SOIL CULTIVATION TECHNIQUES

In smaller areas digging and trenching are still used in the cultivation of soils, but in the majority of cases, nechanical means are employed, ranging from the rotovator or tiotor hoe to the crawler tractor and heavy implements. Praetor ploughing and cultivating are the most economic neans available, largely on account of the time factor.

Contractors’ costs for these operations vary according to ;he district, the type of soil and other factors.

For the preparation of new land for most purposes, deep ploughing is essential. Methods employed vary according to bircumstances, but in the majority of cases, they consist of ploughing to a depth of 8 – 10 inches (20 – 25 cm), followed by sub-soiling to a depth of 15 – 18 inches (38 – 46 cm) or so.

An implement which is freguently used to break down the soil following ploughing (whether initial or subsequent ploughing) is the disc harrow. The use of heavy discs is sometimes referred to as disc ploughing or just as discing.

Usually, it is the first operation following ploughing and Is designed to break down the clods of earth; it constitutes the first step towards producing a tilth. Disc ploughing is also used to cut up bulky organic matter, such as a straw compost, prior to ploughing this under. Ring rollers (Cambridge rollers) may also be used at this time.

Heavy cultivators, springtine cultivators, cage rollers, power harrows and light harrows are all used to produce the necessary tilth for sowing and planting. The timing of cultivations, like harrowing on clay soil, have to be done In relation to the state of the soil. A clay soil which iries out in hard lumps has to be caught when just starting 😮 dry out; it will then break down fairly easily, by cultivating, harrowing or raking. It cannot be worked when sticky, and cultivations have little effect on very hard Lumps in dry conditions.

Several types of rotary cultivators are available, ranging from tractor-driven models for large areas, to smaller ‘walk-behind models. Used when soil conditions are suitable, I.e. not too wet, and in conjunction with other methods of cultivation, rotary cultivation can provide a quick method of preparing a soil for seed sowing. The surfaces may be left loose and puffy and need consolidation before sowing.

Soil cultivation and soil preparation on a small scale may still have to be done by hand, usually by single digging or, for special purposes, by double digging. The latter is often too expensive and too time-consuming, except for very special purposes.

Normally, digging improves the soil by:-

a) allowing air and water to move readily,

b) exposing it to the beneficial effects of frost,

c) making possible the incorporation of heavy dressings of dung or compost, and

d) exposing numerous pests to the effects of frost and the action of birds.

A further advantage of digging (or ploughing) is the opportunity to bury crop residues and annual weed growth.

Single Digging

Objectives

1. To prepare a fresh planting and sowing surface.

2. To bury crop residues and trash.

3. To incorporate farmyard manures or compost.

4. To improve the soil structure, drainage and aeration.

5. To bury annual weeds.

6. To expose pests to birds.

Method

Use digging spade or digging fork. (The fork is more useful on sticky soils and on weedy ground where the thongs of ground elder, couch or convolvulus may be removed in longer pieces – at least that is the hope!)

1. For long narrow borders: dig out a trench 10 to 12 inches (25 – 30 cm) deep and wide at one end of the border and wheel the soil to a tip site close to the far end.

2. For wide beds and borders it is more usual to mark the land out into a number of strips maybe 5 metres (15 feet) wide. Take the soil from one end of one strip and wheel it to the end of the last strip. This will enable the land surface to end up level.

Important points of craftsmanship when digging are:-

(I)

To keep the land as level as possible because this makes subsequent cultivations so much easier. Try and dig out square pieces the width of the spade and the full spit deep. Turn them over so that the weeds stay at the bottom of the trench.

(ii)

bury every part of every annual weed; in this way lal meadow grass, speedwell, annual nettle,

shepherd’s purse, groundsel and cleavers can all be buried with no fears.

