GCA, CCA, NCA, intensity and pattern

Gross Command Area (GCA)

The total area enclosed within the boundary of a canal command, including cultivable land, roads, villages, ponds, forests and barren land. It is the area that can be commanded by the canal by gravity.

Culturable Command Area (CCA)

The part of GCA that is fit for cultivation. CCA = GCA - unculturable area (settlements, rock, water bodies, roads). CCA is the area used for design.

Net Culturable (Cropped) Area (NCA)

The area actually cropped or irrigated in a season. It excludes land kept fallow and is less than or equal to CCA. For a single season, the irrigated area is the part of CCA that actually receives water.

$$GCA \ge CCA \ge NCA$$

CCA is often about 75-85% of GCA.

Cropping intensity

The percentage of the net sown area that is cropped in a year, counting each crop separately (a field with two crops in a year has 200%).

$$\text{Cropping intensity}=\frac{\text{Gross cropped area}}{\text{Net sown area}}\times 100$$

Irrigation intensity

The percentage of CCA irrigated in a season (e.g. 60% of CCA in kharif).

Cropping pattern

The yearly sequence and spatial arrangement of crops on a farm or in the command area, e.g. rice-wheat-fallow, rice-wheat-maize or rice-mustard-maize. It depends on climate, soil, water, market and the farmers' preference.