Introduction to Major Field Crops

Harvesting and Threshing

Drain out the water from the field when grains in the lowest portion of the panicle are in dough stage (about 20 days from 50 per cent flowering). Allow the grains to harden.Harvest the crop at 30-35 days after flowering when stalks still remain green to avoid grain shedding. At this stage at least 80 per cent of the grains are straw coloured. Moisture content in the grains should be around 20 per cent.



Fig: Stages of plant growth.


Fig: Ripening stage.

In general, the crop is harvested with traditional sickles. With the improved design of sickles fabricated from high carbon steel and fitted serrated blades, harvesting is done faster.The improved design requires less muscle power and results in saving of human energy.Harvesting of rice is also done by cutter or power tillers/tractor drawn reapers.



Fig: Manual harvesting.



Fig: Machine harvesting.

Often heavy rains at the time of maturity of the crop may cause germination of grains in the panicles. After the harvest of rice bundles are kept lying in the field for sun drying for about3-5 days.Afterwards bundles are transported to threshing yard. In general, threshing yard is locally prepared in the field itself in one of the plots. Tarpal or plastic sheet are used to avoid mixing of soil or stones during threshing.

Conventional way of threshing is beating on hard surface manually which consumes more time. Threshing is also done mechanically by using pedal operated thresher or power thresher. Mechanical harvester cum thresher does harvesting and threshing simultaneously in the field itself which saves lot of time.


Fig: Manual threshing.



Fig: Combined harvester cum thresher.



Fig: Combined harvester cum thresher.


After threshing, cleaning is done manually by using winnowers. Cleaning of grains depends on natural wind or electrical or power tiller operated fans. For storage the grains are dried so that the moisture content should be around 10-12 per cent. After drying grains are stored in gunny bags or closed containers or storage structures.