soil fertility management recommendations

Soil Fertility Management Recommendations

A framework for the analyses of soil and agronomic data to develop recommendations for ISFM

E. Jeroen Huising

5/24/2015 ISFM data management and analysis WASHC training workshop 1

Fertilizer and ISFM recommendations

5/24/2015 ISFM data management and analysis WASHC training workshoph 2

Inputs (nutrients, water, labour, agro-chemicals,

energy etc.)

Desired

Outputs

(e.g. Yield)

or

Undesired

Outputs

(e.g. N loss,

GHG loss)

0

1000

2000

3000

4000

5000

6000

7000

0 50 100 150 200

Fertilizer N applied (kg N ha-1

)

Yie

ld (

kg

ha

-1)

0

20

40

60

80

N-A

E (k

g (k

g N

)-1)

grain yield

AE

(a)

N response curve and N agronomic efficiency

Fertilizer recommendations – aiming to maximize yield or economic return, assuming risks are low (optimum economic and biophysical conditions and good management – e.g. limited cost for obtaining capital)

ISFM – Aiming at maximizing agronomic efficiency assuming resource constraints and accounting for the farming conditions of smallholder farmers in Africa.

Providing solutions to problems with soil – crop productivity

5/24/2015 ISFM data management and analysis 3

Where?Assessment of soil fertility status and

diagnosis of soil health problems

For What?To improve crop

productivity; Assess crop requirements,

yield gaps etc.

For Whom?Who has to implement;

Assess the socio-economic conditions

(GL GR) E M]

Environment

Management

Germplasm – Genetic potential

Context

Problem

Targets

Potential is not the problemPotential is not the problem!

Finding solutions to soil health problems


Identify (soil health) problem

Identify (alternative) solutions

Recommended optionDecision/ Testing

Implementation

Monitoring and evaluation

From ‘best-bet’ to ‘best fit’; Testing technology and management options on farmer’s fields; Stepwise approach to full implementation of ISFM

Integrated Soil Fertility Management


Specificity of the recommendationGRADIENTS

Country wide

Crop

Farming community

One particular management aspect (e.g. fertilizer)

Site specific

Specific crop, type,

variety, cropping system

Individual farmer

Several management aspects (integrated – or systems) (e.g. integrated nutrient management)


Embracing and understanding variability; spatial and temporal; what is the probability of farmers benefitting

Levels of sophistication - complexity

• Rule of thump

• Expert knowledge (Look-up tables; soil suitability ranking)

• Empirical models (making use of agronomic trials and using statistical models)

• Deterministic models (DSSAT, APSIM, crop growth simulation models


0

1000

2000

3000

low medium high

manage me nt

ma

ize

yie

ld [

kg

ha-1]

control (no fertilizer applied)

fertilizer applied

Mai

ze g

rain

yie

ld (

kg/h

a)

Management

intensity (planting date,

crop density,

time of P

application);

Tinfouga, Mali

Bationo et al.,

1997

Universal principles of nutrient management

Responsive and Non-responsive soils

I. Poor non-responsive soilsII. Poor responsive soilsIII. Fertile non-responsive soils

From diagnosis to management options (best-bets)


X

XX

XXX

X X XXCrop constraints

Management constraints

Nutrient limitations

Soil health constraints

Poor,

non-

responsive

soils

Responsive

soils

Fertile,non-responsivesoils

Attainable yield under rainfed conditions

Potential yield for selected crop for area

under consideration

Agro-climatic constraints

Crop variety or cultivar selection

Water harvesting & irrigation (semi-)

permanent structures

Improved agronomic practices

Nutrient management recommendations

Soil improvement

Diagnostic phase Management options

Practical Definitions for Responsive and Non-Responsive soils

• Soils that respond to N, P or K (individual or in combination) only are called responsive soils; Soils that show a limitation in any of the three nutrients, but not in any other. These limitation may be solved easily with readily available fertilizers

• Soils that are responding well to application of meso- or secondary nutrients (Mg, Ca, S) are called intermediate responsive soils

• Soils that show clear limitations in micro-nutrients and show little or no response to application of macro and secondary nutrients are called non-responsive soils

• Soils that show little response to macro and meso fertilizer application associated with clear limitations in soil organic matter (clear response to manure application), and/or soil acidity (strong response to lime application), and/or any constraints related to water retention and/or constraints towards root development are likewise call non-responsive soils

• Based on the above several response classes could be defined


Different approaches; Making recommendation based on soil testing


Soil Test Critical Values

Calculate nutrient requirements; recommend fertilizer application (crop specific)

Testing/evaluation in farmer’s fields (populations studies)

Soil test values/ soil information

Soil testing (soil test kits, mobile labs, soil labs)

• Aims to give fertilizer recommendation based on soil test values; uses soil test interpretation guide to classify nutrient status of the soil, use crop nutrient requirements (or nutrients removed by the crop) to determine nutrient requirement and modified by soil nutrient status to determine application requirement. Gives indication of possible or likely nutrient limitations

• Is (semi-)quantitative approach; not very accurate or precise; will not predict response accurately; will not capture spatial variability adequately; is simple to understand and use, might be costly if sampling of all farmers field is required

• Possible improvements, soil test kits might provide alternative, however soil nutrient classes could be predicted from improved soil mapping techniques; use models to more accurately predict fertilizer response.

