Increased interest in soybean production in the central part of the country partly explains the reduction in upland rice area. Average yield increases resulted from the larger proportion of irrigated rice in the overall rice crop and higher yields in that environment. The yield has been growing due to gradual reduction in the low-yield upland rice. A variant of the upland system is rice under sprinkler irrigation, as rice has become part of the cropping sequence under central pivot systems. Irrigated rice is concentrated in the southern states of Rio Grande do Sul and Santa Catarina.
Minimum tillage allows farmers to increase machinery use efficiency, and control undesirable weeds.
In Santa Catarina, irrigated rice areas are planted once a year using pregerminated seed in puddled soil. Modern technologies such as fertilizer, chemical weed control, and machinery are used. Other production problems are yield potential, occurrence of low temperatures during flowering, and rice water weevil. As rice is often used as a pioneer crop, very little inputs are used, with the exception of machinery for land preparation, planting, and harvesting in most of the central region. In this region, the trend is to plant rice in areas with minimum risk of drought, and to incorporate rice in a system for pasture establishment and renewal.