(iii)

To remove and burn every part of the perennial weeds dug up (and do try and get out every piece that is there.) This applies to such perennial horrors as convolvulus, creeping thistle, perennial nettle, docks, dandelions, couch grass, creeping yellow cress, creeping sow thistle and the creeping soft grass known as fiorin. Some perennial weeds such as lesser celandine are difficult to remove by digging, and also it may be hard to remove all traces of some buttercups but the effort is worthwhile. Over a

period of a few years of cultivation the gardener is left with the weeds he deserves – no more and no less!

(iv) If it is possible to complete the autumn digging by November it will be a big plus in the garden calendar because this will give the frost a good opportunity to act on the soil. Pests like snails, slugs and millipedes will be buried 8 (200 mm) deep and struggling for survival or dead rather than eating your crop residues and madly propagating themselves.

(v) If you decide to dig in farmyard manure do be generous! Niggardly dressings are a recipe for poor yields. Aim at luxury levels of plant nutrition! Keep a good trench when you are digging – throw the soil well up, so there will be plenty of room to skim the weeds into the bottom of the trench and to put in plenty of muck. If it is available a bucket of muck per foot (300 mm) is not too much.

(vi) When digging there are easier and harder ways to do it. A time-honoured system is to chip the side of the slice about 3 (7.5 cm) deep then cut out the actual spadeful. Keep the spade handle upright, with your knuckles away from you and lift the soil to the height reguired and no higher. (There is no extra reward for lifting all the garden earth 6 (15 cm) and lowering it again other than an extra sense of weariness.) People unfamiliar with digging should take care not to over-do it. Do buy the very best tools on the market, e.g. a stainless steel, ‘D’ handle digging spade without the flat plates at the top of the spade blade. Avoid wheeling barrows over the lawn or elsewhere without the use of a plank. Keep your spade clean with a small piece of flat wood and life will go easily and well. Don’t dig when the soil is too wet and sticky or frozen so hard it is grimly difficult. Some people say don’t dig in snow, and this may be sound enough but I don’t really share the view. Certainly it will keep the sub-soil cooler but I suspect that by mid-April the soil will be warm enough anyway to have provided the heat to recover to normal, and some snow may mean that the garden jobs are restricted enough anyway.

Double digging

Double digging is often well worthwhile before re-planting a herbaceous border, a soft fruit or top fruit garden, an area of semi-permanent vegetables like rhubarb, asparagus or globe artichokes or before setting out a shrub border. It could be a disadvantage before laying a lawn since subsidence over time would almost certainly affect the levels, and turf does not really need the extra depth as much as larger plants.

Double digging takes more than twice as long as single digging so it is worthwhile doing it well. It need not be done too often. If ‘it were done once in 2000 years the results would still show on aerial photographs, so once in 3 years might be a counsel of perfection. Maybe once in 10 years is nearer the mark.

Method

Divide the plot into 2 as for single digging if the border is wide enough to justify it. Mark the land out carefully with canes using a tape measure to allow a wider trench, e.g. 23 (0.7m) at the beginning and at the end because it takes a larger hole to accommodate the loose soil than a precise equation would lead one to believe.

Add the farmyard manure/fertilisers but avoid using lime and fertilisers. Lime could be added on top afterwards if the soil and crops require it. Keep the level carefully. Use the garden line; shovel out enough of the crumbs for each trench so that the forking of the sub-soil is properly achieved and add generous muck. Some authorities advocate forking in the muck to the lower spit. In practice this is difficult to do since it has been forked once and is loose plus the fact one is standing on the f.y.m. It may be worthwhile for soils which are very poor in humus like gravels, sands or silts.

On heavy soils double digging may result in the opposite of good drainage in that a glorious sump hole is prepared into which surface water drains with glee. On such soils drainage pipes may profitably be used to duct off these waters into ditches and away to the streams.

Where there is no outfall for water the extra soil depth may be achieved by lowering the paths. This results in muddy paths but better drained, better aerated and hence earlier cultivating and cropping beds and borders.

