2. Importance of Nutrient Management
Nutrient management is one of the importance in successful
corn production.
Improper nutrient management has various implications on
growth and yield performance corn plant.
Grain yield is enhanced with better nourishment throughout
the growing period, especially during the critical
development stages of the corn plant.
To attain yield potential of most corn varieties, they should
get the optimum amount of nutrients they need.
The final amount of fertilizer to be applied is determined by
the nutrient supply from the soil. when the amount of
available nutrient is low, fertilizer is added to the soil.
3. Correct soil sampling and accurate soil analysis will help in
determining the type and right amount of fertilizer to be
applied in order to have a good yield.
Things to remember in Soil Sampling and Analysis.
Collect soil samples right after harvest or before fertilizer
application.
Avoid sampling directly in the crop row or in the fertilized
band.
It is much easier to collect samples when soil is moist.
Conduct soil sampling and analysis of your cornfield every 3-
5 years.
4. STEPS IN SOIL SAMPLING AND ANALYSIS
STEP 1.
Prepare the following:
1. Spade or shovel
2. Pail
3. Plastic bags
4. Weighing scale
5. Marking pen
6. Step 2.
Divide your field into several sampling areas.
Each sampling area should have similar cropping history.
1. Past fertilizer or lime treatment.
2. Slope
3. Degree of erosion
4. Soil texture (sandy, loamy, or clayey) and color
One sampling area may represent up to five hectares of
field.
Collect 5-15 spot soil from several locations within each
sampling area.
7. Step 3.
Before digging, brush away stones, rubbish and vegetation from
the surface area.
With a spade or shovel, dig at a depth of about 30 cm(11.8 in)
and take a slice of soil about 2 cm thick and 5 cm (2 in) wide.
This represent one spot soil sample. Put the sample in a clean
pail or plastic bag.
Follow step 3 until the total number of spots per sampling area
is completed.
Step 4.
After completing the spot sampling of a particular sampling
area, pulverize the soil, remove the stones and fresh plant
parts and mix the samples thoroughly in the pail.
8. Step 5.
Air dry the soil with care and keep it away from foreign
materials.
Step 6.
Take a composite sample of one kilo and place it in a clean
plastic bag with proper label that includes the name of the
farm owner, farm location and sample number.
Step 7.
The soil is now ready for analysis. You can use a soil test kit
(STK) or send the samples to the nearest soil testing
laboratory in your area.
9.
10. TYPES OF FERTILIZERS
Fertilizers are materials that supply nutrients to plants. They may
be inorganic or organic fertilizers.
Inorganic Fertilizers (NPK) MACRONURIENTS
1. Urea (46-0-0) and Ammonium sulfate (21-0-0) that supply
nitrogen (N).
2. Solophos (0-20-0), Di-ammonium phosphate (18-46-0) and
ammonium phosphate (16-20-0) that supply nitrogen and
phosphorus (NP).
3. Muriate of photash (0-0-60) that supply potassium (K).
4. Complete fertilizers (14-14-14) that supply nitrogen,
phosphorus and potassium (NPK).
11. NPK Requirement of Corn
Nitrogen, Phosphorus and Potassium
Nitrogen (N) is needed to assure adequate growth of the
plant, ensuring its leaves dark green and promoting full
development of ear and grain.
Nitrogen deficiency: yellowing of leaves, thin stems and
small ears with unfilled tips.
Phosphorus (P) is vital in growth process like the use of
sugar and starches. It stimulates good root systems and
flowering. It counterbalance the effect of nitrogen by
strengthening the stem and hastening plant maturity.
12. Phosphorus deficiency: the tips and margins of the young leaves
turn purple, plant grow slowly and the stem remain thin. This
leads to poor grain formation on one side of the ear, causing
uneven rows and curving of the cob.
Potassium (K) is essential in the production of carbohydrates,
formation of proteins, strengthen the stem, improves the
quality of ears and minimizes the susceptibility of the plant
to certain diseases like stalk rots and pest.
When potassium is lacking: short internodes, margins of the
older leaves turn yellow, sharpened of ear tip, poor graing
filling.
13. The rate of fertilizer to be applied should be based on the
results of the soil analysis.
Recommended rate is express in kilograms N, P and K per
hectare, respectively.
For example, the recommended rate 90-60-30 kg means
that 90 kg Nitrogen (N), 60 kg Phosphorus (P) and 30 kg
potassium (K) are needed per hectare.
Fertilizer grade refers to the minimum guarantee of the
nutrients content in terms of percent N, P and K available.
14. Example of fertilizer calculation
Calculate how many kilograms of N, P and K are needed to satisfy the recommended
rate of 90-60-30 per hectare.
Available fertilizer materials: Fertilizer Price:
Urea (46-0-0), ₱ 1,200x4 =4800
solophos (0-20-0) & ₱ 1,100x6 =6600
Muriate of photash (0-0-60) ₱ 1,200x1 =1200
Total ₱ 12,600
Urea (46-0-0) = 90 kg N/ha x 1 hax100 = 196 kg/50 (4 bags)
46% N
solophos (0-20-0) = 60 kg P/ha x 1 ha x 100 = 300 kg/50 (6 bags)
20% P
Muriate of photash (0-0-60) = 30 kg k/ ha x 1 ha x 100 = 50 kg/50 ( 1 bag)
60% K
16. General fertilizer recommendation in the absence of soil
analysis
1. Use four bags of complete fertilizer (14-14-14) per
hectare as basal application.
2. After 25-30 days of planting, side dress with four (4) bags
of ammonium sulfate (21-0-0) or two (2) bags of urea (46-
00).
3. Cover the fertilizer immediately by shallow hilling-up.
17. Fertilizer application
Split application of Nitrogen (N) fertilizer is recommended
Apply all the recommended phosphorus and potassium and
half of the recommended amount of N in the furrows
before planting.
Side dress the other half of N at least 4-5 cm away from
the base of the plant 20-24 days after emergence or
immediate before hilling-up when there is right soil
moisture.
To attain higher yields, apply animal manures and crop
residues just before land preparation.
