Kerry Branson, age 12, of McAllen, Tex., for her question:
HOW IS RICE GROWN?
Rice is one of the world's most important food crops. About half of the people in the world eat rice as their chief food. The best crops grow in river valleys, on deltas and on coastal plains where the soil holds water well.
Rice grows in many types of soil, including some that are too heavy and wet for most other crops.
Most rice soils are low in nitrogen and phosphorus, so fertilizers containing these elements must be added for good crops. Crops are small where rice is grown every year with little or no fertilizer.
Rice grows well at temperatures from 70 degrees to 100 degrees Fahrenheit. It needs an average temperature of at least 75 degrees during the growing season and an average rainfall of at least 45 inches unless irrigation is used. Usually non-irrigated or upland rice yields less per unit of land than irrigated rice.
Few rice farms in Asia are larger than 10 to 15 acres and most of them are only two or three acres. Most Asian farmers use the same primitive methods and crude tools that their ancestors used. Some have water buffalo or oxen for plowing but the rest must use hand labor.
In the United States and a few countries of South America, profitable rice farms range from 300 to 1,000 acres or more/ Despite their size, such farms require few laborers because the work is done almost completely with the aid of modern farm machinery.
Farmers grow lowland rice in fields divided by dirt walls called dikes or levees. An area surrounded by a dike is called a paddy or cut. The dikes range from one of two feet high and from four to six feet wide. On level land, farmers build dikes in straight or wavy lines. On hilly land, they follow the slopes and form terraced paddies that rise like steps.
The dikes hold water on the fields, since flooded fields produce the best crops.
Rice growers often irrigate their fields before working up the soil for planting. They plow the paddies and turn the weeds under the soil or mud.
Lowland rice can be broadcast onto muddy land. In the United States, most seeding is done by low flying airplanes that broadcast sprouted seeds onto flooded fields.
In many places outside the United States, farmers broadcast seeds very thickly over small patches of well fertilized, wet or dry soil. They carefully tend these nursery beds and, after 30 or 40 days, transplant the seedlings or young plants to the flooded fields.
The farmer usually push a clump of from one to six stalks into the soupy mud. The clumps are spaced over the field, sometimes in rows.
Farmers in the Northern Hemisphere usually start to plant rice in April or May, but they may start nurseries earlier. In some parts of Asia, and also in South America, farmers often produce two crops a year on the same land.
Lowland rice consists mainly of controlling the water supply and weeding the rice fields. Workers keep two to six inches of water on the field until the grain starts to ripen. Then the water is drained off through openings in the dikes so the soil can dry by harvest time.