FERTILIZER RECOMMENDATION – HISTORICAL PERSPECTIVE

By

DR. SHAHID MAHMOOD

The ability of a soil to support The ability of a soil to support satisfactory plant growthsatisfactory plant growth

Ensures nutrient and water suppliesEnsures nutrient and water supplies

Provides cosy conditions for root growth, Provides cosy conditions for root growth, development and development and harvesting of potential yieldharvesting of potential yield

SOIL FERTILITY

Soil Fertility

• Reasons of low soil fertility– Inherent– Leaching– Erosion– Fixation– Removal

• How to access– Soil Testing– Tissue Analysis– Fertilizer Trials– Deficiency Symptoms

Soil Quality

• Soil quality is the capacity of soils

within landscapes to sustain biological

productivity, maintain environmental

quality, and promote plant and animal

health.

• Protecting soil quality like protecting

air quality and water quality should

be fundamental goal of our Nation’s

Environmental PolicyPoor Good

Organic MatterOrganic Matter >> 1.3 %1.3 % Extractable PExtractable P >> 21 ppm21 ppm Extractable KExtractable K >> 180 ppm180 ppm

DTPADTPA ZnZn >> 1.0 ppm1.0 ppm DTPADTPA CuCu >> 0.2 ppm0.2 ppm DTPADTPA FeFe >> 4.5 ppm4.5 ppm DTPADTPA MnMn >> 1.0 ppm1.0 ppm 0.1N 0.1N HClHCl >> 0.5 ppm0.5 ppm

Nutrient Composition of a Fertile Soil

INHERITED LOW SOIL FERTILITY

• Parent material (Alluvial)

• Arid / harsh climate

• Low Organic Matter (OM)

• High pH

• Calcareousness

Causes

Nutrients removal per Nutrients removal per tonne of wheat tonne of wheat

25

9

33

20

11

30

62

14

60

24

9

29

0

10

20

30

40

50

60

70

Wheat Rice Cotton S. Cane

N

P

KKg

/ a

cre

Kg

/ a

cre

0

10

20

30

403939

1010

0.30.3

Usage 04

Fertilizer Consumption Pattern

Wheat

Cotton

Sugarcane

Rice

Others

% Fertilizer Consumption

% Area

% Product Share 08 - 09

Major Cause of Low Production: Nutrient Deficiency

Nutrients are taken up primarily by the roots in the form of an aqueous solution in the soil

Photosynthesis: CO2 + H2O carbohydrates (CHO) + O2

•Besides NPK, other nutrients such as Zinc, Iron, Boron etc. though required in small quantities, but their deficiency significantly impacts plant growth & life.

• Micronutrient deficiency (Zinc, Boron, Iron & Mangnese) in Pakistani soils is increasing

Innumerable experiments on farmers fields prove that there is significant increase in Yields by application of micronutrients along with NPK

Effect of Urea and P fertilizers on wheat production in Pakistan

19.018.2

19.219.5

21.6 21.3

23.3

21.0

0.81 0.76 0.85 0.901.02 0.93

1.18

0.79

2.6 2.72.8

3.1

4.1

3.03.3

3.9

0.4

0.9

1.4

1.9

2.4

2.9

3.4

3.9

13

15

17

19

21

23

25

00 - 01 01 - 02 02 - 03 03 - 04 04 - 05 05 - 06 06 - 07 07 - 08

Fer

tili

zer

Off

Tak

e (m

illi

on to

n)

Whe

at P

rodu

ctio

n (m

illi

on to

ns)

- Wheat Production- Sales (DAP+NP+TSP)-- Sales (Urea)

Genetically Modified Crops

0 0

1925

210

20

303025 27

35

80

38 38 40

87

49 5046

0

20

40

60

80

100

Cotton Rice Maize Sunflower

2004 2006 2008 2012 2015

• Area under GMO crops is increasing at higher pace• GMOs consume 50 – 100% more fertilizers than normal varieties of same crop• Higher net return Vs normal verities encourage farmers for higher per acre investment

