Measuring and modeling soil water budgets

水是我们最宝贵的资源。该研究项目将促进在不同农业管理实践和气候制度下测量和模拟农田土壤中的水流和污染物运输的知识。研究结果将引起农产品集团、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和地下水资源的人员的极大兴趣。研究结果可用于预测养分和肥料施用的最小影响时间、灌溉时间和灌溉量、排水系统设计以减少地下水污染等。该研究项目的主要目标是开发在不同农业管理方法和气候条件下测量和模拟土壤水文特性时间变异性的新方法，利用实地数据校准和验证新模型，并为加拿大不同地区建立长期土壤水分平衡数据库。仪器开发、实地工作和计算机建模的结合将用于实现这些目标。第一步是开发利用多用途土壤水分传感器在野外自动连续测量土壤水文特性的新方法。田间数据将用于校准和测试一个新模型，该模型利用作物、气候和土壤水文特性数据作为主要输入来估计土壤水分平衡。新模型将包括对许多加拿大农业地区至关重要的因素，如冻结和解冻的影响，瓦片排水，以及土壤水文特性对估计土壤水分平衡的时间变异性。即使在当今最复杂的水平衡模拟模型中，目前也无法考虑生长期和非生长期土壤水文特性变化的影响。土壤水文特性的时间变异性可能比空间变异性更重要，但它受到的关注相对较少。作为一个长期目标，模型估计的加拿大不同种植制度和地区的蒸散发、深排水和径流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.