Kerala

Alien invasions: How water hyacinth has affected agriculture, fishing in Kerala

Before every crop season, farmers in Kuttanad spend a considerable sum of money to clear their paddy fields of aquatic weeds, mostly plants with ovate leaves and beautiful flowers.

“Farming in Kuttanad depends on the entry of water into the fields. It has become routine for us to remove water hyacinth (Eichhornia crassipes), locally known as pola or kulavazha, before preparing the fields for cultivation. The removal of weeds is labour- and cost-intensive. The government provides us ₹4,880, but sometimes it is too meagre an amount given the degree of infestation. The farmers also face difficulty in transporting machineries and harvested grains in boats through the weed-infested water channels,” says Renil Kumar K.K., a farmer in Kainakary.

Impact on various sectors

But for its vibrant hue, water hyacinth is one of the most noxious aquatic plants. Native to South America, it was introduced here during the colonial rule in the late 1890s. Its ‘mat forming behaviour’ has affected irrigation, agriculture, fishing, inland navigation and tourism.

 

The plant chokes the life out of the freshwater ecosystem by preventing penetration of sunlight, required for the survival of underwater fauna. It also provides a breeding ground for mosquitoes, insects and disease pathogens. A report on aquatic weed infestation in Kuttanad submitted by a team led by A.R. Sharma, Director, ICAR-Directorate of Weed Research, Jabalpur, in 2017 noted that “almost 95% area of the waterbodies in the region is infested with water weeds, mainly water hyacinth” and that “infestation has reached serious proportions requiring measures on a war footing to contain the problem.”

In Alappuzha, its overgrowth in Vembanad Lake, a designated Ramsar site, has affected the movement of passenger boats and houseboats. It causes damage to boats’ engine. Fishing is another sector hit hard with large swathes of waterbodies remaining carpeted with the plant.

Symptom of water pollution

Water hyacinth is a menace and a symptom of water pollution caused by fertilizer residues, urban effluents and sewage,” says K.G. Padmakumar, Director, International Research and Training Centre for Below Sea level Farming.

Efforts to remove the weeds from waterbodies using various methods including physical, mechanical, chemical and biological have so far failed. In fact, the problem has virtually multiplied over the years. A sum of ₹30 crore earmarked under the first Kuttanad Package was “wasted” owing to the unscientific approach adopted.

According to G. Nagendra Prabhu, Principal Investigator, Centre for Research on Aquatic Resources, SD College, Alappuzha, it is nearly impossible to completely eradicate the weeds and the only solution is “eradication through utilisation”.

“These are Invasive Alien Species (IAS) and the IUCN considers their impact as immense, insidious and usually irreversible. The only way to control the weed is to utilise it by making value-added products such as hydroponics/floating agriculture, mushroom cultivation, briquetting, pulp-based value-added products, vermin-composting, biofuels, animal feed, etc.”

Value-added products

He said the current focus of the government was removal of aquatic weeds at exorbitant costs. “A major part of this expense should be channelised for utilising these weeds for making value-added products and thereby generating employment. One of the major advantages is that the negative impact of these weeds on our aquatic systems will be greatly reduced, if they are removed from waterbodies regularly. What is needed is political will and sustained efforts to convert this bane into a boon,” Mr. Prabhu says.

Mr. Padmakumar suggested that water hyacinth could be used as a bioremediator. “Eradication is not the way forward. The need of the hour is wise utilisation. It has the ability to absorb nutrients and clean water. It can also be used for creating various products and vegetable farming.”

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Printable version | Sep 18, 2020 10:25:32 PM | https://www.thehindu.com/news/national/kerala/alien-invasions/article26163850.ece

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