% o

f C

rop

ped

Are

a

Sources•Agri Ext data for Punjab•Multinational Companies

BALANCED FERTILIZTION----A KEY STRATEGY TO ADDRESS THE ISSUE

• Use of Balanced Fertilizers,

Organic fertilizers and Bio-

fertilizers can provide viable

leverage to increase crop

productivity• It enrich the soil with important

nutrients • Bio-fertilizers has potential to

generate additional income to

farmers from the same size of

land

• Improving soil fertility through IPNM

• Improve soil physical conditions by increasing SOM

• Inclusion of leguminous crops in cropping systems

• Proper time and method of fertilizer application

• Narrow down the N:P ratio (1:1 or 3:2)

Response Curve Studies

NPK

No Fertilizer

METHODOLOGY

• Variable treatments

• Different cropping systems

• Long term experiments

• Soil property parameters

• Farmers field

Marginal return (MR) &Marginal rate of return (MRR)

1. Marginal return (MR)The yield increase produced by an additional fertilizer unit

is called the marginal return of unit.

2. Marginal rate of return (MRR)It is the ration between return on the investment obtained

from each additional fertilizer unit over the investment itself.MRR = Value of add. Crop – value of add. FertilizerValue of additional fertilizer

It can be positive or negative. Thus atMRR = 1, Economic optimum rateMRR = 0, Maximum profitMRR = 1, Maximum yield

Economic of Fertilizer Use

The highest profit is usually the main motivation for fertilizer use. The main factors that impact the fertilizer use by the farmers are:

1.The price relationship between fertilizer and crop commodity.2.Response of crop to fertilizer application.3.Economic returns on investment.

The question is to how much fertilizer to apply to a specific crop in order to maximize profit. Before answering the question I would like to explain the following indicators that are used in the economic analysis.

Among different yield controlling factors fertilizers contributing is more than 50 %. Factors contribute for decision making.

FERTILIZER RESPONSE CURVE STUDIES ON WHEAT IN IRRIGATED AREAS

Objectives: Formulation of fertilizer recommendationsLocation: Irrigated area of Punjab province

TREATMENTS

N P K

Kg/ha

0 0 0

0 114 60

80 114 60

160 114 60

240 114 60

160 0 60

160 57 60

160 171 60

160 114 0

160 114 30

160 114 90

Response Curve Studies on Wheat (IRRIGATED)

OPTIMUM LEVELS

• N 140 kg/ha• P2O5 77 kg/ha• K2O ----

SOIL TEST

• OM % 0.78 +/- 0.17

• P mg/kg 5.8 +/- 3.6• K2O mg/kg 131 +/- 35………………………….

KN

P

Wheat Response Curves (Rice Zone)

R2 = 0.9928

R2 = 0.9966

R2 = 0.88442500

3000

3500

4000

4500

5000

0 50 100 150 200 250 300

Nutrient kg/ha

Gra

in Y

ield

kg

/ha

N

P

K

From this graph it appears that increasing the fertilizer level gradually led to the following:

•Diminishing increase in the yield (decreasing marginal per fertilizer unit)•Gradually decreases in the MRR and the VCR•Maximum net profit per ha will be at the point where MRR = 0

Crops No. of Trials

Grain crops 42950

Cash crops 10077

Fodders 1189

Oilseeds 1650

Vegetables, Fruits, Pulses and others 2823

Total

58689

No. of Field Trials Conducted up to 2010 – 11 No. of Field Trials Conducted up to 2010 – 11

Economic of Fertilizer UseThe highest profit is usually the main motivation for fertilizer use. The main factors that impact the fertilizer use by the farmers are:

1.The price relationship between fertilizer and crop commodity.2.Response of crop to fertilizer application.3.Economic returns on investment.

The question is to how much fertilizer to apply to a crop in order to maximize profit. Before answering the question I would like to explain the following indicators that are used in the economic analysis.

