Failed crops can still be an asset to the farm. This year many areas are facing the results of not enough rain. Severe frosts have hit some crops hard too. Failed crops are caused by weather, weeds, pests and disease. Legumes can fail when growers don’t use inoculants or wait too long to plant inoculated seed. If a crop looks like it’s failing, there are some important decisions to make.
When to call it a failed crop?
A crop ‘fails’’ when it will cost more to harvest and sell than what you can earn from the sale. To decide if the crop is a failure, consider:
- cost of harvesting
- grain price
- potential weed seed set
- feed value for livestock.
What to do with a failed crop
The three main options are cutting for hay, grazing, and spraying out. Each has pros and cons and can affect next season’s crop.
1.Cut for hay
Start with crops that have some bulk, but are least likely to respond to rain. Bear in mind that very drought stressed crops are difficult to turn into hay. Cutting further dries the leaf which reduces hay quality and makes it harder to bale. For a canola crop, the best time to cut is late flowering. Cutting earlier improves quality but lowers yield.
Cutting hay will change crop nutrition requirements next season. Hay removes 2 – 3 times more N and up to 10 times more K than if a crop is left for grain. It also makes the soil more acid. This is worth thinking about if acid soils or subsoils are an issue already. Removing cereal or canola hay requires 25 kg lime/ha for each tonne of biomass removed.
Also, think about soil cover, the crop residue will help protect the paddock from erosion by wind or water when rain comes. If soil carbon levels are already low, consider keeping the crop residue in place. The amount of carbon lost when hay is cut is similar to burning stubbles.
Cutting for hay might not be the most cost-effective option. Consider the costs of cutting, curing, logistics, storage – as well as the price you’ll get for it.
2. Spray it
Spraying the crop can be like a chemical fallow. If weeds are becoming a problem, you might spray out the crop and weeds. This can mean a ‘cleaner’ crop with fewer chemical costs in the future. A WA grower saw a 700 kg/ha yield increase in the next years crop from less weeds, more soil nitrogen and moisture.
Another option is to ‘crop top’. This means applying herbicides late to stop weed seed-set. Crop topping costs less than spraying out and leaves more ground cover to protect the soil. It’s not as effective as spraying out, but is better than harvesting and returning weed seeds to the soil.
3. Graze it
Livestock can benefit from a failed crop and help keep weeds down. Check:
- can the soil handle the erosion and compaction risk, and
- what chemicals have been used on the crop, and grazing withholding periods to observe.
Whatever you decide, make protecting the soil until next season a priority. Every millimetre of soil lost to erosion can reduce future crop yields.
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