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
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