Fodder crops such as kale, rape, swedes and stubble turnips gained massive popularity last year, in response to the drought. The time of sowing dictates what crops can be sown.
At this stage in the year, it is too late to sow kale and swedes and achieve decent yields. However, the window for sowing stubble turnips, rape and hybrid brassicas is still open. These can be sown right up to the end of August, or to the end of September in the case of stubble turnips.
The crop with the highest yield potential and can still be sown now is undoubtedly hybrid brassica. This is a hybrid of either rape and kale (Redstart) or rape and rape (Gorilla). Hybrid rape can be sown from June to August but higher yields are associated with earlier sowing.
Lalors in Laois grazing Redstart.
The importance of sowing date for yield cannot be overestimated. One day of growth in July is worth one week’s growth in August and is worth the full month’s growth in September.
Redstart has a yield potential of between six and eight tonnes dry matter per hectare while Gorilla is closer to 5tDM/ha. Gorilla is said to have a higher leaf to stem ratio making it more digestible.
Fodder rape has a yield potential of four to six tonnes dry matter per hectare while stubble turnips is lowest at three to five tonnes dry matter per hectare.
To put these yields in context, kale, while too late to sow now, has a yield potential of 10t DM/ha to 12t DM/ha, so one hectare of good kale is worth four hectares of poor stubble turnips.
Early-sown crops of hybrid rape can be grazed twice during the winter, provided the first grazing is taken early and the stem isn’t damaged.
Sowing
Site selection is important. Very steep fields and heavy soils should be avoided.
Remember, you will be trying to graze these fields in the middle of winter so think of that when choosing what fields to plant.
Soil fertility, particularly pH, is important. Target soil fertility is pH 6 to 6.7 with phosphorus and potassium at index three.
The seed bed requirements for hybrid brassica is similar to that of grass seed.
The existing grass sward should be sprayed off and either grazed or cut for silage to remove the thrash. A fine, firm seedbed is essential.
While direct drilling is possible, some form of cultivation provides a better strike rate.
Most farmers choose to disc the field rather than plough as ploughing can often make the ground too soft, leading to increased risk of poaching when grazing. Disc the field two or three times in opposite directions.
Seeds can be broadcast, but lower seeding rates can be used if precision drilled. Hybrid brassicas should be sown at a rate of 3.6kg/ac to 5kg/ac.
Pests and weeds are generally not a problem when the crop has been sown correctly and gets off to a good start
The fertiliser requirements for this crop, presuming soil fertility is at index three, is 100kgN/ha, 30kgP/ha and 170kgK/ha. The nitrogen applications should be split, with half spread at sowing and half spread three to four weeks later.
Pests and weeds are generally not a problem when the crop has been sown correctly and gets off to a good start. Heavy rolling after sowing is critical from a germination and pest control point of view.
While pests and weeds should always be looked out for, a fast-growing crop will out-compete both.
Grazing
Grazing management plays a huge part in minimising poaching and increasing utilisation of fodder crops.
No more than 70% of the animal’s diet should be fodder crop, with the rest made up of long fibre such as silage, hay or straw.
Best practice is to lay out these bales in the field before the winter, so a tractor will not need to be enter the field at that stage.
Wide and shallow grazing strips are better than narrow and deep grazing strips. The bales should be placed to the sides of the field and a ring feeder rolled over them when it comes to grazing them.
Correctly allocating the feed is essential for good crop utilisation. To do so, you must know the yield of the crop.
Use a large quadrant, one metre by one metre to cut and weigh a representative sample of the field.
Multiply this weight by the dry matter (usually 12% to 14%) and then multiply by 10,000 to get the dry matter yield per hectare.
To work out how much area to feed, let’s use the following example: there are 40 weanling heifers weighing 280kg.
If they are eating 3% of their liveweight per day, they have a total daily intake requirement of 8.4kgDM/day.
If 70% of this intake is to come from the crop, then they will need to eat 5.9kgDM of crop per day.
Across the 40 animals, this is 236kgDM per day. If the crop yields 9tDM/ha, you need 1.1 metre squared to get 1kg of crop (9,000kgDM divided by 10,000 as there are 10,000 square metres in a hectare).
