Deep water varieties will grow in up to 6 m of water. Upland or indica varieties are not adapted to flooding. A basic phosphorus and potash dressing may be required but nitrogen fertilization is a main determinant of yield. The rice is either hand harvested and later threshed or mechanically harvested with combines and hulled and cleaned. Economics Rice is one of the world's two major human food crops, the other being wheat.
Rice straw is retained for feeding draught animals in most rice-producing countries in the tropics.
Rice bran is fed to domestic animals when not required for human consumption in dry years. Paddy straw provides 80 percent of the organized roughage for India and a large part of the roughage for animals in other rice-producing countries where draught animals are used. Molasses-urea also increased digestibility coefficients of crude fibre and crude protein. This supplement increased body weight from 3.5 to 5.5 kg per head in 100 days. The seeds of japonica varieties have no dormancy period.