Estimating nutrient loss to waterways—an overview of models of relevance to New Zealand pastoral farms

摘要

Abstract Reliable estimation of nutrient losses from farmland is of increasing interest, driven by both economic and environmental concerns. Routine direct measurement of nutrient losses is currently impractical given the scale and variability of the problem. Simulation models are the best alternative and their use for assessing potential nutrient losses has been increasing worldwide. In New Zealand, there are a considerable number of models in use, or that are being developed, aiming to estimate N and P losses from pastoral fields. This range of alternative models reflects both the different level of detail and scale at which N and P losses can be estimated, and the diverse range of purposes assumed during the model development. Thus, it is important to understand the differences between models in order to select the one that will produce estimates appropriate to the intended use. This work presents an overview of the principal models for estimating nutrient loss being used or developed in New Zealand. I...