Diagnostic trials to determine soil health constraints

• Nutrient omission trials to determine limiting nutrients (N,P and K, and others as individual nutrients or as complex/compound, e.g. micronutrients), added with treatment like manure, and/or liming

• Identifies limiting nutrients and degree of nutrient limitation, identifies constraints related to SOM and soil acidity.

• Is quantitative: determines attainable yield level under optimal management; allows for calculation of AE and results can be used for calibration of models like QUEFTS

• Multi-location trials allows for determining response classes and assessment of soil fertility status in the region


Nutrient omission trials (diagnostic)

Attainable yield, Soil health constraints, nutrient limitations

Soil Response Category/ Yield gaps

Soil fertility management strategy, based on soil response class and evidence

Agronomic survey; establish yield gaps on farmers fields

There marked differences in response patterns between sites; six response classes distinguished, but…

04/09/2014 IPI-ATA Symposium 15

Non Resp - Fert

Non Resp - PoorPoor Resp. – low fert.

Resp – N&P, intermed fert

Resp. – P&N

Resp – N, rel. fert.

Input (nutrient) response trials

• Determines response to varying rate of input application (nutrients, manures, inoculants, other); allows for recommendation of fertilizer applications rates and optimum rates for highest AE

• Requires insight in limiting nutrients and other soil health constraints; not suited for diagnostic purposes

• Very strong if includes variety trials to select best yield varieties under good management


Agronomy trials, variety and nutrient response trials, including soil amendments

Crop response to nutrient application and soil amendments

Interaction between various crop production factors: GxExM

Best bet technology, Area specific fertilizer recommendation; improved agronomic efficiency

Demonstration plots, testing on farmers fields

Expert systems / Decision Support Systems for making recommendations to individual farmers

Concept based on:

• Indigenous soil nutrient

supply

• Fertilizer nutrient recovery

• Internal nutrient use

efficiency

• Potential yield/attainable

yield

• Nutrient uptake curve


Soil Test Critical Values

Calculate nutrient requirements; recommend fertilizer application (crop specific)

Testing/evaluation in farmer’s fields (populations studies)





Soil Response Category/ Yield gaps

Soil fertility management strategy, based on soil response class and evidence




Interaction between various crop production factors: GxExM

Best bet technology, Area specific fertilizer recommendation; improved agronomic efficiency


QUEFTS – empirical model

Decision support tools (DSSAT, APSIM)

Data and informationKnowledge / interpretation Recommendations and learning

Expert systems/ DST; nutrient manager

Individual and specific recommendations. Crop choice; alternative solutions, farm management

C

o

m

p

l

e

x

i

t

y

5/24/2015 ISFM data management and analysis WASHC Training Workshop 18

Diagnosis of soil health constraints

Diagnostic phase

Type of constraint Variable Analyses and interpretation (explanatory variables, co-variates)

Agro-climatic and agro-ecological constraints

(Ypot,c - Ymax,i), ((Ypot,c-Ymax,i)/Ypot,c)

Rainfall distribution, Rooting depth restrictions, Topographic position, Water supply.

Soil related constraints: responsive and non-responsive soils

(YNPK,i-Ycon,i)/(Yatt,i-Ycon,i), (Yatt,i-Ycon,i), (Yatt,i – YNPK,i)

SCSI, Land degradation index (LDI), pH, CEC, ExAC, etc. spectra

For responsive soils:

Limiting nutrients: K P N

YNPK,i-YNP,i; ((YNPK,i-YNP,i)/(YNPK,i-Ycon,i)) YNPK,i-YNK,i; ((YNPK,i-YNP,i)/(YNPK,i-Ycon,i)) YNPK,i-YPK,i; ((YNPK,i-YNP,i)/(YNPK,i-Ycon,i))

SOM, pH, Minerals, CEC, AEC

For non-responsive soils:

Limiting secondary and micro-nutrients

YNPK+X,i-YNPK,i,> 0; (YNPK+X,i-YNPK,i)/(YNPK+X,i-Ycon,i) YNPK+OM,i-YNPK,i> 0 (YNPK+OM,i-YNPK,i)/(YNPK+OM,i-Ycon,i)

Soil weatherable minerals, Low or high Zn, B, Cu, SOM quality

Soil structure limitations; water retention and water holding capacity

YNPK+OM,i-YNPK,i > 0 (YNPK+OM,i-YNPK,i)/ (YNPK+OM,i-Ycon,i) YNPK+X-YNPK ≤ 0

Soil texture, SOM, SCSI

Soil chemical constrains YNPK+Lime,i-YNPK,I> 0 (YNPK+Lime,i-YNPK,I)/(YNPK+Lime,i-Ycon,I) YNPK+OM,I-YNPK,I> 0 YNPK+X,I-YNPK,I> 0

pH, ExAC,










Data and information

C

o

m

p

l

e

x

i

t

y

Protocols

Data collection templates

Legacy data

Data and information

Databases – Meta data standards5/24/2015 ISFM data management and analysis WASHC Training Workshop 20

What soil and land data do we need to make ISFM recommendation using the different

approaches

5/24/2015 ISFM data management and analysis WASHC Training Workshop 21

Laboratory

Cost!

Time!

Test kits

Accuracy?

Cost?

Local

indicators

Sensitivity?

Extrapolation?

soil fertility management recommendations

Government & Nonprofit