Contents
From biotechnology to bioethics, Biology Topics have significant implications for society as a whole.
What is Harvesting ? and Explain the Process of Harvesting
It normally takes about three or four months for a food crop to mature. Lush green wheat fields and paddy fields turn to golden yellow at the end of this period (see Figure). This change in colour from green to golden is due to the maturity of crop or ripening of crop. Once the crop has matured then it is ready for cutting and gathering.
The cutting and gathering of the matured food crop is called harvesting. In harvesting, the crops like wheat or rice are cut close to the ground by hand using a cutting tool called sickle (see Figure). This is called manual harvesting. In large fields, wheat and paddy crops are cut by a motorised machine called harvester.
After harvesting the crop, the next step is threshing. The process of beating out the grains from the harvested crop plants is called threshing. Threshing is done to take out the grain from its outer covering called chaff. In the traditional method of threshing, the harvested crop is spread on the ground in a small area and various cattle like bullocks, buffaloes and camels are made to walk over it again and again in a circle.
The cattle’s feet crush the harvested crop plants due to which the chaff breaks up and the grain comes out. During threshing, the leaves and stems of the crop plants are converted into very small pieces called hay which is used as a fodder for animals. In larger farms, a motorised machine called thresher is also used for the threshing process.
Though the process of threshing brings out grains from the cut and dried crop plants, but this grain is mixed with chaff (outer inedible covering of grain) and hay, and has to be cleaned by separating from chaff and hay, before it can be used. This is done by the process of winnowing.
The process of separating grain from chaff and hay with the help of wind is called winnowing. When the grain mixed with chaff and hay is made to fall from a height in blowing wind, the grain, being heavy, falls straight to the ground, whereas the chaff and hay, being much lighter, are carried some distance away by the wind. In this way, the grains form a separate heap and can be collected and packed in gunny bags.
The most common method of storing food grains on a large scale is to fill them in gunny bags, stitch the mouth of gunny bags tightly, and keep these gunny bags one over the other in big godowns (see Figure). Pesticide solutions are sprayed on the stacked gunny bags in the godown from time to time to protect the grains from damage by pests during storage.
The population of rats in the godown is also controlled by killing them with rat poison from time to time. Though a gunny bag is not an ideal container for food grains but its greatest advantage is that food grains filled in gunny bags can be easily transported and distributed at various places.
In addition to the gunny-bag method of storing food grains, the grain-silos are also used for storing food grains on large scale (or bulk storage of food grains). The grain-silos are specially designed big and tall cylindrical structures (see Figure). The grain-silos have inbuilt arrangements for the protection of stored food grains from pests (like insects) and micro-organisms.
Food From Animals
Though we get most of our food from crop plants, animals also provide us food. The food provided by animals consists of Milk, Eggs and Meat. The food obtained from animals is very rich in proteins. In fact, animal food provides certain proteins which are not present in plant foods.
Most of the food obtained from animals also contains a good amount of fat but it contains very little of carbohydrates. Animal food, however, contains minerals and vitamins. The food obtained from animals is more expensive than that obtained from plant sources. The animals which provide us food are mainly of two types:
- Milk yielding animals (or Milch animals), and
- Meat and Egg yielding animals.
The examples of milk yielding animals (or milch animals) are : Cow, Buffalo and Goat. Milk is a perfect natural diet. Milk and its products (called dairy products) like Butter, Ghee, Curd and Cheese are highly nutritious foods.
The examples of meat and egg yielding animals are : Goat, Sheep, Fish, and Poultry (Chicken, Hen and Duck). Out of these animals, goat, sheep and fish give us meat. Poultry gives us meat as well as eggs. Honey is another nutritious food obtained from animals. It is obtained from insects called ‘bees’ (or honeybees).
Animal Husbandry
Just as each crop has its own requirements of proper soil, irrigation, manures and fertilisers and weedicides, in the same way, each domestic animal has its own needs of food, shelter, and health care. The branch of agriculture which deals with the feeding, shelter, health and breeding of domestic animals is called animal husbandry. The various practices necessary for raising animals for food and other purposes (or the elements of animal husbandry) are :
- Proper feeding of animals,
- Proper shelter for animals,
- Prevention and cure of animal diseases, and
- Proper breeding of animals.
Milk giving animals (milch animals or milch cattle) like cows and buffaloes are reared on small scale in rural homes. On a large scale, they are reared in big dairy farms.
Fish as Food
Fish is an important source of animal food. Many people living in the coastal areas (sea-side areas) consume fish as a major part of their diet. Fish is rich in proteins. It is a highly nutritious and easily digestible food. Fish liver oil is rich in vitamin A and vitamin D. For example, Cod liver oil (or Cod fish liver oil) is rich in vitamin A and vitamin D.