FACTORS AFFECTING CROP PRODUCTION

FACTORS AFFECTING CROP PRODUCTION

It is categorized under two heads, i.e., Internal and External factors.

INTERNAL FACTORS

Internal factors are related to genetic make-up of plants and thus less influenced by environmental factors. These are called genetic factors which attributes crop yield and other desirable characters for crop production.

• High yielding ability
• Early maturity
• Resistance to lodging
• Tolerance to insect pests and diseases
• Drought, flood and salinity tolerance
• Chemical composition of grains (oil content, protein content) and Quality of grains (fineness, coarseness)
• Quality of straw (sweetness, juiciness)

EXTERNAL FACTORS

1. Climatic
2. Edaphic
3. Biotic
4. Physiographic and
5. Socio economic factors.

 

1. CLIMATIC FACTORS

The climatic factors are the atmospheric weather variables which influences the crop production. In fact, success and failure of crops is intimately related to the weather during the crop periods. Nearly 50 % of yield is attributed to the influence of climatic factors. However, by adjusting cropping pattern and by following suitable agronomic practices one may mitigate the adverse effect of weather in order to get high yield.  The factors are-

(a) Precipitation- It includes all water which falls from atmosphere such as rainfall, snow, hail, fog and dew. Total precipitation in amount and distribution greatly affects the choice of a cultivated species in a place. Rainfall is one of the most important factors influences the vegetation of a place.

• Distribution of rainfall is more important than total rainfall to have longer growing period especially in drylands.
• In heavy and evenly distributed rainfall areas, crops like rice in plains and tea, coffee and rubber in Western Ghats are grown.
• Low and uneven distribution of rainfall is common in dryland farming where drought resistance crops like pearl millet, sorghum and minor millets are grown.
• In desert areas grasses and shrubs are common, because of hot desert climate exists.

Though the rainfall has major influence on yield of crops, yields are not always directly proportional to the amount of Precipitation as excess above optimum reduces the yields.

(b) Temperature- Temperature is a measure of intensity of heat energy. Most of the agricultural plants require temperature between 15 and 40⁰C for growth. The minimum, maximum (above which crop growth ceases) and optimum temperature of individual’s plant is called as cardinal temperature. The temperature of a place is largely determined by its distance from the equator (latitude) and altitude.

• Germination, growth and development of crops are highly influenced by temperature. It affects leaf production, expansion and flowering.
• Physical and chemical processes within the plants are governed by air temperature.
• Diffusion rates of gases and liquids changes with temperature.
• Solubility of different substances in plant is dependent on temperature.

(c) Atmospheric Humidity (Relative Humidity-RH)– Water present in the atmosphere in the form of invisible water vapour, known as humidity. RH is the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature. If relative humidity is 100% it means the entire space is filled with water and there is no soil evaporation and plant transpiration.

• Relative humidity influences the water requirement of crops.
• Relative humidity of 40-60% is suitable for most of the crop plants.
• When relative humidity is high there is chance for the outbreak of pest and disease.

(d) Solar radiation (without which life will not exist)– It is the source of energy for all the physical processes taking place in the atmosphere. It drives the process of photosynthesis, evaporation and heating the soil and air.

• From germination to harvest and even post-harvest crops are affected by solar radiation.
• All physical process taking place in the soil, plant and environment are dependent on light.
• Visible radiation is very important in photosynthetic mechanism of plants. Photosynthetically Active Radiation (PAR – 0.4 – 0.7µ) is essential for production of carbohydrates and ultimately biomass.
• Photoperiodism is a response of plant to day length as they are classified to short day, long day and day neutral plants.
• Phototropism is response of plants to light direction. E.g., Sunflower.
• Photosensitive – Season bound varieties depends on quantity of light received.

(e) Wind velocity– The basic function of wind is to carry moisture (precipitation) and heat. The moving wind also supplies fresh CO₂ for the photosynthesis.

• Wind movement for 4 – 6 km/hour is suitable for more crops.
• When wind speed is very high, it causes mechanical damage of the crops like it removes leaves and twigs and damages crops like banana, sugarcane.
• Pollen and seeds are dispersed by wind, what we call wind dispersal and is necessary for certain crops.
• Helps in cleaning produce to farmers.
• Causes soil erosion, increases evaporation and spread of pest and diseases.

(f) Atmospheric gases on plant growth–

• CO₂ – 0.03%, O₂ – 20.95%, N₂ – 78.09%, Argon – 0.93%, Others- 0.02%.
• CO₂ is important for Photosynthesis and is taken by the plants by diffusion process from leaves through stomata.
• CO₂ is returned to atmosphere during decomposition of organic materials, all farm wastes and by respiration.
• O₂ is important for respiration of both plants and animals while it is released by plants during Photosynthesis
• Nitrogen is one of the important major plant nutrients, Atmospheric N is fixed in the soil by lightning, rainfall and N fixing microbes in leguminous/pulses crops and available to plants.
• Certain gases like SO₂, CO, CH₄, HF released to atmosphere are toxic to plants.

2. EDAPHIC FACTORS (soil)

The soil factors that affect crop growth are-

(a) Soil moisture- Water is an essential constituent of growing plant which it extracts from soil.

• Water is essential for photosynthesis.
• The moisture range between field capacity (1/3 atm, pF- 2.54) and permanent wilting point (15 atm, pF- 4.2) is available to plants.
• Available moisture will be more in clay soil than sandy soil.
• Soil water helps in chemical and biological activities of soil including mineralization.
• It influences the soil environment E.g.; it moderates the soil temperature from extremes.
• Nutrient availability and mobility increase with increase in soil moisture content.

(b) Soil air- Aeration of soil is absolutely essential for the absorption of water by roots.

