Background
Green manuring is seen as a management option to improve the soil nutrient status for future seasons. Any crop can be used to green manure, but the most common options are legumes as an organic source of nitrogen. Brown manuring can refer to a chemical fallow or a sprayed out or unharvested crop. Whether a paddock is green or brown manured, the long term differences are very minor. No export of product occurs with either method, meaning all nutrients remain in the paddock for breakdown by the soil microbes.
This calculator provides a comparison of relative benefits between a green or brown manure phase and a grain crop within a defined rotational sequence. Results provide an indication of economic costs and benefits based on variable inputs. This calculator assumes the use of a legume crop.