Page 156 - Understanding NCERT Science 09
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manure for maintaining soil fertility have to India has a wide variety of water resources
be considered while aiming for optimum yields and a highly varied climate. Under such
in crop production. conditions, several different kinds of irrigation
systems are adopted to supply water to
uestion
Q 1. Compare the use of manure and water resources available. These include wells,
agricultural lands depending on the kinds of
canals, rivers and tanks.
fertilizers in maintaining soil
There are two types of wells,
Wells:
•
fertility.
namely dug wells and tube wells. In a
dug well, water is collected from water
Organic farming is a farming system with bearing strata. Tube wells can tap
minimal or no use of chemicals as fertilizers, water from the deeper strata. From
herbicides, pesticides, etc., and with a these wells, water is lifted by pumps
maximum input of organic manures, recycled for irrigation.
farm-wastes (straw and livestock excreta), use • Canals: This is usually an elaborate
of bio-agents such as culture of blue green and extensive irrigation system. In this
algae in preparation of biofertilizers, neem system canals receive water from one
leaves or turmeric specifically in grain storage or more reservoirs or from rivers. The
as bio-pesticides, with healthy cropping main canal is divided into branch
systems [mixed cropping, inter-cropping and canals having further distributaries to
crop rotation as discussed below in 12.1.2.(iii)]. irrigate fields.
These cropping systems are beneficial in • River Lift Systems: In areas where
insect, pest and wheat control besides canal flow is insufficient or irregular
providing nutrients. due to inadequate reservoir release,
the lift system is more rational. Water
12.1.2 (ii) IRRIGATION is directly drawn from the rivers for
supplementing irrigation in areas
Most agriculture in India is rain-fed, that is,
the success of crops in most areas is close to rivers.
dependent on timely monsoons and sufficient • Tanks: These are small storage
rainfall spread through most of the growing reservoirs, which intercept and store
season. Hence, poor monsoons cause crop the run-off of smaller catchment
failure. Ensuring that the crops get water at areas.
the right stages during their growing season Fresh initiatives for increasing the water
can increase the expected yields of any crop. available for agriculture include rainwater
Therefore, many measures are used to bring harvesting and watershed management. This
more and more agricultural land involves building small check-dams which
under irrigation. lead to an increase in ground water levels.
The check-dams stop the rainwater from
Droughts occur because of scarcity or flowing away and also reduce soil erosion.
irregular distribution of rains. Drought 12.1.2 (iii) CROPPING PATTERNS
poses a threat to rain-fed farming
More to know irrigation for crop production and Different ways of growing crops can be used
areas, where farmers do not use
depend only on rain. Light soils have
to give maximum benefit.
less water retention capacity. In areas
Mixed cropping is growing two or more
with light soils, crops get adversely
crops simultaneously on the same piece of
affected by drought conditions.
Scientists have developed some crop
mustard, or groundnut + sunflower. This
varieties which can tolerate drought land, for example, wheat + gram, or wheat +
reduces risk and gives some insurance
conditions.
against failure of one of the crops.
144 SCIENCE
Rationalised 2023-24
