The number of seedlings per hill may vary from one to eight. Direct seeding is done by broadcasting the pregerminated grain by hand in Asia or by water-seeding by airplane in the United States and Australia. Deep-water rice is commonly dryseeded, but it is occasionally transplanted or double transplanted. Ideally, water is maintained in the rice field to suppress weed growth during the growing season. Hand weeding and mechanical or rotary weeders are popular.
Herbicides are also economical and effective.
Both inorganic and organic fertilizers are used, including green manures such as the leguminous shrub Sesbania spp. Modern rice varieties increase in grain yield by 6 kg per kg of applied fertilizer in the wet season and by 9 kg per kg of applied fertilizer in the dry season. The irrigation water is not received from river diversions, storage reservoirs or deep wells, but from rainfall or runoff from a local catchment area. The prevailing climatic and soil conditions in shallow rain-fed rice areas are extremely variable. Fertilizer use is low, stand establishment difficult and pest control almost impossible, and yields are poor.