There are several nutrients essential for crops. Of these, some are required in large quantities and are known as macro-nutrients whereas rest of the nutrients are required in small quantities and are known as micro-nutrients. • Manure and fertilizers are the main sources of nutrient supply to crops. • Organic farming is a farming system with minimal or no use of chemicals as fertilizers, herbicides, pesticides etc. and with a maximum input of organic manures, recyled farm wastes, and bio-agents, with healthy cropping systems. • Mixed farming is a system of farming on a particular farm which includes crop production, raising of livestock etc. • Mixed cropping is growing of two or more crops simultaneously on the same piece of land. • Growing two or more crops in definite row patterns is known as intercropping. • The growing of different crops on a piece of land in pre-planned succession is called crop rotation. • Varietal improvement is required for higher yield, good quality, biotic and abiotic resistance, shortening the maturity duration, wider adaptability and desirable agronomic characteristics. • Farm animals require proper care and management such as shelter, feeding, breeding and disease control. This is called animal husbandry. • Poultry farming is done to raise domestic fowls. Poultry production includes egg production and broiler production for poultry meat. • To enhance poultry production, cross breeding is done between Indian and exotic breeds for variety improvement. • Fish may be obtained from marine resources as well as inland resources. • To increase production of fish, they can be cultured in marine and inland ecosystems. • Marine fish capture is done by fishing nets guided by echo-sounders and satellites. • Composite fish culture system is commonly used for fish farming. • Bee-keeping is done to get honey and wax.