Lecture 5: CLASS VIII: SCIENCE: CHAPTER 1: HARVESTING

CLASS-VIII; SCIENCE

Prepared by Subhankar Karmakar

6. HARVESTING:

The cutting and gathering of the matured food crop is called harvesting. 

MANUAL HARVESTING:

In harvesting, the crops like wheat or rice are cut close to the ground by hand using a cutting tool called sickle and this is called manual harvesting.

MACHINE HARVESTING:

In large fields, wheat and paddy crops are cut by a motorised machine called harvester.

THRESHING:

After harvesting the crop, the grains are separated from the harvested crops. The process of beating out the grains from the harvested crops plants is called threshing. It can be done manually as well as with the help of a motorised machine called thresher.

WINNOWING: 

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. The process of separating grain from chaff and hay with the help of wind is called winnowing.

COMBINE: 

A combine is a large machine which cuts the standing cereal crop in the fields, threshes it, and separates the chaff from grain in one operation.