Very sticky soils may be improved by digging in straw badly, I.e. not burying it properly and yet having some deep down. The straw tends to act like a rain downpipe helping to dry the surface soil.

Hoeing

The objective is to kill off and remove surface weeds.

Hoe types available:-

draw hoes – e.g. English draw hoe

the push type hoes – e.g. Dutch hoe

push and pull types – e.g. Wilkinson Sword wire types

Canterbury hoe types -. more for chopping

wheel hoes: single and double wheel

rotary hoes.

In the ideal situation the land is level enough and even. A thin cutting action severs the young weed seedling at its hypocotyl region; this kills it. The heads of the weeds are then raked up. Hoe forwards over new ground.

There are occasions when one will stand astride the weeds and hoe to leave the hoed weeds untrodden. Hard and fast rules are given by some but not by me.

Where there are lots of seeding weeds you have left the noeing operation too late. Nevertheless try to pull up the seeding weeds first and remove them before the hoeing Dperation scatters yet more seed pods on to the land. The Did adage One year’s seeding is seven years’ weeding has been substantiated by the Weed Research Organisation as remarkably close to the facts.

Try and hoe in dry weather since it is so much easier. On dry soil the weeds are more easily cut off and raked up, and less soil is taken off the borders.

Always rake up the weeds. It will surely rain and the least shower or heavy dew is enough to enable the weeds to start up again. Remember they are British native plants and they can cope with adversity; also many wild flowers can even set their seeds in death. (The removal of footprints is also the sign of a true craftsman.)

Wheel hoes are excellent for the larger scale crops growing in lines. Double wheel hoes straddle the crop line and single ones steer (less accurately) between the crop rows. (Only good in dry seasons, because one rarely rakes up afterwards by the acre).

Rotary hoes are good for many situations, if not used too deep. However, the result may look great but in fact many of the crop’s surface feeding roots can have been damaged.

It is worth remembering that garden cultivations like hoeing prepare an excellent seed bed for weeds. (One of the greatest advantages of chemical weed control is that it does not disturb the soil and seeds are not brought close to the surface.)

A quick hoe and rake when just the first few seedling weeds are visible will do lots of good. Two such operations are so much quicker than a single later hoeing, but it is a counsel of perfection, and in any event the weather may dictate what is possible.

Weeding

This is a chore, and it should not be necessary in many cases if good husbandry is practiced.

Objectives:

to rid the land of visible weeds and the roots of perennial weeds.

Equipment:

a trug or basket

a barrow or hessian square

a bonfire and a compost bin.

Technique

1. Pull out seeding weeds – Burn

2. Fork out perennial weeds – Burn

3. Pull up the remainder – Compost or Burn

Some people compost their weeds. This is fine if there is a really good hot fermenting compost heap available. The late Mrs. Fish – surely one of the greatest lady gardeners of this century – used to say that really and truly the bonfire was the best place for all weeds since if there was a slip up at the compost heap one spreads the weed seeds back again.

The Preparation of Seed Beds

Objectives;

to give every seed the same opportunity of good germination and growth.

Equipment: base fertiliser garden line garden rake.

Following digging and forking, e.g. the spring after the winter digging:

1. Remove any weeds.

2. Spread the requisite base fertiliser for the seed bed or for the crop if they are to .be grown on site, e.g. 3 oz of a mixed or general NPK fertiliser like National Growmore.

3. Tread the lumps or roll.

4. Rake to spread the hillocks into the hollows. Pushing the rake shatters the clods, pulling it should help level up and bring towards you the hard clods, debris and stones to be removed (if this is the policy).

When a firm fine tilth has been obtained the land can be marked out with canes to position the rows or beds. A tight garden line between the canes is the best guide for drawing a seed drill. A single shallow seed drill for a small seeded crop like lettuce can be achieved with a half-moon shaped draw hoe, walk backwards treading on the line as you draw the drill since this helps to keep the line in place.

