India turns to 'satellite god' for crop mapping

[March 27, 2015]  By Ratnajyoti Dutta

NEW DELHI (Reuters) - Sher Singh, a farmer from India's desert state of Rajasthan, prays to Varuna, the Hindu god of water, for a bountiful harvest. Now, he is also looking to the heavens for satellite imaging to boost his crop.

Prime Minister Narendra Modi wants to promote a "per drop, more crop" approach to farming to make better use of scarce water, and aims to have a new satellite crop monitoring system working in time for the peak of this year's monsoon in July.

Using remote analysis to assess soil moisture and crop development has the potential to cut input costs and raise yields, say experts, in a country of 1.25 billion where half of workers make a living from agriculture.

Under the scheme, farmers would be able to access advisories on their mobile phones to help them to choose seed varieties, apply the right fertilisers or time irrigation 'shots', though some are skeptical about how effective the plan will be given natural or other obstacles.

"I hope to cut at least a tenth of input cost with the help of the 'satellite god'," said Singh, 55, who farms less than a hectare of rapeseed and hopes to use savings to educate his two grandchildren.

By his own admission, Singh doesn't know how much to water his crops, the right fertilizer mix - or even the right crop to plant given the land's soil type.
 

After last year's landslide poll victory, Modi's government rolled out a national Soil Health Card scheme modeled on an initiative he launched as chief minister of Gujarat to help farmers plant crops suited to their farmland.

In addition, satellite analysis can assess vegetation cover down to field level, helping to determine how a crop is developing and whether it has been harmed by pests or needs more water.

"The idea is to integrate information under the Soil Health Card with satellite images to raise productivity," said N. Chattopadhyay, a weather department official who is involved in the project.

PRECISION FARMING, INDIAN STYLE

The approach seeks to apply 'precision' farming methods pioneered in North America that use geo-location technology to help farmers micro-manage exactly how much seed, fertilizer or pesticide they apply to their fields.

In countries such as the United States and Canada unmanned aerial vehicles, or drones, are also used to overfly farms to map soil and crops accurately.

The next-best option is satellite analysis, more affordable for India, that uses a method called Normalized Vegetation Difference Index assess how well a crop is developing.

Chattopadhyay said the analysis can be provided to farmers on a near real-time basis and could also be used for impact assessment after natural hazards like floods.

India can use its own geostationary satellites, but some see obstacles to its plans including a need to check findings on the ground or the risk of cloud obscuring images.

"Don't be under any illusion that the remote sensing based crop mapping technique will be a penance for all problems in the farm sector," said B.C. Barah, a New Delhi-based agriculture economist.

FROM THE TOP

India's top bureaucrat Ajit Seth has urged wider use of remote sensing to benefit farmers, many of whom live a precarious existence on tiny plots of land.

Just over half of India's nearly 200 million hectares of arable land is rainfed, leaving farmers at the mercy of an often uncertain the monsoon.

The remaining arable is under irrigation, which the government plans to expand by a tenth over three years.
 

The loss of more than half of a crop can trigger government payments to farmers, of $72 per hectare for rainfed areas and $144 for irrigated lands.

India is also preparing to use satellite based crop forecasts to develop insurance for farmers. Currently, insurance products cover primarily crop loans and exclude farm activities.

(Editing by Douglas Busvine and Ed Davies)
 

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