Elsevier

Field Crops Research

Volume 143, 1 March 2013, Pages 44-55
Field Crops Research

Use of agro-climatic zones to upscale simulated crop yield potential

https://doi.org/10.1016/j.fcr.2012.11.023Get rights and content
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Abstract

Yield gap analysis, which evaluates magnitude and variability of difference between crop yield potential (Yp) or water limited yield potential (Yw) and actual farm yields, provides a measure of untapped food production capacity. Reliable location-specific estimates of yield gaps, either derived from research plots or simulation models, are available only for a limited number of locations and crops due to cost and time required for field studies or for obtaining data on long-term weather, crop rotations and management practices, and soil properties. Given these constraints, we compare global agro-climatic zonation schemes for suitability to up-scale location-specific estimates of Yp and Yw, which are the basis for estimating yield gaps at regional, national, and global scales. Six global climate zonation schemes were evaluated for climatic homogeneity within delineated climate zones (CZs) and coverage of crop area. An efficient CZ scheme should strike an effective balance between zone size and number of zones required to cover a large portion of harvested area of major food crops. Climate heterogeneity was very large in CZ schemes with less than 100 zones. Of the other four schemes, the Global Yield Gap Atlas Extrapolation Domain (GYGA-ED) approach, based on a matrix of three categorical variables (growing degree days, aridity index, temperature seasonality) to delineate CZs for harvested area of all major food crops, achieved reasonable balance between number of CZs to cover 80% of global crop area and climate homogeneity within zones. While CZ schemes derived from two climate-related categorical variables require a similar number of zones to cover 80% of crop area, within-zone heterogeneity is substantially greater than for the GYGA-ED for most weather variables that are sensitive drivers of crop production. Some CZ schemes are crop-specific, which limits utility for up-scaling location-specific evaluation of yield gaps in regions with crop rotations rather than single crop species.

Highlights

► Six agro-climate zone schemes used in yield gap and crop production analyses were reviewed and compared. ► Within-zone climate heterogeneity was analyzed for each scheme. ► Number of zones required to adequately cover the harvested area of a target crop was calculated for each scheme. ► The Global Yield Gap Atlas Extrapolation Domain seems to be the best currently available scheme for interpolation of point-based simulated yield potential.

Keywords

Agroecological zone
Climate zone
Yield potential
Water-limited yield
Yield gap
Extrapolation domain
Global food security

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