Stephen Flanagan, CAFRE beef and sheep development adviser, discusses one farmer’s approach to growing forage rape.
Samuel Knox, who farms outside Broughshane, is reaping the rewards of catch crops.
He has just recently sown forage rape, following a crop of spring barley. He harvested barley at the end of August, yielding 7.5ton/ha.
It will be crimped and used to feed store cattle over the winter, which will greatly reduce the farm’s meal bill. The barley straw will be used to bed young calves.
Instead of trying to get a full grass reseed completed in September and getting very little benefit from it until the spring, Samuel wanted something that was quite easy to establish even in September.
He required a crop that was:
- Quick growing;
- A quality feed for young cattle;
- Will help reduce fodder demand in November and December.
Forage rape ticks all these boxes and is more flexible than kale in that it can be sown later in the year.
He used a simple yet effective method. He sprayed barley with glyphosate 12 days pre-harvest on August 19th.
Then, he spread FYM post-harvest and power harrowed twice, rolled. Furthermore, he sowed forage rapeseed with a seed cultivator at a rate of 6.25kg/ha and rolled again on September 4th.
As the seed is very small, there is a danger of planting it too deep and, thus killing it, as it does not have the energy reserves to make it to the surface.
Planting the seed at the surface level or no deeper than 10mm is the key to success and the seed rate needs to be at least 6kg/ha.
Lower seed rates can lead to the plant having thicker stalks which are of less nutritional value than the leaf.
Forage rape, like all brassicas, responds well to good soil fertility and particularly nitrogen and phosphorus.
The crop is also prone to sulphur deficiency, so it is recommended to apply 25kg of sulphur (SO3)/ha to the seedbed.
Graze light store cattle
Once the crop is well established, in about 10-12 weeks, Samuel plans to gradually introduce light store cattle and use an electric fence to control and maximize crop utilisation.
He will move the fence daily and each strip will be long and narrow to allow all cattle to feed simultaneity and avoid wastage of the crop.
By sowing forage rape, he should benefit from having a few extra weeks of forage available for young cattle plus saving on-demand for silage.
Benefits of forage rape
He feels, however, that his biggest benefit comes through the soil getting a boost, from:
- Increased organic matter;
- Improved soil structure and fertility;
- A reduced weed burden in the following spring grass reseed.
The other benefit Samuel mentioned were:
- Extending the period that his cattle are outside grazing = means less slurry to store and less to apply in the spring. This helps lower the amount of ammonia the farm produces.
The widely branched root system of the forage rape not only reduces soil compaction but by increasing the gaps between soil aggregates enhances the speed of nutrient infiltration, hence reducing ammonia emissions from the urine and manure produced by grazing animals.
This is a win-win for both Samuel’s farm and the environment.
Benefits of crop rotation
The benefits of crop rotation have been well known and used for generations.
Our forefathers were doing this continually. It would be quite common for a livestock farm to plough the farmyard manure (FYM) down into the soil to prepare for planting potatoes, then harvest them in September or October, followed by planting winter barley or spring barley, then back into grass in the Autumn or Spring of the following year.
This rotation not only allowed the farmer somewhere to go with the FYM. It also helped to reduce the weed burden in the following crop especially after potatoes. Also, it improved soil structure, drainage, soil fertility and thus productivity.
The move away from growing crops on livestock farms due to the changes in farm business structure and efficiencies of scale, has led to the continuous growing of grass on many farms.
However, in recent years there has been somewhat of a revival in growing some winter forage crops. These have the added benefit of extending the grazing season.
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