Organic fertilisers and so-called fertiliser mafia
Posted on November 17th, 2021
By CHANDRE DHARMAWARDANA Canada Courtesy The Island
Not so long ago, Champika Ranavaka championed a hair-brained project known as Polipto”, to make petrol from waste polythene. Ranawaka also pushed the Toxin-Free Nation” programme, and one of his university mates ran a project with the acronym SEMA. It championed the new vision” from the presidential secretariat itself. The then president Maithripala Sirisena had banned glyphosate as a part of the Toxin-Free” project popularised by Ven. Ratana, Ranawaka and others.
Today’s 100% organic policy is the absurd conclusion of the Toxin-free project. It has the support of many senior politicians, such as Chamal Rajapaksa, and juniors like Channa Jayasumana. Influential monks, Ven. Bengamuwe Nalaka, Ven. Bellanvila Dharmaratana and others have backed it with their chinthanaya” and not with science.
At a more sophisticated level, supporters of organic agriculture come up with seemingly scientific” proposals that confuse the uninitiated. An innuendo of conspiracy is added to this narrative, with the question, Why hasn’t the Dept. of Agriculture (DOA) implemented all this”? Are agricultural scientists part of the fertiliser mafia”?
Farming in Sri Lanka is a private business, and if the farmers and plantations have not adopted the methods pushed hard by SEMA, MONLAR, and the chinthanaya” ideologues, as well as Buddhist monks owning much temple land, then something besides conspiracy theories are needed.
The seemingly scientific but false proposals confuse even the professionals. So, we hear of various scientists uttering on TV that organic agriculture is indeed the Holy Grail, but the hasty approach used by this government is at fault. This belief is patently false, as 100% organic agriculture, even at its best, CANNOT feed even a half of the current population of Sri Lanka. It will lead to enormous environmental degradation and dire famine.
However, let us examine some of these seemingly scientific but inadequate or unworkable proposals.
1. Plant a legume crop like Mung beans (Vigna radiata L) that takes 45 days to harvest. The Mung bean fixes nitrogen and will provide the needed N for the rice that should be planted after the Mung harvest. Some have even claimed that the Mung will produce 200-300% more N than what is needed by the paddy.
What is blithely claimed above is factually incorrect. Even short-term Mung varieties need 60-70 days, harvested in 90-100 days. Although Mung bean fixes nitrogen, it is NOT ENOUGH even for itself to produce a good crop. Read the research:
So it is usual to add N:P:K in the ratio 5:12:5 PLUS 4-5 TONNES of farmyard manure (compost) to avoid needing more fertiliser. Pendimethalin and Nitrophen are used as pesticides.
Cost of Mung bean farming is some Rs 95,000 to 100,000 per hectare. The Mung bean can be sold profitably. Instead of harvesting the mung growth, it can be ploughed to provide soil nitrogen. Unfortunately, even with N fixation, the most amount of N that one obtains is 4% of the DRY weight of the mung growth, and woefully inadequate for the rice.
However, as Rahaman et al (2014) have shown, crop rotation together with urea can improve agronomic efficiency. A basic amount of urea, as well as standard P, K are needed. The environmental problems from urea can be largely mitigated using slow-release urea, but NOT nano-urea which poses a serious health danger (see The Island 29-10-2021 https://island.lk/human-health-and-nano-fertilizers-where-is-the-safety-clothing/ )
In growing mung, instead of adding N via the 5:12:5 NPK fertilisser, benefit from biological nitrogen fixation with native rhizobia inhabiting nodule micro-organisms can be attempted, but at the risk of increased microbial CO2 generation. The possibility is still being researched, as may be seen from very recent work on the topic:
Hence it is plain nonsense to ask farmers to adopt a technology which is still on the drawing boards.
2. Another proposal that has been bandied about since the 1960s is that cyanobacterial algal N-fixation can be used to provide a large part of the N-fertilizer needed.
