷的生物有效性,从而提高作物对磷的获取效率。综上所述,本研究系统阐明了我国长江流域磷的表观平衡及演变规律,定量了长江流域水旱轮作体系对该区域粮食生产、资源投入的贡献,评价了水旱轮作、水田连作、旱地轮作三种不同轮作体系的作物生产力与磷平衡状况,作为对比研究,综合分析了具有不同类型根际过程的作物对土壤磷利用方式的差异,揭示了干湿交替与不同根际过程对土壤磷平衡及有效化的影响,为优化磷的管理,提高磷的利用效率提供了科学依据。
[Abstract]:The rotation is a very important to improve the crop yield, food security cropping system, the seasonal alternation of wetting and drying process, and different types of crops (especially crop rhizosphere process differences) in rotation, the rotation system became an ideal model for study of soil processes and plant rhizosphere process violently the interaction of its internal nutrient balance and conversion mechanism is not clear, understanding root mediated rotation system of nutrient balance and effective mechanism, to optimize the traditional system, improve the utilization efficiency of soil phosphorus, has important scientific and practical significance. This research according to the characteristics of paddy soil wetting the phosphorus in the rotation system as the research object, through the systematic collection and comprehensive analysis of a large number of data, focusing on China's Yangtze River in apparent phosphorus balance and evolution. Law, quantitative evaluation of the Yangtze River Basin on the paddy upland rotation system of regional grain production, historical contribution of resources, through a comprehensive analysis of the current situation of the Yangtze River Basin crop production, there is a clear phosphorus balance in the system problems and possible countermeasures: at the same time, by using field test as an empirical study on the key scientific issues, through the field (with the pot) test for comprehensive evaluation of the rotation, paddy cropping, crop productivity and phosphorus balance in early rotation of three different rotation system, and the migration of phosphorus in soil dynamic monitoring, comprehensive analysis of different types of rhizosphere of crops on Soil phosphorus utilization differences revealed dry effect of alternate with different rhizosphere processes on soil phosphorus balance and effective process, and discusses the internal mechanism of the interaction. Based on the principle of the rhizosphere for crop soil system The optimal management, improve the utilization efficiency of phosphorus to achieve sustainable crop production to provide a scientific basis. The main conclusions of this study are as follows: (1) and the progress of the system reveals the balance and loss of water in early round as a typical agricultural planting system in the Yangtze River Basin in the apparent phosphorus way. Phosphorus Input mainly chemical Yangtze River Basin. Fertilizer input, the main way of the Yangtze River Basin is the loss of phosphorus output by the water away, which carry particulate phosphorus in sediment is dominant. The apparent equilibrium performance of the Yangtze River Basin was mainly accumulated phosphorus surplus from 1971, the year surplus increased year by year, in 2010 reached 1 million 800 thousand tons per year. The global fertilizer was equivalent to the total consumption of 1/10. with other Valley historical changes in contrast, prediction of Yangtze River Basin has a huge future phosphorus loss risk, thus improving regional phosphorus cycle Then, the mining soil phosphorus utilization potential, is an important way to avoid the environmental risk of P. (2) reveals the contribution of rotation system on regional grain production, yield and fertilizer. The evolution law of rotation cropping system has been an important agricultural production in the Yangtze River Basin, the rice production accounted for the entire Yangtze River Basin 80%, the rotation for the increase in rice yield in 1970 before the nutrient input under the condition of less, can enhance the total rice production reached 12 million tons, accounting for the effect of fertilizer of rice yield in the Yangtze River Basin 20%. phosphorus fertilizer in paddy upland rotation system is lower than that of paddy or upland crops showed that the paddy upland rotation system can significantly improve the effectiveness of soil itself P. (3) the yield effect of three cropping system, balance and loss way of phosphorus, reveals the paddy upland rotation system of soil phosphorus availability is high, but without fertilization The reason and the mechanism into a large number of accumulation ". Compared with paddy cropping and early cropping system, rotation system of total biomass and phosphorus with the largest amount of that rotation system has high productivity. Phosphorus surplus down deep into the soil (50-60 cm) rate of three, with significant system the difference, down the rate is fastest rotation system, each 100kg Phm-2 earnings can make the lower soil available phosphorus concentration increased by 0.95 mg P kg-1, and mgP kg-1 as the 0.48 round of dryland cropping system of paddy field, the downward trend of phosphorus is not obvious, water drought exacerbated the downward rotation system of phosphorus in the soil profile. This may promote the use of lower phosphorus during the dry season deep root crop wheat, soil biological pore and further promote the wheat root growth and distribution of rice root, this is the high efficient utilization of phosphorus in rice wheat rotation system One of the important mechanisms. (4) proved that there are significant differences in rhizosphere processes of different upland crops to obtain high phosphorus, which can function on packet P utilization. This is the first study using the principal component analysis method for quantitative evaluation of root morphological and physiological responses to phosphorus absorption contribution, the results show that the fine root crops (mainly corn, wheat and rape) mainly depends on the plasticity of root morphological changes improve the spatial effectiveness of soil phosphorus, thereby enhancing the absorption of phosphorus in root crops. The main root crops (mainly coarse white lupin and chickpea) is mainly through the release of root exudates (organic acid and acid phosphatase) enhance the bioavailability of soil P, so as to improve crop P acquisition efficiency. In conclusion, this study clarifies the concept of system balance and the evolution of China's Yangtze River phosphorus quantitative table, the Yangtze River Basin water dry rotation system on The regional food production resources, the contribution of investment, evaluation of the rotation, paddy cropping, crop productivity and phosphorus balance in three different cropping system on rotation, as comparative study, comprehensive analysis of different types of crop rhizosphere processes on soil phosphorus utilization differences, reveals the effect of alternate wetting and drying with different root when the process of soil phosphorus balance and efficiency, to optimize the phosphorus management, provide a scientific basis for improving the utilization efficiency of phosphorus.

【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S344.17;S153.6
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本文编号：1577066