Optimizing water management for increasing production while conserving water and nutrients within agricultural lands

马尼托巴省南部灌溉的高价值作物生产正在扩大，那里劣质地下水造成的盐碱化一直是一个严重的问题。无论作物在哪里灌溉，灌溉用水都会吸收用于蒸散的水分，并留下随时间积累在根区的盐分，从而改变作物的物理性质。通常，粘土颗粒在盐中的钠离子存在的情况下往往会分散，导致土壤结构的破坏，从而使土壤失去生产力。需要排水系统来清除用来淋滤根部以下盐分的多余水。然而，传统的排水系统也可能会过度排干田地，带走宝贵的养分和水。从田间输出的营养物质会影响下游河流和湖泊的水质。控制排水已被用来克服这一缺点。我的这项由NSERC资助的研究是在密歇根州温克勒进行的精心设计和重复的大规模田间试验中进行的，帮助马尼托巴省首次将控制排水/次灌溉作为一种做法。这项研究表明，灌溉和排水系统显著提高了土豆和玉米的产量，分别提高了30%和15%，促进了排水设施的繁荣。然而，在春季融雪期和高强度降雨期间，观察到了显著的营养物质外流。与常规排水相比，控制排水减少了80%~90%的营养物质外流。因此，在春季融雪期和强降雨之后，在根区内保持水分是减少田间养分输出的最佳管理实践(BMP)。然而，由于春季地下水位较高，这种做法可能会对土壤的通过能力产生负面影响。拟议的研究将使我们能够收集实地数据并创建计算机模型，以评估不同水管理战略的影响。这项研究将有助于制定管理控制排水的协议，以优化现场的水管理。在短期内，将对几个计划安装瓦片排水沟的农场的土壤物理性质进行测量，这些农场具有内联排水控制结构，能够进行地下灌溉。这些数据将被用来创建单个农场的计算机模型，并对模型进行校准和验证。经过验证的模型将制定优化的操作计划，以管理田间的水和养分。这项研究计划的长期目标是制定协议，通过控制排水和灌溉来优化农业水管理，以保存田地内的水和养分，并长期保护土壤和水资源。开发基于网络的水和养分管理工具将极大地帮助农民管理水和养分，以在保护环境的同时获得更好的回报。

Irrigated high-value crop production is expanding in Southern Manitoba, where salinization from poor quality groundwater has been a significant concern. Wherever irrigation water is applied to crops, they take up the water for evapotranspiration and leave behind the salts which accumulate within the root zone over time and alter the physical properties. Generally, clay particles tend to disperse in the presence of sodium ions in the salts, leading to the destruction of the soil structure, which renders the soil unproductive. Drainage systems are needed to remove the excess water applied to leach the salts below the root zone. However, conventional drainage systems may also over-drain the field, removing valuable nutrients and water. The exported nutrients from the field can affect the water quality of rivers and lakes downstream. Controlled drainage has been used to overcome this shortcoming. My NSERC-funded research conducted in well-designed and replicated large-scale field experiments in Winkler, MB, helped introduce controlled drainage/subirrigation as a practice for the first time in Manitoba. This research indicated that irrigation and drainage systems significantly improved yield by 30% in potatoes and 15% in corn, contributing to a boom in drainage installations. However, significant nutrient outflows were observed during the spring snowmelt period as well as during high-intensity rainfall. Controlled drainage was shown to decrease the nutrient outflow by 80 to 90% compared to conventional drainage. Therefore, holding the water back within the root zone during the spring snowmelt period and after high-intensity rainfall was a best management practice (BMP) to minimize nutrient export from the field. However, this practice may negatively impact soil trafficability due to high water tables during the spring. The proposed research will allow us to collect field data and create computer models that can assess the impact of different water management strategies. This research will help develop protocols for managing controlled drainage to optimize water management in the field. In the short term, soil physical properties will be measured in several farms planning to install tile drains with inline drainage control structures providing the ability to subirrigate. This data will be used to create computer models of individual farms and calibrate and validate the models. The validated models will develop an optimized operational plan to manage the water and nutrients within the field. The long-term objective of this research program is to establish protocols to optimize farm water management through controlled drainage and irrigation to conserve water and nutrients within the field and protect the soil and water resources for the long term. Developing a web-based water and nutrient management tool will significantly assist farmers in managing the water and nutrients to get a better return while protecting the environment.