Measuring and modeling soil water budgets

水是我们最宝贵的资源。这项研究计划将增进在不同农业管理实践和气候条件下测量和模拟田间土壤中的水流和污染物运移的知识。研究结果将对农业商品组、政府农业研究科学家和工程师以及其他管理和研究农村地区土壤水资源和地下水资源的人产生重大兴趣。研究结果可用于预测养分和有机肥应用的最小影响时间、灌溉时间和数量、设计排水系统以最大限度地减少地下水污染等。该研究计划的主要目标是开发新的方法来测量和模拟不同农业管理措施和气候制度下土壤水文特性的时间变异性，使用田间数据校准和验证新的模型，并开发加拿大不同地区长期土壤水分平衡的数据库。将结合仪器开发、现场工作和计算机建模来实现这些目标。第一步是开发新的方法，利用多用途土壤水分传感器在田间自动和连续地测量土壤水文特性。田间数据将被用来校准和测试一个新的模型，该模型以作物、气候和土壤水文特性数据为主要输入来估计土壤水分平衡。新的模型将包括对许多加拿大农业区至关重要的因素，如冻结和融化、瓦片排水和土壤水文特性的时间变异性对估计的土壤水平衡的影响。即使在当今最复杂的水量平衡模拟模型中，也不能考虑生长季节和非生长季节土壤水文性质变化的影响。土壤水文性质的时间变异性可能比空间变异性更重要，但相对较少受到关注。作为一个长期目标，加拿大不同种植制度和地区的蒸散量、深层排水和径流模型估计数据库将在互联网上向公众开放。

Water is our most precious resource. This research program will advance knowledge on measuring and modeling water flow and contaminant transport through field soils under different agricultural management practices and climatic regimes. The research results will be of significant interest to farm commodity groups, government agricultural research scientists and engineers, and others managing and studying soil water and groundwater resources in rural areas. The results could be used to predict least-impact timing of nutrient and manure applications, irrigation timing and amount, design of drainage systems to minimize groundwater contamination, etc. The main objectives of the research program are to develop new methods of measuring and modeling temporal variability of soil hydrologic properties under different agricultural management practices and climatic regimes, calibrate and validate new models using the field data, and develop a database of long-term soil water balances for different regions of Canada. A combination of instrument development, fieldwork and computer modeling will be used to fulfill the objectives. The first step is to develop novel methods of automatically and continuously measuring soil hydrologic properties in the field using multipurpose soil water sensors. The field data will be used to calibrate and test a new model that estimates the soil water balance using crop, climatic and soil hydrologic property data as main inputs. The new model will include factors critical to many Canadian agricultural regions such as the effects of freezing and thawing, tile drainage, and temporal variability of soil hydrologic properties on the estimated soil water balance. Even in today's most sophisticated water balance simulation models, allowing for the effects of changes in soil hydrologic properties during the growing and non-growing seasons is currently unavailable. Temporal variability in soil hydrologic properties may be even more important than spatial, but it has received relatively little attention. As a long-term goal, the database of model estimated evapotranspiration, deep drainage, and runoff for different cropping systems and regions in Canada will be made available to the public on the Internet.