Long-term urea application degrades the soil, water, and air quality, producing global warming. So there is a biotechnological interest in using nitrogen-fixing microorganisms to enhance crop growth, without using urea, since current poor practices lead to much waste. The wasteful practice of using water to control weeds in paddy fields, where even 60% of the urea applied may get washed away, should be stopped, as it also leads to soil erosion. Growing rice without any more water than for any pasture grasses will be the norm when global warming reduces water availability.
If water logging is to be used even in the short term, then N-fixing algae can be considered, but this is NOT an optimal solution. Kulasooriya and others have reported preliminary studies. However, even a 2021 research publication merely mentions that there is potential but no standardized farm protocol available. See:
3. It has been claimed that fast growing N-fixing aquatic ferns like Azolla Pinnata with 20-25% protein content can be used to make N-fertiliser. It is known to double in size every two days if adequate nutrients are provided. So, it is proposed to grow it in lakes and tanks, and harvested to produce organic N fertiliser.
This is a complete myth. Azolla Pinnata grows exponentially but exponential amounts of P, K must be supplied, e.g., as phosphate fertiliser. If it acquires 25% protein, its nitrogen content would be 4% and no better than from Salvinia Molesta, which is already widely present. I have discussed both Salvinia Molesta and Azolla Pinnata in my plant website:
More details, including the fact that both A. Pinnata and Salvinia also accumulate heavy-metal toxins during their rapid growth are given there.
4. It has been claimed that when scientifically fertilised paddy fields were grown with zero fertiliser, it was only in the 4th year that the yield dropped to 45%, and that from then on two tonnes per hectare were assured!
One has to only look at the annual reports of the DOA in the 1940s, 1950s to get decades of data to show that such magical claims may require the intervention of God Natha. Even the ancients knew that after every three or four years it was necessary to burn a forest and make a new chena”, even to get one or one and a half tonnes of rice per hectare. There is no way to cut through the gullibility of those who are faithful to an ideology.
5. The work of Dr. Premakumar of the ITI, and Dr. Roshan Perera of Kotelawala Defence Academy, has been cited for isolating many soil microorganisms that can enhance nutrient delivery to plants. So, has the fertilizer mafia” prevented its use in farming!
The microorganisms that enhance nutrient delivery by various mechanisms, also enhance the uptake of heavy metal toxins like cadmium, lead, etc., by plants, making any water insoluble (i.e.non-bio-available) forms soluble. Such methods may upset the microbial balance of the soil, and spawn new toxic forms as happens in eutrophic systems. Enhanced microbial action leads to enhanced green-house gas emission of CO2 and reactive Nitrogen forms. Long term research is needed before such methods can be adopted in the farm.
Those who ask this kind of question know that we can use bovine DNA in a nutrient vat and create beef, without cattle and slaughter houses. Why is that DNA technology not being widely adopted? There can be decades between a laboratory result and farm applications. It is this lack of understanding and judgment that propelled the ban on glyphosate, or the100% organic policy, in the belief that there ARE practical alternatives suppressed by big agri-business.
6. Another typical question is why biochar and other carbon remediation methods had not been used as a soil conditioner in the plantations, where soil quality has grossly deteriorated, especially in tea.
Soil deterioration became increasingly acute after the nationalisation of the estates, when many of the standard maintenance practices were short-circuited by new managers. Many of the experienced managers left for South Africa and other countries that began to grow tea. The TRI is currently investigating biochar usage and soil remediation.
Those who ask these questions should note that this is not the only thing neglected since the 1970s. Neglect of most maintenance protocols, be they for tanks and rivers and their desilting, or due collection of garbage, or control of noxious fumes from vehicle traffic and increase in submicron particles etc., can be mentioned.
While submicron particles are probably the biggest environmental danger to health, the unproven danger of there being a few parts per billion of glyphosate in the environment, and the unsubstantiated claim that local glyphosate contains more toxic additives than used in Europe, led two medical doctors to demand the ban of glyphosate on the basis of the precautionary principle”! Why didn’t they demand a ban on sugar which causes more diabetes and chronic kidney disease than any other toxin?