EFFECTS OF SOME FARMING PRACTICES ON THE SOIL

FARMING PRACTICES

The following farming practices by farmers have various consequences or effects on the soil.

a) Bush Burning: This involves the setting of fire on the bush to clear out the vegetation.

 

Merits

1. It releases minerals like potassium and phosphorus to the soil in form of ash.
2. Burning has some sterilizing effects on the soil.
3. It stimulates the growth of fresh grasses, especially during dry season.
4. It also destroys soil-borne pathogens or germs.
5. It destroys the seeds of weeds.

 

Demerits

1. It destroys the organic matter content of the soil.
2. It reduces the population of soil living organisms.
3. It oxidises nitrogen and sulphur into their gaseous forms, thus reducing their levels in the soil.
4. It exposes the soil to erosion and leaching.
5. It may raise the pH level of the soil.
6. It leads to environmental pollution.
7. It destroys the soil structure.
8. It reduces the soil-water content.
9. It may affect the soil pH.

 

b) Overgrazing: Overgrazing is a situation where more animals than can be supported on a particular pasture are put there to graze. In other words, overgrazing is a way of exceeding the carrying capacity of the soil.

 

Merits

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

 

Demerits

1. Overgrazing 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 the soil structure.
5. It leads to compaction of the soil, resulting from continuous trampling under animal hoofs.
6. Compacted soil (hard pan) reduces water infiltration and this leads to surface run-off of the soil or waterlogging.
7. Pore spaces in soils are reduced, leading to poor soil aeration.
8. Overgrazing exposes the soil to increased soil water evaporation.
9. It leads to loss in soil fertility.

 

c) Clean Clearing: Clean clearing is the practice whereby the whole vegetation is cleared and removed, thus leaving the land clean.

 

Merits

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

 

Demerits

1. It results in the disturbance or removal of top soil.
2. It exposes the soil to direct sunshine, hence it affects evaporation of water.
3. It increases the temperature of the soil.
4. It exposes the soil to erosion increase.
5. It leads to reduction of soil organisms.
6. It also leads to reduction of organic matter.
7. It leads to loss of soil nutrients.
8. It leads to destruction of soil structure or soil compaction.
9. It exposes the soil surface to rainfall which leads to leaching.
10. It upsets the ecosystem or ecological balance.

 

d) Fertilizer Application: Fertilizer application involves the application of certain chemicals or substances to the soil to improve its fertility.

 

Merits

1. It suppliments nutrient content of the soil.
2. It enhances the productive capacity of the soil.
3. It increases the population of micro-organisms in the soil.
4. It stimulates vegetation growth. Hence, it reduces erosion.
5. Excessive or prolonged use reduces the availability of some essential plant nutrients, e.g ., potassium and calcium.

 

Demerits

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

 

e) Organic Manuring: Organic manuring 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 water conservation in the soil.
5. It regulates the temperature fluctuations in the soil.
6. It prevents soil erosion.
7. It has a buffering effect on the soil.
8. It improves water-holding capacity of the soil.

 

Demerits

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

 

f) 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 so as 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 maximises the use of available land.
5. It controls pests and diseases associated with soil.
6. It controls erosion.

 

g) 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 maximises 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 yield of crops.

 

h) Flooding: Flooding is defined as the accumulation of an abnormal large quantity of water in an area which refuses to percolate or flow away.

 

Demerits

1. It washes away the top soil which is rich in nutrients.
2. It destroys crops.
3. It leads to low yield of crops.
4. It causes erosion and leaching.
5. It renders the soil infertile.

 

i) Tillage: Tillage is defined as the working, digging or breaking up of the soil in preparation for planting of crops.

 

Types of Tillage

There are three main types of tillage. These are:

• Zero tillage: This refers to the situation where there is no tilling of the soil at all. In other words, the plant residues are not removed from the top of the soil before the seeds are introduced through them.
• Minimum tillage: This involves the tilling of the top soil at minimal level so as not to destroy the top soil.
• Total tillage: This involves the use of heavy implements like ploughs. harrows and ridgers to till the soil and prepare seed beds or ridges before planting. Common tillage implements are ploughs, harrows and ridgers.

 

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 which increases the water
   content of the soil.
4. It improves the aeration of the soil.
5. It leads to compaction of the soil.
6. It spreads disease-causing
   organisms in the soil.
7. It exposes soil organisms to
   external hostile environment.
8. It generally helps to control weeds.
9. It leads to destruction of soil structure.

 

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 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 top soil,thus increasing nutrient availability.
3. It improves aeration and root penetration.
4. It improves water conservation in the soil.
5. It also facilitates the harvesting of root crops.
6. It causes the development of hard pan layer which leads to water logging.