盐分胁迫条件下设施番茄根系吸氮模型构建

Under protected cultivation, vegetables could be produced around the whole year, significantly improving land utilization efficiency and crop output. However, salt accumulation in topsoil has become a common problem due to the closed environment and high input of water/fertilizer. Root uptake ability can be inhibited by saline stress. In this project, we will perform the hydroponic, pot and field experiments in tomato plants with different salt and nitrogen treatments, in order to explore the quantitative relation among tomato root nitrogen uptake, soil nitrogen, soil salt and root water uptake under saline stress. Meanwhile, we will build a root nitrogen uptake model under saline stress in tomato plant based on water/nitrogen uptake theories and data collected from our experiments. We will improve soil water-nitrogen-salt transport coupling model using the established root nitrogen uptake model under saline stress. The modified soil-nitrogen-salt transport coupling model will be used to simulate soil water, nitrogen and salt dynamics synchronously under saline stress, and optimize reasonable irrigation and N fertilization schedule. The results of this project could provide scientific basis and technical support for improving water and nitrogen use efficiency.

设施栽培可以周年生产蔬菜，显著提高了土地的利用率与产出率。由于设施封闭的环境和高投入的水肥管理模式，表层土壤盐分富集现象已经普遍发生。在盐分胁迫条件下，作物根系吸收功能会受到抑制。本项目拟以番茄为研究对象，通过布置水培、盆栽和设施生产试验，设置不同的氮素与盐分梯度，致力于探索盐分胁迫条件下番茄根系吸氮与土壤盐分、氮素及根系吸水之间的定量关系。同时，应用部分已有的根系吸水、吸氮模型构建理论及研究成果，构建盐分胁迫条件下的番茄根系吸氮模型，并对番茄栽培土壤水分、盐分、氮素运移耦合模型进行完善，同步模拟盐分胁迫条件下土壤水分、氮素、盐分动态。基于模拟结果，对灌溉施肥制度进行优化，为提高水分、氮素利用效率提供科学依据和技术支持。

设施农业可以周年生产各类蔬菜，显著提高了土地的利用率与产出率，已成为我国农业发展的主导产业之一。由于设施封闭的环境和高投入的水肥管理模式，土壤盐渍化的现象普遍发生，严重制约了设施农业的可持续发展。如果根区盐分过高，作物必然会受到盐分胁迫的影响。在盐分胁迫作用下，作物根系吸收功能会受到抑制，当前盐分胁迫对作物吸收功能的影响定量化表述的研究工作多围绕根系吸水模型构建开展，盐分胁迫对作物氮素吸收影响模型构建工作鲜有见到。本项目以设施番茄为研究对象，通过布置盆栽和设施生产试验，设置不同的养分和盐分处理，从模型构建角度研究盐分胁迫对番茄水分与氮素吸收影响机理，进一步建立盐分胁迫条件下设施番茄水分与氮素吸收模拟模型。结果表明，在设施条件下，通过灌溉水带入土壤中的盐分在番茄根系层出现了明显的富集。与此同时，番茄根区的土壤水分含量与氮素含量出现了明显的升高，这表明在作物根区土壤盐分累积形成的盐分胁迫作用件下，设施番茄的水分与氮素吸收功能受到了抑制。番茄的相对蒸腾速率与根区土壤饱和浸出液电导率呈线性关系；番茄氮素吸收速率与蒸腾速率呈线性正比关系。在此基础上，构建了盐分胁迫条件下设施番茄水分、氮素吸收模型，并进行了验证。验证结果表明，所构建模型输出的模拟值与实测值吻合良好，可以用于预测设施土壤盐分累积对设施番茄水分和氮素吸收过程的影响。从而为设施土壤盐分调控及作物水氮智能管理提供科学依据和技术支持。