Rice vs Other Grains
Cereal yields are generally higher in temperate areas than in tropical countries.
Rice has the highest extraction rate of any cereal, meaning when considering the fraction of each grain utilized to as food, rice produces more energy per hectare than any other cereal.
Total food protein per production hectare for rice is second only to wheat. However, when the superior quality of rice protein is considered, the yield per hectare of utilizable protein is actually higher for rice than for wheat.
Four Major Rice Ecosystems
Irrigated Rice: Spend more to make more. Irrigated rice consists of about 55% of global rice area and about 75% of global rice production - thanks to typically higher yields. However, the higher yields typically mean more purchased input costs. Irrigated rice areas are mostly concentrated in humid and sub humid subtropics and humid tropics.
Rainfed Lowland Rice: Accounts for about 25% of global rice area and about 17% of global rice production. Rainfed rice is found in South and Southeast Asia. Rice is transplanted or direct-seeded into puddled soil on level to slight sloping, bunded (diked) fields that are flooded for at least part of the cropping season – leaving the crop vulnerable to a lack of water control. Farmers grow traditional, photoperiod-sensitive varieties and rely more on labor than purchasing inputs.
Upland Rice: Consists of about 13% of global rice area and about 4% of global rice production, due to extremely low yields. Upland rice is grown without standing water. Despite the low yields this is the dominant rice culture in parts of Latin America and West Africa.
Flood-Prone Rice: Accounts for about 9% of global rice area and about 4% of world production, due to low yields as a result of problem soils and unpredictable droughts and floods. This includes both deep-water rice and floating rice. About 90% is farmed in South and Southeast Asia with the remaining 10% farmed in parts of West Africa and South America.