滨海盐碱地滴灌水盐调控植物适生土壤环境形成机制及快速构建途径研究

Drip irrigation technology has become an effective way to salt leaching and reclamation of saline land, and been successfully used in vegetation construction of coastal saline soil as a water-salt regulation method, because of its characteristics that the unsaturated movement of water does not destroy the soil structure and high frequency irrigation can compensate for the reduced water potential due to the presence of salt. However, the quantitative research on soil environment dynamic process, such as salt leaching process, salt ions content variation and microbiological status, under water-salt regulation by an unsaturated soil moisture flow of drip irrigation, has not been well studied currently, and there is also little systematic knowledge on formation mechanism of soil environment suitable for plant by water-salt regulation of drip irrigation. So we selecting silt and sandy loam coastal saline soils as research object, this study mainly focus on (1) the effects of water-salt regulation of drip irrigation on the main soil environmental factors, such as soil physical and chemical properties and microbiological status, in coastal saline land, as well as the quantification of its dynamic process; (2) the response mechanism of plant growth, physiological and biochemical to soil environmental variation processes, by means of soil column experiments, soil cultivation experiments, field trials, statistical analysis and model construction, in order to reveal the interaction mechanism between soil environment dynamic process and plant under water-salt regulation of drip irrigation, and propose a rapid construction approach of suitable soil environment for plant. The research results have important guiding values for the agriculture and vegetation ecological system construction in coastal saline land.

滴灌技术因水分非饱和运动不破坏土壤结构,高频灌溉可补偿因盐分存在而降低的水势等特点，成为一种淋洗盐分、改良盐碱地的有效途径，并被成功应用于滨海盐碱地水盐调控原土植被建设。但目前有关滴灌土壤水分非饱和运动水盐调控盐分淋洗过程、盐离子组分含量变化、微生物状况等土壤环境动态过程的定量化研究尚不深入，缺乏对滴灌水盐调控植物适生土壤环境形成机制的系统认识。本项目选择泥质和沙质两种典型滨海盐渍土，采用室内土柱模拟实验、土柱栽培实验与田间试验相结合的方法，通过统计分析与模型构建，重点研究（1）滴灌水盐调控对滨海盐碱地土壤理化性质和微生物状况等主要环境因子的影响及其动态过程的定量化；（2）植物生长、生理、生化对土壤环境变化过程的响应机制。以期揭示滨海盐碱地滴灌水盐调控土壤环境动态变化过程与植物相互作用机理，提出植物适生土壤环境快速构建途径。研究成果对于盐碱地农业利用与植被生态系统构建具有重要的指导价值。

滨海盐渍土是沿海地区重要的后备耕地以及建设用地资源。滴灌技术因水分非饱和运动不破坏土壤结构，高频灌溉可补偿因盐分存在而降低的水势等特点，成为一种淋洗盐分、改良盐碱地的有效途径，并被成功应用于滨海盐碱地水盐调控原土植被建设。但目前有关滴灌土壤水分非饱和运动水盐调控盐分淋洗过程、盐离子组分含量变化、微生物状况等土壤环境动态过程的定量化研究尚不深入，缺乏对滴灌水盐调控植物适生土壤环境形成机制的系统认识。本项目选择泥质和沙质两种典型滨海盐渍土，采用室内土柱模拟实验与田间试验相结合的方法，通过统计分析与数值方程构建，重点研究（1）滴灌水盐调控对滨海盐碱地土壤理化性质和微生物状况等主要环境因子的影响及其动态过程的定量化；（2）植物对滨海盐碱地土壤环境变化过程的响应机制；（3）特定盐渍逆境因子调控的滨海盐碱地土壤环境和植物响应机制等内容。通过开展系统的试验研究与数值分析，明确和定量化了典型滨海盐渍土滴灌非饱和水盐调控下土壤水盐运移规律及土壤盐分、pH、养分、微生物等理化性质和生物性状的改良过程，揭示滨海盐碱地滴灌水盐调控过程中盐渍逆境胁迫因子动态过程及植物生长响应关系，深化了盐渍土土壤-植物互作互馈机制的认识，在对特定盐渍逆境胁迫因子调控植物适生土壤环境形成过程试验研究基础上，提出了滨海盐碱地滴灌水盐调控植物适生土壤环境的快速构建方法。暨采用滴灌水肥一体化添加工业用粗磷酸致微咸水（3g/L）灌溉水pH为7.5时，加工业用粗磷酸致淡水灌溉水pH为7左右，施用钾肥含量为测土配方钾肥施用量的160%，可为滨海盐碱地滴灌条件下植物生长创造一个适宜的土壤环境。采用该方法可以有效调控盐碱地脱盐过程中pH升高和钠离子存在造成的盐碱胁迫，增强植物长势，提高植物成活率，增加作物产量，方法简便、省工、成本低，对滨海地区盐碱地的农业开发和植被建设具有重要的应用价值和意义，也可以应用到内陆盐碱地的治理中，应用前景广阔。