No till crop establishment practices
The use of no-till crop establishment is essential for farming raised beds and there a number of aspects to the agronomy that are specific for the raised beds.
People unfamiliar with raised beds are often concerned with the proportion of land occupied by furrows. Unseeded furrows are perceived to be a loss of productive land and potential productivity. The evidence supports the recommendation that furrows should not be sown and the seed and fertiliser inputs that would be normally placed there should be placed in the beds. However in the absence of regular furrow cleaning, it is recommended that furrows be sown otherwise they become a haven for weeds.
2. Row spacing
The options for row spacing on the raised beds (no sowing in furrows), and seed and fertiliser are to: increase the seed and fertiliser rates in the rows on the beds without altering their spacing (that is, the five rows on the beds at 26 cm spacing receive the seed and fertiliser normally supplied to seven rows at that spacing); or increase the number of rows on the beds to seven by reducing their spacing to 20 cm (that is, each row receives the same amount of seed and fertiliser). Both combinations have been tried with no production advantage for either.
Choosing rotations for raised beds is the same as choosing for standard cropping except for the constraints caused by having to use furrows to track vehicles, and some difficulties when swathing and stubble handling.
4. Crop fertilising
The raised-bed system greatly improves all-weather access on waterlogged sites. This improves the opportunity for growers to apply mid-season fertiliser. On raised beds, it is important to apply fertiliser precisely on the sown rows of crop on the beds, and to minimise fertiliser in the furrows.
Fertiliser that lands in furrows is unlikely to be used by the crop and is very likely to be transported off-site and become a nutrient pollutant to streams and rivers.
Spraying for the control of weeds, diseases and insects in crops on raised beds is the same as for crops grown on normal seedbeds.
6. Swathing and harvesting
Harvesting crops on raised beds differs from harvesting on normal seedbeds only in terms of the constraints imposed by tracking the harvesting equipment in furrows. Ensure all mobile machinery has wheel tracks that fit the furrows, otherwise they need to operate on specially-constructed access tracks, cross-drains, or at the end of the field on the headland or catch drain. Swathing is possible with some adaptions.
7. Stubble management
Stubble management on raised beds is done specifically to reduce the build-up of stubble in the furrows. Stubble in the furrows will impede water flow, creating waterlogged conditions in adjacent beds, causing the beds to subside and lose their improved infiltration and aeration properties.