After successful completion of this Unit, you will be able to answer:

1
Module V Groundnut Plant Nutrition
Virtual Academy for the Semi Arid Tropics

• After successful completion of this Unit, you
  will be able to answer
• What is the role of phosphorus in plants?
• How phosphorus application is important for
  ground crop?
• What is the recommended rate of phosphorus
  application to groundnut crop?

Course on Groundnut Production Practices
2

• After successful completion of this Unit, you
  will be able to answer
• Why entire phosphorus application is applied as
  basal dose?
• What is the method of phosphorus application to
  groundnut?
• Which phosphatic fertilizer is useful to
  groundnut crop and why?

3
Phosphorus application is not only important for
groundnut crop growth but also equally important
for biological nitrogen fixation. Phosphorus
is essential for root and shoot growth and
lengthening. It stimulates the setting of
pods, decreases the number of unfilled pods
(pops) and hastens the maturity of the crop.
4
Phosphorus is essential to form compounds in the
plant body that provide energy for the growth and
development of groundnut plants. Phosphorus is
to a plant what wheels are for a car. As a car
cannot run on flat tyre even if the petrol tank
is full, without phosphorus plant cannot grow
even nitrogen supply is in plenty.
5
Phosphorus availability helps in increased
efficiency of nitrogen use by plants. About
25-50 kg of phosphorus (P2O5)/ha has been
recommended for different groundnut-growing
regions in India. However, it is a good
practice and also economical to apply phosphorus
based on soil- test recommendations.
6
Entire phosphorus (P2O5) should be applied at
the time of sowing as a basal-dressing as the
demand for phosphorus is high during the early
stages of crop growth.
7
Furrow placement or side dressing is the best
method of phosphorus application in the soil.
This method of application minimizes the fixation
of phosphorus in the soil. Phosphorus fixation
means unavailability of phosphorus for plants
use.
Furrow placement
8
Side Dressing of phosphorus fertilizer
9
Groundnuts are extremely sensitive to fertilizer
burn. Do not apply fertilizer in the furrow with
the seed nor over the row after planting. It
has been found that single super phosphate is the
best source of phosphorus as it also contains
calcium (19.5), sulphur (12.5) in addition to
phosphorus (16). Super phosphate also contains
zinc and magnesium in traces.
10
Module V Groundnut Plant Nutrition
Virtual Academy for the Semi Arid Tropics
Lesson 2 Importance of Primary Plant Nutrients
With this, the Unit 3 on Phosphorus Nutrition in
this Lesson concludes. The next Unit in this
Lesson is about potassium nutrition in
groundnut. The subsequent Units in this Lesson
deal with the other aspects of groundnut
nutrition. Select Unit 4 in Lesson 2 of Module
V from Course contents
Course on Groundnut Production Practices