USE OF DECISION DIAGRAMMES WITH SEASONAL OUTLOOKS

TO CHOOSEAGRICULTURAL INTERVENTIONS

Sue Walker Professor in

Agrometeorology Dept Soil, Crop & Climate Sciences

9) Construct decision trees for climate sensitive on-farm decisions

Maak besluitnemingsdiagrame (“decision trees”) vir klimaatsensitieve plaasbesluite

USING SCENARIOS IN PLANNINGClimate forecasts are a potentially valuable tool for many planning situations. But the probabilistic

nature of climate forecasts means that we need to use special planning strategies. One such strategy is scenario building.

Scenario building constructs scenarios of what the future might be like by combining information on (1) the current situation, (2) the range of possible climate outcomes, and (3) the variety of decisions we can make.

The scenarios help us appreciate the consequences of any potential decisions, and therefore they can help us to choose the most appropriate ones.

• About this guide applies to a broad range of planning situations, but actual scenarios that are built are unique to each situation. This guide takes you step-by-step thru process of scenario building with climate forecasts for your situation. Each step includes a short description of the you need to consider, information you need to gather, & where you can go for more information.

• Using this guide You can go through the steps in guide in two ways. Under 'Principles', you will find a general description of each step. This is a good place to start. To see examples of the steps for specific situations, go to 'Cases'. This will open a new frame in your window with a menu of illustrative case studies. Once you select a case study, you can see and navigate through the steps in both the case study and the general principles at the same time.

• To build the scenarios, you might also want to look up some climate information for your area on the IRI web site. Under 'Tutorials' you will find four tutorials on finding specific information on the web site and customizing it to your requirements. For your convenience, we have put the tutorials and the IRI web site side by side, so that you can try the instructions as you go through the tutorial.

GEBRUIK VAN SCENARIOS IN BEPLANNING

Klimaatvoorspelings is waardevol helpmiddels vit baie beplanning situasies. Maar hulle is gegee as waarskynlikhede van klimaatvoorspelings wat beteken dat U moet spesiaal beplanning strategies gebruik.

Een tipe strategie is scenario-bou. In scenario-bou – U moet scenarios uitdink wat kan inligting kombineer oordie

toekoms(1) die hudige situasie;(2) ‘n reeks van mootlike klimaat uitkoms, en(3) die omgang van besluite U kan maak.

Die scenarios help one om die konsekwente van potentialle besluite te sien, en daarom kan hulle one help om die regte keuse te maak.

• About this guide applies to a broad range of planning situations, but actual scenarios that are built are unique to each situation. This guide takes you step-by-step thru process of scenario building with climate forecasts for your situation. Each step includes a short description of the you need to consider, information you need to gather, & where you can go for more information.

• Using this guide You can go through the steps in guide in two ways. Under 'Principles', you will find a general description of each step. This is a good place to start. To see examples of the steps for specific situations, go to 'Cases'. This will open a new frame in your window with a menu of illustrative case studies. Once you select a case study, you can see and navigate through the steps in both the case study and the general principles at the same time.

• To build the scenarios, you might also want to look up some climate information for your area on the IRI web site. Under 'Tutorials' you will find four tutorials on finding specific information on the web site and customizing it to your requirements. For your convenience, we have put the tutorials and the IRI web site side by side, so that you can try the instructions as you go through the tutorial.

GENERAL PRINCIPLES1. What are my goals?

2. How does climate matter to me?

3. What choices do I have to respond to climate forecasts?

4. What is the climate going to be like?

5. What are potential impacts of climate on me, given a climate forecast?

6. What decisions should I use to increase odds of an outcome that is preferred?

ALGEMENE BEGINSELS

1. Wat is my doelwitte?

2. Hoekom is klimaat belangrik vir my?

3. Watte keuse het ek om te reageer ivm klimaat voorspellings?

4. Hoe gaan die weer lyk?

5. Wat is die potensiaal impakte van klimaat op my, met ‘n sekere voorspeling?

6. Watte besluite kan ek gebruik om my kanse vir ‘n goeie resultaat beter te maak?

DECISION TREES – PRINCIPLE FORMAT

• Outcomes of decisions depend on both decisions under our control and events, or states of nature, outside our control.

• One way to represent the relationship between decision options, uncertain events and outcomes is through a decision tree

BESLUITNEMINGSDIAGRAME = DECISION TREES

• Uitkoms van besluite is volgens besluite onder ons eie beheer EN die buite ons beheer.

