1.1-1.5 Site and windbreaks Flashcards
Plot - size, soil, and exposure
Large plots: more versatile (eg crop rotation)
Enables use of machinery
Enables planting of widely spaced crops and fruit trees
Smaller size: converse is true
Texture/structure - sandy soils, light, easy to cultivate, free draining, warm up quickly. Not moisture retentive and leach nutrients - suited to root and salad crops
Clay soils - cultivated in autumn, warm slowly, delays sowing, suitable for brassicas and blackcurrants
Drainage - moisture retentive and free draining is optimum. Waterlogged soils lead to aerobic conditions. Blackcurrants more tolerant of poor drainage
Slopes - risk of erosion, frost pockets
Accessibility to water, electric and to wheelbarrows, machinery
Limitations of a small garden
Difficult to rotate crops (or less effective)
Lack of space for top fruit
Difficult to grow permanent plantings eg. asparagus, rhubarb, soft fruit
May have to reduce optimum spacing
Not possible to use machinery
Soil texture - significance
Liability to compaction
Aggregregate-forming ability
Cooling/warming properties
Nutrient-retaining ability
Drainage
Moisture-retention qualities
Soil depth for food production
Vegetables 30cm
Fruit 45cm
Deep top soil provides:
Good anchorage for fruit trees
Unimpeded root growth for vegetables
More space for roots to spread and access nutrients
Soil qualities desirable for most vegetables
Free draining
moisture-retentive
Good crumb structure (variety of pore sizes)
fertile
pH variable - alkaline for brassicas, acidic for raspberries, neutral suitable for most
neutral ensures fewer problems with diseases and nutrient deficiencies
Aspect - part shade - vegetables that thrive
2
lettuce and runnerbeans
Slopes - adverse effects
4
frost collects at bottom of slope
soil erosion
difficult to access machinery
access to site
Frost pockets - locations
2
bottom of hills
depressions in landsape
Frost - adverse effects
4
Inhibit germination of most seeds
Damage blossum (eg beans, fruit)
Shorter cultivation window
Damage to plant
Windbreaks - living - advantages
5
Many are very long-lived if cultivated well
They can be decorative (blossoms, fruit, stem)
They can act as wildlife havens
Can be formal/informal
Wide range of suitable species
Wind - adverse effects
4
Damage to plants
Support structures may be blown over
Discourage pollinating insects
Increase in rate of transpiration - can lead to scorching of leafy and tender plants
Wind chill can slow growth (esp in spring)
Blossom and fruit may be wind-blown
Windbreaks - living - disadvantages
4
Require regular maintenance
Not instant fix (unless expensive)
They increase in size over time (can take up lots of space)
Compete with crop plants for light, water and nutrients
May harbour pests and diseases
Windbreaks - living - examples
5
Fagus sylvatica
Carpinus betulis
Taxus baccata
Escallonia ‘Apple Blossum’
Crataegus monogyna
Windbreaks - non-living - examples
- Mesh netting with posts at intervals (2-3m usually)
- Hit and miss fencing (chestnut)
- open patterned brickwork
- Wooden hurdles and trellising (eg hazel)
- Woven wooden or bamboo screens
- Coir or reed screens
- Proprietary windbreaks eg Paraweb
Windbreaks - non-living - advantages
4
Can provide immediate protection
Takes up less space than living windbreaks
Remain the same size
Can be repaired/adapted as required (1m high provides protection 10m across)
Can blend well in garden (eg hazel)
Windbreaks - non-living - disadvantages
4
Finite lifespan
Can be unattractive
Less likely to offer wildlife cover
If too dense can result in turbulence on the lee side
Soil depth for food production
Vegetables 30cm
Fruit 45cm
Soil qualities desirable for most vegetables
Free draining
moisture-retentive
Good crumb structure (variety of pore sizes)
fertile
Soil texture - significance
Liability to compaction
Aggregregate-forming ability
Cooling/warming properties
Nutrient-retaining ability
Drainage
Moisture-retention qualities
Double digging
Mark out plot. Dig a trench one spit deep and place at the opposite end of the area. Fork base of trench to one spit deep incorporating OM. Dig next trench, inverting soil into previous one. Continue to the end, final trench filled with soil from first trench
Define cultivation window
It is the optimum time to cultivate any soil type, including a heavy clay or loam soil without damaging the structure. Cultivation is carried out when the soil in not too dry or too wet.
The window can be very narrow and is ideally optimised before any inclement weather, including winter frosts.
Soil texture and food production
Texture refers to the proportion of clay, silt and sandy particles in a given soil and effects the suitability to provide a suitable root environment for crops. Whether a soil is sandy or a clay soil affects the variety of pore sizes, ability to form aggregates, nutrient holding ability, drainage and moisture retentive qualities and heating and cooling qualities.
For example:
Sandy soils warm up earlier in spring enabling earlier sowing and planting of crops
Sandy soils have poor moisture retention
Root crops eg carrots prefer sandy soil
Clay soils retain warmth for longer in autumn
Clay soils are slow to warm in spring
Clay soils are nutrient rich
Brassicas perform better on clay soils
