Rubber Research Institute of India
From the very beginning of the rubber plantation industry rubber tapping has been practiced using the technology of Downward Tapping on Vertical panel. Since the flow direction of latex in the stem portion is downwards this technology is unscientific and hence it results in yield reduction and gradual stoppage of latex known as Tapping Panel Dryness syndrome. Since the most popular clone RRII-105 is highly metabolically active this TPD became a serious problem and as such tapping frequency was reduced from once in 2 days to once in 3 days. Hence to make up for the loss in tapping days rainy season tapping with rain guard was recommended . This again resulted in tapping panel diseases warranting fungicide application. Moreover Controlled Upward Tapping and low frequency Tapping have been recommended by the Board and have been spread in all the large plantations many moderate plantations and to some small holdings from seventies onwards. These systems are with the use of the chemical yield stimulant Ethrel, a hazardous one.
Ethrel or Ethephon is a yield stimulant with impiricial formula C2H6Cl03P . The residues of monochloroacetic acid possibly found in Ethephon treated commodities is a potential degradation product which is extremely toxic metabolic inhibitor via the inhalation route which has caused human death. This impurity could pose a hazard when Ethrel is stored in poorly ventilated spaces. It is warned against discharging of effluents containing Ethrel into streams ponds estuaries and other water bodies due to its toxicity to fish. It is toxic to birds as well . Harmful to aquatic organisms, may cause long term adverse effect in the aquatic environment. Due to its high toxicity by inhalation as well as contact with skin, users are strictly instructed to wear protective shield, long trousers long sleeved shirt, gloves and boots to avoid possible contact. It is manufactured by Rhone Poulenc. Ag Company North Carolina USA
The Chemical being one of such toxicity once it gets applied on the tree it is gradually leached into running water, spreading in the soil, contaminating the water sources reaching even to the ground water. In low wet lands the whole water will get polluted and plants will absorb the pollutant and get transmitted to the ruminant animals feeding on them and pass on to human beings through meat and milk. Water bodies including rivulets, rivers lakes and even the sea will get polluted by this hazardous chemical and will get transmitted to the fish and through them also will reach human beings. So consumption of vegetables fish and meat will cause the spread of the chemical to man. Since Rubber Board has extended its use to all large plantations, many moderate ones and to some small holdings from seventies onwards it is definite that the chemical has already done serious damage to the environment. The situation has been aggravated by the fact that since pineapple has been accepted as intercrop its cultivation is with enormous quantity of Ethrel to induce flowering as well as for uniform ripening. So rubber and pineapple joined together is doing serious damage to the environment in the rubber areas.
An innovative rubber tapping technology by name Inclined Upward Tapping (IUT) developed at the Rubber Research Institute itself, where tapping is invariably carried out from the base upwards, has been proved to be effective in productivity enhancement to the tune of 45%, tapping panel dryness reduction to a one third, with a good number of other benefits as well such as doubling the economic life span of the tree, saving an interim replanting enhancing quantum of wood enhancing income to the labourer etc . But it has been totally ignored by the Rubber Board for the last one decade. Besides causing immense loss to the rubber plantation industry it has caused irreparable damage to the environment by the releasing of the highly hazardous pollutant Ethrel along with a good number of other fungicides unnecesarily. By mere adoption of the new tapping technology, IUT, the first of its kind in the whole rubber growing countries in the world the problem can very well be solved, thereby ensuring the ecofriendly credentials of the rubber tree.
My (S.Chandrasekharan Nair’s) opinion on above article as follows.
The above mentioned article is published in this blog for a discussion on it. In view of the above IUT I am not able to present physiological condition of a rubber tree. In my opinion lenticells are functioning for respiration and photosynthesis. As a result of this food storage is occurring and is capable to give latex. By the application of Magnesium sulphate on alkaline soil will protect the bark from necrosis by live cells. I felt the flow of latex over phloem is upwards from my experiments. The growth of wood and bark of stem from top to bottom by cambium. Thus I will recommend CUT & IUT are harmful to rubber trees. Downward tapping will help the new bark to grow from top to bottom with a greenish colour which is visible on a scratch. Only downward tapping is helpful to get an average yield. Deficiency of Magnesium is the reason for bark island, pink, patch canker, brown bast etc. It is necessary to avoid chemical Nitrogen to get the pH of the soil above 6.5 to apply Magnesium. The swelling of wood on new bark due to low drc of latex through tapping and it can be avoided by increasing tapping intervals at the time of rainy and winter season. Application of Ethephon is a reason for brown bast.
As a farmer I got a chance in Kairali People channel. The telecasted programme was presented by NTV through technics today about the reason and remedy for brown bast (in Malayalam) from my experiments and experiences. The same programme shown to Dr.N.Krishnan Nair Retd. from Kerala Agricultural University Mob. 9388635168 (Agriculture Botany) and he appreciated me on my findings.