Command area, crop rotation, necessity

Command area

The area that can be irrigated by gravity from a canal or project. Gross command area (GCA) is the total area; culturable command area (CCA) is the part fit for cultivation.

Cropping pattern

The yearly sequence and arrangement of crops grown in an area (e.g. rice-wheat-fallow).

Crop (cropping) intensity

The percentage ratio of gross cropped area to net sown area in a year.

Crop rotation

Growing different crops one after another on the same land in a planned order, e.g. rice - wheat - pulses.

Necessity of crop rotation

1. Maintains and improves soil fertility: legumes fix nitrogen, deep-rooted and shallow-rooted crops use different soil layers.
2. Controls pests, diseases and weeds, since their life cycles are broken.
3. Prevents exhaustion of the same nutrients.
4. Improves soil structure and organic matter.
5. Reduces waterlogging and salinity and spreads the water demand over the year.
6. Gives better use of labour and machinery, risk spreading and higher income.