infiltration is the process by which water on the ground surface enters the soil. infiltration rate in soil science is the measure of the rate at which soil is able to absorb rainfall or irrigation. it is measured in inches per hour or millimeter per hour. the rate decreases as the soil becomes saturated
infiltation can be visualized by pouring water into grass filled with dry powdered soil, slightly tamped. the water seeps into the soil and becomes darker as it is wetted
factors affecting the infiltration rate
the following factors affects the infiltration rate of soil water or moisture in the soil
the soil moisture content: the soil water infiltrate faster (high infiltration rate) when the soil is dry than when it is wet.as the consequence, when irrigation water is applied to a field the water at first infiltrate easily, but as the soil becomes wet, the inflitration rate decreases.
soil texture: coarse textured soil have mainly large particles in between therefore it has larger pores. on the other hand fine textured soil have mainly small particles in between therfore it has small pores. in coarse soils, the rain or irrigation water moves more easily (infiltration rate is higher as compared to fine textured soil)
the soil structure: water infiltrate quicky (there is higher infiltration rate) into granular soil than in the massive and compact soils
percolation soil water movement
percolation is downward movement of water through saturated or nearly saturated soil in the response to the force of gravity. percolation occurs when water is under pressure or when the tension is smaller than about 1/2 atmosphere. percolation rate is synonymous with infiltration rate with the qualitative provision of saturated or near-saturated conditions.
interflow soil water movement
interflow is the lateral seepage of water in relatively pervious soil above a less pervious layer. such water usually reapper on the surface of the soil at lower elevation.
leaching (refers to soluble chemical or minerals draining away from the soil, ash, or similar materials by the action of percolating liquid, especially rainwater or irrigation water.
Poor Water-Holding Capacity: Sandy soils have low water-holding capacity due to their coarse texture and large particle size. Water tends to drain quickly through the large spaces between the sand particles, resulting in poor water retention.
Coarse Texture: Sandy soils have a coarse texture because they predominantly consist of sand particles. These particles are relatively large, which gives the soil a gritty feel when touched.
Well-Aerated: Due to their coarse texture, sandy soils are well aerated. The larger spaces between sand particles allow for efficient air movement and oxygen circulation within the soil, promoting good root respiration.
High Rate of Leaching: Sandy soils have a high rate of leaching, which refers to the rapid movement of water and dissolved nutrients through the soil profile. The coarse texture of sandy soils facilitates fast drainage, causing nutrients to leach out quickly, potentially leading to nutrient deficiencies.
Low Capillarity: Sandy soils have low capillarity, meaning they have a limited ability to draw water upwards through capillary action. The large spaces between sand particles do not facilitate the upward movement of water against gravity as effectively as finer-textured soils.
Less Stable Structure and Erosion Susceptibility: Sandy soils have a less stable soil structure compared to other soil types. Their loose arrangement of large particles makes them prone to erosion by wind or water, leading to soil loss and reduced fertility if not properly managed.
Acidic pH: Sandy soils typically have acidic pH levels. The low water-holding capacity of these soils contributes to leaching of basic cations (such as calcium, magnesium, and potassium), leading to an accumulation of acidic substances.
Quick Temperature Response: Sandy soils warm up quickly during the day due to their low water-holding capacity and good drainage. They also cool down rapidly at night as heat is released from the soil surface. This characteristic can influence plant growth and affect the choice of crops in specific climates.
Composition: Sandy soils primarily consist of 80-95% sand particles, with smaller proportions of silt (5-2%) and clay (0.1-1%). The organic matter content is generally low, ranging from 0.1% to 1%.
Light and Easy to Work: Sandy soils are lightweight and easy to work with due to their loose structure. They can be easily tilled, cultivated, or amended, which can be advantageous for gardening and agricultural practices.