MANAGEMENT OPTIONS FOR DROUGHT PRONE RAINFED LOWLAND RICE IN ASIA: A REVIEW

Abstract

The rice-based rainfed lowland system in Asia covers about 45 million hectares which is almost 30% of the total rice area worldwide. Rice (Oryza sativa L.) is the main crop in this system and grown in bunded fields that are flooded for at least part of the season. Altogether, drought stress is the most important limitation to production in rainfed lowlands and is estimated to affect frequently about 19 to 23 million hectares resulting the reduced yield and hunger problems. In addition, drought-prone environments are often simultaneously affected by other abiotic stresses like submergence, adverse soil conditions, pests and weeds. In turn two main management strategies for drought stress alleviation in rice can be distinguished. The first strategy is based on management options which allow to escape drought by either avoiding severe dry periods or by providing access to additional water resources. The second strategy is to moderate drought by reducing unproductive water losses and thereby “saving” water for productive transpiration. Within both strategies there are several management options which offer considerable scope for improvement of drought-prone rainfed lowlands, however, direct seeding and improved nutrient management are probably the most widely applicable options. “Aeroabic rice” a new system of rice cultivation still under development and is thought to have potential to adopt in specific target environments within the rainfed lowlands of Asia.