盐渍农田间作系统的水肥耦合效应、机理及模拟研究

Efficient use of water and fertilizers is particularly crucial for the agricultural development in saline soils. The previously related studies mainly focused on monoculture. Compared with monoculture, intercropping makes better use of resources both in time and space, which has been an important planting pattern for the sustainable development of agriculture. However, the different salt tolerance of intercrops could change the distribution of salt in saline soils, which affects the use of resources (e.g. water and nutrient) and crop growth. Nevertheless, very few studies about intercropping, neither experiments nor modeling, were conducted on the above topics. This proposed project is to be carried out in Hetao Irrigation District where soil has been greatly influenced by salt. Sunflower and suaeda, which are then main industrial crop and halophytic crop in the study area, are selected as the study crops. Pot culture experiments are designed to precisely control the water, nitrogen, and root growth conditions. Meanwhile, field experiments are designed for additional evaluation and supplement and also for considering the effects of intercropping arrangements. The physio-ecological characteristics of sunflower and suaeda and the dynamics of soil water, salt, and nitrogen will be measured to (1) analyze the rule for water-fertilizer coupling of intercropping system; and (2) reveal the mechanism for the effects of salt on water-fertilizer coupling of intercropping system; and (3) establish crop growth model for intercropping system in saline soils. The expected achievements of this project will provide both the theoretical basis and strong practical tool for water and fertilizer managements and agricultural sustainable development.

水肥高效利用对于盐渍土地区的农业发展尤为关键，但目前相关的研究大多针对单作模式。与单作相比，间作在时间和空间上能够更有效地利用资源，是发展可持续农业的重要途径。但是在盐分胁迫下，不同间作作物由于其耐盐性的差异可能会改变土壤的盐分状况，影响作物对水肥等资源的利用，造成与单作不同的生长状况，但已有的间作系统实验和模型研究都极少考虑这些方面。本项目以内蒙古河套灌区盐渍化农田为背景，以当地主要的经济作物向日葵和盐生作物碱蓬为研究对象，通过盆栽实验精确控制间作系统的水肥条件和根系生长环境，通过大田实验进一步补充和验证，并考虑不同间作模式的影响，监测不同条件下间作作物的生理生态特征和土壤水、肥、盐动态。从而探索盐渍农田间作系统的水肥耦合效应；揭示盐分对间作系统水肥耦合的影响机理；建立盐渍农田间作系统的作物生长模型。本课题的研究成果可为我国北方盐渍农田的水肥管理和农业可持续发展提供理论依据和实用工具。

水肥高效利用对于盐渍土地区的农业发展尤为关键，但目前相关的研究大多针对单作模式。与单作相比，间作在时间和空间上能够更有效地利用资源，是发展可持续农业的重要途径。但是在盐分胁迫下，不同间作作物由于其耐盐性的差异可能会改变土壤的盐分状况，影响作物对水肥等资源的利用，造成与单作不同的生长状况，但已有的间作系统实验和模型研究都极少考虑这些方面。本项目以盐碱农田间作系统为研究对象，开展了田间试验，取得了大量试验数据，分析了盐碱农田间作系统的水盐运移与作物生长规律，初步揭示了盐碱农田间作系统的水肥耦合效应及盐分对间作系统水肥耦合的影响机理。在此基础上，对间作系统的辐射竞争与作物生长进行了定量描述，构建了盐碱农田间作系统的作物生长模型，并根据田间试验数据与已有文献中的数据对模型进行了率定和验证。本项目所揭示的规律与建立的模型能够为我国盐碱农田水肥管理和农业可持续发展提供理论依据和实用工具。