Spring Cropping in a Wet Spring
The weather may have dried up in the last week, but the effects of the wettest March in a decade are still being felt on farms up and down the country. Here, Soils and Arable Advisor, Jerry Alford, looks at the organic options available for spring cropping.
For many organic farmers, spring cropping is a very important part of the rotation. Used to break the pest, disease and weeds cycles within rotations, it also provides an easy way to get the fertility-building crop up and growing through under-sowing. This year, some will have got their crops into the ground during the short spell of dry weather in March but for many on heavier ground, or in the wetter regions, the seed will still be in the bag and the plough still waiting in the shed. So, is this a time to sow or wait?
I'm afraid there is no simple answer to that question, because your farm's system is an important part of the answer. In general, spring barley can be drilled until the middle of May, but yield may be lower, harvest slightly delayed and the crop will mature over a narrower window. Make sure the variety is best suited to spring sowing, with a high tillering rate. Crops sown into poor soil conditions can fall to as low as 55% establishment so it may be worth increasing seed rates for late sown crops to reduce the risk of low plant numbers. Barley will be less able to compensate by tillering at this stage. Seedbeds should be consolidated to discourage slugs and leather jackets but be wary if the soil is still moist, a following dry spell can lead to capping and a further reduction in germination, yield and soil health. The later harvest may also lead to harvesting issues with the under-sown grass.
Could seed wait until next year?
Assessing the cost implications are also important, growing a break-even cash crop just because "I have the seed" may not be the best long-term decision. One advantage of using untreated seed is that it can be kept until next year, provided it is kept dry, cool and pest free. If using non-organic seed, a derogation would to be reapplied for, but the justifications would remain the same.
The negative effects of the wet spring on the soil also need to be considered, mauling a crop into wet ground has long term consequences which will take time, and cost money through reduced yields, to resolve. Protecting the soil by not ploughing now might be the best long-term policy, waiting for the ground to be right and then making a decision. Where crops are grown largely for straw on a mixed farm the situation may be different but if straw is not fed, non-organic straw can be bought in for the winter.
Could a late-sown alternative crop work?
If the plan was to under-sow, the grass seed can still be used when the soil dries out and so there is no real rotation change. If the crop was earlier in the rotation there may be implications so other options need to be considered. Changing to maize or linseed, both of which are commonly planted in May, is an option although varietal choice for early harvest is important. A fallow, where a stale seedbed is maintained to reduce weeds, could also benefit the farm long term but does have a cost, but may be beneficial if there is a perennial weed problem like couch grass. Growing a forage crop such as kale can provide summer grazing for livestock, which may take pressure off the grazing area and have whole farm benefits. In a stockless system, a green manure including mustards, crimson and berseem clovers could be used to harvest summer sun, and provide nitrogen for the following crops, improving soil organic matter at the same time.
As always on an organic farm, taking the time to review the long-term situation can make the answers more obvious.