Organic green manure
Growing the crop & wildlife conservation
Sowing:
- We sow in late August, as soon as possible after harvesting the preceeding crop of spring wheat
- The green manure is made up of a mix of grasses (ryegrass and colts-foot), legumes (clover, trefoil and sainfoin) and deep-rooted plants such as chicory
Fertiliser:
- We sometimes apply farmyard manure just before drilling
- We may apply trace elements such as zinc and copper is soil tests have shown levels of these nutrients are too low
Weed control:
- In the first spring and summer after sowing we may mow the green manure to prevent too many arable weeds producing seed
Insect pest & control:
- We have had no significant problems with insect pests
Disease control:
- We have had no serious problems with disease in organic cereals
Threats to the crop:
- Drought can reduce growth on our sandy soils
- Rabbit grazing
What helps:
- A warm autumn helps get the crop established quickly
- Spring and summer rainfall can increase growth
Wildlife conservation:
- The ploughing up of green manure before a wheat crop attracts good numbers of lapwing and other species such as starling. I assume this is because there are a lot of invertebrates in the soil after two years under the mix of grass and legumes. This seems to get lapwing onto the farm at the right time for breeding and the invertebrates may help hold lapwing here. In some years organic spring wheat fields have 25% of our lapwing nests but cover only 5% of the farm
- From autumn to spring green manure is good for meadow pipit and skylark. In spring it attracts small flocks of starling
- Of our arable crops, green manure is the one most frequently used by hunting kestrels. It is also used by barn owls
Harvest & what the crop is used for
Harvest and what the crop is used for:
- There is no harvest of green manure
- It is grown for the nutrients and organic matter that it adds to the soil, especially nitrogen which is fixed by bacteria in the nodules of legumes such as clover
The crop is left to grow for two summers during which time enough (or almost enough) nitrogen is fixed for two following crops of spring wheat
By-products:
- One or two cuts of silage are taken to feed the cattle on the farm. The output of silage is better in the green manure’s second summer