Assessing the Spatial Distribution of Crop Production Using a Cross-Entropy Method

Assessing the Spatial Distribution of Crop Production Using a Cross-Entropy Method
Author: Liangzhi You and Stanley Wood
Publisher: Intl Food Policy Res Inst
Total Pages: 48
Release: 2012
Genre: Social Science
ISBN:

While agricultural production statistics are reported on a geopolitical - often national - basis we often need to know the status of production or productivity within specific sub-regions, watersheds, or agro-ecological zones. Such re-aggregations are typically made using expert judgments or simple area-weighting rules. We describe a new, entropy-based approach to making spatially disaggregated assessments of the distribution of crop production. Using this approach tabular crop production statistics are blended judiciously with an array of other secondary data to assess the production of specific crops within individual "pixels" - typically 25 to 100 square kilometers in size. The information utilized includes crop production statistics, farming system characteristics, satellite-derived land cover data, biophysical crop suitability assessments, and population density. An application is presented in which Brazilian state level production statistics are used to generate pixel level crop production data for eight crops. To validate the spatial allocation we aggregated the pixel estimates to obtain synthetic estimates of municipio level production in Brazil, and compared those estimates with actual municipio statistics. The approach produced extremely promising results. We then examined the robustness of these results compared to short-cut approaches to spatializing crop production statistics and showed that, while computationally intensive, the cross-entropy method does provide more reliable estimates of crop production patterns.

Land Quality, Agricultural Productivity, and Food Security

Land Quality, Agricultural Productivity, and Food Security
Author: Keith Daniel Wiebe
Publisher: Edward Elgar Publishing
Total Pages: 478
Release: 2003-01-01
Genre: Technology & Engineering
ISBN: 9781781956977

'Action is needed to fight poverty by sustaining the environment and the use of natural resources. Land Quality, Agricultural Productivity, and Food Security explores a range of factors driving food security. The book offers an assessment to link quality of the available land resources with productivity of land and the ability to ensure food security. It offers a mixture of broad-scale assessments across the globe, with detailed case studies, deepening our understanding of economics and decision-making mechanisms. It is recommended to researchers, as well as actors in the private and public domain, who are keen to improve their understanding of the appropriate actions that ensure food security in the decade to come.' - Floor Brouwer, Agricultural Economics Research Institute (LEI), The Hague, The Netherlands Land quality and land degradation affect agricultural productivity and food security, but quantifying these relationships has been difficult. Data are extremely limited and outcomes are sensitive to the choices that farmers make. The contributors to this book - including soil scientists, geographers, and economists - analyse data on soils, climate, land cover, agricultural inputs and outputs, and a variety of socio-economic factors to provide new insights into three key issues: * the extent to which differences in land quality generate differences in agricultural productivity across countries * how farmers' responses to differences or changes in land quality are influenced by economic, environmental, and institutional factors, and * whether land degradation over time threatens productivity growth and food security at local, regional, and global levels.