Sugarcane: The much maligned crop Business Daily from THE HINDU group of publications Tuesday, Feb 19, 2008
Sugarcane scores over most crops in the efficient use of solar energy and water for biomass conversion, implying that its environmental damage potential is not as serious as often presumed.
Harish Damodaran
Sugarcane, unlike many other crops, suffers from an image problem. For the historian, it epitomises the worst excesses of colonialism: From Fiji, Java and Mauritius right across to the Caribbean islands, Surinam, Cuba and Brazil, sugarcane plantations were originally worked by slaves or indentured labour brought in from Africa and India.
Even today, the Brazilian sugar industry is organised around 20,000 hectare-plus plantations, owned directly by mills or wealthy latifundistas employing migrant workers in none-too-hospitable conditions.
In India, cane producers are, by contrast, predominantly peasant-proprietors with holdings of one hectare or less. Yet, sugar mills per se are seen to be controlled either by mofussil politicians or rapacious barons. There is no industry to which the suffix ‘lobby’ seemingly attaches more effortlessly than sugar, just as no commodity is more political and subject to controls than sugar.
The extensive regulatory paraphernalia governing the sector — extending from fixation of cane prices to deciding how much sugar each factory can sell every month — is virtually predicated upon the miller’s predisposition to short-change both growers and consumers. To top it, sugarcane is considered a water-guzzling, environment-unfriendly crop, whose cultivation is to be actively discouraged. Water consumption
As is often the case with sweeping generalisations, these perceptions are not without exaggeration. Take first the environmental dimension. Sugarcane, no doubt, requires 8-10 irrigations, compared to say, 4-6 for wheat. But then, cane is typically grown over 11 months, whereas wheat is a four- to 4.5-month crop.
So, on a daily basis, sugarcane consumes less water than wheat and, even more definitely, rice. The accompanying table shows the irrigation requirement (amount of water, exclusive of precipitation) for different crops over their full maturity cycle.
Besides lower water consumption per day, a related factor concerns biomass productivity. The best wheat farmers of Punjab do not harvest more than 5-6 tonnes per hectare, while this may not exceed 7-8 tonnes for paddy (rice in husk) and 30-35 tonnes for potato.
As against this, the worst sugarcane grower of Uttar Pradesh gets at least 40 tonnes a hectare: the all-India average yield during 2005-06 was 66.9 tonnes, varying from 42.8 tonnes in Bihar to 58.2 tonnes in UP and 104.7 tonnes in Tamil Nadu. There is hardly any crop to compete with cane in terms of yield; this is even after allowance is made for its comparatively longer maturity. Efficient photosynthesis
The higher yield, in turn, has to do with sugarcane being one of the few crops (besides sorghum and maize) to exhibit what scientists term ‘C-4’ photosynthesis — a more efficient solar energy-deploying mechanism for capturing atmospheric carbon dioxide and water, and converting into starch matter or sugar.
This is unlike paddy, wheat or groundnut, which employ the less efficient ‘C-3’ pathway. Indeed, recent research efforts have focussed on reengineering crops such as paddy from ‘C-3’ to ‘C-4’ plants a la cane, as a plausible means to break existing yield barriers through enhanced photosynthetic efficiency!
Whichever way one looks at, sugarcane scores over most crops in the efficient use of solar energy and water for biomass conversion, implying that its environmental damage potential is not as serious as often presumed. In any case, the total cane acreage for the country has hovered between 4-5 million hectares (mh), which is way below the 43-44 mh for rice, 26-28 mh for wheat, 29-30 mh for coarse grains and 22-23 mh for pulses.
Even if an additional 1-2 mh area were to come under cane, the threat posed to environment or food security is not all that great.
Why is cane, then, such a widely misunderstood crop? One reason perhaps is due to its exclusive identification with sugar. The latter, for all its sweetness, is obviously not as indispensable a food as wheat, rice or pulses. But sugarcane’s usefulness extends way beyond sugar.
For every 100 tonnes of cane that a mill crushes, it recovers not just 10 tonnes of sugar, but additionally generates 30 tonnes of bagasse and 4.5 tonnes of molasses. Self-sufficient operation
Bagasse is normally burnt by mills to produce steam for their captive needs, so much so that sugar is a unique industry that is completely energy self-sufficient and not dependent on coal or other external fuel sources. Every tonne of bagasse yields roughly 2.1 tonnes of steam.
