Monday, 29 April 2013

Cover crops for Rubber plantation: Benefit aplenty but not in practice

     In middle of the March,2013, I happened to visit three rubber plantation in the Dhalai district of the state. Those plantations were in the road side of the national high way therefore, I could make it possible to inspect on my way to north Tripura district for my personal visit.
      Rubber plantations, which I referred above, were of 2 to 3 years old, cleanly weeded and topography of the land is sloppy.
      After inspection of the rubber plantation what come to understanding is; young seedlings are suffering from excessive heat due to scorching sun which was further escalated by soil temperature surrounding the rubber seedling.
      Soil seems to be excessively dry due to lack of any coverage either through natural vegetation or mulching of the soil surrounding the seedlings.
      After visiting these three rubber plantations, what I felt is; the concept of cover crops raising in the rubber plantation is either not known or adopted by the growers. The general scenario in the state also reflects the same trends that I have observed with my little observation.
        Raising or growing of cover crop preferable leguminous crops has been advocated by the Rubber board and it’s to provide the following benefits:
      1.Enhancing soil fertility through fixation of atmospheric nitrogen through leguminous crops
      2.Increasing the biomass content of the soil through growing of cover crops
      3.Decreasing the soil erosion through growing of cover crops
      4.Suppressing the weed growths in the plantation through growing of cover crops
      Despite these ample benefits, practically in field level it’s not implemented by all growers.  The resultant affect for not taking up this easy to use concept are very much felt by the growers that has been  observed the way  expenditure incurred  for weed management by the small rubber growers.
      The process of growing leguminous cover crops is very easy due to availability of seed material from the rubber board with affordable rate and also locally available cover crops of the state.
      The most popular and easy to grow cover crop is Pueraria and locally available cover crop is Mucona.
      As general practice, seeds of the cover crops are sown after onset of pre-monsoon shower in patches between the rows of the rubber seedling.
      Based on the nutrient condition of the soil, fertilizer like phosphorus is applied while sowing of cover crop seeds.  Within a year, cover crops establishes in the plantation successfully with profuse growth.
      Benefits as narrated above, these leguminous crops, fixes atmospheric nitrogen with the help of rhizobium bacteria that lives in the root system of the cover crops which helps in increasing nitrogen content of the soil in the plantation.
      Cover crops that sheds dry leaves helps in increasing the biomass content of the soil thereby improving overall soil condition of the plantation.
      Cover crops,  as rubber plantation is carried out in hill and sloppy topography helps to reduce the soil erosion due to it’s thick canopy so is preventing the removal nutrient rich top soil of the rubber plantation.
      Another felt need for every rubber grower is; minimizing the expenditure in weed management of the plantation, Tripura which receives fairly good amount of rain fall due to south west monsoon also helps in uncontrollable growth of weeds in the rubber plantation.
      Rubber growers have to spend a good chunk of money in weed management in the initial year of rubber plantation. Cover crops if taken up in the plantation as advocated by the rubber board can substantially reduce the extra expenditure through growing of cover crops.
      However, one important point that should be taken into consideration is cover crops should not compete with the rubber seedling therefore; cover crops should not allow for growing in the periphery of the seedlings to avoid competition. A distance of 2-3 meter is maintained around the rubber seedling for avoiding competition between rubber seedling and cover crops.
      In Tripura, the time for new rubber plantation has already started, new growers are busy with field preparation and planting of rubber seedling with the onset of monsoon rain that is expected to arrive from the month of June but the concept of cover crops should also be their one of the agenda for raising rubber plantation successfully and economically.
      N:B:  Suitable cover crops for Tripura, per ha seed  rate and details procedure for seed treatment for  ensuring successful germination may be referred in rubber board of India.