Last week’s Teagasc/Irish Farmers Journal BETTER farm summer open day on Harry and Joe Lalor’s farm in Laois featured a stand on alternative forages.

Without growing alternative forage, the Lalors would only be able to make half of their winter feed requirements through grass crops alone.

By growing 5ac of kale, 11ac of arable silage and 10ac of Redstart, reserves will meet nearly 95% of requirements – and that’s including a four- to six-week buffer.

Teagasc crops specialist Shay Phelan was present on the day to give farms some useful pointers around sowing brassicas (kale, rape and Redstart).

Take time to think

The most important thing to do is take time to think about the field you are sowing the crop in. Remember you will have to manage stock here in the depths of winter. Ideally, you’re looking for a dry field with plenty of shelter, easily accessible with vehicles and a good water supply.

It’s also important not to keep going back to the same field year after year with brassicas as they are likely to succumb to a disease called club-root. Ideally you’re looking at a one-in-five-year rotation.

Once the location is selected, sowing the crop properly is the most important step. Most of the cost comes at sowing time so it is important to get it right. If you sow properly, you will leave yourself with a lot less to do management-wise while the crop is growing.

Kale

The ideal sowing date for Kale is April to the end of June, so at this stage it should already be sown.

It is likely that only half of the crop N will have been applied at sowing so the top-up application will be due soon. Total N requirement is 100-105 units/ac.

The only other thing is to monitor weeds and pests. Weeds should not be a problem in June-sown crops. They may have been an issue in April- or May-sown fields but should have been spayed before emergence of the crop.

The most damaging moth is the Diamond Back Moth which will lay eggs on the underside of each kale leaf. It is particularly damaging in warm weather.

Rape

Rape has a flexible sowing date ranging from May to September. That said, the earlier you sow it, the better the yield. Many will have heard the saying “a week in June is worth two weeks in August.” Yield potential is 2.5-4.5t DM/ha, utilised.

A fine, firm seedbed (like grass) and moisture is essential for rapid emergence of brassicas as they have small seeds with low reserves. Rolling after sowing is extremely important.

Ploughing and powered cultivation is the surest method of establishment but in well-structured soils, direct drilling will also be successful. With direct drilling, it is essential to achieve a good weed kill with glyphosate pre-cultivation. Rape can be direct-drilled at a rate of 6.5kg/ha or broadcast at 9-11kg/ha.

The ideal soil pH is 6.5-7 and assuming an index 3 soil, the crop needs 16-20 units/ac of P and 40-48 units/ac of K. Boron and sulphur should also be allocated. The crop also requires 70-100 units/ac N. Splitting the application of N (at sowing and post-sowing) often works best.

In terms of weeds, there are normally very few, which results in little need for action.

Strip-grazing Redstart on Tullamore Farm in January.

Redstart

Redstart is a hybrid of rape and kale – rape gives fast growth while kale gives winter hardiness. It has very vigorous growth and good late-season yield potential. In optimal conditions, the crop has the potential to yield 6-8t DM/ha, utilised.

The sowing requirement and indeed seeding rates are the same as rape.

In terms of soil fertility, a pH of 6 to 7 should be the first port of call. After this, comes fertiliser. Assuming an index 3 soil, the crop requires 16-24 units/ac of P and 40-48 units/ac of K. The N requirement of the crop is 70-100 units/ac. Again, splitting the application (at sowing and post-sowing) often works best.