The Catch Crop Sediment Mitigation Group aim to:
1) Prove the hypothesis that using catch crop technology will reduce sediment losses after the winter grazing of hill country forage crops
2) Maximise the uptake of catch crop technology and best practice cropping techniques
3) Aid farm profitability
There will be on-farm benefits of:
1) A reduction in soils losses in grazed winter crops
2) A reduction in N losses to water
3) Further late winter early spring grazing
What is a Catch Crop?
Typically winter forage crops are grazed off by livestock and then left fallow until spring. 'Catch Crop' refers to a short term crop that is established before, during or after a winter crop is first grazed off and before the next main crop or new pasture is established.
A catch crop would cover the whole area grazed after each break (and leaving the ground bare) and requires repeated sowings as new ground is progressively grazed off.
The term catch crop was first used by New Zealand Plant and Food Research Ltd to define a crop sown after grazing that captures surplus soil nutrients that could otherwise be lost to leaching. But in this project’s case, a catch crop refers to catching sediment as well.
Years 1, 2 and 3 of the project
Over the course of the next two years, the project will evaluate a range of catch crop species (initially Rye Grass and Oats, followed by Plantain and Clover) and establishment techniques and barriers for uptake. The project will take place in hill country in Hawke's Bay and the Horizons Region, but will have spill-over benefits to all farming regions and terrains nationally.
Improvements in sediment losses will be measured across different soil types as well evaluation of economic benefits of a range of catch crops.
The first and second years are focused on data collection and proof of concept. The third and final year will be more focused on extension with some final trial work as needed.
The potential environmental benefits
The main aim of the project is to reduce sediment and surface flow losses following the winter grazing of forage crops.
Catch crops are seen as a practical solution to reduce sediment losses by reducing the amount of bare ground and thereby reducing runoff and sediment loss. Catch crops physically hold the soil, trap any surface flow and help with soil aeration and structure, thus reducing soil movement, sediment and nutrient loss. As sediment acts as a vector for phosphate it will also reduce phosphate losses. Escherichia coli entering the waterways will also be minimised via the capture of this sediment.
The potential economic benefits
In addition to monitoring the environmental impact, the project will also record and monitor productivity benefits and the economic benefits to farmers.
A detailed understanding
The result will be a detailed understanding of the value of catch-crops, both economically and environmentally, by sediment control and reducing overland nutrient losses and E. coli entering waterways. The project will highlight relevant establishment techniques, grazing systems, and what catch crops work best in which environments.
This technology will be applicable across all of New Zealand and terrains, with sediment reductions benefiting water quality and the whole community. Individual farmers conducting winter crop grazing programmes will have an additional feed supply/ financial benefits as well as meeting community expectations around good farming practice.