Science 7 - LAND and SEA BREEZE and its Characteristics
Rice
1.
2. Rice is a grain belonging to the grass family. It is related to other grass plants such as wheat, oats and barley which produce grain for food and are known as cereals. Rice refers to two species (Oryza sativa and Oryza glaberrima) of grass, native to tropical and subtropical southeastern Asia and to Africa, which together provide more than one-fifth of the calories consumed by humans. The plant, which needs both warmth and moisture to grow, measures 2-6 feet tall and has long, flat, pointy leaves and stalk-bearing flowers which produce the grain known as rice. Rice is rich in genetic diversity, with thousands of varieties grown throughout the world. Rice
3. Throughout history rice has been one of man's most important foods. Today, this unique grain helps sustain two-thirds of the world's population. It is life for thousands of millions of people. It is deeply embedded in the cultural heritage of their societies. About four-fifths of the world's rice is produced by small-scale farmers and is consumed locally. Rice cultivation is the principal activity and source of income for about 100 million households in Asia and Africa.
28. Under Wet or Lowland Cultivation, the land is ploughed thoroughly and puddled with 3-5 cm of standing water in the field. The optimum depth of puddling is found to be around 10 cm in the clay and clay-loam types of soils. The primary objective is to obtain a soft seedbed for the seedlings to establish themselves faster, to minimize the leaching losses of nutrients and thereby increase the availability of plant nutrients by achieving a reduced soil conditions which facilitates a better availability of nutrient elements, to incorporate the weeds and stubble into the soil and to minimize the weed problem. Puddling can be done with ploughs, tillers or tractors, depending upon their availability and soil conditions. The land is leveled after puddling to facilitate a uniform distribution of water and fertilizers.