EVENTS
CONVENT HIGH SCHOOL
27/07/2021 CLASS-8 SESSION2021-22(SLOT-1)
SCIENCE
Chapter-1
CROP PRODUCTION AND MANAGEMENT
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Question
1.Select the correct word from the follow¬ing list and fill in the blanks:
float, water, crop, nutrients, preparation
(a)
The same kind of plants grown and cultivated on a large scale at a place is
called crop
(b)
The first step before growing Cropsis Prepration of the soil.
(c)
Damaged seeds would flot on top of the water.
(d)
For growing a crop, sufficient sunlight and water and nutrition from
the soil are essential.
Question
2.Match items in column ‘A’ with those in column ‘B.
A B
(i)
Kharif crops Paddy and
maize
(ii)
Rabi crops Wheat, gram, pea
(iii)
Chemical fertilizers urea and
superphosphate
(iv)
Organic manure Animal excreta,
cow dung, urine and plant waste
Question
3.Gine two examples of each.
(a) Examples
of Kharif crop – maize and paddy.
(b)
Examples of rabi crop – wheat and mustard.
(a)
Preparation of soil
(b)
Sowing
(c)
Weeding
(d)
Threshing
Answer:
(a)
Preparation of soil: It is the first step before growing a crop. First task in
the process is to turn the soil and loosen it. This allows the roots to
penetrate deep in the soil. The process of loosening and turning of soil is
called tilling or ploughing which is done by a plough. Ploughs are made of wood
or iron. If the soil is very dry, it may need watering before ploughing
(b)
Sowing: It is the process of putting seeds in the soil. For this purpose, good
quality seeds are selected which are clean, healthy, of good variety and give a
high yield. Tools for sowing seeds are traditional tools shaped like funnel and
a seed drill. An appropriate distance between the seeds is also important to
avoid overcrowding of plants.
(c) Weeding: In a crop field many other
undesirable plants may grow naturally along with the crop. These are called
weeds. Weeds are to be removed to protect the crops. The process of removal of
weeds is called weeding. If weeding is not done, the growth of the crop is
adversely affected. Some weeds are poisonous for animals and human beings.
(d)
Threshing: When the crop mature, they are cut. This process is called harvesting.
After harvesting the crops are threshed for removing grain seeds from the
chaff. This is carried out with the help of a machine called combine, which is
in fact a combined harvester and thresher.
Answer:Irrigation
means supply of water to plants at different intervals. It helps absorption of
nutrient elements by the. plants from the soil. It is essential for i growth
and elongation of the roots of crop plants. It is also essential for providing
moisture for the germination of seeds. Water supplied to plants by irrigation
provides hydrogen and oxygen. Irrigation is essential to increase 1 the number
of aerial branches in crop plants which in turn will increase the yields also.
Question
6.If wheat is sown in the kharif season, what would happen? Discuss.
Answer:
Kharif crops need lot of rainfall, whereas wheat needs winter (cold) season and
not heavy rainfall. So if wheat were sown in kharif season, the crop will
damage due to heavy rainfall as well as collection of water in the fields.
Question
7.Explain how soil gets affected by the continuous plantation of crops in a
field?
Answer:Soil
supplies mineral nutrients to the crop. The nutrients are essential for the
proper growth of the crop. Continuous growing of crops makes the soil poorer in
certain nutrients. To avoid this, a method of crop-rotation is adopted, which
maintains the nutrients of the soil intact.
Question
8.What are weeds? How can we control them?
Answer:Weeds
are undesired plants which are grown among crop plants. They absorb water,
nutrients etc., of the crop plants. Therefore, their removal from the field is
a must. Farmers adopt many ways to remove weeds and control their growth.
The
weeds may be removed manually before they produce flowers and seeds.
Weeds
can be controlled by spraying certain chemicals called weedicides. These
weedicides do not damage the crops.
Question
9 Define agriculture.
Answer:Agriculture
is the branch of biology which deals with the production of plants and animals
useful to man, involving soil cultivation, breeding and management of crops and
livestock.
Question
10.What is necessary to provide food for a large population?
Answer:In order to provide food for a large population – regular production, proper management and distribution of food is necessary.
