Various modes of weed control are
(a) mechanical removal
(b) proper seed bed preparation to avoid the weed growth
(c) timely sowing of crop to avoid the growth of weed.
(d) intercropping and crop rotation also help in weed control.

Differentiate between the following
(i) Capture fishery and Culture fishery
(ii) Mixed cropping and Inter cropping
(iii) Bee keeping and Poultry farming

Ans. (a) Capture fishery is the method of obtaining fish from natural resources while culture fishery is the method of obtaining fish by fish farming.
(b) Mixed cropping is growing two or more crops simultaneously on the same piece of land; while intercropping is growing two or more crops simultaneously on the same field in a definite pattern. i.e., in different rows.
(c) Bee keeping is the practice to rear the honey bee for obtaining honey; while poultry farming is the practice to raise the domestic fowl for egg and meat production. 

Demerits (i) threat to bio-diversity (ii) only economically important and valued fishes will be cultured.

Merits (i) large amount of desired fishes can be obtained in small area (ii) improvement can be done.

Composite fish culture is the method to culture five or six species, both indegenous and exotic, together in a single fish pond. These species are selected so that they do not compete for food among themselves having different types of food habits. As a result food available in all the parts of the pond is used. For example— Catlas are surface feeders, Rohu is middle zone feeder and Mrigals and common carps are bottom feeders.

Bees need nectar to make honey. A good pasturage con provided plenty of flowers with good quality nectar. This will help the bees in making good quality honey; in larger quantity. Thus, a good pasturage will help in improving honey yield. Moreover, if bees are confined in order to utilize nectar only from a particular variety of flower, the taste, colour and consistency of honey will be entirely unique. Many beekeepers make honey prepared from nectar from a particular variety of flower only

Following are the different modes by which insect pests affect the crop yield.
(i) Cutting: Some insect pests cut different plant parts; like leaves, fruits and flowers. Thus, they damage the plant. Damaged leaves would result in lower rate of photosynthesis. Damaged flowers will result in less production of seeds.

(ii) Borers: Some pests make a burrow in a plant part and live inside. There can be stem borers or fruit borers. These pests utilize resources from plants.
(iii) Suckers: Some pests use their proboscis to suck cell sap from plant parts.

Pesticides are used in very accurate concentration and in a very appropriate manner, because if used in excess it
(a) harms the soil and causes loss of fertility
(b) checks the replenishment of organic matter
(c) kills the micro-organism of soil
(d) causes air, water and soil pollution

Two types of animal feed are as follows:

Roughage: Roughage makes the bulk of animal feed. Roughage helps the animal in getting satiated. Roughage also helps in proper digestion of food. Roughage is provided by husk and hay and also by grass and chopped leaves.

Concentrates: Concentrates are rich in proteins and minerals. Concentrate are specially prepared according to the requirement of a particular cattle. Concentrates are also available in market.