The next step is to multiply 1.1 by 236kg to work out how much area to give the animals per day.
This means you need to allocate 260 metres squared every day. If the strip is 150m long, the fence should be moved back 1.73m.
However, these calculations are based on 100% utilisation which is not possible as there will always be some wastage.
However, how much is wasted all depends on the crop and weather and ground conditions. The best policy is to presume an 85% utilisation rate and go from there.
So, in this example, the 8.4kg intake per day changes to 9.9kg allowance per day (8.4 divided by 85%).
Other considerations
This time last year, the country was in the middle of a bad drought and the fear was that there wouldn’t be enough winter feed made on farms.
Most parts of the country were already four weeks into the drought and while grass growth was severely curtailed, the realisation that the following winter’s fodder deficit wasn’t going to be breached was only just dawning.
A massive industry-wide effort was made to ensure enough winter feed was made, helped in no small way by a kind autumn in 2018 and an excellent spring in 2019.
Redstart hybrid rape/kale at Tullamore Farm.
One of the main planks of ensuring enough winter feed was the huge increase in the area of land planted under fodder crops.
These fodder crops were sown into fields that were planned to be reseeded in 2019, but most were sown in tillage fields after the crops were harvested.
So was it a success and is it something that should be repeated again? Like most things, it all depends on the factors involved.
There is no doubt about it but excellent growth rates in autumn helped to push yields of fodder crops and the reasonably kind winter from a rainfall and temperature point of view made grazing of these crops easy. It was a good winter for man and beast.
If the weather was wetter and colder would we be as positive about fodder crops now?
I know many farmers who used to do a lot of out-wintering in the past, look back at that period and shudder at the memories of wading through muck to move the fence and feed out bales in the middle of the field. The point here is that out-wintering is not always easy, so careful planning around the crop, the field and the animals to graze it is necessary.
Read more
Watch: a good start on the Redstart in Laois
Watch: managing forage crops – how to feed out
Fodder crops such as kale, rape, swedes and stubble turnips gained massive popularity last year, in response to the drought. The time of sowing dictates what crops can be sown.
At this stage in the year, it is too late to sow kale and swedes and achieve decent yields. However, the window for sowing stubble turnips, rape and hybrid brassicas is still open. These can be sown right up to the end of August, or to the end of September in the case of stubble turnips.
The crop with the highest yield potential and can still be sown now is undoubtedly hybrid brassica. This is a hybrid of either rape and kale (Redstart) or rape and rape (Gorilla). Hybrid rape can be sown from June to August but higher yields are associated with earlier sowing.
Lalors in Laois grazing Redstart.
The importance of sowing date for yield cannot be overestimated. One day of growth in July is worth one week’s growth in August and is worth the full month’s growth in September.
Redstart has a yield potential of between six and eight tonnes dry matter per hectare while Gorilla is closer to 5tDM/ha. Gorilla is said to have a higher leaf to stem ratio making it more digestible.
Fodder rape has a yield potential of four to six tonnes dry matter per hectare while stubble turnips is lowest at three to five tonnes dry matter per hectare.
To put these yields in context, kale, while too late to sow now, has a yield potential of 10t DM/ha to 12t DM/ha, so one hectare of good kale is worth four hectares of poor stubble turnips.
Early-sown crops of hybrid rape can be grazed twice during the winter, provided the first grazing is taken early and the stem isn’t damaged.
Sowing
Site selection is important. Very steep fields and heavy soils should be avoided.
Remember, you will be trying to graze these fields in the middle of winter so think of that when choosing what fields to plant.
Soil fertility, particularly pH, is important. Target soil fertility is pH 6 to 6.7 with phosphorus and potassium at index three.
The seed bed requirements for hybrid brassica is similar to that of grass seed.
The existing grass sward should be sprayed off and either grazed or cut for silage to remove the thrash. A fine, firm seedbed is essential.
While direct drilling is possible, some form of cultivation provides a better strike rate.
