When it comes to maximising yields of home-grown forage the first consideration must be the soil, says ForFarmers forage manager Mel Digger.
“Poor soil is one of the biggest factors impacting crop yield,” she says. “Identifying issues with the soil such as nutrient deficiencies is really important. Regular soil testing helps assess your most important resource, identifying any limiting factors which would then affect your choice of crop.”
It also means that steps can be taken improve the condition of the soil. Soil carbon, structure and organic matter all need to be taken into account, she says. “They will all influence how capable your soil is of keeping hold of moisture and nutrients. A Nutrient Management Plan (NMP) is a good way of assessing the farm’s soil through extensive testing and analysis.”
Testing slurry is also advised, to see how well it can address any nutrient deficiencies and gives the opportunity to identify any gaps between what the soil needs and what is being applied.
Mel encourages organic farmers to consider the range of forage crops available including lucerne, clover, roots and herbal leys. A variety of crops helps to spread risk and boost resilience and some options also play a useful role in improving soil condition.
First on the list to consider is red clover, a high-yielding option typically producing 13t DM/ha/year although mostly used in a mixture with perennial ryegrass. This is the equivalent to an Italian hybrid grass ley receiving 250kg of nitrogen per hectare, says Mel.
“Not only can it produce high protein silage it is also suitable for grazing. At 14 to 22% crude protein it’s a reliable option.” Many dairy producers report an uplift in milk yields after introducing red clover which is usually used in mixes alongside perennial ryegrass. “It’s also well-known for its ability to fix nitrogen in the soil and improve the structure and fertility of the soil for the following crop. Red clover can fix up to 200kg of nitrogen per hectare.” It suppresses weeds quickly and then performs well all through the season, she says.
Lucerne is also well worth investigating, says Mel. Yields are comparable to red clover at 12-14t DM/ha/year at 18-24% protein. The main benefit above red clover is the ‘scratch factor’ it provides in the diet, along with a high level of minerals and trace elements, explains Mel.
“With its very deep roots lucerne can tolerate drought conditions well while also contributing to improved soil structure. It can be tricky to establish and it’s important not to over graze in its first year, but it can be a very rewarding forage crop.” Lucerne crops can be cut up to four times a year and then clamped or baled and are typically productive for three to five years.
Root crops are a cost-effective option to fill gaps in summer, autumn or winter, explains Mel. Hybrid brassica are an option where derogation is granted. An alternative is forage rape which is typically used in a 30/70 mixture with organic Italian ryegrass and can provide cost-effective grazing when other crops are struggling.
Herbal leys have been gaining ground recently and for good reason, says Mel. “As diverse mixes they offer the best of several worlds. They yield well while also bringing the soil conditioning benefits of the leguminous crops.” Highly palatable to cows they can help to boost forage intakes and improve yields, she explains. “The variety of deep and shallow rooting plants means that all available nutrients are maximised as they are being accessed across the soil profile.
“Tolerance to drought is improved by the deeper-rooted species so they should definitely be considered by those looking to improve their resilience. Many farmers say that their herbal leys are the only green fields at time of drought.” Other benefits include the anthelmintic properties of some species including sanfoin, chicory and birdsfoot trefoil, due to the presence of tannin.
However it is important to note that not all herbal leys comply with GS4 requirements under the Mid and High Tier Countryside Stewardship Schemes so it is important to check before investing. Please check with your organic body prior to purchasing crops for organic situations.