RAINFED TAPIOCA, is cultivated extensively in Salem, Namakkal, Erode and Tirunelveli districts. In Salem and Namakkal districts, the crop is being raised in nearly 20,000 hectares.
Further in these districts there are more than 700 sago factories functioning. Several starch based products from glucose to explosives, from savouries to cosmetics, from capsules to pills depend on this low cost starch emanating from tapioca flour.
As such, Tamilnadu stands top in the international industry. Further the productivity rate of tapioca in Tamilnadu is the highest in the world.
Harnessing energy from the skins and peels of tapioca (sago mill waste) is being attempted in Salem district and may come out as a success in the near future.
Central Tuber Crops Research Institute, Trivandrum is taking up several research programmes on the evolution of varieties of different duration, suited to table and higher starch production nutrient management and pests and disease management, etc.
Likewise the recently started Tapioca and Castor Research Station (T&C RS) at Yethapur is engaged in various research programmes on nutrient management, pests and disease management to improve the production and productivity of this wonder crop.
The nutrients management in tapioca is a very important issue. Most of the farmers never apply proper nutrients at various stages of plant growth or apply indiscriminately as they like. Ultimately, this practice reduces plant productivity and stand.
In tapioca crop the normal recommended dose for all major nutrients is 60N2 65 P2O5, 125K2O/ha.
As a tuber crop, Phosphorus and Potassium are essential from the point of tuber development which reflects on its yield and quality.
Phosphorus is applied as Super phosphate or Diammonium phosphate, while Potassium is applied as muriate of Potash.
In order to find out the efficacy of phosphatic fertilizers and VAM (Vesicular Arbuscular Mycorrhiza) an experiment was conducted at T& C RS for two consecutive years.
Applying DiAmmonium phosphate at 75 per cent of the recommended dose, applied in two splits as basal and 30 days after planting with application of VAM at 2kg/ha after 10 days of DAP application yielded 27.5 tonnes/ ha compared to control (no Phosphorus or VAM) registering 10.6 tonnes/ ha (61.5 per cent increase).
Nitrogen and potassium were applied to all the trial plots as recommendation.
All other plots applied with either super phosphate or DAP or supplemented with DAP spray registered an increased yield ranging from 40.7 per cent to 58.1 per cent.
The DAP applied plots showed a much greater yield than Super phosphate applied fields by over 50 per cent.
The study revealed that phosphorus application is very much needed for higher yield,
application of phosphorus through DAP results in better yield, The VAM application causes much effect in utilization of phosphorus efficiently, DAP perhaps efficiently increased the plant growth physiologically due to Nitrogen in the fertilizer (in ammoniacal form) for a greater response in increasing tuber yield.
P. Vasudevan and K. Shanmugam
T&C RS, Yethapur-636119