Page 157 - Understanding NCERT Science 09

Inter-cropping is growing two or more (gokhroo), Parthenium (gajar ghas), Cyperinus
crops simultaneously on the same field in a rotundus (motha). They compete for food,
definite pattern (Fig.12.2). A few rows of one space and light. Weeds take up nutrients and
crop alternate with a few rows of a second reduce the growth of the crop. Therefore,
crop, for example, soyabean + maize, or finger removal of weeds from cultivated fields during
millet (bajra) + cowpea (lobia). The crops are the early stages of crop growth is essential for
selected such that their nutrient a good harvest.
requirements are different. This ensures Generally insect pests attack the plants
maximum utilisation of the nutrients in three ways: (i) they cut the root, stem and
supplied, and also prevents pests and leaf, (ii) they suck the cell sap from various
diseases from spreading to all the plants parts of the plant, and (iii) they bore into stem
belonging to one crop in a field. This way, and fruits. They thus affect the health of the
both crops can give better returns. crop and reduce yields.
Diseases in plants are caused by
pathogens such as bacteria, fungi and viruses.
These pathogens can be present in and
transmitted through the soil, water and air.
Weeds, insects and diseases can be
controlled by various methods. One of the
most commonly used methods is the use of
pesticides, which include herbicides,
insecticides and fungicides. These chemicals
are sprayed on crop plants or used for treating
seeds and soil. However, excessive use of
these chemicals creates problems, since they
can be poisonous to many plant and animal
species and cause environmental pollution.
Weed control methods also include
mechanical removal. Preventive methods
Fig. 12.2 : Intercropping such as proper seed bed preparation, timely
sowing of crops, intercropping and crop
The growing of different crops on a piece rotation also help in weed control. Some other
of land in a pre-planned succession is known preventive measures against pests are the use
as crop rotation. Depending upon the of resistant varieties, and summer ploughing,
duration, crop rotation is done for different in which fields are ploughed deep in summers
crop combinations. The availability of moisture to destroy weeds and pests.
and irrigation facilities decide the choice of the
crop to be cultivated after one harvest. If crop uestion
rotation is done properly then two or three
crops can be grown in a year with 1. Which of the following conditions
good harvests. Q will give the most benefits? Why?
(a)
Farmers use high-quality
12.1.3 CROP PROTECTION MANAGEMENT seeds, do not adopt
irrigation or use fertilizers.
Field crops are infested by a large number of (b) Farmers use ordinary
weeds, insect pests and diseases. If weeds and seeds, adopt irrigation and
pests are not controlled at the appropriate use fertilizer.
time then they can damage the crops so much (c) Farmers use quality seeds,
that most of the crop is lost. adopt irrigation, use
Weeds are unwanted plants in the fertilizer and use crop
cultivated field, for example, Xanthium protection measures.

IMPROVEMENT IN FOOD RESOURCES 145

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