The process steam requirement for a modern sugar plant equipped with high-pressure, high-temperature boilers is about 45 tonnes per 100 tonnes of cane. Thus, for every 30 tonnes of bagasse, there is 8-9 tonnes surplus available after meeting the mill’s steam consumption.
Earlier, this entire surplus bagasse was sold to paper and particle-board making units as an alternative fibre material to bamboo and wood. More recently, mills have started exploring the co-generation option, i.e. utilising the whole bagasse to directly produce steam and electricity, and supplying the surplus power to the State grid.
From one tonne of cane (300 kg of bagasse or 630 kg steam), it is possible to generate anywhere from 120 units (kilowatt-hours) to 150 units, depending on the pressure at which the steam is raised in the boiler and taken to the turbine.
After adjusting for 25 units of in-process consumption by the mill and 10 per cent (12-15 units) of auxiliary consumption in the boilers and turbo-generators, 85 to 110 units of power per tonne of cane can be exported to the grid. Alcohol yield
Likewise, molasses is a substrate for alcohol, with every tonne yielding 220 litres that can be used for potable purposes or even for blending with petrol. Simply put, processing of one tonne of cane yields not merely 100 kg of sugar, but also 100 units of surplus power and 9.9 litres of alcohol.
A one-hectare farmer in UP producing 60 tonnes of cane annually contributes 6,000 kg of sugar, 6,000 units of surplus electricity and 600 litres of alcohol to the economy — a far cry from the notion of him being a drain on natural resources.
Further, sugarcane has immense fodder value: the plant’s top green leaf portions supply the entire raw feed requirements of cattle and buffaloes during the winter-spring months from November to April.
While sugarcane’s alleged water-guzzling nature has made it a whipping-boy for environmentalists, its exclusive identification with sugar has probably benefited the mills themselves more than anybody else. By linking production costs solely to sugar realisations and not adequately factoring in revenues from co-generation or alcohol, factories have often got away by paying less for their cane purchased from growers. Historical legacy
Finally, there is sugarcane’s historical legacy — its perceived association with exploitation. It is again seldom recognised that few industries are inherently more rural-based than sugar.
This is because cane, like milk, fruits and vegetables, is perishable, and cannot – unlike wheat, paddy or oilseeds — be bought in bulk at rock-bottom prices during harvest time and stored away in warehouses.
Sugarcane, moreover, is different from even milk or fruits, since it cannot be transported over long distances.
Once harvested, the crop has to be crushed within 24 hours, after which its sucrose content tends to deplete rapidly – something that even maintenance of a cold chain cannot prevent.
A factory, thus, has to be located close to where the cane is grown. For efficient recovery, the crop must be freshly sourced from within 50 km, so that harvesting in the fields and crushing by the factory are dovetailed into a rigorous time schedule.
Mills, on their part, have an interest in developing a proper rural transport infrastructure for orderly movement of cane from the fields. Sugar, thus, is an agro-industry in the complete sense, exercising remarkable rural transformatory potential. This aspect comes out clearer if one looks at a typical mill that can crush 5,000 tonnes of cane daily. If the plant were to run for 150 days, this translates into a total requirement of 750,000 tonnes, which, at an average 60 tonnes per hectare yield, would mean bringing in some 12,500 hectares (10,000-plus farmers) under its command.
In addition, it generates jobs for over 2,000 people, of which 700-800 are employed directly and the rest involved in loading and transportation of the cane. Much of this may not be of a permanent nature, but it is guaranteed employment at some minimum wage for 150-160 days of the year. Versatile crop
In areas with canal or other perennial irrigation sources, it makes every sense to promote scientific, water-saving planting of sugarcane and realise the enormous food, energy, fibre and fodder potential offered by this versatile crop.
The sugar belt of western Maharashtra is seen today by many as having unduly prospered from State largesse and the political clout of its cooperative magnates.
But it is also a fact of history that this very pampered region was not too long ago – in 1875 – the scene of the infamous ‘Deccan Riots’, which saw indebted ryots break into the houses of moneylenders and burn mortgage deeds!
