Farming Practices and Factors influencing nutrient availability in the soil

CONTENT

• Types of farming practices
• Methods of Replenishing lost nutrients
• Factors influencing nutrient availability in the soil

FARMING PRACTICES

The following farming practices have consequences or effects on the soil;

1. BUSH BURNING

This involves the setting of fire on the bushes to clear out the vegetation

MERITS

1. It releases potassium and phosphorus as ash
2. It has some sterilizing effect on the soil
3. It stimulate the growth of fresh grass
4. It destroys soil borne pathogen or germs
5. It destroys the seeds of weeds

DEMERITS

1. It destroys the organic content of the soil
2. It reduces the population of soil live organisms
3. It oxidase nitrogen and sulphur into gaseous forms
4. It exposes the soil to erosion and leaching
5. It may raise the PH level of the soil
6. It causes environmental pollution
7. It destroys the soil structure
8. It reduces soil water content

• OVERGRAZING

Overgrazing is a situation where more animals than can be supported on a particular pasture are put there to graze.

MERIT

1. More feaces are dropped which could improve the fertility of the soil
2. Weeds can easily be eradicated from such land.

DEMERITS

1. It depletes the vegetative cover of the soil
2. It causes poor growth and regenerative capacity of vegetation
3.  It exposes soil to erosion
4. It destroys soil structure
5. It leads to soil compaction
6. Compacted soil reduces water infiltration
7. Pore spaces in the soil in the soil are reduced

3.         CLEAN CLEARING

This is the removal of the entire vegetation on a piece of land.

MERITS

1. It gets rid of weeds from the land
2. It may leave land free of all obstacles

DEMERITS

1. It leads to disturbance or removal of top soil
2. It leads to increase evaporation of water
3. It exposes the soil to erosion
4. It leads to reduction in organic matter
5. It leads to loss of soil nutrients
6. It leads to leaching
7. It destroys the soil structure

• FERTILIZER APPLICATION

This involves the application of certain chemical substance to the soil to increase its fertility

MERITS

1. It supplements nutrients content of the soil
2. It enhances the productive capacity of the soil
3. It increases the population of microorganism in the soil
4. It stimulates vegetation growth

DEMERITS

1. Excessive application of fertilizers can cause soil acidity
2. Excess application can also reduce the activities of soil organism
3. Excessive application may also hinder the growth of crops

• ORGANIC MANURING

It involves the application of manure e.g green manure, farm yard manure and compost manure to the soil in order to improve its fertility.

MERITS

1. Organic manuring returns nutrients to the soil
2. It improves the texture and structure of the soil
3. It encourages the activities of soil organisms
4.  It improves the water temperature fluctuations in the soil
5. It prevents soil erosion
6. It improves water holding capacity of the soil

DEMERITS

1. The process may lead to introduction of pathogens to the soil
2. It may have adverse effects on crops, if not properly applied

• CROP ROTATION

Crop rotation is the system of farming whereby different crops are grown on the same piece of land year after year on a definite manner so as to maintain the fertility of the soil

MERITS

1. It adds nutrient to the soil through nitrogen fixation
2. It increases the yield of crops
3. It controls the growth of weeds
4. It maximizes the use of available land
5. It control pests and diseases associated with soil
6. If controls erosion
7. CONTINOUS CROPPING

This involves the growing of crops on the same piece of land every year without the application of manure or fertilizers

MERITS

1. It enables different crops to be grown and harvested
2. It maximizes the use of available land

DEMERITS

1. It depletes soil nutrients
2. It ensures the spread or multiplication of germs
3. It ensures the multiplication of pests and parasites
4. It results in low yields of crops

• FLOODING: It is defined as the accumulation of an abnormal large quantity of water in an area which refuses to percolate or flows away.

