A study on synchronizing the supply of n from green manure in order to reduce or replace the use of swine slurry as a fertilizer for post-emergent corn, in the context of the transition to organic farming

Description

The organic field crop sector seeks to gain a better understanding of how the application of green manure (GM), as compared to animal manure (AM), can impact crop yields. Therefore, it is important to identify protocols that maximize nitrogen (N) intake, a critical aspect of organic farming, given the prohibition of mineral fertilizers. Generally a large portion of a crop’s nutritional requirements is met by AM, as compared to GM, because the former is rich in bioavailable N. However, AM also contains high phosphorus (P) levels, which can pose a major problem in areas where soils are already P saturated. The application of GM can also present challenges. For example, unlike AM--which can be applied as needed to satisfy crop N requirements, e.g., for post-emergent corn—GM needs time to accumulate adequate N levels in its tissue and this N must be made available through effective mineralization in a manner that synchronizes with the peak period of crop N requirements.

Another way to get the required N at the right time is to obtain a very fermentable N-rich GM cut a few days before the corn’s peak N need. The practice of obtaining such a cut, which can be taken from a nearby legume field, is commonly referred to as “cut and carry”. This may provide an alternative to GM sown at the height of the season or from catch crops during the prior year. Furthermore, this practice may lead to the preservation or restoration of grassland areas; which over the past 30 years have diminished by 25%, as more land is utilized for annual crops.

Objective(s)

This project aims to reduce or replace the use of swine slurry as a fertilizer for post-emergent corn, in the context of the transition to organic farming in Chaudière-Appalaches.