2. Crop rotation
Repeated cultivation of crops or crops
and fallow in a certain sequence on the
same land is called crop rotation.
Example: Rice- Wheat- Moong
It is the reverse of land rotation.
Here crop is rotated year after year.
3. Definition of crop rotation:
It refers to recurrent succession of crops
on the same piece of land either in a year
or over a longer period of time.
It is a process of growing different crops
in succession on a piece of land in a
specific period of time, with an objective
to get maximum profit from least
investment without impairing the soil
fertility.
6. 1. The leguminous plants are grown alternately
with non-leguminous plants to restore the fertility
of the soil.
In the rotation of crops, leguminous crops like pulses, beans,
peas, groundnut and Bengal gram are sown after cereal crops
like wheat, maize and pearl millet.
When the cereal crops like rice, wheat, maize are grown in
the soil, it uses up a lot of nitrogenous salts from the soil. If
another crop of cereal is grown in the same soil, the soil
becomes nitrogen deficient.
So by rotation a leguminous crop is grown. These plants have
the ability to fix atmospheric nitrogen to form nitrogen
compounds through the help of certain bacteria present in
their root nodules. These nitrogen compounds go into the
soil and make it more fertile.
7. 2. The exhaustive crops are grown
alternately with less exhaustive crops to
restore the fertility of the soil.
The crops which uptake higher amount of nutrients from the
soil are called exhaustive crops like potato, sugarcane.
The crops which uptake lesser amount of nutrients from the soil
are called less exhaustive crops like oilseeds & pulses.
Continuous cultivation of exhaustive crops in the same land
leads to gradual reduction of soil fertility or nutrient status of the
soil.
Therefore, The exhaustive crops are grown alternately with less
exhaustive crops to restore the fertility of the soil.
8. 3. The tap root crops are grown alternately with
fibrous root crops for uniform utilization of soil
nutrients.
The crops with tap roots should be followed by those which have fibrous root
system.
This helps in proper & uniform use of nutrients from the soil.
The roots do not compete with each other for uptake of nutrients.
Examples: rice- pigeon pea
Relative depth of rooting of various crops
Deep Moderate Shallow
Alfalfa Barley Field Pea
Safflower Canola Flax
Sunflower Mustard Lentil
Wheat
9. PRINCIPLES OF CROP ROTATION:
contd
4. The rotation should provide roughage and pasturage for the
livestock kept on farm. Therefore, fodder crop must be included in
the rotation to feed the animals.
Examples: rice- black gram-fodder maize/ berseem
5. On sloppy lands alternate cropping of erosion promoting and
erosion resisting crops should be adopted.
Examples: Maize (erosion promoting )- cow pea/ green gram
(erosion resisting ).
6. Under Dryland or limited irrigation condition, drought tolerant
crops (Jowar, Bajra), in low lying & flood prone areas, water
stagnation tolerant crops (Paddy, Jute) should be adopted.
10. PRINCIPLES OF CROP ROTATION: contd
7. The crops of the same family should not be grown in succession
because they act like alternate hosts for insect pests & disease
pathogens and weeds associated with crops.
8. The selection of crops should be according to the need/demand
base. That is according to need of the people of the area & family.
Example: Vegetables and flowers are grown in areas closer to the
cities for higher income.
9. It should be adaptable to the existing soil, climatic and economic
factors.
10. The sequence of cropping adopted for any specific area
should be based on proper land utilization.
11. Advantages of Crop Rotation
There is an overall increase in the yield of crops due to maintenance of proper
physical condition of the soil and its OM content.
Rotation of crops helps in saving on nitrogenous fertilizers, because
leguminous plants grown during the rotation of crops can fix atmospheric
nitrogen in the soil with the help of nitrogen fixing bacteria.
Rotation of crops help in weed control and pest control. This is because
weeds and pests are very choosy about the host crop plant, which they attack.
When the crop is changed the cycle is broken. Hence, pesticide cost is
reduced.
There is regular flow of income over the year.
Proper choice of crops in rotation helps to prevent soil erosion.
It supplies various needs of farmer & his cattle.
Crop rotation adds diversity to the farm.