Factors responsible for lost of soil nutrients, Effects of conservation practices on environmental pollution.

CLASS : JSS2

 

SUBJECT : AGRICULTURAL SCIENCE

 

TERM : FIRST  TERM E-NOTE

 

WEEK : WEEK 4

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WEEK 4

DATE:

TOPIC: Soil conservation

Content:

Meaning of soil conservation.

Ways by which soil losses its nutrients.

Effects of soil conservation practices on the environment.

SUB TOPIC 1: MEANING OF SOIL CONSERVATION.

Conservation is regarded as plans used for any natural resources to avoid exploitation and destruction.

Soil conservation is the use of soil without waste so as to sustain higher crop production or yield. OR. The measures the farmer adopts for maintaining the soil and its resources is termed soil conservation.

It is important to conserve soil so as to prevent wastage of soil and depletion of its nutrients.

EVALUATION

1. What is soil conservation?

2. State the importance of soil conservation.

SUB TOPIC 2: WAYS BY WHICH SOIL LOST ITS NUTRIENTS.

Nutrients are usually lost from the soil through leaching, crop removal, burning, erosion, oxidation and reduction and clean clearing.

1. Leaching: This is the washing away of nutrients from the topsoil down through the soil profile by rain water. This can be controlled by either planting of cover crops and addition of manure.

2.Crop removal: Soil nutrients are used by plants for growth and development ,when such crops are harvested the nutrients take up are lost completely from the soil.

3.Bushburning: The burning of vegetation reduces soil fertility. This is because it exposes the surface of the soil to the agents of erosion like water and wind.

4.Oxidation and reduction: Oxidation and reduction reaction in the soil lead to loss of soil nutrients . The oxidized or reduced radical goes into the atmosphere in gaseous form.

5. Erosion: Erosion is the wearing away of the top soil by agents such as water, wind and activities of man. This causes loss of soil nutrients.

TYPES OF EROSION

Types of erosion include, splash erosion , sheet erosion, rill erosion, gully erosion and wind or suspension erosion.

(a) Splash erosion: It is the removal of soil particles by the forces of rain drops.(It is the first stage of soil erosion)

(b) Sheet erosion: The soil particles scattered by raindrops block the soil pores, this will make it difficult for the rain water to enter the soil. This results in water flowing on the surface of the soil. it is common on gentle sloppy area.

(c) Rill erosion: This occurs when rain drops on the soil surface cause gradual removal of soil particles along a narrow channels.(3rd stage)

(d) Gully erosion: This occurs in a place when rainwater does not sink into the soil, it therefore runs off over land. (4th stage)

WAYS OF CONTROLLING EROSION.

  1. Planting of cover crops.
  2. Crop rotation.
  3. Application of organic manure.
  4. Mulching
  5. Preventing bush burning.
  6. Preventing overgrazing

Vii. Establishment of wind breaks

 

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EVALUATION

1. Mention five ways by which nutrient can be loss in the soil.

2. Differentiate between erosion and leaching.

3. What are the types of erosion?

4 State four ways of preventing erosion.

SUB- TOPIC 3:METHODS OF SOIL CONSERVATION

Conservation of soil nutrients entails methods of controlling soil erosion and methods involved in preventing loss of soil water in the soil. This includes

  1. Planting of cover crops.
  2. Crop rotation.
  3. Application of organic manure.
  4. Mulching
  5. Preventing overgrazing
  6. Establishment of wind breaks
  7. Irrigation
  8. Good cultivation methods.
  9. Regular weeding
  10. Preventing bush burning.

EFFECTS OF SOIL CONSERVATION PRACTICES ON THE ENVIRONMENT.

1. Excessive use of nitrogenous fertilizer results in acidification of the soil.

2. Some fertilizer have harmful effects on soil organisms.

3. Continuous use of some fertilizers lead to unavailability of some essential

plant nutrients.

Irrigation could lead to salt build-up in the soil if the source of irrigation water

is salty.

5. Irrigation can also lead to leaching and erosion when not well handled.

6. Flooding can lead to build up of pests and diseases.

7. Mulching materials could harbor pests and diseases which later attack

the crops

EVALUATION

a) State five methods of conserving nutrients in the soil.

b) What are the effects of conservation practices on our environment.

ASSIGNMENT

  1. What is irrigation?
  2. List the types of irrigation.