What about Soil Fertility?

Most modern farmers are not too worried about what might be termed inherent soil fertility since they are accustomed to correct-ing most deficiencies out of a bag. There are, however, certain cardinal issues. Most soils tend to be acid and, in some, this can. be very costly to put right. Some upland peats can be very acid indeed and one can apply tons of lime with little effect. On some very sandy soils the lime will leach out very quickly and annual applications are needed to maintain the balance. On the other hand, soil that is too alkaline is extremely difficult to correct and, at any rate in the short term, this could seriously limit the variety of crops that can be grown. The ideal acidity for most crops is just below neutral (that is between neutral and slightly acid). If you intend to rely upon, or experiment with, 'no digging.' techniques it is important to maintain the soil at only just below neutral to ensure that you provide a flourishing environment for the earthworms that are an essential requirement.

A soil that is either too acid or too alkaline will tend to tie up essential nutrients in unavailable forms and thus restrict the range of crops that can be grown and their yield. Generally the heavier the soil the more lime it will require to correct the acidity, but the lighter the soil the more quickly the lime will wash out. Again the advantage of a medium loam is demonstrated.

Soil testing kits for measuring the acidity are available quite cheaply but the readings should be treated with some caution and should be backed up by consulting people living in the locality. For information about the quality of agricultural land the Agricultural Land Classification maps, published by the Ministry of Agriculture, should be consulted. These cover the whole of England and Wales, and all land is graded on a scale from 1-5, and generally the better an area of land performs the higher it will be graded. These grades are designed to reflect:
- the range of crops which may be grown.
- the level of yield.
- the consistency of yield.
- the cost of obtaining it.

However, there are problems associated with these classifications:
- there is too much emphasis on the range of crops which may be be grown; very often grass will yield better on grade 3 land than grade 1;
- the mapping units are very inaccurate; so that there may be pockets of a different -grade within a broadly-graded area.
- to achieve best results on high grade land it may be necessary to irrigate.

The ALC maps and descriptive booklets may be obtained from: Ministry of Agriculture, Fisheries and Food, Publications, Tolcarne Drive, Pinner, Middlesex HA5 2DT.

The Soil Survey (see above) have a similar system (The Land Use Capability Classification) which is much more accurate for those areas covered. Soil Survey publications also include details of soil fertility factors for different types of soils in the area.

The Ministry will (at a price; often quite high depending upon your requirements) undertake soil sample analysis to identify any plant nutrient deficiencies. You should contact the Chief Soil Scientist at the Ministry Regional Office for details of this service. (address under Ministry of Agriculture, Fisheries and Food in your local telephone directory).