Nitrogen for the soil

Paddy farmers across the country, from Uttar Pradesh to Maharashtra and down in the South are learning to spell S-e-s-b-a-n-i-a R-o-s-t-r-a-...

int(3)

Paddy farmers across the country, from Uttar Pradesh to Maharashtra and down in the South are learning to spell S-e-s-b-a-n-i-a R-o-s-t-r-a-t-a to post letters to a nuclear agriculture laboratory in Trombay.

In the letters, they plead for mutant freebies: a handful of seeds of a plant born in Senegal, West Africa, which have now grown as high as a horse in fields aptly named Gamma Gardens.

Some 10 years ago, when organic farming had none of the buzz that surrounds it today, scientists at the Bhabha Atomic Research Centre (BARC) imported the Sesbania Rostrata — a green manure that gobbles nitrogen — from Senegal. After much gamma ray irradiation, they gave birth to the TSR-1, a new mutant superior to the African original.

Story continues below this ad

The plant guzzles atmospheric nitrogen through its roots and stem. When it is ploughed and buried into the soil 55 days after sowing, it decays within 2-3 weeks — and, in the process, nourishes the soil with a thumping 120-150 kg nitrogen per hectare.

‘‘TSR-1 can grow even in saline or waterlogged areas,’’ says S F D’Souza, head of BARC’s nuclear agriculture division. BARC experiments with TSR-1 have reported rice yields equivalent to that produced by pumping in 60 kg of urea/hectare. The implication: a huge saving on chemical fertilisers.

But best of all, the desi mutant is a hit because it is all-season. The Senegal original, on the other hand, is best grown only in summers; in winter, it flowers too early, resulting in less vegetative growth and less fixing of nitrogen for the soil.

‘‘The Trombay mutant is insensitive to long or short daylight and works year-long. The Senegal plant works best only till September,’’ beam BARC officers on the TSR team.

Story continues below this ad

Now registered with the National Bureau of Plant Genetic Resources, TSR-1 is growing up to a height of five metres at Gamma Gardens. Its roots, though, are still clogged in paperwork. ‘‘There is no characterisation of green manure as a plant variety in India. So it will be a year or two before TSR-1 hits the market,’’ says D’Souza.

At present, seeds nurtured at BARC are distributed only on request, with a one-page user tip-sheet.

Most green manures plug nitrogen through their roots. This hard-working plant has nodules along the stem as well, all of which trap nitrogen. Some 250,000 plants, when grown for 55 days on a hectare of land, fix 120-150 kg nitrogen/hectare. Half of this stays put for the next crop on the plot.