The word `agriculture’ is derived from ager, which means `filed’ in Latin, and cultura, which men `cultivation’. In a wider sense, agriculture includes the improvement of crops, rearing of animals and the protection, harvesting and strong of crops. The term sustainable agriculture means the production of food to meet the needs of the present generation without destroying the ability of nature to produce food for future generations.

Agronomy and horticulture are branches of agriculture. Agronomy deals with the principles and practices of soil, water and crop management. The word is derived from the Greek words agros, meaning field, and nomos, meaning law. Horticulture is the science of growing fruit, vegetables and ornamental plants. It comes from hortus, the Latin word for `garden’.

Types of crops

Crops maybe classified into certain categories, such as cereals, pulses, oil seeds, fiber-yielding plants, beverage plants, vegetables, fruit and medicinal plants. Cereals, pulses seeds, and other crops cultivated for the production of food are called food crops.

Jute, cotton, rubber, and so on, grown or commercial purposes, are called cash crops. Cash crops, like coffee, tea, rubber and Pisces, re grown over large areas called plantations, wile food crops are grow in fields. Fruit gardens are called orchards. In India, crops are clasifi9ed in to Kharif crops and Rabi crops on the basis of when hey are cultivated. Kharif crops, like rice, jute, maize, groundnut and cotton, are sown during the monsoon. Rabi crops. Like wheat, mustard, potato, barely and gram, are sown after monsoon, around October.

Types of soil

Agriculture production depends upon the quality of soil. Soil must be fertile, or contain the nutrients required by plants. It must be able to retain moisture and not be too acidic or too alkaline.

There are many ways of classifying soil. It can be classified on the basis of the types of soil particles that constitute it. Soil particles are of four types. The largest particles, called gravel, are more than 2.0 mm in diameter. Sand particulars range from 0.02-2.0 mm, wile silt particles are 0.002 -0.02 mm. clay particles measure less than 0.002 mm. depending upon the proportion in which these particles are present, soil may be of the following three types soil may e of the following three types.

Sandy soil

Sandy oil contains 70% -85% Sand. It is not good foe agriculture because it does not retain water. Unlike clayey soil, it has also of air spaces. Its water holding capacity can be improved with the addition of humus, or decomposed plant matter.

Clayey soil

This type of soil I made up mostly of clay particles. The fine particles cling together, leaving little space or air. This is not god for the growth of plants, but clayey soil is good in that it can hold water. However, this also makes it prone to water logging. The addition of humus improves clayey soil too, by making the fine particles clump together to form lager particles and thus, creating air spaces.

Loamy soil

This is the type of soil that is best suited for cultivation as it contains the right mixture of sand, clay and silt. This type of soil has adequate air paces and can also hold water. Loamy soil contains humus, which provides nutrients for the growth of plants.

Acidic and alkaline soils

Soils may be acidic or alkaline due to the presence of certain minerals. Certain crop plants thrive in alkaline soil and others in acidic oil. Or example, some cereal plants grow well in slightly acidic oil, wile pulses prefer slightly alkaline soil. However, oil that is too acidic or too alkaline is bad for plants.

Soil may turn acidic due to various reasons. The excessive use of certain fertilizers, for example, sulphur and ammonia, is one of the reasons. Water logging and leaching, or the washing away of soluble minerals from the soil, are other reasons. The presence of an excessive amount of humus may also turn soil acidic. Acidic soils are common in the Himalayan region and the plains of Bengal and Assam. Lime is often added to treat such soils.

Soil may naturally contain lime or other bases which make it alkaline. Groundwater used for irrigation can also carry bases from deeper layers of the soil. Certain chemical fertilizers too can increase the alkalinity of soil. Sulphate and phosphates are added to make soil less alkaline.