Soil Management - Horticulture

Course CodeBHT105
Fee CodeS2
Duration (approx)100 hours
QualificationStatement of Attainment

Soil management is the basis for healthy plants and conservation for future generations.

The Soil is a living biological ecosystem that must be managed to the benefit of the crop and to the broader ecosystem of the region. The reason we investigate soil and its characteristics it to understand it in relation to plant growth, how to manage and manipulate it without causing damage, how to improve it generally or how to modify it for the growing of specific crops. Good soil conditions are critical to the healthy growth of most plants.

Nutrient levels, pH, salinity, depth, texture (properties of sand and clay), structure (form and arrangement), porosity (air space), consistence (the ability of soil to withstand rupture) and even colour can affect plant growth independently or interdependently.

Over eight lessons this course will develop an understanding of physical and chemical properties of soils, the ability to carry out simple tests and determine soil characteristics, and to decide ways of treating a soil to improve its ability to grow plants.

Lesson Structure

There are 8 lessons in this course:

  1. Physical and Chemical Properties of Soils
    • How soils develop
    • The main rock forming minerals: silicates, carbonates, oxides and sulphates
    • Types of rock: igneous, sedimentary, metamorphic
    • Denitrification, immobilisation, mineralisation and ammonium fixation
    • Understanding soil function: plant nutrition, support, water and air supply
    • Naming a soil
    • Improving soils for plant culture
    • Organic matter
    • Plant nutrition
    • Nutrient availability and pH
    • Cation exchange capacity
    • Conductivity
    • Salinity build up
    • The nutrient elements
    • Major elements and minor elements
    • Total salts
    • Diagnosing nutrient problems
    • Fertilisers
    • Composting
  2. Soil and Plant Tissue Test Methods
    • Soil sampling
    • Common soil tests: pH, texture, structure, etc
    • Tissue analysis
    • Different methods od measuring pH
    • Water content of soil
    • Fertiliser solubility
    • Testing the effect of lime
    • Laboratory testing of soils
    • Measuring salinity
    • Colorimeters
    • Bulk density
    • Understanding soil analysis
    • Deciding when and how to test
  3. Soil Science and Health
    • Organic carbon
    • Available phosphorus
    • Soil colour
    • Texture and its affect on plant growth
    • Structure and its affect on plant growth
    • Consistence: affect on plant growth
    • Depth of profile, pH, porosity and other things affecting plant growth
    • Soil classification and description: different horizons
    • Factors affecting soil formation: parent material, climate, ecosystem, etc
    • Weathering processes in soil formation: physical, chemical, geochemical
    • Pedochemical weathering
  4. Container Growing
    • Introduction
    • What to grow
    • Problems with containers
    • Care of containers
    • Comparing materials: plastics, terracotta, fibreglass, etc
    • Aesthetics of containers
    • Potting up
    • Potting mixes
    • Ideas for container gardens
    • History of potting mxes
    • UC mixes
    • Soilless mixes
    • Testing for toxins in potting media
    • Propagating media
    • Problems with Organic materials in media
    • Coir
    • Rockwool
    • Components of potting media
    • Cleanliness with soils and potting media
    • Hydroponics
  5. Land Degradation and Other Soil Problems
    • Chemical damage to soil
    • Builders rubbish in soils
    • Salinity
    • Dogs or cats urinating
    • Growing plants in dry areas
    • Soil degradation
    • Erosion
    • Salinity
    • Acidification
    • Compaction
    • Chemical residues
  6. Soil Management Applications
    • Aims of soil management
    • Soil management in orchards
    • Fertilizer application
    • Soil covers
    • Soil management for Vegetables
  7. Organic Techniques and Soil Management
    • What is organic growing
    • Organic principles for overcoming soil problems
    • Natural plant nutrition
    • Trace elements
    • Earthworms
    • Types of mulch and its use
    • Nutrition managementin a plant nursery
    • Applying liquid fertilizers
    • Organic fertilizers
    • Natural fertilizers
    • Mineral rock fertilizers and soil conditioners
    • Apatite phosphate rock
    • Dolamite
    • Gypsum
    • Soil management in market gardens
    • Crop rotation
    • Determining kind and quantity of fertilizer to use
    • Cover crops
  8. Soils and Managing Earthworks
    • Eath forming
    • Machinery
    • Creating mounds
    • Sources of "fill"
    • Drainage
    • Improving drainage
    • Improving surface drainage after construction
    • Designing a drainage system
    • Improving permeability during construction
    • Layout of drains
    • Types of drains

