Soil-Moisture-Characteristics.pptx 1/6..

Simple soil moisture characteristics

1. Soil Moisture Characteristics It is the maximum soil moisture content that the soil can contain. Saturation Point It is the maximum soil moisture content that the soil can hold against gravitational forces. Field Capacity The soil moisture content at which the plants wilt permanently. Permanent Wilting Point

2. It is the moisture contained between field capacity and permanent wilting point. Available Moisture (Available water holding capacity) Approximately equal to 75% of the available moisture. Readily Available Moisture (RAM)    

3. Classes and availability of soil water Soil water has been classified as: Hygroscopic water (unavailable moisture) – is on the surface of the soil grains and is not capable of significant movement by the action of gravity or capillary forces. Capillary water (available moisture) – is that part in excess of hygroscopic which exists in the pore space of the soil and is retained against the force of gravity in a soil that permits unobstructed drainage. Gravitational water (free water) – is that part in excess of hygroscopic and capillary water which will readily move out of the soil if favorable drainage is provided.

4. Classes of soil-water availability to plants and drainage characteristics.

5. Assignment #1 (in 1/2 sheet of paper, crosswise, to be submitted tomorrow, 7:00 AM) A soil sample was taken with core sampler from a field when soil reached field capacity. The oven dry sample weighed 1.065 kg. The inside diameter of the core was 7.5 cm and the length was 15 cm. Determine the dry bulk density and the apparent specific gravity of dry soil.