Polluting the environment at the cost of Rs 31.80 crores (approx)
MS Khaidem *
Rice straw, Rice straw, everywhere in the field during the harvesting season, straw it sounds very simple and cheap, once threshing is over the straw becomes ownerless with little or no care has been taken at all.
However, for the next cropping the straws or crop residues have to be either removed or burnt in situ as these interfere in farm operation/ tillage.
But have we ever thought how valuable byproduct is the Rice straw. Forget about the other industrial uses but it is one of the best organic materials available in plenty for enriching soil health.
Total rice cultivated area in Manipur is 1,95,000 ha. While calculating rice straw produced (6-12% moisture) at the rate of 2.5 tons per ha. the total straw produced out of these rice fields could be estimated to the tune of 4.87 lakhs tons.
Of late nineties on one side farm mechanisation have tremendously increased and on the other use of bullocks for ploughing have decreased considerably thereby collection of straw for fodder is also significantly reduced which may be accounted to the tune of 20% of the total straw produced including other uses.
Therefore, 3.87 lakhs tons of straw are either removed from the field or burnt in situ or incorporated in the soil or used as mulch for the next crop.
Each of these measures has a different effect on overall nutrient balance and long-term soil fertility.
As per published report of "Food, Agriculture & Environment Vol-2 2004"; out of the total nutrients taken up by rice during its growth period about 40% of the nitrogen (N), 30 to 35% of the phosphorus (P), 80 to 85% of the potassium (K), and 40 to 50% of the sulfur (S) remains in vegetative plant parts at crop maturity.
In other perception when one ton of straw is removed there is loss of 6.525 kgs of Nitrogen, 14.715 kgs of Potash, 0.855 kgs of Phosphorous.
Therefore, when 3.87 lakhs tons of straws are removed there will be heavy losses of Nutrients from the soil to the tune of 2525.175 tons of Nitrogen, 5694.705 tons of Potash and 330.885 tons of Phosphate, which is equivalent to 5611.50 tons of Urea, 9458.28 tons of MOP and 2089.80 tons of SSP respectively.
As such, when incorporated in the soil, cost of the above quantities of fertilizer will be an additional income.
On the contrary when burnt in situ except few loses of potash all the rest of nutrients will be lost, beneficial soil insects and microorganisms will be killed and not the least instantly generate as much as 13 tons of CO2 when 2.5 tons of straw is burnt contaminating the environment.
If this is the situation can we imagine the quantities of CO2 that would have emitted when 3.87 lakhs tons of straw have been burnt which is equivalent to 20.13 lakh tons of CO2, one of the main factors contributing to Global Warming resulting to Climate Change.
* MS Khaidem wrote this article for The Sangai Express
The writer is a Project Coordinator, Manipur SFAC, Directorate of Agriculture Sanjenthong, Imphal. This article was posted on October 11, 2011.
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