Page 34 - Introduction to Agriculture by: Aqleem Abbas
P. 34
Introduction to Agriculture Notes prepared by: Aqleem Abbas
For example
A wheat sample five hundred gram having four hundred and thirty three gram pure seed, twenty five gram
other seed, and forty two gram inert material. Than calculate percent purity.
Percent purity = pure seed weight/sample wheat ×100
433/500×100 =87%
In 100 kg wheat sample 87 percent pure seed or purity.
We do purity test to adjust seed rate because the market seed are not hundred percent pure or hundred
percent germinable.
Emergence
When plumule comes out of soil surface is called emergence.
Germination
The protrusion of radical and plumule of seed.
Adjusted seed rate:
Market seed are not 100% pure or 100% germinable. Thus seed rate higher than recommended seed rate
is used for uniform crop growth and stand. It is calculated as
Adjusted seed rate = normal (recommended) seed rate/useful seed rate
Useful seed rate= %purity ×%germination /100
Percent germination
Percent germinated seed out of total seed.
%Germination = germinated seed/total no of seed ×100
Classification based on climate
Based on different climatic factors (light, temp etc) plants are classified as;
Temperate zone crops
These crops are winter hardy and tolerate very low temperature. Around the world these plants grow in a
belt between 30 and 50 north and south latitude. They even existed a tropic of high altitude e.g. chitral,
kalam, gilgit . Some of these crops require chilly temperature e.g. wheat, oat, barley, rye, and rice.
Tropical zone crops
These crops grow between 20 norths and 20 south latitude where frost does not occur during the growing
season. Normal growth is affected by temp below 10 degree centigrade and plants are killed at freezing