An Overview of CERES–Sorghum as Implemented in the Cropping System Model Version 4.5

Abstract

Sorghum [Sorghum bicolor (L.) Moench] is the fi ft h most important grain crop globally. It stands out for its diversity of plant types, end-uses, and roles in cropping systems. Th is diversity presents opportunities but also complicates evaluation of production options, especially under climate uncertainty. Ecophysiological models can dissect interacting eff ects of plant genotypes, crop management, and environment. We describe the sorghum module of the Cropping System Model (CSM) as implemented in the Decision Support System for Agrotechnology Transfer (DSSAT) to illustrate potential applications and suggest areas for model improvement. Crop growth is simulated based on radiation use effi ciency. Development responds to temperature and photoperiod. Partitioning rules vary with growth stages, respecting mass balance and maintaining functional equilibrium between roots and shoots. Routines for climate, soil, crop management, and model controls are shared with other crops in CSM. Modeled responses for eight real-world and hypothetical cases are presented. Th ese include growth under well-managed conditions, responses to row-spacing, population, sowing date, irrigation, defoliation, and increased atmospheric carbon dioxide concentration ([CO 2 ]), and a long-term sorghum and winter wheat (Triticum aestivum L.) rotation. Among traits and experiments considered, model accuracy was high for phenology (r 2 = 0.96, P < 0.01 for anthesis and r 2 = 0.91, P < 0.01 for maturity), moderate for grain yields (r 2 values from 0.30 to 0.52, P < 0.01), depending on the simulated experiments, and low for unit grain weight (r 2 = 0.02, not signifi cant, NS) and leaf area index for forage sorghum (r 2 = 0.18, NS). V alued for its heat and drought tolerance, sorghum is the fi ft h most important grain crop globally aft er wheat, rice (Oryza sativa L.), maize (Zea mays L.), and barley (Hordeum vulgare L.) (FAOSTAT, 2015). Among cereal crops, sorghum stands out for its diversity of plant types, cropping systems, growing environment, and end-uses (Dahlberg et al., 2011). Sorghum is variously grown to provide grain, forage, sugar, and bioenergy feedstocks, and crop architecture and other traits vary accordingly. While this diversity presents opportunities, it complicates attempts to assess potential impacts of innovations, especially as aff ected by climate uncertainty.Th e CSM (Jones et al., 2003) as implemented in the DSSAT has submodels that allow simulation of more than 25 crop species, including sorghum (Hoogenboom et al., 2011). Th e sorghum submodule uses shared routines for model control (including input and output), soil physical and chemical processes, evapotranspiration, and all aspects of crop management including tillage, planting, fertilization, irrigation, mulching, and other practices. Eight subroutines describe sorghum-specifi c crop processes. Th e shared routines simplify model improvement and simulating cropping sequences and rotations with diff erent crops and management practices. While based on the widelyused Crop ...

Simulation of climate change impacts on grain sorghum production grown under free air CO2 enrichment

“…The effects of elevated CO 2 on RUE are modeled empirically using curvilinear multipliers based on a lookup function to fit crop responses to CO 2 concentration. The potential daily biomass production per plant, PCARB, is calculated using the following equation (White et al, 2015):…”

“…The CERES-Sorghum model was enhanced to simulate the effect of elevated CO 2 on the potential evapotranspiration by increasing stomatal resistances in the Penman-Monteith equation (Acock and Allen, 1985;Allen et al, 1987). More detailed information about the CERES-Sorghum model has been described previously (White et al, 2015).…”

Optimizing Dryland Crop Management to Regional Climate. Part II: U.S. Southern High Plains Grain Sorghum Production

“…The CERES-Sorghum Model CERES-Sorghum (Alagarswamy and Ritchie, 1991;White et al, 2015) is the sorghum growth module of the Decision Support System for Agrotechnology Transfer cropping system model (DSSAT-CSM) (Jones et al, 2003;Hoogenboom et al, 2017). As described in greater detail in Jones et al (2003), the DSSAT-CSM is an integrated collection of software components that includes a main program, management module, soil module, weather module, and a soil-plant-atmosphere module.…”

“…Each crop growth module requires environmental data, genetic and ecotype parameters, and crop management parameters as inputs. A more complete description of the CERES-Sorghum growth module, and its ability to reproduce sorghum phenology, yield variation, and management effects found in field studies can be found in White et al (2015).…”

A Crop Simulation Model for Tef (Eragrostis tef (Zucc.) Trotter)

“…Though there were no radiation use efficiency (RUE) data available for tef, it was assumed that, as a C4 crop, tef would have a higher RUE than wheat. Models for the C4 crops maize, millet, and sorghum all have higher aboveground RUE values than wheat models [20,[44][45][46]. In order to calculate the DSSAT-Tef aboveground RUE, the percent difference between the DSSAT-CERES-Wheat and DSSAT-Sorghum aboveground RUE was used to estimate the ratio RUE ratio between wheat and a C4 crop.…”