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

曼尼托巴省南部的高价值灌溉作物生产正在扩大，那里水质差的地下水造成的盐碱化一直是一个重大问题。无论作物在哪里灌溉，它们都会吸收水分进行蒸发蒸腾，并留下盐分，随着时间的推移，这些盐分会在根区积累，改变其物理性质。一般来说，粘土颗粒在盐中钠离子存在的情况下容易分散，导致土壤结构的破坏，从而使土壤失去生产力。排水系统需要除去多余的水，用于浸出根区以下的盐。然而，传统的排水系统也可能会过度排水，导致宝贵的养分和水分流失。从田间输出的养分会影响下游河流和湖泊的水质。控制排水已被用于克服这一缺点。我的nserc资助的研究在温克勒进行了精心设计和复制的大规模现场实验，帮助马尼托巴首次将控制排水/地下灌溉作为一种实践。这项研究表明，灌溉和排水系统显著提高了马铃薯和玉米的产量，分别提高了30%和15%，促进了排水装置的蓬勃发展。然而，在春季融雪期和强降水期间，观察到显著的养分外流。与常规排水相比，控制排水可使养分流出量减少80 - 90%。因此，在春季融雪期和高强度降雨后，将水分保留在根区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。拟议的研究将使我们能够收集实地数据并创建计算机模型，以评估不同的水管理策略的影响。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，土壤物理特性将在几个农场进行测量，这些农场计划安装带有在线排水控制结构的瓦片排水沟，以提供地下灌溉的能力。这些数据将用于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，以管理油田内的水和养分。该研究项目的长期目标是建立方案，通过控制排水和灌溉来优化农田水资源管理，以长期保存农田内的水和养分，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，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.