A lysimeter study of the effects of a ryegrass
catch crop, during a winter wheat/maize rotation, on nitrate leaching and on the following crop.
Biomass of
catch crops and straw incorporated into the soil and their quality DM t [ha.sup.-1]
Catch crop Above-ground biomass --red clover 3.0 --mixture of white clover 2.32 and Italian ryegrass --white mustard 3.42 Underground biomass --red clover 2.53 --mixture of white clover 2.16 and Italian ryegrass --white mustard 2.21 Straw 5.0 Chemical composition crude
Catch crop N% P% K% fibre% C:N Above-ground biomass --red clover 3.58 0.26 3.15 17.4 12.5 --mixture of white clover 2.90 0.26 3.54 24.0 18.1 and Italian ryegrass --white mustard 2.1 0.34 4.28 20.3 19.3 Underground biomass --red clover 2.09 0.39 1.75 28.3 17.1 --mixture of white clover 1.89 0.40 1.76 31.4 18.4 and Italian ryegrass --white mustard 1.62 0.26 1.17 39.0 21.2 Straw 0.41 0.06 0.90 -- 109 Table 2.
If you have to deal with a situation where you feel a flush of nutrients (large amounts of fresh green material or manures incorporated into the soil) creates the danger of leaching and potential nutrient loss, plant a "
catch crop" (rye planted as an over-winter crop is a good example) that aggressively "scavenges" or "sops up" excess nutrients, preventing their loss from the soil and retaining them for future availability when the
catch crop itself dies.
Lettuce is often grown between rows of slowing-growing vegetables or as a
catch crop, using ground before or after another crop - and for that reason is ideally suited to small gardens.
In the following ryegrass
catch crop and in Years 2 and 3, N uptake was higher after manure application than in the mineral fertiliser reference (Table 1).
They can be used as a
catch crop between rows of garlic, onions, carrots and other slower growing vegetables to make the most of your veg plot.
I hope not, because, with a small amount of effort, you can increase the productivity of your plot, no matter what size it is, by as much as 30%, according to some 'experts.' Put simply, if you plant a crop such a leeks in May or June, that start life as small, thin, insignificant plantlets, spaced quite widely to allow for a long growing season, the gaps between the rows will not be filled in until late August, giving you up to three months to use the unplanted land to grow
catch crops of rocket, radish, lettuce and other fast growing salads, whilst the leeks chug along slowly in the background.
There is an age-old solution to the problem - the growing of
catch crops.
Nitrogen-fixing crops,
catch crops and land lying fallow are all on the proposed list, along with buffer strips, agro-forestry and landscape features.
Sow some winter cabbages now for planting out in early June - interplant these young plants with
catch crops of salad leaves.
Catch crops such as lettuces can be grown in spaces between them until they fill out.
