How can I get the best results from a crop of kale this year?
What a difference a year makes. This time last year farmers were facing into a major fodder crisis due to the prolonged winter in 2018, which exhausted winter feed supplies.
This year, livestock were turned out on-time – and earlier in some parts. The fine weather has lead to plenty of silage being harvested right across the country.
However, with the potential to yield 8-12t/ha of dry matter (DM), farmers may be looking at kale to bolster fodder reserves next winter.
Kale has a high feeding value, with a dry matter digestibility (DMD) of >80% and a UFL/kg content of 1.03-1.05. It’s the equivalent of early spring grass in terms of quality. It also has a high level of crude protein (16-18%), which helps to promote animal growth.
Crops sown in mid-June – permitting they are provided with the right conditions and fertiliser inputs – will generally generate high yields.
When it comes to seeding rate, kale may be precision drilled at 3kg/ha, direct drilled at 4-5kg/ha or broadcast at 5-8kg/ha.
Like grass, a fine, firm seedbed and moisture are essential for rapid emergence; the surest method of establishment is through ploughing and powered cultivation. However, in well-structure soils, direct drilling will also be successful.
Kale grows best on well-drained soils with a pH of 6.0-7.0. Unlike other members of the brassica family, kale is not as sensitive to boron deficiency.
Slurry or farmyard manure applied pre-ploughing will normally provide enough boron for the crop. Where this is not applied, the use of a boron-enriched fertiliser should be considered.
When it comes to the nitrogen (N), phosphorous (P) and potassium (K) requirements of kale, Teagasc recommends the following application rates for a crop grown in an index 3 (both P and K) soil:
- Nitrogen – 130kg/ha;
- Phosphorous – 30kg/ha;
- Potassium – 170kg/ha.
Club root is the main disease threat. However, kale is not as prone to the disease as other members of the brassica family.
A one in five year rotation is suggested to keep club root levels low. Grampian and Caladonian are tolerant of club root. However, these varieties do not reduce the levels of the pathogen in the soil and, as a result, subsequent brassica crops may suffer from the disease.