Notes On Crop Protection - CBSE Class 8 Science
Agriculture is the cultivation of crop on large areas to provide food for all life forms. Replenishment of nutrients:  As the seeds germinate, the growing saplings should be provided with nutrients and water. Hence soil should be replenished with minerals in periodic intervals of time. Manure and fertilisers supply nutrients to the soil.                            MANURE                          FERTILISERS It is the organic matter which replenishes the soil with nutrients. These are chemical substances which maintain the soil fertility by adding required minerals to the soil. It is clean and does not pollute the soil. Overuse may lead to toxicity and reduction of soil fertility. Increases the water holding capacity of the soil. Easy to use as many of them are easily soluble in water.  Provides favourable conditions for growth of microbes. These are nutrient specific  and add nitrates, phosphorous and potassium to the soil. Preparation requires some period of time. Can be easily prepared in large quantities. Storage is complicated. Can be easily stored if kept away from the moisture. Irrigation:  The supply of water to crop is called as irrigation. The frequency of irrigation varies from season to season and crop to crop. Plants contain nearly 90% water, and need water for proper development of flowers, fruits and seeds. Irrigation can be done by two methods - Traditional methods and Modern methods.        •  Traditional methods of irrigation require animal and human labour to draw water. these are the cheapest methods available and are still in use. These include moat, chain pump, dhekli and rahat.                    •  Modern methods are the irrigation methods which are efficient in supplying water to the crops. They help us to use water economically without wastage. They include drip irrigation and sprinkler system which require power from solar energy or biogas.            Crop protection: Standing crops are prone to attacks by insects, pests etc.         •  Insects are six legged arthropods which create heavy loss to crop plants.        •  Pests are the organisms that cause diseases in crop plants.        •  Insects are controlled by spraying insecticides over the crop.        •  Insecticides are the chemicals which kill the insects, their eggs and larvae without affecting the crop.        •  Pests are controlled by spraying chemicals called as pesticides.        •  Pesticides kill disease causing pathogens without showing any harmful effect to crop plants and human beings.        •  Some of the examples of pesticides are Malathion, Disyston, B.H.C etc. Weeding:  The process of removal of waste plants competing with crop plants is called as weeding. Weeds compete with crops in obtaining water, sunlight and nutrients.  Controlling methods for weeds:        •  Weeds can be tilled along with the soil to kill them. Tilling uproots the weeds and they are mixed with the soil.        •  Weeds are removed manually by using harrow before they produce flowers and seeds.        •  Weeds can also be controlled by using chemicals called as weedicides. Weedicides are poisonous to humans.

#### Summary

Agriculture is the cultivation of crop on large areas to provide food for all life forms. Replenishment of nutrients:  As the seeds germinate, the growing saplings should be provided with nutrients and water. Hence soil should be replenished with minerals in periodic intervals of time. Manure and fertilisers supply nutrients to the soil.                            MANURE                          FERTILISERS It is the organic matter which replenishes the soil with nutrients. These are chemical substances which maintain the soil fertility by adding required minerals to the soil. It is clean and does not pollute the soil. Overuse may lead to toxicity and reduction of soil fertility. Increases the water holding capacity of the soil. Easy to use as many of them are easily soluble in water.  Provides favourable conditions for growth of microbes. These are nutrient specific  and add nitrates, phosphorous and potassium to the soil. Preparation requires some period of time. Can be easily prepared in large quantities. Storage is complicated. Can be easily stored if kept away from the moisture. Irrigation:  The supply of water to crop is called as irrigation. The frequency of irrigation varies from season to season and crop to crop. Plants contain nearly 90% water, and need water for proper development of flowers, fruits and seeds. Irrigation can be done by two methods - Traditional methods and Modern methods.        •  Traditional methods of irrigation require animal and human labour to draw water. these are the cheapest methods available and are still in use. These include moat, chain pump, dhekli and rahat.                    •  Modern methods are the irrigation methods which are efficient in supplying water to the crops. They help us to use water economically without wastage. They include drip irrigation and sprinkler system which require power from solar energy or biogas.            Crop protection: Standing crops are prone to attacks by insects, pests etc.         •  Insects are six legged arthropods which create heavy loss to crop plants.        •  Pests are the organisms that cause diseases in crop plants.        •  Insects are controlled by spraying insecticides over the crop.        •  Insecticides are the chemicals which kill the insects, their eggs and larvae without affecting the crop.        •  Pests are controlled by spraying chemicals called as pesticides.        •  Pesticides kill disease causing pathogens without showing any harmful effect to crop plants and human beings.        •  Some of the examples of pesticides are Malathion, Disyston, B.H.C etc. Weeding:  The process of removal of waste plants competing with crop plants is called as weeding. Weeds compete with crops in obtaining water, sunlight and nutrients.  Controlling methods for weeds:        •  Weeds can be tilled along with the soil to kill them. Tilling uproots the weeds and they are mixed with the soil.        •  Weeds are removed manually by using harrow before they produce flowers and seeds.        •  Weeds can also be controlled by using chemicals called as weedicides. Weedicides are poisonous to humans.

#### Activities

Activity 1 Wsu.edu unravelled the use of compost and its preparation under the topic'Composting horse manure'. It emphasised role of compost in increasing the growth of plants. It also shows how composts control the growth of pathogens, parasites and other organisms which harm the plants. Go to Activity Activity 2 Greencrop.co.in has devise a template to describe its webpage. When the student clicks on the 'Our Product Basket' button a list of substances that are used to enhance crop productivity are displayed. When we roll over the product displayed different products are shown in their photographs. Student can know that pesticides, fungicides, weedicides, growth regulators, micronutrients, water soluble substances are used in crop protection management.  Go to Activity

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