Question

In which of the following processes is chaff removed from grains?
(a) Weeding
(b) Threshing
(c) Harvesting
(d) Winnowing

Answer 1

Hint: Chaff is removed from grains by a separation technique that takes advantage of the effect of gravity and the wind. It is a post-agricultural process that is usually accompanied in concert with two other processes.

Complete answer:
Winnowing is an agricultural method that has been used since ancient times to separate the grain from the chaff. Chaff is the protective, dry, and scaly covering that encloses grains. But upon harvesting, they lose their moisture and break open to reveal its contents i.e seeds or grains. The mixture is dropped from a height with the help of a winnowing fan-shaped basket. The lighter component i.e the husk is carried by the wind some distance away from the place where grain falls. The grain being heavier falls vertically downward. The chaff and the grain are thus separated into two different heaps.

Additional Information:
- Weeding is an important step in farming wherein the unwanted plants are selectively removed from a field. These unwanted plants are termed as weeds. They grow along with the main crop and compete with available nutrients in the soil. In this way, there is a shortage of sufficient nutrients for the main crops. Also, they are tough competitors in the sense that they have better adaptation characteristics and their population also increases at a faster rate.
- Threshing is an agricultural practice wherein the edible part of grains is made to separate or loosen out from the straw. Traditional methods include hand threshing with the help of bushel but it is a labor-intensive process. Today, a combine harvester is used. It is efficient in combining three post-production processes which are reaping, threshing, and winnowing.
- When all the edible parts of a plant have matured i.e the plant bears some characteristic physical characteristics as well as moisture content, the ripe plants are then gathered from the fields. This is known as harvesting.
So, the correct answer is ‘(d) Winnowing.’

Note: Conventionally, weeds are removed via hand pulling or by using tools such as a shovel. But nowadays weedicides are used. These are chemicals like MCPA or 2,4-D which are sprayed before the seeds are sown. Additionally, they are also applied during the crop cultivation period if some weed emerges. But these have been reported to cause some health hazards and also pollutes the water and land.