Topography
Topography is a nonliving factor that refers to the “lay of the land.” It includes the physical features of the earth such as the land elevation, slope, terrain (flat, rolling, hilly, etc.), mountain ranges and bodies of water.
The slope or inclination of a land is the percentage change in its elevation over a certain distance. It is measured by dividing the vertical distance from the foot to the top of the land by the horizontal distance between …show more content…
The relationship of this abiotic factor to temperature is like that of distance from the equator to the arctic poles. According to Stiling (1999), temperature decreases by 1 C for every 100 m increase in altitude in dry air.
This abiotic factor is an important consideration in crop or site selection for more productive crop farming. Coconut prefers an elevation not exceeding 600 meters above sea level (masl) (PCARRD 1982); for better quality, tea is best grown above 1000 masl while rubber requires not more than 500 masl because at higher elevation latex flow is restricted (Abellanosa and Pava 1987); the seasonality of ripening of various fruit crops, e.g. durian , is modified when they are planted in different elevations.
The effect of land elevation on plant growth and development is apparent when exploring a high-rise mountain. Dominance of certain plant types varies with elevation. With change in height from sea level to 16,000 feet (4,876.8 meters) from the foot to the top of a mountain in the Peruvian Andes or New Guinea, temperatures change from tropical to subtropical, temperate, and subarctic to …show more content…
Soil
Soil is the outermost layer of the surface of the earth in which plants grow. It is composed of eroded rock, mineral nutrients, decaying plant and animal matter, water and air. This abiotic factor is likewise important in crop farming and is treated under the heading Soil and Climatic Adaptation or Requirement of crops.
Most plants are terrestrial in that they are anchored to the soil through their roots, with which they absorb water and nutrients. But epiphytes and floating hydrophytes do not need soil to live. Variation in the physical, chemical, and biological properties of the soil have distinct effects on plant growth and development, depending on natural adaptation.
There are two properties of the soil having pronounced direct effects on plant growth and crop production: physical and chemical properties. There are also biological factors or living organisms in the soil such as the earthworms, insects, nematodes and microorganisms like bacteria, fungi, actinomycetes, algae, and protozoa. These organisms help in improving soil structure, tilth, aeration, water permeability and soil nutrient