Most farmers choose to disc the field rather than plough as ploughing can often make the ground too soft, leading to increased risk of poaching when grazing. Disc the field two or three times in opposite directions.
Seeds can be broadcast, but lower seeding rates can be used if precision drilled. Hybrid brassicas should be sown at a rate of 3.6kg/ac to 5kg/ac.
Pests and weeds are generally not a problem when the crop has been sown correctly and gets off to a good start
The fertiliser requirements for this crop, presuming soil fertility is at index three, is 100kgN/ha, 30kgP/ha and 170kgK/ha. The nitrogen applications should be split, with half spread at sowing and half spread three to four weeks later.
Pests and weeds are generally not a problem when the crop has been sown correctly and gets off to a good start. Heavy rolling after sowing is critical from a germination and pest control point of view.
While pests and weeds should always be looked out for, a fast-growing crop will out-compete both.
Grazing
Grazing management plays a huge part in minimising poaching and increasing utilisation of fodder crops.
No more than 70% of the animal’s diet should be fodder crop, with the rest made up of long fibre such as silage, hay or straw.
Best practice is to lay out these bales in the field before the winter, so a tractor will not need to be enter the field at that stage.
Wide and shallow grazing strips are better than narrow and deep grazing strips. The bales should be placed to the sides of the field and a ring feeder rolled over them when it comes to grazing them.
Correctly allocating the feed is essential for good crop utilisation. To do so, you must know the yield of the crop.
Use a large quadrant, one metre by one metre to cut and weigh a representative sample of the field.
Multiply this weight by the dry matter (usually 12% to 14%) and then multiply by 10,000 to get the dry matter yield per hectare.
To work out how much area to feed, let’s use the following example: there are 40 weanling heifers weighing 280kg.
If they are eating 3% of their liveweight per day, they have a total daily intake requirement of 8.4kgDM/day.
If 70% of this intake is to come from the crop, then they will need to eat 5.9kgDM of crop per day.
Across the 40 animals, this is 236kgDM per day. If the crop yields 9tDM/ha, you need 1.1 metre squared to get 1kg of crop (9,000kgDM divided by 10,000 as there are 10,000 square metres in a hectare).
The next step is to multiply 1.1 by 236kg to work out how much area to give the animals per day.
This means you need to allocate 260 metres squared every day. If the strip is 150m long, the fence should be moved back 1.73m.
However, these calculations are based on 100% utilisation which is not possible as there will always be some wastage.
However, how much is wasted all depends on the crop and weather and ground conditions. The best policy is to presume an 85% utilisation rate and go from there.
So, in this example, the 8.4kg intake per day changes to 9.9kg allowance per day (8.4 divided by 85%).
Other considerations
This time last year, the country was in the middle of a bad drought and the fear was that there wouldn’t be enough winter feed made on farms.
Most parts of the country were already four weeks into the drought and while grass growth was severely curtailed, the realisation that the following winter’s fodder deficit wasn’t going to be breached was only just dawning.
A massive industry-wide effort was made to ensure enough winter feed was made, helped in no small way by a kind autumn in 2018 and an excellent spring in 2019.
Redstart hybrid rape/kale at Tullamore Farm.
One of the main planks of ensuring enough winter feed was the huge increase in the area of land planted under fodder crops.
These fodder crops were sown into fields that were planned to be reseeded in 2019, but most were sown in tillage fields after the crops were harvested.
So was it a success and is it something that should be repeated again? Like most things, it all depends on the factors involved.
There is no doubt about it but excellent growth rates in autumn helped to push yields of fodder crops and the reasonably kind winter from a rainfall and temperature point of view made grazing of these crops easy. It was a good winter for man and beast.
If the weather was wetter and colder would we be as positive about fodder crops now?
I know many farmers who used to do a lot of out-wintering in the past, look back at that period and shudder at the memories of wading through muck to move the fence and feed out bales in the middle of the field. The point here is that out-wintering is not always easy, so careful planning around the crop, the field and the animals to graze it is necessary.
Read more
Watch: a good start on the Redstart in Laois
Watch: managing forage crops – how to feed out
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