AGRIC/O: MAINTAINING SOIL FERTILITY

This Unit is about Fertilizers used in Agriculture.

MAINTAINING SOIL FERTILITY

THROUGH THE USE OF MULCHES

A much is any material used to cover the soil surface to prevent excessive loss of water through evaporation, to control surface runoff of suppress weeds.

Materials commonly used include dry grass, banana leaves , coffee husks, crop residues  e.g. Maize straw and black polythene.

Where plant materials are used, care should be taken to make sure they do not re-grow into weeds and that they are not transmitters of pests and diseases.

Advantages of mulches.

  • They conserve soil moisture by preventing evaporation.
  • Improves on rain water infiltration.
  • It protects the soil against erosion which may have been caused by impact of rain drops or wind .
  • It suppresses weed especially the annual ones.
  • Mulches improve on the soil structure.
  • When mulches rot, they form organic matter that will release nutrients to plants.
  • They moderate soil temperatures making it suitable for the presence and activities of some soil organisms.
  • Mulches improve yield in some crops for example in tomatoes and in pineapples.
  • They can be used in the control of some pests for example in bananas in making a weevil

Disadvantages  of mulches

Mulches are a fire hazard

Mulches can be a breeding place for pests e.g. termites.

They may encourage soil bome diseases especially fungal diseases.

Mulches may bring about an inbalance of soil nutrients for example magnesium becomes deficient in heavily mulched coffee. Some nutrients may increase in the soil to toxic levels.

IF the mulch is not well dried, it may regrow into weeds e.g. elephant grass.

Mulching is expensive because we have to cut transport it and lay it in the garden all these require alt of a labour.

When the mulch is laid too thick, it can interfere with infiltration of water into the soil.

 

THROUGH THE USE OF ORGANIC MANURE

Example

  1. Green manure
  2. Farm yard manure
  • Compost manure

GREEN MANURE

It  is  made by incorporating green vigorously growing  plants to the soil just before flowering time (this is when  they contain most nutrients.  The method works well where the permanent plant to be grown is propagated vegetatively for example sugar cane that is propagated with stem crops with very small seeds may not germinate.

A good green manure crop should have the following characteristics.

  • High nitrogen content so most times legumes are used.
  • It should have a high ratio of leaves on the stem.
  • It should be able to grow rapidly.
  • It should be easy to in cooperate into the soil.
  • It should not be able to propagate vegetatively to avoid re-growth.

Advantages of green manure:

  • Where leguminous plants are used, they help to fix atmospheric nitrogen in to the soil.
  • Increases organic matter and humas content of the soil which will lead to a better soils structure with good aeration and drainage.
  • It will provide nutrients for crop growth.
  • It will encourage presence and activity of soil organisms.
  • It will encourage presence of and activity of soil organisms.
  • Will improve on water infiltration into the soil.

Disadvantages of green manure

  1. Most of the crops that are used as green manure are food crops so it will
  2. Be difficult to convince the farmers to grow  them just for the purpose of incorporating them in to the soil.
  3. When the manure crops are left to become hard and fibrous, they will not easily be decomposed by the soil organism. So they will end up using a lot of nitrogen which would have been used by the permanent crop.
  4. It is difficult to Incorporated green manure in the soil without the use of machinery.
  5. Green manure has a short lived effect in soil.
  6. It takes a lot of time an labour to grow the manure crop and plough it into the soil before a permanent crop can be grown.
  7. It increases the cost of production since one has to buy seeds of the manure plant.

GREEN MANURE IS EXPLAINED MORE IN THE VIDEO BELOW;

FARM YARD MANURE:

Is made of fermented dung and urine of animals together with rotting vegetation matter, left over feeds and beddings.

The quality of the farm yard manure will depend or the following:-

The type of animal giving the manure: e.g. Ruminants (cow, goat, sheep) are  capable of making some amino acids and vitamins in the rumen.

The age and purpose for which the animal is used g. claves take a lot of nutrients from their feeds so their manure will not as rich as rich as rich as that of old animals.  Milking animals used most of the nutrients in the feeds to make milk so their manure is not rich.

The type of food given to the animal for example when cattle feed on concentrates (dairy meal ) that has a lot of proteins) vitamins and minerals. It will give manure that is richer than cattle feeding on grass alone.

The type of bedding for example straw will have a greater capacity to absorb urine and dung than so dust there will give better manure.

The method of storage; manure heaps should be sheltered from direct sun shine to avoid lots  of nutrients through leaching and evaporation especially of Nitrogen phosphorus and sulphur.

The length of time for which the manure is stored; the longer it is left to frot the richer it becomes.

PRESERVATION OF FARM YARD MANURE

  • It adds nutrients to the soil i.e. it has all the nutrients but particularly rich in nitrogen phosphorus and potassium.
  • It improves on soil structure and so improves on air and water movements.
  • It makes the soil more workable.
  • It encourages presence and activities of soil organisms that break down organic matter.
  • IT makes the soil less acidic.
  • It has a long lasting effect in soil.
  • It can be used to improve on the quality of other manures for example compost manure.

