Dear Sir,

I believed in that the different soil particles with various shape size and different parameters such as EC , Clay content etc could hold water so that different pores in the soil structure ultimately causing water holding capacity of its own. so when different climate and soil properties , water holding capacity is different

For example,

high clay and humus soil with hard pan in the soil column can hold more water than soil and gravel soil.

Dr Sameera Madusanka Hewa Kattuge 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. Clay soil retains more water because of the presence of small and fine particles. Loamy soils have medium size particles, so it retains moderate amount of water. Sand with low nutritional content and larger particles retain the least amount of water. Sandy soils contain less amount of silt so they hold less amount of water when compared to other types of soils. The quantity of water that soil can retain after flowing down of the gravitational water is called its field capacity or water holding capacity. It depends on chemical composition of the soil which means types of ions present and hence pH of the soil. Size of soil particles and their aggregation form pores in soil.Soil texture and organic matter are the key components that determine soil water holding capacity. In terms of soil texture, those made up of smaller particle sizes, such as in the case of silt and clay, have larger surface area. Increased soil organic matter enhances your soil's ability to absorb water, leading to less water stress during both dry and wet periods. This can be achieved by: Incorporate compost, manures, or other stable organic materials. Grow and incorporate a high biomass cover crop.The water holding capacity of soil is important for plant growth because it determines how much water is available to the plant. If the soil has a high water holding capacity, it can retain more water and make it available to the plant for a longer period of time, which can be beneficial during dry periods. The composition of the soil is the most important in determining the water holding capacity. Clay generally has a much higher water holding capacity than that of silt or sand because the particle size of the clay is much smaller allowing much less water to escape. Water holding capacity of desert soil is less. Clay soil retains more water because of the presence of small and fine particles. Loamy soils have medium size particles, so it retains moderate amount of water. Sand with low nutritional content and larger particles retain the least amount of water.

The maximum water holding capacity of soils varies due to several factors, including soil texture, organic matter content, and soil structure. Soils with a higher proportion of fine particles, such as silt and clay, have a larger surface area to hold water molecules. Additionally, organic matter acts like a sponge, increasing the soil's ability to retain water. Soil structure also plays a role, as well-structured soils with large pores allow for better water infiltration and retention.

In desert soils, the A horizon, which is the uppermost surface layer, typically has a lower water holding capacity than deeper horizons due to several reasons:

Despite these factors, the A horizon of desert soils can still hold some water, especially if it contains clay particles or has a slightly organic-rich surface layer. This water can be crucial for plant growth, particularly during periods of infrequent rainfall.

Dr Murtadha Shukur thank you for your contribution to the discussion

All soils hold water, just some more than others. The primary property determining soil water holding capacity is soil texture. The smaller the particle size the greater the surface area and the greater the water holding capacity. So, coarse texture soils (sands) hold less total water than clay soils. 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. Clay soil retains more water because of the presence of small and fine particles. Loamy soils have medium size particles, so it retains moderate amount of water. Sand with low nutritional content and larger particles retain the least amount of water. The quantity of water that soil can retain after flowing down of the gravitational water is called its field capacity or water holding capacity. It depends on chemical composition of the soil which means types of ions present and hence pH of the soil. Size of soil particles and their aggregation form pores in soil.Soil texture and organic matter are the key components that determine soil water holding capacity. In terms of soil texture, those made up of smaller particle sizes, such as in the case of silt and clay, have larger surface area. 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. Conversely, sands provide easier passage or transmission of water through the profile. Some desert soils look like a layered cake with one or more clayey, reddish-brown horizons directly above the white calcic horizon. These clay-rich layers are called argillic horizons, formed over long period of time when clay particles suspended in water are carried downward into the soil and accumulate. Desert soils are dry, and tend to have clumpy vegetation. Desert soils form in areas where the demand for water by the atmosphere (evaporation) and plants (transpiration) is much greater than precipitation.