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Senanayake N Senior Lecturer (retired), Faculty of Agriculture, Rajarata University of Sri Lanka
Puliyankulama, Sri Lanka
Abstract
Rice cultivation in the country dates back to time immemorial, though the rice production was not sufficient to meet the demand with the increasing population lately. Rice breeding work started during the last phase of the colonial era and continued with the green revolution in the 1960s. As a result, the national average yield improved from 0.75mt/ha during the colonial time to 4.82 mt/ha today. Improved varieties today are highly responsive to inorganic fertilizers, high tillering and high yielding with some insect and disease resistance. However, inorganic fertilizer use in the country since the 1950s resulted in soil degradation and was further aggravated by inappropriate mechanization and weedicide use. This led the department of agriculture to recommend the use of organic matter to supplement inorganic fertilizer applications to sustain production. The situation was viewed superficially and the government took a policy decision to ban the import of inorganic fertilizer and agrochemicals without any valid research data or suitable organic alternatives for pesticides, disregarding the high shriek from the eminent scientists and paddy farmers. Ad-hoc fertilizer recommendations provided to farmers and the use of alien fertilizer formulations without any field research data locally were either rejected or used sparingly by the farming community. This huge cry was later politicized and prevented the President to change his decision, though some flexibility was approved. Policy decisions ultimately ended up in huge rice imports, amidst a shortage of foreign currency, to prevent food shortages. Organic fertilizer sources are many though their availability individually is not adequate for the rice sector. There are many compost producers whose products vary in nutritive content from producer to producer and from batch to batch of the same producer. Thus, organic fertilizer standardization and providing a single fertilizer recommendation is impossible if not time and labor intensive and financially very expensive. However, a concrete single recommendation for organic fertilizer is not possible even with extensive field experimentation. Therefore use of organic fertilizer as a basal application alone with inorganic fertilizer to meet the peak nutrient demand at several stages of rice plant growth can be a good option to sustain rice production, of course after a minimum of two season’s adaptive field research. This paper reviews the pros and cons of sustainable rice production in the country under the organic fertilizer policy of the government.
Keywords: Agrochemicals, Compost, Manures, Organic fertilizers, Rice production
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