Exams   »   Factors Affecting Plant Population

Factors Affecting Plant Population and Growth- Complete List

An entire species of plants that are found in a given location or habitat is referred to as a plant population. It is similar to tallying every single member of a particular plant species in a field forest or other natural setting. The size and density of plant populations can fluctuate based on conditions such as interactions with other organisms environmental factors and the availability of resources like space, water, and nutrients. To research ecosystems biodiversity and ecological processes it is crucial to comprehend plant populations.

Plant growth factors regulate or impact both the adaptability of plants and their traits. Two factors typically affect the growth and development of plants:

  • Genetic Factors
  • Environmental Factors

Genetic Factors

The genetic factor is also called the internal factor because the basis of plant expression (the gene) is located within the cell. Check the table below to learn more about genetic factors.

Genetic Factors
Size of the plant
  • The crop’s spacing is determined by the volume occupied by the plant during flowering.
  • Plants of red gram, cotton, sugarcane, etc. occupy a larger volume of space in the field compared to rice and wheat.
  • Even the varieties of the same crop differ in the size of the plant
Elasticity of the plant
  • The plant’s elasticity is its ability to vary in size between the smallest size at which it can yield a reasonable amount of fruit and the largest size it can attain in an environment with limitless resources and space.
  • The optimum plant population range is high in indeterminate plants. Ex. Redgram- 55,000 to 1,33,000 plants/ha.
  • The elasticity is due to the tillering and branching habit of the plants.
  • For determinate plants like pearl millet, sorghum’s elasticity range is less.
  • More branches will be produced by the crop in the case of indeterminate plants like Redgram and cotton.
Foraging area or soil cover
  • Crops should cover the soil as early as possible to intercept maximum sunlight.
  • The higher the intercepted radiation more will be the dry matter produced.
  • Close-spaced crops intercept more solar radiation than wide-spaced crops.
Dry matter partitioning
  • Dry matter production is related to the amount of solar radiation intercepted by the canopy which depends on plant density.
  • There is a faster canopy expansion, more radiation absorption, and increased production of dry matter as plant density rises.
Crop and Variety
  • Depending on the crops and varieties, the plant population varies.
  • Rice : Short duration – 6,66,666 plants/ha (15 cm x 10 cm)
  • Medium – 5,00,000 plants/ha (20 cm x 10 cm)
  • Long – 3,33,000 plants/ha (20 cm x 15 cm)
  • Cotton : Medium – 55,555 plants/ha (60 cm x 30 cm)
  • Long – 44444 plants/ha (75 cm x 30 cm)
  • Hybrids – 18,518 plants/ha (120 cm x 45 cm)
  • Maize : Varieties – 83,333 plants/ha (60 x 20 cm)
  • Hybrids – 47,620 plants/ha (60 x 35 cm)

Environmental Factors

The environmental factor is considered external and refers to all factors, biotic and abiotic, other than the genetic factor. Check the table below to learn more about environmental factors.

Environmental Factors
Time of sowing
  • When the crop is sown at different times, it is exposed to different weather conditions.
  • Among weather factors, day length and temperature influence much of the plant population. As low temperature retards growth, a high plant population is required to cover the soil.
  • When plants are rainfed as opposed to being irrigated, their population must be lower.
  • More transpirational water loss occurs at higher plant densities.
  • Under adequate rainfall/irrigation, a high plant population is recommended.
Fertilizer application
  • A higher plant population is necessary to fully utilize higher levels of nutrients in the soil to realize higher yields.
  • Nutrient uptake increases at optimum plant population.
  • High population under low fertility soils leads to nutrient deficiency symptoms leading to low yield.
Seed rate
  • The plant population is determined by the viability, establishing rate, and amount of seed sown/unit area.
  • When comparing broadcasting to line sowing/transplanting, the seed rate is higher.
  • For example, Rice. 100 kg/ha for direct sowing, 60 kg/ha for line sowing, and 40 kg/ha for transplanting.

Other Factors that Affect Plant Population and Growth

Let’s learn about some other factors that affect plant population and growth. These are:

  1. Light: Plant development and photosynthesis rates are influenced by the quantity quality and duration of light.
  2. Water: As water is necessary for photosynthesis nutrient uptake and cell expansion it is essential for plant growth.
  3. Temperature: Extreme temperatures can stunt growth or cause damage to plants that have specific temperature requirements for healthy growth.
  4. Nutrients: Iron, zinc, and manganese are micronutrients while nitrogen, phosphorus, and potassium are macronutrients that plants need for vital processes like growth development and metabolism.
  5. Soil Quality: Nutrient availability water retention and root growth are all influenced by the texture pH fertility and structure of the soil. The quality of the air can have an impact on photosynthesis and plant respiration rates. This includes the amount of carbon dioxide and oxygen in the air.
  6. Competition: Plant growth and population density can be restricted by competition with other plants for resources like light water and nutrients.
  7. Predation and Herbivory: By feeding on plants or indirectly by dispersing diseases herbivores pathogens and pests can cause direct harm to plants as well as affect population density and growth.
  8. Mutualistic Relationships: Plant health can be improved by symbiotic relationships with beneficial organisms such as nitrogen-fixing bacteria or mycorrhizal fungi which facilitate nutrient uptake.
  9. Pollination: In many plant species pollination by animals or the wind is necessary for successful reproduction and affects population dynamics.
  10. Genetics: Genetic variables impact the characteristics of populations by determining traits like growth rate resistance to disease and environmental adaptability.
  11. Disturbance: Plant populations and growth patterns can be disturbed by man-made activities like land clearing or deforestation as well as by natural occurrences like fires and floods.
  12. Allelopathy: Certain plants emit substances that prevent nearby plants from growing altering the dynamics of the population.
  13. Microclimate: Small-scale changes in temperature humidity and light intensity can produce microhabitats that affect the distribution and growth of plants. The phenomenon of urbanization can have an impact on plant populations by generating heat islands air pollution and altered hydrological cycles.
  14. Climate Change: Variations in temperature precipitation patterns and atmospheric CO2 concentrations can have a significant impact on plant growth dynamics and populations.


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