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

  • Describe the significance of different physical and chemical properties of soil, in relation to the growing of plants.
  • Take samples of soil, appropriate to different situations; and then conduct a range of simple tests to determine varying characteristics of the sample taken.
  • Explain the characteristics of a soil, scientifically; and relate those characteristics to the capacity of a soil to grow plants.
  • Select and manage potting and other alternative media for growing plants in containers.
  • Diagnose and recommend the treatment of a variety of soil degradation problems
  • Explain principles of sustainable soil management
  • Manage programs for different soils in horticultural situations.
  • Recommend soil management practices which are not going to cause a degradation of soil quality.
  • Explain the methods used in managing earthworks in a way which is sensitive to soil condition

Managing Soil Can Make all the Difference to Plant Growth
 
Studying soil management may seem like a "dry" subject for anyone who is simply passionate about growing beautiful or productive plants; but it is an inescapable fact that your success with plants will be directly affected by your ability to understand and manage soil.
 
Different soils have different characteristics with respect to the a whole range of factors. For example, a sandy soil provides less support than a clay soil, although fast growing plants often fall over in heavy clay soils, due to poor root penetration from a pot-pound root system. A clay soil provides less air, but a greater capacity to hold water than sand. A soil high in organic matter has a good ability to hold water, but doesn’t always provide good support and so on.
 
 
 
How Can Soils be Improved?
 
Cultivation opens up the soil and improves air and water penetration. Cultivation, if it is done at all, should only be done once, as it destroys soil structure, and the opportunity should be used to incorporate compost and gypsum.
 
Ripping does not turn the soil over, nor damage soil structure. It is used to break through impermeable layers and compacted soil. It allows air and water into the soil and enables roots to penetrate through the soil easily. It is quite commonly used to aid quick tree establishment on farms, for example.
 
Drainage systems are often installed to carry excess water away. A simple surface trench may be sufficient, or subsurface piping may be needed. It may be easier to build a raised bed, or simply choose plants tolerant of waterlogged conditions. 
 
Irrigation may be needed for dry soils, or low rainfall areas. There are many easy-to-install, black polythene micro-irrigation systems available. If you have a rainforest you may want misters and sprayers well distributed throughout the garden. A heathland would be better suited to drippers in order to keep foliage dry and humidity low.
 
 
Organic Matter can be a Great Help
Adding compost, manure or mulch would be the single most important way to improve soils and solve the majority of soil problems. Both in light sands and heavy clay it adds nutrients, improves structure and provides a buffering capacity against temperature and chemical changes. It improves moisture retention in sands, and aeration as well as drainage in clays.
 
Many organic materials are available. Making your own compost at home is the cheapest, using kitchen scraps, weeds and lawn clippings. This type of organic matter may be too rich in nutrients for some natives, such as Banksias and Grevilleas, so use only small amounts. Wood and leaves that have been chipped in a mulcher are excellent once composted, or use them as mulch and allow the material to compost on the ground. This may cause nitrogen deficiency so add sulphate of ammonia or some other nitrogen fertiliser. Some materials that may be available include eucymulch (eucalyptus mulch), stable and bagged manures, pine bark, peatmoss, mushroom compost, bagasse and seaweed. Most may require composting for a month or so. Simply leave the material in a pile, or better, work some gypsum, lime and nitrogen fertiliser through the pile as required
 

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