• Occupation of nearly 1/3^rd of the pore space in the soil by air and 2/3^rd by water constitutes the most favourable condition for plant growth.
• Germination is inhibited in the absence of oxygen. Plant growth suffers when oxygen diffusion rate (ODR) below 40*10^-8 gm/cm²/minute. The growth of root is ceased at 20*10^-8 gm/cm²/minute ODR.
• Soil air constitute >25% or equal in sandy soil, 15-20% in loamy and <10% in clay of the total soil volume. Clay soil retains more water hence has the lower air capacity.
• O₂ is required for respiration of roots and microorganisms.
• Soil air is essential for nutrient availability of the soil by breaking down insoluble mineral to soluble salts
• For proper decomposition of organic matter.
• Potato, tobacco, cotton linseed, tea and legumes need higher O2 in soil air.
• Rice requires low level of O₂ and can tolerate water logged (absence of O₂) condition.

(c) Soil temperature-It affects the physical and chemical processes going on in the soil.

• For optimum root development- 10-27⁰C, for optimum crop root development- 15-45⁰
• It affects the germination of seeds and growth rate of underground portions of the crops like tapioca, sweet potato.
• It influences the rate of absorption of water and solutes (nutrients).
• Soil temperature controls the microbial activity and processes involved in the nutrient availability.
• Cold soils are not conducive for rapid growth of most of agricultural crops. Black cotton soil absorbs about 86%, alluvial soil 40% and grass covered soil about 60% of solar radiation. On an average the specific heat of the soil ranges from 0.20- 0.23.

(d) Soil mineral matter- The mineral content of soil is derived from the weathering of rocks. These are the sources of plant nutrients e.g.; Ca, Mg, S, Mn, Fe, K etc.

(e) Soil organic matter- It is composed of humic and non-humic substances and supplies all the major and micro nutrients to crops.

• OM is source of plant nutrients which are liberated in available forms during mineralization.
• It improves soil structure, its drainage and aeration, water holding capacity buffer and exchange capacities, influences the solubility of minerals.
• It is a source of food for most microorganisms.
• Nearly 95% of Nitrogen and 33% of Phosphorus of soil are obtained from OM.
• It has the capacity to control soil temperature.

(f) Soil organisms- The raw organic matter in the soil is decomposed by different micro-organisms which in turn releases the plant nutrients. Atmospheric nitrogen is also fixed by microbes in the soil and is available to crop plants through symbiotic (Rhizobium) or non-symbiotic (Azospirillum) association.

(g) Soil reaction (pH)– Soil reaction is the pH (hydrogen ion concentration) of the soil.

• Soil pH affects crop growth and neutral soils with pH 7.0 are best for growth of most of the crops.
• Soils with low pH is injurious to plants due high toxicity of Fe and Al.
• Low pH also interferes with availability of other plant nutrients.

3. BIOTIC FACTORS

Beneficial and harmful effects caused by other biological organism (plants and animals) on the crop plants.

(a) Plants-

• Competitive (allelopathy) and complimentary nature among field crops when grown together.
• Competition between plants occurs when there is demand for nutrients, moisture and sunlight particularly when they are in short supply or when plants are closely spaced. Competitive interaction may be also due to release of chemical substances or toxins called allelopathy.
• When different crops of cereals and legumes are grown together, mutual benefit results in higher yield (synergistic effect).
• Competition between weed and crop plants as parasites eg: Striga parasite weed on sugarcane crop.

(b) Animals

• Soil fauna like protozoa, nematode, snails, and insects help in organic matter decomposition, while using organic matter for their living.
• Insects and nematodes cause damage to crop yield and considered as harmful organisms.
• Honey bees and wasps help in cross pollination and increases yield and considered as beneficial organisms
• Burrowing earthworm facilitates aeration and drainage of the soil as ingestion of organic and mineral matter by earthworm results in constant mixing of these materials in the soils.
• Large animals cause damage to crop plants by grazing (cattle, goats etc).

4. Physiographic factors

(a) Topography is the nature of surface earth (leveled or sloppy) is known as topography. Topographic factors affect the crop growth indirectly.

(b) Variation in aspects and elevation influence the climatic factors. Altitude – increase in altitude cause a decrease in temperature and increase in precipitation and wind velocity (hills and plains).

(c) Steepness of slope: it results in run off of rain water and loss of nutrient rich top soil.

(d) Exposure to light and wind: a mountain slope exposed to low intensity of light and strong dry winds may results in poor crop yields (coastal areas and interior pockets).

5. Socio-economic factors

1. Society inclination to farming, land tenancy, size of land holdings, fragmentation of field.
2. Availability of labour, capital.

• The economic condition of the farmers greatly decides the input/ resource mobilizing ability.

1. Government policies.
2. Appropriate choice of crops by human beings to satisfy the food and fodder requirement of farm household.
3. Breeding varieties by human invention for increased yield or pest & disease resistance.

Frequently Asked Question (FAQ)

What are the various factors which affect crop production?

1. Internal (Genetic) factors)
2. Climatic
3. Edaphic
4. Biotic
5. Physiographic and
6. Socio economic factors.

What % age of Relative humidity suitable for most of the crop plants?

Relative humidity of 40-60% is suitable for most of the crop plants.

What is Biotic & A-biotic factors?

Biotic factors include flora and fauna, while A-biotic include light, temperature, water, nutrients etc.

Read also…
CROPPING SEASONS OF INDIA
MAJOR CROPS IN INDIA- AN OVERVIEW
FARM TYPES- AN OVERVIEW
FARM MANAGEMENT- DEFINITION & OBJECTIVES
AGROFORESTRY- FEATURE,TYPES & BENEFITS