FAR launches FAR Focus 5 – ‘Grass 2 Crop’, a one stop shop demonstating the
most effective ways of harnessing key benefits of the grass phase for the successive cropping phase.
For cropping farmers, minimising the release of nutrients to the ground water and maximising soil carbon retention is paramount to productivity and profitability; this three year project entitled ‘Grass 2 Crop’ was set up to research the most effective ways of going through this phase.
In New Zealand arable cropping systems involve a grass phase of various durations, ranging from six months under continuous cropping to up to six years or longer in the mixed arable cropping system. The benefits of the grass phase (e.g. soil quality and disease management) are well understood, however converting that grass back into cropping, or “breaking” grass, presents a number of problems:
• The 2006 MAF SFF, FAR and Crop & Food Research Cropping Sequence Survey (approximately 400 returns) revealed that in both the North and South Islands the most intensive cultivation (plough) used on cropping farms was to go from the grass phase back into cropping. Thus following the primary means of restoring the health of New Zealand cropping soils the most intensive cultivation system is used.
• Intensive cultivation has detrimental effects on soil quality by increasing the rate of organic matter decomposition, resulting in a breakdown of soil structure.
• Cultivation of grass can cause the release of large amounts of mineral nitrogen into the soil which, if not properly managed, is both a waste for the grower and an emission to the environment.
• There are a number of issues associated with going from grass to the cropping phase with less intensive cultivation. Some of these problems include ley pests such as grass grub or argentine stem weevil, less inversion of the soil also results in greater grassweed pressure in the following crop and greater dependence on agrichemicals. Another key issue is the matted nature of the root systems in grass which make it more difficult to lightly cultivate.
The trial results that are the foundation for this FAR Focus were conducted over the three years from 2008 - 2010; these included three long term trials that were superimposed on the same trial site for all three years (and which have been continued by FAR for another two years), each following a grass phase of different lengths (>30 years, 4.5 years and 2.5 years). The other eight trials were conducted for one year only following grass phases of between one and two years and were not subject to the same level of assessment and analysis.
This project was funded by the MAF Sustainable Farming Fund (MAF SFF) and the FAR levy.
Copies of the booklet have been disseminated to FAR levy payers.
Copies can be purchased from the FAR office – cost $30.00 (inc GST).
ISSN – 1175-5504
ISBN – 978-0-9864533-9-7
The do's and don'ts when moving from 'Grass 2 Crop'