Particulars Impacts

Balanced fertilization (BF) Yield = 3926 kg/ha

Farmers’ practices Yield = 2905 kg/ha

Increased yield due to BF Yield = 1.021 ton/ha

% increase in yield due to BF = 35 %

Gross return = 101278 Rs. in million

Additional expenditure for BF = 7172 Rs./ha

Net return = 55747 Rs. in million

Impact of balanced fertilization on Wheat

Particulars Impacts

Balanced fertilization (BF) Yield = 5472 kg/ha

Farmers’ practices Yield = 4583 kg/ha

Increased yield due to BF Yield = 0.889 tons/ha

% increase in yield due to BF = 19.4 %

Gross return = 32594 Rs. in million

Additional expenditure for BF = 8463 Rs./ha

Net return = 20183 Rs. in million

Impact of balanced fertilization on Fine Rice

Particulars Impacts

Balanced fertilization (BF) Yield = 4352 kg/ha

Farmers’ practices Yield = 3056 kg/ha

Increased yield due to BF Yield = 1296 kg/ha

% increase in yield due to BF = 42.4%

Gross return = 11081 Rs. in million

Additional expenditure for BF = 6313 Rs./ha

Net return = 8082 Rs. in million

Impact of balanced fertilization on Maize

Particulars Impacts

Balanced fertilization (BF) Yield = 3167 kg/ha

Farmers’ practices Yield = 2372 kg/ha

Increased yield due to BF Yield = 795 kg/ha

% increase in yield due to BF = 33.52 %

Gross return = 50051.4 Rs. in million

Additional expenditure for BF = 7610 Rs./ha

Net return = 30887.1 Rs. in million

Impact of balanced fertilization on Cotton

Particulars Impacts

Balanced fertilization (BF) Yield = 89.64 ton /ha

Farmers’ practices Yield = 82.97 ton /ha

Increased yield due to BF Yield = 6.67 ton /ha

% increase in yield due to BF = 8 %

Gross return = 5267.7 Rs. in million

Additional expenditure for BF = 6125 Rs./ha

Net return = 1318.9 Rs. in million

Impact of balanced fertilization on Sugarcane

Treatments

B0Zn0 B25Zn0 B50Zn0 B0Zn50 B0Zn100 B25Zn50

Fru

its

no

./p

lan

t

0

100

200

300

400

500a

bbbb

c

Number of fruits (>35%) were counted in Zn50-B25 compared to control.

Treatments

B0Zn0 B25Zn0 B50Zn0 B0Zn50 B0Zn100 B25Zn50

10

0 f

ruit

wt.

(kg

)

0

5

10

15

20 aab

babab

c

Harvested fruits were higher (19%) in Zn50-B25 compared to control.

Fertilizer Use Efficiency: An Old Topic but With Great Importance

As food demands to increase per acre yield to feed surging population.Fundamentals of natural systems ….indicate a major and expanding role of fertilizers in food

production

– Issue: to optimize N and P beneficial role in sustainable crop production and minimize N’s negative effects in the environment resulting from crop production.

– Issue: focus attention on improving fertilizer N and P efficiency

– Issue: Poor efficiency in plant uptake of nutrients applied.

Increasing Nutrient Use Efficiency– Synchrony of Nutrient Supply with Crop Nutrient Demand– Balanced Fertilization– Integrated Crop Management– Nutrient Efficient Genotypes– Improve farming practices that improve nutrient use efficiency– Need extension of collective understanding about nutrient use

efficiency for N and P

Areas of opportunity for improvement in fertilizer use efficiency

• Continued improvement in cropping system management– Optimizing production – Yield potential protection – pest management and

other cultural practices– Use of site-specific fertilizer application– Understanding of soil N mineralization, P & K fixation– Best time of fertilizer application– Use of organic sources – Improving quality (nutrition) – Biotechnology?

Site Specific Nutrients Management:

STRATEGIES • Improvement in soil, water , fertilizer testing facilities• Nutrient dynamics and indexation in cropping

systems for precise diagnosis of the nature, extent and severity of Macro + Micro nutrient disorders

• Long term micronutrient balance sheet studies in major cropping sequences to permit efficient management and provide negative impact on environment

• Nutritional requirements of horticultural and high value crops

• Sustaining agricultural systems through IPNS• Development of critical limits for different cropping

systems in different agro-eco-zones• Plant nutrition management on problem soils• Policy makers should devise long term strategy to address

fertilizer shortage particularly at the time of sowing