Optimizing water management for sustainable use of agricultural lands and water

在马尼托巴南部，由于地下水质量差而造成的盐碱化一直是一个主要问题，因此灌溉正在扩大。只要灌溉水被用于植物，植物就会吸收水分，并在根区留下盐分，导致盐碱化。排水系统可以用来去除多余的水，用于冲洗根区以下的盐，以减轻盐碱化。然而，传统的排水系统也可能过度排水，带走宝贵的养分和水分。 控制排水可以用来克服这一缺点。* 以前NSERC资助的田间规模研究表明，适当设计和管理的灌溉和排水系统可以显着提高马铃薯产量30%和玉米产量15%。 然而，主要的营养外流观察瓷砖排水在春季融雪期，以及在高强度降雨。 与传统排水相比，使用排水控制结构（DCS）的控制排水可以将田间的水截留下来，从而降低90%的养分流失。DCS的使用被认为是最佳的管理实践，以尽量减少营养输出从外地。 然而，由于春季地下水位较高，这种做法可能会对土壤的可通行性产生负面影响。 拟议的研究将优化控制排水的操作，以阻止田间的水和养分，同时提高通行能力。DCS还可以促进地下灌溉，其中灌溉水通过DCS进入地下排水沟。 然而，地下灌溉水的向上通量可能会受到限制，如果根区下面的土壤变得太干。 这项研究的数据将用于Hydrus 2D/3D模型，以模拟不同的土壤类型和天气条件，并确定适合地下灌溉的土壤。短期内的主要目标是：（1）监测根部区域内的水和养分流动情况，以评估地下灌溉/排水系统对作物产量和水质的影响;（2）确定地下水位的最佳深度，以便在保持田地内的水和养分的同时，仍能进行田地作业;（3）确定了高蒸散期地下灌溉的最佳水位深度。 我将使用NSERC发现补助金部分支持三个博士，五个硕士和十二个理学士学生。农民将受益于提高产量和更好地保持农田内的养分。从长远来看，目标将是优化结合地下灌溉/控制排水系统的综合水管理系统，并制定一项成功实施的选址协议。长期目标是管理农田内的水和养分，实现农场规模的农业可持续性，并尽量减少养分流入河流和湖泊。 ********

Irrigation is expanding in Southern Manitoba in areas where salinization from poor quality groundwater has been a major problem. Wherever irrigation water is applied to plants, the plants take up the water and leave behind the salts within the root zone leading to salinization. Drainage systems can be used to remove the excess water applied to wash the salts below the rootzone to mitigate salinization. However, conventional drainage systems may also over-drain the field, removing valuable nutrients and water. Controlled drainage can be used to overcome this shortcoming. ***Previous NSERC funded field-scale research showed that properly designed and managed irrigation and drainage systems can significantly improve yield by 30% in potatoes and 15% in corn. However, major nutrient outflows were observed in tile drainage during spring snowmelt period as well as during high intensity rainfall. Controlled drainage using Drainage Control Structures (DCS) that can hold back the water within the field was shown to lower the nutrient outflow by 90% compared to conventional drainage. The use of DCS was found to be a best management practice to minimize nutrient export from the field. However, this practice may negatively impact soil trafficability due to the high water table in the spring. The proposed research will optimize the operation of controlled drainage to hold back the water and nutrients within the field while allowing improved trafficability. The DCS can also facilitate subirrigation where the irrigation water is applied through the DCS into the subsurface drains. However, the upward flux of subirrigated water may be restricted if the soil beneath the root zone becomes too dry. The data from this research will be used in Hydrus 2D/3D model to simulate different soil types and weather conditions and identify soils suitable for subirrigation.***In the short term, the main objectives will be to (1) monitor the water and nutrient movement within the root zone to assess the impact of subirrigation/drainage systems on crop yield and water quality; (2) determine the optimum depth of the water table that will still allow field operations while conserving the water and nutrients within the field; (3) determined the optimum depth of water table that will allow subirrigation during periods of high evapotranspiration. I will use the NSERC Discovery grant to partially support three PhD, five MSc, and twelve BSc students. Farmers will benefit from improved yields and better nutrient retention within the field.***In the long term, the objective will be to optimize the integrated water management systems combining subirrigation/controlled drainage systems and develop a protocol for site selection for successful implementation. The long-term goal is to manage the water and nutrients within the field and attain agricultural sustainability at the farm-scale and minimize the nutrient outflow into the rivers and lakes. ********