DESIGN AND DEVELOPMENT OF WEEDING MACHINE

DESIGN AND DEVELOPMENT OF WEEDING MACHINE

INTRODUCTION

Production of crops for sale and profit, although the farmers and their families may use a small amount of what they produce. Profits may be re-invested to improve the farm. Large-scale commercial farming is called agribusiness. The opposite of commercial farming is subsistence farming, in which no food is produced for sale.

MACHINERY USED IN FARMING

Modern large agricultural implements, adapted to large-scale farming methods, are usually powered by diesel- or gasoline-fueled internal-combustion engines. The most important implement of modern agriculture is the tractor. It provides locomotion for many other implements and can furnish power, via its power shaft, for the operation of machines drawn behind the tractor. The power shafts of tractors can also be set up to drive belts that operate equipment such as feed grinders, pumps, and electric-power generators. Individual motors often power small implements, such as portable irrigators.

IMPLEMENTS FOR GROWING CROPS

.Many types of implements have been developed for the activities involved in growing crops. These activities include breaking ground, planting, weeding, fertilizing, and combating pests.

1.    Breaking ground
    Ground is broken by plows to prepare the seedbed. A plow consists of a bladelike plowshare that cuts under, then lifts, turns, and pulverizes the soil. Modern tractor plows are usually equipped with two or more plowshares so that a wide area of ground can be broken at a single sweep. Harrows are used to smooth the plowed land and sometimes to cover seeds and fertilizer with earth. The disk harrow, which has curved, sharp-edged steel disks, is used mainly to cut up crop residues before plowing and to bury weeds during seedbed preparation. Rollers with V-shaped wheels break up clods of soil to improve the aeration of the soil and its capacity for taking in water.

2.    Planting
    Some cereal crops are still planted by broadcasting seeds-that is, by scattering the seeds over a wide area. Machines for broadcasting usually consist of a long seed box mounted on wheels and equipped with an agitator to distribute the seeds. A uniform or sufficient depth of soil does not always cover broadcast seeds, so seeding is more often done with drills, which produce continuous furrows of uniform depth. Specialized implements called planters are necessary for sowing crops that are planted in rows, such as corn. Corn planters and other similar machines have a special feed wheel that picks up small quantities of grain or separate kernels and places them in the ground.

3.    Fertilizing
    Fertilizer can be distributed during the winter or shortly before seeding time. Commercial fertilizers are commonly distributed, along with seeds, by drills and planters. Manure is distributed most efficiently by a manure spreader, which is a wagon equipped with a bottom conveyor to carry the fertilizer back to a beater attachment, which disintegrates it and then scatters it on the ground.

4.    Weeding
    After crops have begun to grow, a cultivator is used to destroy weeds and loosen and aerate the soil. A flame weeder, which produces a hot-air blast, can be used to destroy weeds growing around crops, such as cotton, that have stems of tough bark. The weeds are vulnerable to the hot air, but the tough stems protect the crops from damage. Chemical herbicides applied in the form of a spray or as granules are used extensively for destroying weeds (see Weed Control).

5.    Combating pests
Insecticides are applied to soil and crops in the form of granules, dust, or liquid sprays (see Pest Control). A variety of mechanical spraying and dusting equipment is used to spread chemicals on crops and fields; the machinery may be self-powered, or drawn and powered by a tractor. In areas where large crops of vegetables and grain are grown, airplanes are sometimes used to dust or spray pesticides.
Chemical pesticides are used in nearly all-modern farming operations. However, increasing concern over the harmful effects that pesticides may have on the environment has led to the use of alternative forms of pest control. For example, farmers use crop rotation to prevent pests that feed on a certain crop from becoming entrenched and infesting the field. Also, certain pests are controlled by introducing an organism that damage or kill the pests, but leaves the crops unharmed. Finally, scientists genetically engineer crops to be more resistant to troublesome pests. See also Environment.