The following terms are generally used in irrigation:
1) saturation capacity:-the amount of water required to fill up the pore spaces in soil particles by replacing all air held in pore spaces is known as saturation capacity or total capacity or maximum holding capacity of the soil.
2) field capacity:-the moisture content of the soil after free drainage has removed most of the gravity water is known as field capacity. The field capacity of the soil depends upon capillary tension in soil and porosity of soil.
3) permanent wilting point:-the water content at which plants can no longer extract sufficient water from the soil for its growth is known as permanent wilting point.
4) available moisture:-the difference in water content of the soil between field capacity and permanent wilting is known as available moisture.
5) kor -watering:-the first watering given to the crop when it has grown a few centimetres is called kor- watering.
6) paleo (paleva):-the first watering before sowing the crop is called paleo.
7) root zone depth:-the maximum depth in soil strata in which the crop spreads its root system and derives water from the soil is called root zone depth.
8) overlap allowance:-the extent of water to be supplied for maturing a particular crop which extends from one season to another is called overlap allowance.
9) crop ratio:-the ratio of the areas of the two main crop seasons i.e kharif and rabi, is known as crop ratio.
10) intensity of irrigation:-the ratio of cultivated land for a particular crop to the total culturable command area is called intensity of irrigation.
11) base period:-the whole period of cultivation from the time when irrigation water is first supplied for preparation for the ground to its last watering before harvesting the crop is called base period.
12) crop period:-the crop period is defined as the time in days that crop takes from the instant of its sowing to that of its harvest.
13) delta of the crop:-the total depth of irrigation water required by a crop during the entire period the crop is in the field, is called a delta of the crop.
14) duty:-the ratio between the area of crop irrigated and the quantity of water required during its entire period of the growth is known as duty. It depends upon type of crop, type of soil, climatic conditions, method of irrigation etc.
