By Chandre Dharmawardana –

Dr. Chandre Dharmawardana

According to the news item that appeared in the Daily Mirror, 15-July-2018, the government plans to “hand over” the maintenance of village tanks to villagers themselves. The Prime Minster is supposed to have said: 

“we have decided to focus on villages. If we renovate tanks the villages will benefit from these projects. The contracts to desilt them will be given to the villagers themselves. The soil collected from desilting will be given to farmers. They can earn something from that. At the same time, the concessionary loans schemes will be launched for the rural people. The money would be pumped into the villages by these projects.”

This could degenerate into  a scheme of handing over the tanks to selected political friends, who will immediately build houses on the tank bunds and other high ground. The village tanks  will be completely encroached (as it is mostly  the case) and natural habitat and tanks will be lost. The tanks will be lost for ever and replaced  by homesteads, asphalt and concrete. The present government has made many attempts to destroy agriculture in Sri Lanka, by its banning of pesticides (e.g., Glyphosate), control of fertilizers and telling farmers to not to use fertilizers (where by they end up with poor  harvests) because “they contain toxins”. The latter is a complete lie.  The government banned glyphosate  in 2015 succumbing to false propaganda that it was one of the causes of kidney disease prevalent in the North-Central Province, where as it is most likely caused by drinking stagnant well water containing fluorides and magnesium ions (found in hard water). 

This is a very misguided  proposal and signals the end of the village tanks which are already in bad shape. Their repair and  maintenance are  not a matter for amateurs, or for villagers who already find it hard to eke out an existence even at subsistence level. These tank cascades need a detailed plan taking account of their cascade structure. You may read Dr. Panabokke’s article about tank-cascade systems here.

The Prime Minster is proposing to use the silt at the bottom of tanks for making fertilizer. The silt at the bottom of tanks has a very high level of Cadmium (Cd) and other metal toxins, and their use in compost or as fertilizers for growing food is very dangerous, and smacks of  naive thinking typical of  Ven. Ratana, Asoka Abeygunawardana, Channa Jayasumana and others who talk of the “Toxin-free” (Vasha Visha Neathi) traditional agricultural program. The natural average Cd in the soils of  Sri Lanka are reported to range from 0.42 mg/kg in virgin forest soils, to values  as high as 5 mg/kg in  tank sediments [Chandrajith et al 2012].  These numbers are consistent with values found in the WHO-sponsored study {Jayatilleke et al , 2014}. For a detailed report on such toxins in fertilizers, soil and food, their bio-availability etc., please see my most recent research paper published in Environmental Geochemistry and Health (Springer Nature B.V. 2018)

More detailed comments.

1.  Scale of the work.

In the old days, there was a whole hierarchy of knowledgeable people, Wel Mudiyanses, Wel Widane’s, Wel peramukas, wel ralas, gama ralas etc. The emphasis was on the paddy fields (“wel”) as they were the key and the “Tank” was just the means of storing the water. There were even caste designations with assigned duties, and mandatory labour (Rajakariya) for repairing tanks or “waev”, “sorow, niyara”, etc. All those traditions and know-how are lost today. Rajakariya was abolished in the 19^th century. Even scholars do  not know what was known, what was handed down etc. Organizing the needed labour to do this is a Herculean task in today’s political climate where forced labour (Rajakariya) or even paid labour  is impossible, with little  manual labour available in villages today. A more sensible solution would be to use the army, with its corp of engineers to guide the work.

2.  Tank cascades.

Today, given the state of the tanks, and the scale of the work, it is essential to use machinery and coordination of the work on tank cascades by knowledgeable irrigation engineers. One tank in  a tank cascade cannot be repaired without coordinating with what is done in another tank belonging to the same cascade. The water-feed from each tank is regulated to match what is needed downstream. This matching was done in the old days by trial and error as well as traditional knowledge, usually taking decades as these tanks were built gradually. Today, given the rapid pace of social change, nothing can await decades. Unless a master plan for each cascade is set up, and modern engineering principles are used, we will end up with a total mess.

3. Using the silt for fertilizer etc.

This is again a simplistic proposal with little knowledge behind it. The essential requirements of a fertilizer are the macro-constituents; namely, Nitrogen (N), Potassium (K), and Phosphorous (P).  The micro-organisms in the soil also need these very same nutrients. They also need humus (decomposed plant matter) which should already be there in the soil, or supplemented with the fertilizer. If the soil is too acidic, or too alkaline, it  needs to be mixed with the right amount of  limestone, dolomite or acidifying agents. The fertilizer should be tailored to each soil, and not a mere matter of adding some tank silt mixed with decomposed straw and cow dung. Furthermore, cow-dung and such nutrients are in extreme short supply in the country. Both straw and cow dung contain high amounts of metal toxins due to phyto-accumulation.

4. Organic food.

The Department of Agriculture has issued a set of books, targeting each district, and specifying the type of fertilizer optimal for each soil. All that has been brushed aside and we have a destruction of scientific agriculture by Ven. Ratana and his followers. The monk says that Dr. Ranil Senanayake is a scientist who supports his views. However, Dr. Senanayake merely writes popular newspaper articles striking fear into the public mind about herbicides like glyphosate, but has not come up with any evidence against the use of such pesticides, or offered no practicable alternatives. When it is pointed out that “organic agriculture” produces such low yields that the product has to be priced at 3-5 times the normal product, Dr. Ranil Senanayake claimed in an Island newspaper article that “computer projections” show that organic agriculture can feed the world, if certain conditions are met.

That claim was also made by Dr. Adrian Mueller of the Swiss Organic Food Research Institute. He shows using  computer projections that organic agriculture can feed the world if the world population is sharply reduced, and if, say,  twice the amount of land and water were available. He proposed to make the land available by getting the whole world to becomes vegetarian, and stopping livestock farming. The latter suggestion is very welcome, but there is no likelihood of the world  population becoming vegetarian, or the population sharply reducing itself.  I have discussed these matters in detail in my article replying Mueller.  

Currently about 2% (or less) of the world’s food is produced using “organic methods”, and it serves to feed the frightened members of the elite class who believe that their health problems are due to the “commercial food” they eat. They refuse to admit that their decadent  life styles with high stress, no exercise, consumption of fast foods, sugar etc., are the main causes of their obesity and ill health.

To claim that fertilizers from tank silt (or, alternatively, composted urban waste) is safer than the use of conventional mineral fertilizers is to endanger the whole country from toxins in silt and in urban waste. Fertilizer from silt or urban waste  must be subject to a chemical analysis before use in growing food.

[The author pioneered the teaching of food science and environmental chemistry in Sri Lanka in the 1970s as part of the applied science program at Vidyodaya University, now known as the SJP university.]