Threshing: it is done by beating the sheaves against the wooden bars to separate the grains from the stalks. 

Winnowing: it is the process of removing the unwanted husk from the grains...

Threshing and winnowing are agricultural processes used to separate grains from the chaff or husk. While both techniques are employed in grain processing, they differ in terms of the stage at which they are performed and the methods used. Let's delve into the details of each process:

Threshing:
Threshing is the initial step in grain processing, where the grains are separated from the rest of the plant, including the stalks, husks, and chaff. This process involves the removal of the edible part of the crop, which is the grain, from the non-edible parts. The traditional method of threshing involves the use of a threshing tool, such as a flail or a wooden stick, to beat the crop. However, modern farming practices employ mechanized threshing machines, which are more efficient and save time.

Winnowing:
Winnowing, on the other hand, is the process of separating the grain from the chaff or husk after threshing. It is performed to remove any remaining plant material, including the lighter chaff, dust, and other impurities that are undesirable for consumption. Winnowing utilizes the principle of air current to separate the lighter chaff from the heavier grains. Traditionally, this process involves tossing the threshed mixture into the air using a winnowing basket or a shallow tray, allowing the wind to blow away the lighter chaff while the heavier grains fall back into the tray.

The differences between threshing and winnowing can be summarized as follows:

1. Stage: Threshing is the initial step in grain processing, separating the grain from the rest of the plant, while winnowing is performed after threshing to separate the grain from the chaff.

2. Objective: Threshing aims to separate the edible part of the crop, the grain, from the non-edible parts, while winnowing is performed to remove any remaining impurities, such as chaff and dust, from the grain.

3. Tools and Methods: Threshing can be done manually using tools like flails or mechanized using threshing machines. Winnowing traditionally involves tossing the mixture into the air using winnowing baskets or trays to allow the wind to blow away the lighter chaff.

4. Outcome: Threshing results in the separation of the grain from the rest of the plant, while winnowing separates the grain from the chaff and other impurities present in the mixture.

In conclusion, threshing and winnowing are integral processes in grain processing, with threshing being the initial step to separate the grain from the non-edible parts of the crop, and winnowing being the subsequent step to remove any remaining impurities. These processes contribute to producing clean and edible grains for consumption or further processing.