Page 46 - SV 3 2024

or even the perfect loam and no matter its current condition.
Another advantage of cover crops is that research has shown that they can remove up to 27 tonnes per hectare of carbon dioxide equivalents which helps to reduce the farmers carbon footprint. Even on a smaller scale any green manure crop will use carbon dioxide, so it all helps.
Also there is a relationship between the cover crop biomass and worm numbers in the soil, as the biomass increases so does the worm numbers which then improves the water infiltration (especially important in these times of wet weather), this is owing to more worm channels in the soil as well as more roots. If sowing after an early vegetable crop in the late summer try to sow the green manure as soon as you can as it produces more biomass which is what you want for digging in. The use of cover crops has greatly improved the organic matter content of soils in trials and is well worth considering. As this magazine is due out in July order your seed now ready for sowing when any vacant land occurs.
Just using cover crops one arable farmer increased the organic matter in his soil by 1% over four years on a chalky soil. This may not seem like a lot but even good soils usually only have 5 to 6% organic matter, so a 1% improvement is pretty good. This particular farmer grows 200 hectares of cover crops to help improve his light loam soil over chalk. When testing his soils last year both the phosphate and potash were at good levels despite not applying any phosphate and potash fertilisers for 8 to
9 years. He uses a range of cover crops including sunflowers, phacelia, vetch, crimson clover, buckwheat and lupins. The hardy ones help to reduce leaching over winter and also soil erosion.
Soil structure is also important to the growing of good crops, a good, structured soil will be open (that is contains air spaces
or pores (also called air filled porosity)). Roots need air for respiration if they are
to grow and thrive. Open soils also allow the soil creatures to move through and roots to grow without too much physical obstruction. Good, structured soils will hold a certain amount of water without being waterlogged or anaerobic (lacking oxygen).
A well-structured soil is made up of many aggregates (soil crumbs) with small gaps between, these aggregates are of varying sizes. The aggregates are made from a number of soil particles “glued” together
by substances produced by earthworms, bacteria, and fungi hyphae.
Larger invertebrate animals will mix
the soil as they bury and move through
it, this includes beetles, mites, centipedes and dare I say it slugs! Not to mention the earthworms that incorporate the organic matter and produce channels as they move through the soil which improves soil drainage, aeration and root growth.
Organic matter is important because it: • Provides a valuable source of plant
nutrients
• Is able to hold and retain nutrients
against leaching
• Improves soil structure
• Increases water retention in sandy
soils
• Improves aeration on clay soils by
opening up pore spaces between
particles
• Is a source of food for soil organisms • Darkens soil, which aids heat
retention and gives an earlier warming
in the spring
• Adds carbon to the soil which is
usually held in the soil for many years. Aim to obtain as much organic matter as
you can. Unless you have easy access to
a farm, stables or similar it is unlikely you will get too much! The materials to look out for is anything that has once lived and will decompose such as:
• Farmyard manure (cattle, sheep, goat, chicken)
• Municipal compost (from council composting plants)
• Leaf mould
• Spent hops and spent mushroom
compost.
• Bark, woodchip, shredded pruning’s,
raminal woodchip.
• Horse manure
• Straw
• Homemade compost
• Composted sawdust.
It is well worth looking around your area
to see what types of wastes are available and whether they could be used to make compost / organic matter. What do your neighbours do with their garden waste? Are there any factories that produce waste that is suitable? Any local shops like greengrocers (not many of them these days!)
You can improve your soil and reduce waste in one operation!
Phacelia Green manure
Strawy manure
46 Simply Vegetables