DISADVANTAGES

  • It has a high content of potash so it applied in excess it will interfere with uptake of magnesium by plants.
  • It has a high moisture content so it can easily decrease in quality if its not stored well.
  • It can easily pass on parasites if the animal from which it is obtained has those particular parasites e.g. worms.
  • It may increase the level of nutrients in the soil to toxic levels e.g. when you use manure from pigs it may have a lot of copper and zinc.
  • Farm yard manure tints pastures and the animal rejects such pastures and this will lower the yield.

COMPOST MANURE:

This is a mixture of poshaly decomposed crop remains, vegetable matter e.g. weeds and sometimes livestock faeces and urine are added.

Materials that are good for making compost should have the following characteristics:-

  • Diseases and pest free.
  • If weeds are being used, it should be before they produce seeds, and weeds that a re-grow vegetatively e.g. coach grass should have a moisture content between 20-50%
  • The material should have almost equal proportions of carbon and Nitrogen – common in young plants – otherwise it will not easily rot and the organisms that bring about decay will use up much of the nitrogen.

PREPARATION OF COMPOST MANURE:

  1. Compost manure should be prepared using the heap or pit method but either way, the following will encourage rapid rotting.
  2. Phosphate fertilizer of 5 – 10kg of ssp and if you do not have a phosphate fertilizer  add wood ash.
  3. Proper aeration and this can be achieved by regular turning of the composting material and the material to be composed should not be higher than 1.5m.
  4. Providing a starter material. This can be well rotted farm yard manure and will provide the organisms   that will  start off rotting.
  5. Covering material to reduce excessive loss of moisture and in the wet season to avoid excessive wetness of the material as this will reduce the rate of decomposition.
  6. Maintain PH around neutral so agriculture lime or sulphate of Ammonia should beaded covering material.
  7. The heap method is recommended in place with  high rainfall to avoid water logging in the posting material.  Four poles are put in place to act as support and then the walls are made by weaving grass around these poles.
  8. The foundation is made by putting stones, sticks or maize stalks to a depth of about 10cm to allow free air circulation within the heap.
  9. The material to be composed is chopped up and thoroughly mixes before being put on top of the foundation.
  10. A layer of well rotten farm yard manure is added this will provide the bacteria that will start off the process of decomposition.
  11. A layer wood arch is then added to prevent excessive acidity in the  heap.
  12. The materials are arranged in this order until the material comes almost to the top of the post. Every after 0.3 m some sulphate of Ammonia is sprinkled .
  13. The top is covered with a thin layer of top soil that has been mixed with agriculture lime.
  14. Sprinkle water on the whole  heap to create moist environment  that will favour activities of micro organisms and at the same time regulate temperature switching the heap.
  15. Use of dry grass or papyrus to cover the heap to prevent excessive evaporation of water. After some days the heap should be tested to make sure decomposition is taking place.
  16. A dry stick known as a tester is pushed in mid way through the heap then removed after 5 – 6 days.  It should be feeling warm. If it is cold, then decomposition is not taking place so the material should be turned to allow in ore air. If it is very hot then more water should be sprinkled on the heap.
  17. After 2-3 weeks, turning of the heaps begin.

mulch

Pit Method

It is also known as the in door method because it was first used in a place called indoor in India.  It is recommended for dry areas so that as much water as possible can get into the pit.

mulch1

After pit has bee dug, foundation stones are laid and materials are arranged in the same order as the heap method.

Every 2-3 weeks material ore turned from one pit to the other.

Turning:

mulch2

After pit 5, the manure will be ready for use.

Precautions taken when preparing compost manure:

  • It should be made in a place sheltered from direct sunshine, rain and wind and water logged conditions should be avoided.
  • The heaps should not be made too big as this makes turning of materials difficult which will bring about an imbalance between air and water.
  • As the material is being rain, avoid trapping in afflies as this will lower the quality of the manure.
  • Avoid putting in sticks, plastic materials, broken materials and coloured material.

Advantages of using  compost manure:

  1.  It improves on activities of soil organisms.
  2. It helps in conserving soil moisture by lowering the rate of evaporation and during the dry season it can absorb water vapour from the atmosphere.
  3. Fully composted manure is black so it helps to regulate soil temperatures it improves on soil structure allowing free movement of air and soil water.
  4. It improves on soil structure allowing free movement of air and soil water.
  5. It easily releases plant nutrients.
  6. It helps to maintain neutral conditions of the soil.

Disadvantages of compost manure:

  1. If it is applied to the garden immediately, it will heat up the soil  and damage plant roots.
  2. Its making requires a lot of labour.
  3. Large quantities of different material have to be collected.
  4. It requires large volumes of water in making and some times this water can not be obtained.

Follow this link for more information

120 Things You Can Compost from Home

 

Attachments3

ASSIGNMENT : MAINTAINING SOIL FERTILITY IN AGRICULTURE assignment MARKS : 10  DURATION : 1 week, 3 days

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