Sow the seeds thinly and shuffle the earth back into the drill with one’s heels walking back along the row, or with a rake. Firm in by walking back down the row heel to toe. In a dry moment lightly rake out all the footprints and level

up; this will help with subsequent hoeing. Spray with the appropriate pre-emergence residual herbicide treatment if necessary.

Rolling Techniques For Soil Preparation

Rolling and the proper use of the roller is quite an art.

1. If soil is rolled when it is too wet or plastic the valuable soil structure will be lost.

2. Rolling at just the right dryness will break rough clods and help make a tilth for planting and sowing.

3. Rolling does tend to ‘bring up the moisture’ so it can help to bring the moisture within the clods of rather a dry seedbed into close contact with seed coats and so aid germination.

4. The impression that rolling makes a garden flat is erroneous. Rolling tends to even the lumps. Very heavy rollers like road rollers are quite unsuitable because they will eliminate the surface soil structure.

5. Ring rollers and cage rollers are helpful in breaking clods and they may be more helpful in leaving a cloddy surface. Very flat surfaces left by the flat rollers may cap more easily after heavy rain and also tend to produce a greater crop of weeds.

Raking

This has been mentioned before under seed sowing but it is worth reviewing the equipment including:-

The hay rake, landscape or Chelwood rake

The iron rake

The Springbok or lawn rake

The rubber rake.

Landscape rakes may produce a seedbed and level surfaces quickly on a large scale.

Iron rakes over 12 (30 cm) wide are helpful with seedbeds.

Springbok rakes are valuable on borders and near lawn edges for moving along the small weeds cut off after Dutch hoeing.

Rubber rakes are excellent at leaving the ground behind when raking weeds off the ground surface.

Use 2 boards to pick up the raked litter. It works well.

Seed Sowing Techniques

Essential conditions:

1. Adequate warmth, e.g. for most vegetables 10 to 20°C.

2. Ample water, e.g. field capacity (this is not the same as waterlogged).

3. Ample oxygen, e.g. provide a good tilth.

4. Viable seed – all commercial seed houses provide these.

5. A suitable resting place for the seed, I.e. not too deep.

6. Sufficient nutrients to give a good start in life.

Desirable:

7. No poisons, e.g. Coz or ammonia in toxic quantities or herbicide residues.

8. Low levels of competition from pests, diseases, weeds or sowing the crop too thickly.

9. A few specialised seeds require light or darkness. This is not a problem for most vegetable seeds.

In practice seed sown in the traditional seasons will have these conditions met in full. Just occasionally a problem may occur; for example lettuce may refuse to germinate if the soil temperature is higher than about 22°C (71.6°F).

Transplanting

Objectives: To lift and transplant plants or seedlings with minimal check to growth.

A technique:

1. Water the plants if there is even a hint of dryness.

2. Lift the plants carefully, perhaps with a fork to conserve as much root as possible.

3. Keep the roots and top sheltered from sunshine and drying winds during transfers to avoid water loss.

4. Re-plant into a well prepared hole large enough to accommodate the roots spread out comfortably; surround the roots with good earth and firm diligently.

5. Water if there is any likelihood of this need.

6. Re-water as many times as it takes before the plant may be said to be fully established.

Thinning

Objectives; to space apart the crop plants so that they may develop fully to maturity. It may be done to most in situ sowings of vegetable crops such as carrots, onions, lettuce, beetroot.

Techniques: hoe to single or crawl to single the crop plants and space them apart suitably. Outdoor lettuces might be left 300 mm or 12 apart. Closer spacings would reduce the individual plant size at harvest. Too close spacings like 150 mm (6 inches) would reduce the marketability of the crop.

e.g. Transplanting ‘sprouts’ in late May which may be a dry month.

In dry conditions planting at the bottom of a furrow is a help because:

a) the roots are deeper down and hopefully in moister soil;

b) they are easier to water;

c) there is a microclimate and some wind protection in the furrow.

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