• Ons kan die verhouding tussen opsies, onsekeheid & uitkoms met ‘n besluitdiagrame uitstip

DECISION TREES - DETAILS

• A decision tree can help you map out decision options and uncertain events so that you can see the range of possible outcomes from the choices you could make. Remember that for each potential decision, a range of possible outcomes follows from the uncertain events in question.

• As you can see, decision trees represent the decisions, states of nature, and outcomes as discrete--that is, there are only a limited number of options (such as "to buy or not to buy"). In reality, most decisions, states of nature, and outcomes are continuous, rather than discrete. For example, you could "not buy", "buy a little", "buy a lot", or anything in between.

• As the climate in the future is uncertain and out of our control (generally), it is represented in decision trees as "uncertain events or states of nature". Climate itself is continuous, but forecasts of climate are generally categorical, so they usually fit well into decision trees because they refer to distinct events: for example, rainfall being either above average, average, or below average; or El Niño or no El Niño.

• Above is a very brief description of the concept of decision trees and its qualitative uses, but there is much more to decision trees than that. Their main use is to think explicitly and quantitatively about decision options and uncertain outcomes. But this theory is beyond the scope of this tutorial.

BESLUITNEMINGSDIAGRAME - DETAILS

• ‘n besluitnemingsdiagrame kan one help om die opsies & onsekerheid uit te stip sodat ons die reeks uitkoms kan seen volgens die keuses. Onthou dat vir elke poteniaal besluit, daar is ‘n reeks uitkoms in gevolg van die onsekerheid van die weer of onbeheerbaar faktore

• Vanaf die besluitdiagrame – die besluite, “states of nature”, en uitkoms is spesifiek, daar is ‘n beperkte nr. opsies (soos “om te koop OF nie te koop nie"). In werklikheid, die meeste besluite, “states of nature”, en uitkoms is ‘n kontinuum, & nie spesifiek nie. b.v. jy kan "nie koop nie” OF “koop ‘n bietjie”, OF “koop baie", OF enige iets tussen in.

• Omdat die klimaat van die future is uncertain and out of our control (generally), it is represented in decision trees as "uncertain events or states of nature". Climate itself is continuous, but forecasts of climate are generally categorical, so they usually fit well into decision trees because they refer to distinct events: for example, rainfall being either above average, average, or below average; or El Niño or no El Niño.

• Above is a very brief description of the concept of decision trees and its qualitative uses, but there is much more to decision trees than that. Their main use is to think explicitly and quantitatively about decision options and uncertain outcomes. But this theory is beyond the scope of this tutorial.

EXAMPLES FROM GUGU ZUMA-NETSHIUKHWI

Yes

Yes

Yes

No

Yes

Yes

Select region: Ehler’s Climatic Zones

4616, 4614, 5714, 6714, 7714, 7725, 8815, 8825

Plant

Seek alternative livelihood

Advisory display for suitable options

Start

Is it?NN-NN, AN-NN,

AN-AN NN-AN, AN-BN

Is it?BN-NN, BN-AN AN-BN, BN-BN

Have you selected suitable options?

•short, medium or long cultivar, •early or late planting, •sequential planting,•high plant density•high fertiliser,•frequent weeding,•good top dressing,•variety of crops, etc.

Have you selected suitable options?

•drought tolerant crops•short to medium cultivars,•medium to low plant density• planting dates early•minimise fertilizer application, •control weeds frequently,

Are resources available?Total budget (seeds, seedlings, fertilizer, water, labourers,

land preparation, etc)Expertise (agricultural management practices)

Land (35ha, 50ha, 70ha or greater)Labour (number, experience)

Implements (Own, rental)What is the seasonal forecast?

Input variables used for look-up decision support table for south-western Free State farmers for decisions to plant or not, based on the seasonal forecast.

Yes

Yes

Yes

No

Yes

Yes

Is it? NN-NN, AN-NN, AN-AN NN-AN, AN-BN

Select region: Ehler’s Climatic Zones 4616, 4614, 5714, 6714, 7714, 7725, 8815, 8825

Plant Seek alternative livelihood

Advisory display for suitable options

Start

Is it?BN-NN, BN-AN AN-BN,

BN-BN

Have you selected suitable options?•short, medium or long cultivar, •early or late planting, sequential planting,•high plant density•high fertiliser, good top dressing,•frequent weeding,•variety of crops, etc.

Have you selected suitable options?•drought tolerant crops; short to medium cultivars,•medium to low plant density• planting dates early•minimise fertilizer application, •control weeds frequently,

Are resources available?Total budget (seeds, seedlings, fertilizer, water, labourers, land preparation, etc)

Expertise (agricultural management practices); Land (35ha, 50ha, 70ha or greater)Labour (number, experience); Implements (Own, rental)

What is the seasonal forecast?

