What the soil provides for the plants
Nutrients, water and air extracted via a vigorous and health root system. (and not much competition) Pores in fact make up about 60% of the soil structure. The ratio between large and small pores is important because it controls the balance of air and accessible water to the roots. If there is not enough air in the soil , root can’t follow the pores. This is a problem with compacted, silty soils especially for fat rooted plants like peas and beans. Thin rooted brassicas don’t suffer so much. This is why soil compaction by over cultivation or walking on it is to be avoided. Grass generally improves soil structure – which is why permaculture has its benefits. Chalky soils hold their structure better than acidic soils
Soils are made up of Sand, silt and clay – as follows
|Silt Clay Loam|
Soil also contains 1-5% animal matter which supports soil bacteria and fung I – vegetables will deplete this over 2-4 years.
Signs of lack of organic material are
- Seedbeds are difficult to prepare
- Soil doesn’t drain so quickly
- Crops wilt in dry weather
- Yields are poor despite nutrients and absence of pests
Good drainage is key to successful growing. Waterlogged soils kill plants by lack of oxygen. Hard pans must be pierced. The most common problem is an impervious clay subsoil. Remedies are
- Add more compost
- Drain by a ditch
- Build a raised bed to improve drainage – 4-5 feet wide.
Wet soils are cold in spring and take a long time to get going – wait till it warms up and then transplant seedlings from modules
Raising the level of organic matter requires 5.4 kg per sq meter annually.
Adding organic manure through the top soil delivers these benefits
- Breaks up clay
- Improves water retention in sandy soils
- Use it intensively on things that are gross feeders like leeks and runner beans
- Variability of supplies indicates use of a soil tester
Liming promotes crop growth and encourages earthworm and micro-organism activity.
If you don’t dig you may find that sands and silt with low organic content may slump and lose structure so causing lack of root growth which can be a problem for short season veg crops.
Soil management is about producing and maintaining a structure to a good depth. Using beds increases the depth and helps avoid compaction.
Even if you don’t dig – it may be worthwhile double digging once as this breaks up subsoil compaction – try and put a lot of organic matter in at this time.
Try and plan the garden so its easy to be timely and that plants are spaces so its easy to hoe them. In winter its ok to have weeds on the surface as long as they don’t seed.
Traditional 3 course rotation
|Year 1||Year 2||Year 3|
|Add Organic Manure||Lime and Fertiliser|
|Peas Beans, Onions Leeks|
Brassica type Roots
5.4kg / sq meter of farm yard manure does not give forking in roots so you can add it every year. This equals 54 tonnes per hectare. Or 1.5 tonnes per year for a 10 rod allotment. (This will represent around two cubic metres)
Keeping the nutrients up means that the land can move on immediately to its next crop.
Key action points
- Make sure your drainage is right
- Check acidity and lime
- Eliminate compaction – double dig once – then go to no-dig
- Apply large amounts of organic materials regularly
- Compost crop remains unless serious diseases like blight are present
- Leave the soil alone when its very wet
- Do the minimum of cultivation
- Only hoe if weeds are present an be shallow
- Rotate the crops