Important formulas

a) Cropping intensity = (Total cropped area/ Net area available) X 100

b) Rotational intensity = (No. of crop grown in rotation/Duration of crop rotation) x 100

c) Land equivalent ratio (LER) =(Yield of crop A at intercropping/Yield of Crop A as pure) + (Yield of crop B at intercropping/Yield of Crop B as pure)

Note:

LER> 1, intercropping accepted

LER<1, intercropping rejected.

If B/C > 2 à Agribusiness

If B/C = 2 à Sustainable or subsistence

If B/C < 2 à Below subsistence

d) Moisture Availability index (MAI) = Dependable ppt/Potential evapotranspiration

e) Water use efficiency = Dry matter produced / Water evaporated

Note:

• Awn is absent in sugarcane
• Maize is a rainy season crop.
• Millet is a xerophyte
• Mesophyte à Growing in moderate amount of water. Eg: Maize, wheat.
• Frost tolerant à Sugar beet.
• Based on structure and form: Lianas : Mucuna spp.
• Crop tolerant to acid soil: Potato, wheat, Soyabean
• Crop tolerant to basic soil : Barley, Sugar beet and cotton.

Food security @3A

• Availability
• Affordability
• Accessibility of food

Meaning of sign

1. (-) à Crops are sequenced
2. (+) à Crops planted simultaneously
3. (/) à Crops are relayed

Crop classification

a) Pseudocereal : Buckwheat and Amaranthus

b) Fiber crops : Agave

c) Tuber crops: Potato and Yam

Tillage

• Father of tillage: Jethro Tull ( 1731)
• Book : Essay on principles of tillage and vegetation.
• Old concept of tillage also known as Jethro Tull concept of tillage involves maximum manipulation of soil.

Dry farming

• Without irrigation.
• Annual rainfall is < 750 mm/year.

Note:

• Higher yield of starchy crop : Eg: Potato and corn in cool climate is due to optimum temperature of photosynthesis low than that of temperature of respiration.