Adapting the Cropgro Model to Simulate Growth, Development, and Yield of Bambara Groundnut (Vigna Subterranea L. Verdc), an Underutilized Crop

Abstract

Abstract The technology development in past few decades in terms of breeding and agronomy, major crops; wheat, rice, and maize are under pressure from climate change and threats of marginal soil nutrients in degraded agricultural lands. Underutilized crops are identified as resilient to local environments that can cope with climatic variations.  Bambara groundnut, an African legume that is grown with low input subsistence farming systems in sub–Saharan Africa and Asia has been identified as a potential future crop under climate change. Improving its productivity and suitability under future climates and future locations, requires comprehensive analysis of growth and development of Bambara groundnut under different growing conditions. Process- based crop simulation models facilitate the evaluation of management options for variable growing environments and soil conditions. Therefore, the current study was aimed to evaluate growth and development of Bambara groundnut and to adapt the generic legume model CROPGRO for explaining crop response to management and environment. The parameters used for modelling growth and development of peanut (Arachis hypogea) served as the initial reference values for adapting CROPGRO model. Crop information from the published sources were applied to the functions and parameters of the model. Crop phenology, canopy development, growth and yield were calibrated for two contrasting Bambara groundnut landraces using experimental data from controlled-environment experiments conducted in 2003 and 2006 at Tropical Crops Research Unit (TCRU), Sutton Bonington Campus, University of Nottingham, UK. The cardinal base temperatures for leaf photosynthesis of Bambara groundnut had to be set higher than those for peanut, in order to simulate the reduced growth observed during relatively low temperatures The value for the specific leaf weight (SLWREF) at which light-saturated leaf photosynthesis is defined, was increased from 0.0043 to 0.0063 g cm-2 to reduce the productivity of Bambara groundnut compared to peanut.  The new model will be incorporated in the DSSAT version 4.8 software and will provide capability for assessing management practices in matching environments and suggesting potential regions for future expansion of Bambara groundnut cultivation into resilient cropping systems. Highlights• Bambara groundnut as an underutilized crop can provide resilience in cropping systems• There is insufficient research for underutilized crops• The generic grain legume model CROPGRO was adapted for Bambara groundnut• The new CSM-CROPGRO-Bambara groundnut has been integrated in DSSAT version 4.8• The new model provides opportunities to evaluate the potential for underutilized crops

Keywords: temperature response, landraces, simulation modelling, DSSAT