No

Yes

Yes

Yes

Start Where are your co-ordinates?

Seek help from EO, ARC, UFS, etc

Outside M/R catchment

Search Eco-Crop2 database: In what ecological sub-region are you located?

Not here

4616, 4614, 5714, 6714, 7714, 7725, 8815, 8825 (Chapter 5)

e.g. 6714, 5714

Are the financial aspects in place?

Yes

Do cash flow to buy input, for land preparation, pay labour, fertilizer, insecticides, etc.

Have I got enough labour?

≥ 200 ha

Make arrangements for full time or seasonal labour

Contact EO, Land Affairs, Estate agents, other farmers to rent or headman for allocation

Contact local EO, ARC, UFS, Agricultural unions, etc for information

Seek for assistance from Commercial banks, Land bank or somewhere else to obtain loan

100 ha

50 ha

No

Back-yard

Do I know enough about farming in south-western Free State

How much land available for crop production?

Do I have land available for this season?

No

Yes

Yes

Yes

Check seasonal forecast go to Fig 8.2 or 8.4

Yes

Decision tree to ascertain if general conditions are in place prior engaging to field activities in Modder/Riet catchment.

No

Yes

Yes

Yes

Start Where are your co-ordinates? Seek help from EO, ARC, UFS, etc

Outside M/R catchment

Search Eco-Crop2 database: In what ecological sub-region are you located?

Not here

4616, 4614, 5714, 6714, 7714, 7725, 8815, 8825

e.g. 6714, 5714

Are the financial aspects in place?

Yes

Do cash flow to buy input, for land preparation, pay labour, fertilizer, insecticides, etc.

Have I got enough labour?

≥ 200 ha

Make arrangements for full time or seasonal labour

Contact EO, Land Affairs, Estate agents, other farmers to rent or headman for allocation

Contact local EO, ARC, UFS, Agricultural unions, etc for information

Seek for assistance from Commercial banks, Land bank or somewhere else to obtain loan

100 ha50 ha

No

Back-yard

Do I know enough about farming in south-western Free State

How much land available for crop production?

Do I have land available for this season?

No

Yes

Yes

Yes

Check seasonal forecast go to Fig 8.2 or 8.4

Yes

No

No

Yes

Yes

Yes

Start Where are your co-ordinates? Seek help from EO, ARC, UFS, etc

Outside M/R catchment

Search Eco-Crop2 database: In what ecological sub-region are you located?

Not here

e.g. 6714, 5714

Are the financial aspects in place?

Yes

Do cash flow to buy input, for land preparation, pay labour, fertilizer, insecticides, etc.

Have I got enough labour?

≥ 200 ha

Make arrangements for full time or seasonal labour

Contact EO, Land Affairs, Estate agents, other farmers to rent or headman for allocation

Contact local EO, ARC, UFS, Agricultural unions, etc for information

Seek for assistance from Commercial banks, Land bank or somewhere else to obtain loan

100 ha50 ha

No

Back-yard

Do I know enough about farming in south-western Free State

How much land available for crop production?

Do I have land available for this season?

No

Yes

Yes

Yes

Check seasonal forecast go to Fig 8.2 or 8.4

Yes

No

10) Choose interventions a/c to probabilities & soils & crop choices

Kies intervensies volgens waarskylikhede & gronde & gewas kiese

No

Yes

Have I got the latest seasonal forecast? Available from ARC-ISCW, SAWS, UFS, ADRM

What is the seasonal rainfall forecast for my specific location?

Above-normal rainfall Normal rainfall, see Fig 8.5 Below normal rainfall, see Fig 8.6

Above normal rainfall in 1st part of season OND

Above normal rainfall in 2nd part of season JFM (AN-AN)

•long growing maize cultivars, •Select alternative crops e.g. sunflower,•consider sequential planting,• increase planting density,• select variety of cultivar,• early weeding •try inter-cropping, •Good fertilization•good top dressing•sand, clay, loam soil,

Near Normal 2nd part of the season (AN-NN)

•medium to long cultivar•medium to high density•sequential planting•early weeding•top dressing when good rains forecasted

Below Normal 2nd part of the season (AN-BN)

•early planting•lower plant density•early maturing cultivar•for late planting select drought tolerant crops,•choose clay soil to hold water

Decision tree for general options for maize production under rainfed conditions in the south-western Free State when a normal to above-normal rainfall seasonal forecast is issued.

