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 setting fire to the bushes to clear out the vegetation

MERITS

1. It releases potassium and phosphorus as ash

2. It has a sterilizing effect on the soil

3. It stimulates the growth of fresh grass

4. It destroys soil-borne pathogens 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 the soil’s live organisms

3. It oxidizes 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 the soil water content

2) OVERGRAZING

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

MERIT

1. More feces 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 the 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

4) FERTILIZER APPLICATION

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

 MERITS

1. It supplements the nutrient content of the soil

2. It enhances the productive capacity of the soil

3. It increases the population of microorganisms in the soil

4. It stimulates vegetation growth

DEMERITS

1. Excessive application of fertilizers can cause soil acidity

2. An excessive application can also reduce the activities of soil organisms

3. An excessive application may also hinder the growth of crops

5) ORGANIC MANURING

It involves the application of manure, e.g, green manure, farmyard manure, and compost manure to the soil 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 the water-holding capacity of the soil

DEMERITS

1. The process may lead to the introduction of pathogens to the soil

2. It may have adverse effects on crops if not properly applied

6) CROP ROTATION

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

MERITS

1. It adds nutrients 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 controls pests and diseases associated with the soil. If controls erosion

7) CONTINUOUS 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

8) FLOODING

It is defined as the accumulation of an abnormally large quantity of water in an area that refuses to percolate or flow away.

EFFECTS OF TILLAGE IMPLEMENTS ON THE SOIL

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

 B) HARROWING

1. It leads to fine tilth through the mixing of soil
2. It increases aeration and water infiltration
3. It increases root penetration
4. It leads to the destruction of soil structure
5. It may lead to soil erosion

C) RIDGING

1. It prevents erosion and improves water penetration
2. It collects together rich topsoil
3. It improves aeration and root penetration
4. It improves water conservation in the soil
5. It also facilitates the harvesting of root 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 yams and cassava should not follow each other

2. Shallow-rooted crops should not follow each other

3. Crops that have the same diseases should not follow each other

4. Crops that have the same pests should not follow each other

5. Crops of the same family should not follow each other

6. Crops that control weeds should be planted

7. Legumes should be included in crop rotation

CONDITIONS NECESSARY FOR THE PRACTICE OF CROP ROTATION

1. Where land is scarce or limited in supply

2. Where the 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 nutrients

A. ORGANIC MANURING
Organic manure refers to the decomposed plant and animal products that have been carefully prepared to supply nutrients to plants or crops.

B. 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.

C. COVER CROPPING

It is the process of planting certain plants mainly to cover the soil surface to conserve the soil nutrients. Some common examples of cover crops are: mucuna, Pueraria, Centro, crotalaria, calapogonium, and cowpea

D. 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 the form of powder, granules, pellets, or crystals that 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. The 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 of Organic matter/Micro-Organisms in the soil

WAYS IN WHICH SOIL NUTRIENTS CAN BE LOST

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

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