usbax oscjudksi dsk

1. Biological Tests
• Field Experiment
• comparison of several treatments
of fertilizer, lime, etc., including a
control to answer specific
questions under field condition.
• Principles: comparison of plant
growth rate at different treatments
or levels of the selected factor
under actual field condition better
reflects the influence of the
environment.
• Plants are harvested after a
uniform time interval, usually at
the end of the growing season
• Microbiological Test
• use of microorganism to determine
the presence of nutrients in the soil:
Azotobacter or Aspergillus niger
reflects nutrient deficiency in the soil.
• Azotobacter and Aspergillus niger
were used to determined phosphorus
and potassium.
• Small amounts of soil are incubated
for a period of four days in flask
containing the appropriate nutrient
solutions. The weight of the mycelial
par or the amount of potassium
absorbed by these pads is used as a
measure of the nutrient deficiency.

2. Biological Tests
• Pot Experiment
• comparison of several
fertilizer treatments
including a control
using small amount of
soil in pots to have
better control of
environmental factors.
• under artificial
conditions.
• Soil in pot; short
duration; preliminary in
nature
• Sunflower test for
boron
• Minus One Element Technique
• developed by Dr. Cesar P. Mamaril in PhilRice
• compares pots with one missing element to a
pot with complete N, P, K, S, Zn, Cu; most
common nutrient deficiencies associated with
lowland rice soils

3. Fertilizer
• Fertilizer – any substance that is added to the soil to supply the plants with one or
more elements
• Inorganic fertilizers – it has definite chemical composition; man made
• Organic fertilizer – fertilizer materials of organic origin
• Fertilizer element – macro or micronutrient supplied by a fert material (ex. N, P, K)
• Fertilizer nutrient – available or soluble form of fertilizer element (ex. P205, K20)
• Fertilizer material – organic or inorganic material used as fertilizer (ex. Urea, guano)
• Fertilizer grade – percent nutrient in a fert material (Ammophos: 16% N, 20% P2O5)
• Fertilizer ratio – relative proportion of nutrients in lowest term (T14 1:1:1)
• Fertilizer recommendation – expressed in either wt of fertilizer material or wt of
fert nutrient per ha basis (ex. 2 bags MOP per ha., 120 N-90 P2O5-60K2O/ha)

4. Fertilizer
• Single/straight fertilizer –carries only one element
• Compound fertilizer –it carries two elements
• Complete fertilizer – it contains all the three basic (primary) elements. N P K)
• Mixed fertilizer – it contains several elements and the source of elements can
not be identified, achemical or mechanical combination of two or more
fertilizers