The etymology of the word Agronomy owes its origin to ancient Greece. It is a compound word combining  Agros(field) and Nomos(to manage). In modern terminology however the word has come to mean and denote a branch of science dealing with all aspects of crop cultivation and production. A study of agronomy often involves a summoning of resources from related disciplines such as Botany, Soil Science, Irrigation, Plant protection, Plant Genetics and Breeding, Agro-meteorology etc. In a more fundamental sense it can be categorized as an applied Science, the object of which is crop cultivation and management for the purpose of producing food for humans, feed for animals as well as raw materials for the industry.

 The preponderance of Agronomy cannot be overstated as from very ancient times it has been recognized as the mother branch of agricultural science. There are however two aspects of Agronomy which need to be explained to beginners as they are likely to encounter ambiguity and misconceptions here

  1).It is often distinguished from related fields such as Horticulture and Forestry or Silviculture, but this difference is not generic, not in kind but in degree. The principles remain the same but the practices are a shade apart. Agronomy generally refers to the growth of crops on extensive farms involving food-grains, pulses, grasses etc and requiring comparatively less day-to-day management. Horticulture on the other hand is a term used to denote an activity related to crop growth involving orchards, gardens and plantations and is intensive in nature, needs greater care and management and its products are fruits, vegetables, nuts and beverages. The time cycles are less than agronomic crops. Forestry is meant to grow trees for the purpose of lumbering (wood and timber needs). Forests are by and large a gift of nature and are found in the wild but can also be generated artificially through the practice of silviculture.

 2).The second point that is likely to pose confusion to beginners is how far can we synthesize the science of Agronomy. Crop-Soil-Environment synthesis is too generalized and broad so we can conveniently delineate Soil and Environment and concentrate on Crop only. This narrows down our focus to specific subtopics such as Crop Production and Crop Protection only. Which is what Agronomy is all about. Topics which should ideally be covered by Botany(Anatomy,  Morphology, Physiology and Taxonomy) and Plant Improvement(Genetics, Biotechnology and Breeding) should be left out.

     The Functions of Agronomy may summarily be stated as follows:

     Crop Production:

• Crop Planning in terms of types, varieties, pattern(single, multiple, inter)
• Field Preparation( tillage, preparing bunds and channels, checking soil erosion)
• Soil Management( soil testing, nutrient application, desalination if reqd,)
• Water Management(irrigation)
• Sowing or Seeding with respect to geometry
• Harvesting and Post harvest management

     Crop Protection:

• Weed management
• Insect control through pesticides
• Disease management
• Nematode control

  Reference Sources:
1. www.answers.com

 2. A Textbook of Agronomy( by B.Chandrashekharan, K.Annadurai, E.Somasundaram) published by New Age International