Yes

Select suitable crops for region (Chapter 6)What is the seasonal rainfall forecast for my specific location?

Normal rainfall produced for OND 1st partBelow normal rainfall

Near Normal 1st and 2nd part of season (NN-NN) Above-Normal 2nd part

of the season (NN-AN) Below-Normal 2nd part of the season (NN-BN)

•Select suitable crops, •consider sequential planting,•medium planting density,•medium to short cultivar,• early weeding •inter-cropping, •mulch•In-field water harvesting, etc

•early or late planting, •medium density,•good fertilization,•cropping systems,•weed frequently, •early maturing crops,

•early planting, •lower fertilization,•control weeds,•cropping systems,•weed frequently,•drought tolerant crops,•decrease plant population

Decision tree for general options for near-normal rainfall conditions.

Select suitable crops for region (Chapter 5)What is the seasonal rainfall forecast for my specific location?

Below Normal rainfall 1st part OND

Below Normal 1st and 2nd part of season (BN-BN)

Above-Normal 2nd part of the season (BN-AN)

Near-Normal 2nd part of the season (BN- NN)

•choose short season cultivars, •select drought resistant crops, •decrease planting density, •plant wide rows,•use IRWH,•minimise fertilizer application, •select planting dates matching rainfall onset,•top dress when receive rains,• minimise weeds during prolonged dry spells,• consider supplementary irrigation if possible, •check short-term forecast continuously, etc.

•Short cultivar crops,•Select drought resistant,•Late planting,•Follow short term forecast, etc.

•plant short cultivar,•wide row spaces ‘•late planting, •minimum tillage,•intercropping,•minimum fertilizer•control weeds, etc

Decision tree for general options for maize production under rainfed conditions in south-western Free State when a below-normal rainfall seasonal forecast is issued.

Plant Maize Legumes

Choose planting date

15-30 November 1-15 December 16 December- Early January

Long to medium cultivar

Medium to short cultivar

Normal & Above-normal rainfall

Short cultivar

Good fertilizer application

Good fertilizer application

Medium fertilizer application

Crop selection

Scenarios for decision-making under normal to above-normal seasonal forecast for maize production, to make planting dates with cultivar choice.

EXERCISE FOR TODAY: DRAW DECISION DIAGRAMMES

• A decision tree to decide on which field i will plant which crop?– Have 3 fields – wetland = clay soil; or mid-slope

= loam soil; top of plateau = sandy soil.– Want to choose between maize; potatoes;

sunflower?– Make decision diagramme to decide which crop

to plant where?

• A decision tree for implements – time & type – to plan request for rental – for field preparation & planting.

• Decision-making for maize production in the south-western Free State when a below-normal seasonal forecast is issued with two planting dates and short season cultivar.

OEFENING VIR VANDAG: TEKEN……..

• Besluitneemings diagram vir land distrubusie vir gewasproduksie.

• Besluitneemings diagram vir keuse van implemente – tyd & tipe vir grondbewerking & plant.

• Besluitneemings diagram vir mielieproduksie in SW-VS in onder-normaal seisonallevoorspelling – met 2 plantdatuums en kortgroei kultivar.

OTHER CASES STUDIES FROM WEB

• Seed distribution in East Africa   Fine tuning crop seed distribution based on expected seasonal rainfall  

• Orange County Sanitation District Response to El Niño forecast

   How Orange County California used a seasonal forecast in wastewater planning during the 1997-98 El Niño 

• Hydro-Management on Lake Chicamba in Mozambique   Improving multi-use reservoir management with forecasts

IRI WEB TUTORIALS

• Finding information on the IRI web site • a) Temperature and Precipitation Climatologies

b) Temperature and Precipitation Seasonal Forecastsc) Drought Monitoring Informationd) Temperature and Precipitation Time Series

CONCEPT TUTORIALS Decision Trees • http://ccnmtl.columbia.edu/projects/iri/responding/tutorial.html

SELF STUDY FOR PRACTICAL

IRI-ENSO-Quick Look

http://iri.columbia.edu/climate/ENSO/currentinfo/QuickLook.html

3-Month Seasonal Rainfall - SAWS

http://www.weathersa.co.za/Menus/WXandClimate.jsp

IRI - tutorialhttp://ccnmtl.columbia.edu/projects/iri/responding/tutorial.html• International Research Institute for Climate and Society

• 3-month outlook Africa = http://iri.columbia.edu/climate/forecast/net_asmt/index.html#February_2006

SEASONAL CLIMATE FORECASTS BASED ON ENSO

The More Realistic Picture