Wheat: Its plant requires a cool climate in the beginning, warm and dry weather at the time of harvesting and rainfall at intervals—between 20'' to 30''. A clayey soil is very favourable.
Barley: cool climate and a soil poorer than that required for wheat.
Rice: hot and moist climate with rainfall from 40'' to 80'' or over and rich soil. The plant is required to remain under water for several days in the beginning. A marshy soil is very suitable.
Sugarcane: an evenly high temperature with sufficient rainfall—about 40''. It needs a fertile soil, having lime and salt in it.
Tobacco: hot and moist climate; rich soil.
Spices: (pepper, cinnamon, cardamom, cloves, nutmegs) hot, moist and even climate.
Opium: It requires hot and moist climate with a rich soil.
Maize: warm and moist (but not very moist) climate.
Cotton: It requires warm, moist and even climate where summer is long and where the soil contains salt. Sea-breeze is beneficial for quality of the fibre. The ideal situation for plantation is lowlands near the sea coast or on islands in semi-tropical latitudes.
Jute: It requires a high temperature with a minimum of about 80°F during the period of growth. It also needs rich sandy soil, sufficient rainfall well distributed over the period of growth, ample supply of water for soaking of plants and for washing the stripped fibre. It also needs suitable and sufficient labour to handle the crop at the proper time.
Rubber: The plantation of rubber trees is better adapted to areas where the climate is warm and humid.
Tea: (Tea is dried leaves of an evergreen shrub). It requires warm and moist climate. It is grown on mountain slopes. At least 60'' annual rainfall in showers is needed for the new leaves to sprout. If water is allowed to stay, the roots are destroyed. So mountain slopes on which water does not accumulate are necessary. Soil containing iron is an additional advantage.
Coffee: requires warm and moist climate and a height between 457 metres and 762 metres—rainfall above 60''. The plant cannot stand extreme cold. When young, the plant is required to be protected from strong sunshine.
Millets: (Jawar and Bajra) require a hot and sufficiently dry climate and poor soil.
Groundnuts: require a hot climate and moderate rainfall 29'' to 40''. Soil should be light and sandy.
Oilseeds: require hot and moist climate and a rich soil.
Diseases of Crops
Black heart: Potatoes
Kernel bunt: Wheat
Powdery Mildew: Peas
Red Rot: Sugarcane
Fertilizers normally contain three main ingredients namely nitrogen, phosphorus and potassium.
Nitrogen: imports a healthy green colour to the leaves.
Phosphorus: hastens leaf development and promotes root growth.
Potassium: plays an essential part in the formation of starch.