Update of I&D No 33 Procedures for Yield Response to Water

Findings

The procedures as presented in I&D No 33 have found an extensive group of users in a wide range applications. Although several crop growth models have been developed that would allow a more sophisticated assessment of the effect of reduced water supply on yield, the group of experts reached unanimous consensus that I&D 33 procedures provide a proven and still highly relevant tool to be used in many practical applications at field, farm, scheme, regional and national level. Advances in research and the extensive data available worldwide would make however an update of the parameters and procedures now opportune, for which following objectives and activities are proposed:

Objectives

• review and update procedures introduced in FAO Irrigation and Drainage Paper No 33 methods, including the update of relevant crop parameters: Ky factor, p-factor, length growth stages;
• To review and update relevant crop information on crop water relationships and the impact of stress on sensitive stages on yield and yield quality and differences among various gentypes.

Actions:

1. define procedures for processing of data and calibration of the parameters and sensitivity analysis including the minimum data to be made available for an review of the crop parameters
2. testing of procedures at the hand of set of data and consultation with core group on procedures;
3. identification of research groups and compilation of appropriate data sets
4. review of data on reliability and minimum data
5. processing of data in uniform procedures with the help of various research groups
6. Analysis and synthesis of results into FAO publication

Development Dynamic CWP Model

Findings

The presentations of the experts demonstrated that research in crop water productivity would seem sufficiently advanced to allow the development of consolidated procedures for a certain number of crops (cereals, legumes, oil crops) in a simple dynamic CWP model that would allow direct estimates of yields under various level of water supply with assumptions on biomass production, harvest index and fertility level. To further elaborate the following objectives and activities are proposed to enhance such model:

Objectives

• development of simple dynamic model to estimate yield under deficient water supply based on biomass water productivity with appropriate procedures to estimate harvest index, the impact of fertility, genotype and eco-system.

Actions:

• consolidation of basic growth and water plant relationships in a number of basic algorithms and proposal of simple model
• review of the algorithms and model by small group of core experts
• testing of model performance on standard data sets
• comparison with Stewart/FAO33 concept
• processing of wider data set and various applications
• synthesis of results in FAO pubication

Development of Relevant Applications

Findings

During the expert meeting, a number of pertinent applications and models were presented showing the relevance of crop water productivity in a range of studies in rainfed and irrigated crop production at field and farm level, but also at scheme, basin and national level. In particular in decision making and optimization of inputs, it was demonstrated that economic and environmental parameters play a decisive role in the practical use of crop water productivity for which simple but solid procedures such as developed in I&D No 33 are highly relevant. In order to highlight the importance of developing reliable information and procedures in crop water productivity it was recommended to classify the various applications and to demonstrate the use of CWP functions in decision making and optimization applications under water scarcity.

Objectives

• to define the relevant CWP information to be generated to allow meaningful applications at field, farm, scheme, basin and national level, including;

• Field Level :for application in supplemental and irrigation scheduling etc.
• Scheme level: to develop yield relevant irrigation water allocation models under conditions of varying water supply
• River Basin: to develop relevant water allocations models at river basin scale and regional water development planning
• National Level: applications in food security strategies to face droughts

• To assess complexity of introducing additional parameters in various applications and models related to

• economic and financial parameters in various applications,
• environmental applications and parameters
• spatial scale (horizontal variability) in various applications

Actions:

• collection and compilation of specific applications and models developed by different groups of users and planners for varying water supply conditions and scarcity scenarios in both rainfed and irrigated agriculture.
• review of the objectives and procedures and input output requirements
• categorization of the different applications according scale, objectives, target group and complexity;
• assess and define relevant field and pilot applications to be tested;
• compilation of relevant field data and testing of various CWP models;
• selection of typical applications and models that highlight the importance of reliable and robust CWP information.

Review Crop Growth Models

Findings

In the expert meeting adequate reference was given to an extensive range of crop growth models developed over the last twenty years, that in different degrees allow an estimate of crop production under limited water supply. Most models have been developed by research groups and require often rigorous calibration to be applied meaningfully elsewhere. In order to provide the framework for the use of the I&D No 33 procedures there is a need to compare the applications and underlying principles for those models that are widely used. The following procedures and actions are proposed for that purpose:

Objectives

• to assess validity of FAO recommended procedures towards the more advanced and sophisticated modelling approaches
• to recommend on the use of the models tested

Actions:

• identification and selection common schools of crop growth models

• CERES (Cordoba)
• CROPSYST
• WOFOST - SUCROS - SWATRE (Wageningen)
• APSIM (Australia)

• review of procedures, data input, calibration and applications
• assessment of relevance vis à vis FAO Procedures
• formulate recommendations on the use of such models.

Networking

Findings

To enhance further activities in the above identified activities, there is a need to consult and closely work together with a large group of experts, who have relevant data and can assist in the compilation and processing of the research data. Moreover a feedback is required from different groups of users on the relevance of the models and outputs to be provided with available data. Present IT technologies would favour the use of a web based platform to promote the exchange of experiences.:

Objectives:

• To develop a network of research groups to assist in the providing relevant information on CWP and the development and validations of procedures to predict crop yields under deficient water supply
• To provide a platform of information exchange among various users of CWP information and applications

Actions:

• identification of key persons and institutes to contribute to the knowledge base on crop water relationships in particular in relation to :

• provide information on various aspects of CWP for major crops
• make available relevant research data
• assist in the processing of CWP research data according standardized procedures

• identification of key groups of users involved in various CWP applications:

• compile relevant applications from different groups of users
• promote information exchange on crop yield relations and on procedures for the use different application under water scarcity

• establishment of Website in which relevant key information on crop water relationships is compiled providing platform for information exchange and update of information

CWP Project Development and Cooperation

Findings

In order to ensure the implementation of the project programme there is a need to integrate project activities within the wider framework of the global action programmes on water in the wake of the World Water Forum and more particularly in the framework of the IWMI led iniative of the Comprehensive Assessment and the CGIAR priority programme on Water.

Considerable support and inputs from a large number of experts is essential to achieve the objectives of the different activities outlined above. Furthermore considerable resources are required to develop the knowledge base in crop water productivity and the practical guidelines at farm and scheme level to optimise water productivity and food security under deficient water supply, as outlined in the background paper prepared for the expert meeting. Additional resources are therefore required to further enhance the project to tangible outputs. The following activities are proposed to identify additional resources for the expansion of the project.

Objectives

• to ensure the integration within the Global water programme and CGIAR priority programme;
• to identify appropriate resources to implement and expand the CWP project

Actions:

• elaboration of the different project components with specification of activities and resources;
• define FAO resources, support and resources;
• to identify suitable sponsors for specific project component;