Dear Naresh,

soil water retention capacity is directly related to soil texture and structure.

The highest soil water capacity occurs in heavy soils like clay, clay-silty. Aeration and soil structure are essential parameters that affect infiltration. If the soil structure is disturbed, infiltration will increase the same as the increase in aeration.

Article Appraisal of groundwater recharge in Neelum watershed (Upper...

Might be helpful to you

Clay soil .A well-structured soil with good aggregation allows for better

Dr Mehmet Sener, Dr Fazle Yar Khan and Dr Arshdeep Kirar thank you for your contribution to the discussion

Clayey soil contains small sized particles, sandy contains large particles while loamy is the mixture of both small and large particles in equal proportions. Thus, the water holding capacity is highest in the clayey soil. The soil which has maximum water retention capacity is clayey. This is because the particles are very closely packed in clayey soil, and the percolation rate is very low. The particle of the soil thus holds the water in it. Soils with smaller particles (silt and clay) have a larger surface area than those with larger sand particles, and a large surface area allows a soil to hold more water. In other words, a soil with a high percentage of silt and clay particles, which describes fine soil, has a higher water-holding capacity. Clay soils retain more water and nutrients than sand, but there is little percolation of the water and less oxygen for the plant due to smaller pore sizes than those of coarser textures. Soil structure will influence the drainage and water holding capacity of the soil as well as other crucial factors including the aeration available in the soil. Soil structure also has a big physical impact on plants by influencing root growth and penetration and aiding the flow of nutrients. Soil texture, or the percentage of sand, silt, and clay in a soil, is the major inherent factor affecting infiltration. Water moves more quickly through the large pores in sandy soil than it does through the small pores in clayey soil, especially if the clay is compacted and has little or no structure or aggregation. In soil with a good structure, the particles of sand and silt are held together in aggregates by clay, humus and calcium. The large empty spaces between the aggregates allow water and air to circulate and plant roots to grow down into the soil. The gaps between these aggregates are the pore spaces. For soil used in agriculture, a 'well-structured soil' will have a continuous network of pore spaces to allow drainage of water, free movement of air and unrestricted growth of roots.Soil texture, soil structure, and slope have the largest impact on infiltration rate. Water moves by gravity into the open pore spaces in the soil, and the size of the soil particles and their spacing determines how much water can flow in. When compared to pores between aggregates and between single soil particles, pores within an aggregate are quite small. This balance of large and small pores promotes soil aeration, permeability, and water retention. Root growth and the addition of organic material promote aggregate formation.

Dr. Naresh reply above is fairly thorough and accurate--to add to Dr. Naresh's reply, soil water moves not only by gravity forces, but by matric potential forces--i.e. the attractive forces that exist between water molecules and typical mineral surfaces of soil particles; such that water is attracted from wetter soil particles towards dryer soil particles.

Dr James C Trask thank you for your contribution to the discussion

The soil which has maximum water retention capacity is clayey. This is because the particles are very closely packed in clayey soil, and the percolation rate is very low. The particle of the soil thus holds the water in it. Clayey soil contains small sized particles, sandy contains large particles while loamy is the mixture of both small and large particles in equal proportions. Thus, the water holding capacity is highest in the clayey soil. Soils with smaller particles (silt and clay) have a larger surface area than those with larger sand particles, and a large surface area allows a soil to hold more water. In other words, a soil with a high percentage of silt and clay particles, which describes fine soil, has a higher water-holding capacity. The soil's ability to retain water is strongly related to particle size; water molecules hold more tightly to the fine particles of a clay soil than to coarser particles of a sandy soil, so clays generally retain more water. Sand has the lowest water holding capacity because they have coarse particles that leave a huge gap between the particles. Thus, a large amount of water and nutrients easily escape from the soil and cannot be retained within the sand. Each soil texture is capable of holding a certain amount of water: Sand: 0.8”/ft. Loamy Sand: 1.2”/ft. Clay: 1.35”/ft. A combination of sand, silt, and clay particles, this soil absorbs water readily and is able to store it for use by plants. Loam absorbs water at a rate between 1/4 and 2 inches per hour. Sandy Soil, because it has very large spaces, absorbs water at a rate of more than 2 inches per hour. Because of their high clay content, the black soil has wide crack during summers but they are resistant to wind and water erosion. They are highly moisture-retentive. This retention of moisture makes sure that the crop gets water for a long time without irrigation or rains. Soil structure will influence the drainage and water holding capacity of the soil as well as other crucial factors including the aeration available in the soil. Soil structure also has a big physical impact on plants by influencing root growth and penetration and aiding the flow of nutrients.Soil texture, or the percentage of sand, silt, and clay in a soil, is the major inherent factor affecting infiltration. Water moves more quickly through the large pores in sandy soil than it does through the small pores in clayey soil, especially if the clay is compacted and has little or no structure or aggregation. In soil with a good structure, the particles of sand and silt are held together in aggregates (small clumps) by clay, humus and calcium. The large empty spaces between the aggregates (macropores) allow water and air to circulate and plant roots to grow down into the soil. The gaps between these aggregates are the pore spaces. For soil used in agriculture, a 'well-structured soil' will have a continuous network of pore spaces to allow drainage of water, free movement of air and unrestricted growth of roots. Soil texture, soil structure, and slope have the largest impact on infiltration rate. Water moves by gravity into the open pore spaces in the soil, and the size of the soil particles and their spacing determines how much water can flow in. The soil properties such as soil texture, bulk density and aggregation affect the amount of pore space and hence the soil aeration. When compared to pores between aggregates and between single soil particles, pores within an aggregate are quite small. This balance of large and small pores promotes soil aeration, permeability, and water retention. Root growth and the addition of organic material promote aggregate formation. The drainage of excess water from soil macropores improves soil aeration. If the volumes of soil macropores are high, soil aeration will be good. Soil texture, bulk density, aggregate stability and organic matter contents influence the soil macropores.