EFFECTS OF TILLAGE IMPLEMENTS ON THE SOIL

1. PLOUGHING
2. It increases the soil organic matter content
3. It helps to mix the soil together
4. It improves water infiltration capacity
5. It improves the aeration of the soil
6. It leads to compaction of the soil
7. It spreads disease causing organism in the soil

• HARROWING
• It leads to fine tilth through the mixing of soil
• It increases aeration and water infiltration
• It increases root penetration
• It leads to destruction of soil structure
• It may lead to soil erosion

• RIDGING
• It prevents erosion and improves water penetration
• It collects together rich top soil
• It improves aeration and root penetration
• It improves water conservation in the soil
• It also facilitates the harvesting of roots crops

EVALUATION

1. List five effects of bush burning on the soil
2. (a) Define Tillage

            (b) Explain Zero tillage

METHODS OF REPLENISHING LOST NUTRIENTS

1. CROP ROTATION: It is a system of farming whereby different crops are grown on the same piece of land year after year in a definite manner so as to maintain the fertility of the soil.

The layout of a four-year crop rotation plan is shown in this table

YEAR	PLOT I	PLOT II	PLOT III	PLOT IV
1	Yam	Cowpea	Cassava	Maize
2	Cowpea	Cassava	Maize	Yam
3	Cassava	Maize	Yam	Cowpea
4	Maize	Yam	Cowpea	Cassava

PRINCIPLES OF CROP ROTATION

1. Deep-rooted crops like yam and cassava should not follow each other
2. Shallow-rooted  crops should not follow each other
3. Crops which have the same diseases should not follow each other
4. Crops which have the same pests should not follow each other
5. Crops of the same family should not follow each other
6. Crops which control weeds should be planted
7. Legumes should be included in crop rotation

CONDITIONS NECESSARY FOR THE PRACTISE OF CROP ROTATION

1. Where land is scarce or limited in supply
2. Where population is high
3. The need to have different varieties of crops
4. The need to maintain soil fertility
5. Where the soil is exhausted of nutrient

• ORGANIC MANURING

Organic manure refers to the delayed plant and animal products which have been carefully prepared to supply nutrients to plants or crops.

• BUSH FALLOWING

This is the practice in which farmlands are left to lie fallow after one or two years of cultivation to allow the nutrients to revert to the soil.

• COVER CROPING

It is the process of planting certain plants mainly to cover soil surface to conserver the soil nutrient.

Some common examples of cover crops are: mucuna pueraria, centro, clotalaria, calapogonium and cowpea

• LIMING

It is the process whereby Calcium or magnesium containing compounds are added to the soil to reduce soil acidity. Some common liming materials are: limestone, quicklime, slaked lime, basic slag, dolomite, gypsum, wood, ash etc.

• APPLICATION OF INORGANIC FERTILIZERS

Fertilizers are chemical substances in form of powder, granules, pellets, or crystals which can be added to the soil to increase fertility.

EVALUATION

1. What is crop rotation?
2. List five principles of crop rotation

FACTORS INFLUENCING NUTRIENTS

Availability in the soil

1. Soil PH
2. Concentration of other nutrients
3. Leaching
4. Crop removal
5. Oxidation and Reduction of organic materials
6. Burning
7. Soil Texture
8. Erosion
9. Soil moisture content
10. Level or Organic matter/Micro Organisms in the soil

WAYS IN WHICH SOIL NUTRIENTS CAN BE LEST

1. Crop removal
2. Erosion
3. Leaching
4. Soil Acidity
5. Excess of other nutrients
6. Oxidation and reduction of organic materials

GENERAL EVALUATION

1. What is Bush burning?
2. State the merits of bush burning
3. What is crop rotation?
4. List five principles of crop rotation 
5. State four effects of ploughing on the soil

READING ASIGNMENT

Essential Agricultural Science for Senior Secondary Schools, Chapter 18, pages 187 – 201

WEEKEND ASSIGNMENT

1. The following are pre planting activities except (a) ploughing (b) bush clearing  (c) harrowing (d) thinning
2. The following are types of manure except (a) green manure (b) farm yard manure (c) NPK (d) compost
3. The following are methods of fertilizer application except (a) broadcasting (b) ring method (c) Top dressing (d) Eroding
4. The following are liming materials except (a) limestone (b) Urea (c) quicklime (d) slaked lime
5. Nutrients are lost through the following means except (a) crop removal (b) Erosion (c) leaching (d) mulching

SECTION B

1.         (a) State four demerits of bush burning

            (b) State four uses of lime in Agriculture

2.         (a) Define soil organic matter

            (b) State five ways in which soil organic matter is important in Agriculture.