Page 34 - Introduction to Agriculture by: Aqleem Abbas

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