With harvest in full swing now is a good time to consider the different management options for those blocks that are going to be knocked out this year – are you going to fallow them or plough them out and replant?
Benefits of fallowing
There are several benefits to having a well-managed fallow system including:
- Having time to plan effectively for the next crop
- Breaking the pest and disease cycle
- Correcting nutritional disorders
- Managing weeds
- Carrying out works to improve drainage and farm layout
- Planting a fallow crop to reduce nitrogen inputs eg. Legumes
- Preventing soil erosion from fallow blocks
Different types of fallow
Depending on your reason for fallowing a block there are four basic management options:
- Cultivated fallow
A cultivated fallow is sometimes required when you need to do earthworks, drainage works or block realignment, although it is generally recommended that fallow blocks should have ground cover to prevent soil erosion.
- Spray out fallow
A spray out fallow means leaving the ground to rest with a ground cover and controlling problem weeds with broad spectrum herbicides.
- Legume fallow
Planting a legume crop during fallow, provides a break from sugarcane monoculture and pest pressure depending on variety. It can also provide significant amounts of nitrogen for the following crop if grown well.
- Mixed species cover crops
A lot of growers are experimenting with mixed species fallow crops to determine how beneficial they are and what combinations to use so talk to your local WTSIP extension officer for the latest information.
How to manage a fallow crop
Fallows need to be well managed in order to get the most benefit out of them. The following key factors are important in all fallow systems:
- Protect fallow land from erosion as much as possible. The best way to achieve this is by planting a cover crop or leaving the trash blanket intact.
- Eliminate all sugarcane regrowth to break the soil pest and disease cycles.
- Plant a cover crop such as a legume to provide nitrogen for the next crop cycle and maintain ground cover.
- Manage pests, weeds and diseases in the fallow crop.
- Do your soil test early in the fallow to identify and ameliorate limiting factors unless you are undertaking earthworks, in which case soil testing should be carried out once the earthworks are completed. If you’re planting a cover crop, soil testing should be completed and any required amelioration carried out prior to planting the cover crop.
- Maintain effective weed control
It is important to remember that fallow management is not a one size fits all recipe and your approach to fallow needs to be adjusted to suit your farm and situation.
For more information:
- Benefits of different cover crop species
- Three main cover crop strategies
- Fallow crops reduce soil erosion in Herbert floods