In order to develop a rice-transplanting machine, I will have to understand how it is traditionally done. There are many methods to increase the yields of rice crops, however, if we come up with a disruptive technology, the farmers won’t adopt it.
A local student from Amrita University is also working on the rice-planting machine project, and has been in the village to understand how the woman plant rice in this particular village.
The rice field is irrigated for several days, then the field is ploughed either by tractor or animal power. This will kill weeds and mix the soil. The field is then flooded for 10-14 days then puddled, that is, the soil is mixed with the water into mud. The surface is then smoothed by harrowing several times. Two days before planting, the field is levelled by dragging a wooden plank behind an animal or a tractor.
On average, it takes 1,432 liters of water to produce 1 kg of rice in an irrigated lowland production system. Irrigated rice receives an estimated 34−43% of the total world’s irrigation water, or about 24−30% of the entire world’s developed fresh water resources. Source IRRI
Seeds are grown in seedbeds, also called nurseries, very close to each other, before being transplanted. The nurseries take up 5-10% of the rice fields. Transplanting requires around 30-50kg of seeds per hectare.
Wet-bed: Pre-germinated seeds are sown in a strip of flooded land, then covered in manure and fertiliser. The seedlings are transplanted after 15 to 21 days. Requires 40kg of seeds for 1ha.
This is the traditional method used in the village we are working on.
Dry-bed: Seeds are grown on raised strips of land, kept humid by irrigation. The seedlings are transplanted after 15 to 21 days. Requires 60-80kg of seeds for 1ha.
Dapog or Mat method: Nurseries are prepared on a flat firm surface, covered with banana leaves of plastic film. The seedbed is covered in burnt paddy husk or compost, and pre-germinated seeds are sown with a thickness of around 6 seeds, then the seeds are flattened. The seedlings are transplanted after 9 to 14 days. Requires 1% of the fields and 40-50kg of seeds for 1ha.
This a method used for mechanised transplanting. Modified methods exist to lessen the water and seed use.
After around 20 days, the seedlings are transplanted into the flooded paddies. The seedlings are harvested into bunches, then a few seedlings are planted in an approximate square pattern every 10-20cm. Manual transplantation requires around 30 person days to plant one hectare of rice field, while mechanical transplantation requires 1 person day for a field of one hectare. However, mechanical transplantation requires a specific type of nursery.
Plant spacing is an important factor in transplanting rice. Proper spacing can increase the yield by 25−40% over improper spacing. You will also save money on inputs, labor, and materials. Source IRRI
When the crop is mature, the fields are drained and the rice is harvested by hand (mechanised in larger fields and industrialised countries)
The rice is dried then milled to remove the outer layers of the grain and obtain brown rice. To obtain white rice, bran layers are rubbed off in a huller machine.