Science of the soil to help sons of the soil

Discoveries and analyses of everyday problems and suggestions to handle them, often published in more modest journals are ignored

March 05, 2014 11:35 pm | Updated May 19, 2016 06:28 am IST

Fertilizer overuse has led to high phosphorus levels in Kerala soils. Photo: B. Velankanni Raj

Fertilizer overuse has led to high phosphorus levels in Kerala soils. Photo: B. Velankanni Raj

Way too often, media coverage on science and technology tends to concentrate on topics of current fashion or what some people call as “high-fi” themes — be it the God particle, stem cell biology, or yet another nanomaterial. Articles that appear in “high impact” journals are covered more often while discoveries and analysis of everyday problems and suggestions to handle them, usually published in more modest journals are given the go-by. Two such reports concerned with pressing problems of everyday importance to India appear in the latest issue of Current Science (Volume 106, 10 February 2014, pages 343-345), which need to be highlighted. One of them has to do with the overload of phosphorus in the soils of Kerala and how it affects the health of the land and the waters of the region and what may be done about it. And the other is a report about the discovery of a few bacteria in the coast of Gujarat which can degrade plastic materials such as polythene. And it is a pity that main line media, right here in India, have not found them worthy of coverage and publicity.

The first is a short report (just about 1200 words and two figures) by scientists from the Indian Institute of Spices Research in Calicut, concerning the massive accumulation of phosphorus in the soils of Kerala. The Kerala State Planning Board has taken up the massive (and rather “boring”) task of analyzing the status of acidity in the agricultural field in all the Panchayats of the state. As many as 1,56,801 samples across the state were analysed (a huge exercise in itself) and of these about 91 per cent of the fields were found to be moderate to strongly acidic (pH between 6.5 and 4.5). This is bad because plants grow best by absorbing nutrients from soil whose pH is between 6.5 and 7.5. This is the ideal pH range for plant root growth; when the pH reduces below 6.5, the phosphorus (P) in the soil gets “fixed” by the metals present in the soil (such as aluminum and iron) and no longer available in the soluble form for absorption by the plant roots. And P is vital since it is used not only to make the DNA and RNA of the plant cells but also as the energy currency in the biochemical processes that all living beings use for metabolism (just as we use the rupee in our daily live transactions).

How did this high level of P come about? Through the overuse of fertilizers and manure by the farmers. As the Calicut scientists report, soil in Kerala is already inherently acidic and the overuse of fertilizers and manure only adds to the problem. Not only does much of the P in the soil gets fixed and becomes unavailable for plant growth but even some of the soluble phosphorus is lost through the run-off water from these sites and affects the quality of water in the nearby lakes and water bodies.

The Kerala State Planning Board’s report is thus an important and admirable exercise that calls for action. The Calicut scientists make some relevant suggestions towards this, e. g., skip the applications of high P fertilizers, test the soil periodically and reduce (or avoid) manure that contains high amounts of P. We must express our appreciation to Drs K. M. Nair, P, Rajasekharan, G. Rajasree, P. Suresh Kumar and M. C.Narayanan Kutty of the National Bureau of Soil Survey and Land Use Planning (of the Indian Council of Agricultural Research), the Kerala State Planning Board, and Drs R. Dinesh, V. Srinivasan, S. Hamza and M. Anandaraj, at the Indian Institute of Spices Research at Calicut for this important and relevant research and analysis. The second report in page 345 of the same issue of Current Science , by the budding science writer Ipsita Herlekar, highlights the discovery by scientists at the Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat. These scientists analysed as many as 60 types of bacteria in the Arabian Sea along the coast of Gujarat and found three species from there, namely, K. Palustris M16, B. Pumilus M27, and B. Subtilis H1584 , are able to “eat” polyethylene — the synthetic plastic used in everyday life as bags and films to cover materials, and that the B. Subtilis H158 strain was the best among the three. This calls for further work which might help us find an eco-friendly way to manage this totally out of hand (and totally man-made) menace of plastic waste and pollution.

Let us applaud Drs K. Harshvardhan and B.Jha, the CSMCRI scientists for this discovery and hope they will take this further into the level of practical application, Ipsita for elegantly highlighting this CSMCRI work, and the journal Current Science for publishing these reports which are of “high impact” at the practical and actionable level. Bread and butter science is just important as “blue sky” science.

dbala@lvpei.org

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