Aerobic rice is a production system where rice is grown in well-drained, non-puddled, and non-saturated soils. Water requirements can be lowered by reducing water losses due to seepage, percolation, and evaporation.
Promising technologies include saturated soil culture and intermittent irrigation during the growing period. However, these technologies still use prolonged periods of flooding, so water losses remain high.
A fundamentally different approach is to grow rice like an upland crop, such as wheat, on nonflooded aerobic soils, thereby eliminating continuous seepage and percolation. This also reduces evaporation. Traditional upland rice has been bred for the unfavorable uplands to give a stable, though low, yield with minimal external inputs.
Previous experiments of growing high-yielding lowland rice under aerobic conditions have shown great potential to save water but it has severe yield penalty. A new type of rice is needed to achieve high yields under high-input aerobic conditions.
Aerobic rice can be found, or can be a suitable technology, in the following areas:
- “Favorable uplands”: areas where the land is flat, where rainfall with or without supplemental irrigation is sufficient to frequently bring the soil water content close to field capacity, and where farmers have access to external inputs such as fertilizers.
- Fields on upper slopes or terraces in undulating, rainfed lowlands. Quite often, soils in these areas are relatively coarse-textured and well-drained, so that ponding of water occurs only briefly or not at all during the growing season.
- Water-short irrigated lowlands: areas where farmers do not have access to sufficient water anymore to keep rice fields flooded for a substantial period of time.
The usual establishment method is dry direct seeding. Aerobic rice also allows practices of conservation agriculture as used in upland crops, such as mulching and minimum tillage.