CROP PRODUCTION

C. CLIMATIC FACTORS

Weather is the atmospheric condition of a place over a given short period of time. Climate is weather condition observed and recorded for a long period e.g. 30 – 40 years.

 

1. Rainfall:

- Is the main source of water required by all life processes.

- It must be adequate to sustain both animal and plant life.

 

Aspects of rainfall important in Agriculture

 

1. Rainfall reliability

- Depending on meteorological timing of the onset of rainfall. I.e. long rains begin around March- April of every year and continue for around 3 months.

- Short rains begin in October to November.

- Reliability determines the time for land preparation and planting.

- When rains fail to follow this expected-patterns massive crop failure occur and sometimes domestic animals die due to lack of food and water.

 

ii. Rainfall quantity

- This is the amount of rain that falls in a given area within a given year measured in mm

- It determines the type of crop to be grown and the type of livestock to be reared in an area.

 

iii. Rainfall distribution

- Is the number of wet months in a year.

- It influences the choice of crop varieties growing in a given area.

 

iv. Rainfall intensity

- this is the amount of rain that falls in an area with a period of one hour and is measured in mm/hour

- High rainfall intensity damage crops and causes soil erosion. It may also lead to destruction of soil structures.

 

2. Temperature

- This is the degree of hotness or coldness of a place measured in (C0)

i. Cardinal temperature

-Is the temperature in which plants grow and thrive well.

ii. Optimum Temperature

Is temperature which has a narrow range within the cardinal range which allows the plant to thrive best and produce well.

Effects of temperature on crop production

Low Temperature

 Slow growth rate of crop as the process of photosynthesis is slowed.

 Increases incidences of disease infection to crop e.g. C.B.D. in coffee.

 Quality of crops such as tea and pyrethrum improve with lowering of temperatures.

 

High temperatures

-Increases evaporation leading to wilting of crops

Increases the rate of growth and hastens the maturity of crop Improves the quality of crops such as Pineapples and oranges Increases incidences of plant pests and diseases e.g. Aphids, Leaf rust.

 Wind

Effects of Strong Wind on Agriculture

o Increases evaporation leading to wilting of crops.

o Causing lodging of crops and damage to plants.

o Acting as an agent of soil erosion

o Blowing away or bring rain bearing clouds.

o Increasing the rate of evapotranspiration.

o Destroying farm structures

o Areas with high humidity tend to be hotter but when wind takes away atmospheric water a cooling effect occurs.

 

4. Relative Humidity

- Is the amount of water vapor held by air at a given temperature compared to what it would hold when saturated.

- It affects the rate of evaporation and transpiration.

- At high relative humidity the rate of evapotranspiration is low.

 

5. Light

- It provides the energy required for photosynthesis.

 

Aspects of light important to crop growth

1. Light intensity

-Is the strength with which the light is harnessed by chloroplasts for the purpose of photosynthesis.

-The amount of light harnessed can be increased by pruning, thinning, weeding or wider spacing.

2. Light duration

- is the period during which light is available to plants per day.

- Plant varieties can be classified as long, short, or day neutral depending on the hours of light required for proper growth.

 

Short day plants – Require less than 12 hours of day light e.g. tobacco, rice, soya beans e.t.c.

Long day plants – Require more than 12 hours of day light e.g wheat varieties.

Day neutral plants - Require 12 hours of day light e.g. coffee, maize beans e.t.c.

3. Light Wave length

- Chlorophyll absorbs certain wave lengths of light which are not present in artificial light unless in case of U.v. or infra- red rays.

- This makes natural light more suitable for plant growth than artificial light.

 

D. EDAPHIC FACTORS OR SOIL FACTORS

 Soil formation

 Soil profile

 Soil structure

 Soil texture

 Soil constituent

 

ECOLOGICAL ZONES

(1) TROPICAL ALPHINE

(c) Found at the pick of high mountains e.g. Mt Kenya my Elgon etc.

(d) Found at an altitude of 3000m above sea level.

(e) Temperatures are low or below 10oc

(f) Has moorland vegetation i.e. short grass and no trees

(g) Have two sub-zones.

 

Tropical Alpine (I) TA1 and TA2

Tropical alpine (1) (TA1)

-Natural pasture utilized by cattle is found.

-The area is alienated with game parks.

-Soil erosion in experienced e.g. Areas near Mount Kenya.

Tropical alpine (2) TA2

-Annual rainfall is lower than in TA1 and drier than TA1.

- soil erosion is experienced

-Good for wood production

-Livestock pasture found here

-Good for crop production

 

(2) UPPER HIGH LAND ZONES (UH)

- Altitude falls at 2200 – 3000m above sea level.

-Temperature range is between 10 – 170C

-Frost is experience

-Subdivided into four major sub-zones