# Water Holding Capacity of Soil Experiment

Soil experiment is used to test the water holding capacity of soil. The Amount of water retained and stored in a soil after watering and subsequent drainage is important in plant growth and hydrological studies. This storage capacity of the soil is called its water holding capacity.

Water Holding Capacity of Soil Experiment

That part of the stored water can be subsequently being removed by a plant for its use. This fact makes this characteristic of the soil important for plant growth.

Apparatus/Chemicals for Soil Experiment

Plastic bags (one for each sample), a water proof marker, a trowel, top pan balance, a laboratory oven, evaporating dishes.

Procedure  for Soil Experiment

Collect soil sample after 24 hours of watering the soil from rain or irrigation. Collect the sample in plastic bag, tie the opening of the bag and label it with water proof marker. Collect number of soil samples from different places like sandy soil, clay soil, humus rich soil etc. Weight a dish or tray for each sample, label it clearly and enter the weight on a recorder sheet as given in table below. Place enough soil to cover the bottom of the tray to a depth of .1 to 2 cm (25 to 50g) and weight. Repeat all samples one by one. Record weight of tray + wet soil on the table and calculate weight of wet soil by subtraction. Place the trays in the oven. Heat at 100°C till the weight of the samples no more changes. Usually heating for 24 hours, or even overnight, achieves this target. Record the final weight (tray + dry soil) on the table given below. Calculate the moisture contents as given in the table.

 Sample Number. Weight of Samples in Grams Percentage Weight a Tray Alone b Tray + Wet Soil c Tray + Dry Soil d Wet Soil (b-a) e Dry Soil (c-a) f Soil Water (d-e) f/d x 100 1 2 3 4 5

Precautions for Soil Experiment

1. Collect soil sample after drainage of water stops.
2. Properly oven dry soil.