CBSE Notes Class 8 Science Chapter 1 - Crop Production and Management

Crop production is cultivating plants on a large scale to provide food, fiber, and other essential resources for human consumption and industrial use. Crop management, involving various farming practices, is crucial to ensuring high yields, superior quality, and long-term sustainability.

1.0Crops 

• Plants of the same kind which are grown and cultivated at one place on a large scale are known as crops. Different types of crops require different climatic conditions like temperature, humidity and rainfall. Crops are divided into two main groups on the basis of growing season.
• Kharif crops : These crops are sown in the month of June/July and harvested in September/October every year. e.g. Paddy, maize, sugarcane, sorghum (Jowar), pearl millet (Bajra). 
• Rabi crops : These crops are sown in the months of October/November and harvested in March/April every year. e.g. Wheat, oat, barley and pea.

2.0Agriculture practices 

• Activities which are carried out by the farmer to ensure good crop yield, in particular sequence, till the crop matures at harvest are known as agriculture practices. 
• Soil preparation : (a) Ploughing (b) Leveling 
• Sowing 
• Manuring 
• Irrigation 
• Weeding 
• Harvesting 
• Threshing 
• Winnowing 
• Storage

1. Soil preparation 

• Various processes are included in it.  
• Ploughing or tilling : Process of loosening and turning of the soil is called ploughing or tilling. 
• Agriculture implements : The tools required for carrying out the activities involved in the cultivation of plants are known as agriculture implements.

• Ploughing can be done by Plough, Hoe and Cultivator.

Leveling : Tilled soil may have big blocks of soil (crumbs). Crumbs are broken down and the soil is leveled with wooden planks or iron levelers, the process called leveling. Leveling is done for better sowing and irrigation. 

2. Sowing 

• The process of putting the seeds in the soil is known as sowing. Before sowing, good quality seeds are selected.
• Sowing can be done by 
• Broadcasting
• Traditional tool
• Seed drill

3. Manuring 

• Farmers have to add manure to the field to replenish the soil with nutrients, this process is known as manuring.

Fertilizers 

• These are commercially manufactured inorganic salts containing one or more essential plant nutrients like NPK, which are used to increase soil fertility. 

Methods for maintaining soil fertility without use of fertilizers

• Field fallow : The practice of leaving the field uncultivated for a season is called field fallow. 
• Crop rotation : The practice of growing different crops alternately in the same field is called crop rotation. e.g. farmers used to grow legume as fodder in one season and wheat in the next season. This helps in the replenishment of the soil with nitrogen. (iii) 
• Biofertilizers : Organisms which enrich the soil nutrients due to their biological activities are called biofertilizers. e.g. Rhizobium (bacteria), Nostoc and Anabaena (BGA-Blue Green Algae). 

4. Irrigation 

• The process of artificial supplying of water to the crop at different intervals is called irrigation. The time and frequency of irrigation varies from crop to crop, soil to soil and season to season. 
• Sources of irrigation : Well, tube well, ponds, lakes, river, canal and dams.

Modern methods of irrigation 

• The following modern ways of irrigation are used which help to conserve water.

a. Sprinkler system 

• In this system, the perpendicular pipes having rotating nozzles on top, are joined to the main pipe line at regular intervals. When water is allowed to flow through the main pipeline under pressure with the help of a pump, it escapes from the rotating nozzle. 
• It spreads water uniformly over crop plants and fields.
• This method is useful for sandy soil and uneven land, where sufficient water is not available.
• It is an efficient system in the canal irrigated area of Haryana and Rajasthan. 

b. Drip system or trickle irrigation  

• It involves the use of pipes fitted with small tubes called emitters. The pipes are laid over or under the soil and emitters release water drop by drop around the roots of the plants.
• In this method water is not wasted at all. 
• This method is a boon in poor water regions. 
• This is the best irrigation technique for fruit crops, gardens and trees. 

5. Weeding 

• Removal of weeds or undesirable plants is called weeding. 
• It can be done by khurpa (trowel) and harrow. 
• Weed : They are unwanted plants which grow along with a cultivated crop in a field. They can severely reduce crop yields by competing for light, water and nutrients. 
• Some weeds interfere in harvesting and may be poisonous for animals and human beings. 
• Some common weeds : Parthenium (Gajar grass), Convolvulus, Amaranthus (Chaulai), Chenopodium (Bathua), Xanthium (Gokhroo) and Dandelions. 

6. Harvesting : The cutting and gathering of crops after its maturation is called harvesting. It can be done manually by sickle or by a machine called a harvester.

7. Threshing : In the harvested crop, the grain seeds need to be separated from the chaff. This process of beating out the grain from the crop is called threshing. It can be done by threshers.
8. Winnowing : In this process, the grain-chaff mixture is gradually dropped on the ground from a height. The heavier seeds fall vertically down, while the lighter chaff is blown away by wind.

9. Storage : Proper storage is necessary to get seasonal food regularly throughout the year. Freshly harvested grains have more moisture. If freshly harvested grains are stored without drying, then they may get spoil and loose their germination capacity

3.0Animal husbandry

• The branch of agriculture that deals with the feeding, caring and breeding of domestic animals is called animal husbandry.
• The main elements of animal husbandry are : 

(i) Proper feeding 

(ii) Providing good shelter 

(iii) Proper health 

(iv) Proper breeding 

Cattle Farming 

Cattle husbandry is done for two purposes, milk production and draught labor for agricultural work like tilling and irrigation.

Poultry Farming

• The rearing and caring of birds for obtaining eggs and meat for the commercial purpose is known as poultry farming. 
• It includes chickens (fowls), ducks, geese, turkeys, guinea-fowls, peafowls, pigeons and quails.

Fisheries 

• The rearing of fish on a large scale is called pisciculture. 
• The fish eggs are introduced into small ponds called hatcheries. 
• Fish is a rich source of proteins and oils. These are a good source of vitamin A and vitamin D. 
• Freshwater fishes : Catla, Rohu and Mrigal.
• Marine fishes : Tuna, Cod and Pomfret. 

Apiculture 

• The rearing of honey bees for a large scale production of honey and beeswax, is known as apiculture. Bees are reared in wooden boxes for commercial production of honey called apiaries.