Aim:
There has been little work done on developing management options for cover crops and determining their benefits in the cropping rotation. This project aims to identify suitable cover crops, develop methods for managing the cover crops in the rotation and determine their benefits to subsequent crops. Growers will therefore be more confident about the use of cover crops and this will have a positive impact on grain production. In addition, the longer term benefits of cover crops in the rotation will be determined through another closely linked WANTFA project "New Frontiers No-Tillage Farming Systems". This long term study is designed to develop a more sustainable no-tillage system through the retention of complete cover on the soil, use of cover crops and disc seeders. This long term study will further emphasise the role of cover crops and promote their use.
Background:
The benefits of no-till are obvious; however, the system appears to have reached a plateau in Australia and a number of challenges have emerged. A recent situation analysis of no-till carried out by Rolf Derpsch, an international conservation agriculture expert, identified the main threats to no-till as: insufficient crop residues remaining on the soil surface, cereal monoculture hence a lack of crop diversity and herbicide resistant weeds. One of his key recommendations was to select and develop suitable cover crops to provide soil protection, add diversity to the system and to smother weeds (Derpsch, 2005). Cover crops are plants that are primarily sown not to be harvested for food but to produce biomass and keep the soil covered in order to prevent erosion. They can assist weed control, add diversity to the system and improve soil health by conserving and loosening the soil, cycling nutrients, contributing nitrogen and organic matter and promoting soil biological activity. Therefore, the successful adoption of cover crops will have a major impact on conservation farming systems.
Cover crops must be cheap to manage and provide some benefits to farmers if they are to be used in the rotation. There are a number of different options for cover crops including warm season (summer), cool season (winter) and plants such as grass species, brasicca, and various legumes. Two cover crop screening trials have already been done by WANTFA and some promising material identified. In addition, the project will build upon the work of the Centre for Legumes in Mediterranean Agriculture (CLIMA), Department of Agriculture Western Australia (DAFWA) and Murdoch University scientists who have developed some excellent pasture material that is suited to WA and could be used for low cost cover crops. The hard seeded characteristic of some of these new species of pastures (e.g. serradella, biserrula, Prima Gland Clover and Eastern Star Clover) and the recent, concurrent, development of ALOSCA granules for inoculation (the inoculant can survive in dry soil) now provide a tremendous opportunity for low cost cover crops: The cover crop and inoculant can be under sown with hard seed at seeding time of a cereal crop and the following year the cover crop will establish itself. The creation of a sufficiently large seed bank in the first year or two will mean that the cover crop can re-establish itself every few years after cropping at virtually no cost.
Objectives:
The information generated in this project will improve the management of cover crops and highlight the benefits. This will encourage the use of these crops in the rotation. The expected environmental benefits include increased diversity and soil cover, addition of nitrogen from legumes and improved weed control. The economic benefits are from the reduced cost of nitrogen fertiliser and improved yields in the subsequent cash crops.
Output:
The output from the project was achieved by a series of trials, field days, widely distributed publications and travel to our CAAANZ collaborators. A comprehensive guide to cover cropping, including all CAAANZ member information on cover cropping, will be written under the banner "CAAANZ Essential Guide to No-Till" at the conclusion of the project and published in 2010.
Length of the project: 3 years (Commenced in July 2006)
Funding body: Grains Research & Development Corporation (GRDC)
Status: Completed
Contact:
Neil Cordingley (WANTFA): neil.cordingley@wantfa.com.au |
