Modification of the CERES grain sorghum model to simulate optimum sweet sorghum rooting depth for rainfed production on coarse textured soils in a sub-tropical environment

Jose R. Lopez, John E. Erickson, Senthold Asseng and Edmundo Lopez Bobeda

Agricultural Water Management, 2017, vol. 181, issue C, 47-55

Abstract: There is potential to reduce irrigation water requirements in bioenergy feedstock cropping systems by breeding for deep rooted sweet sorghum cultivars that intercept more rainfall water. Such cultivars would require little or no irrigation in some environments. Consequently, the objective of this study was to quantify the potential benefit of deeper rooted sweet sorghum cultivars by simulating a range of root depth and planting date scenarios in the subtropical climate of the southeastern USA by modifying the CERES grain sorghum cropping system model for sweet sorghum. A two year field study was conducted to collect data for model development. The new sweet sorghum model was validated against independent studies from six different locations around the world. The root mean squared error of prediction of the model was 4.7% for days to maturity (6 days), 21% for total biomass weight, and 22.6% for stem dry weight. We then simulated sweet sorghum growth and yield for nineteen hypothetical rooting depths between 30 and 210cm. Based on model simulations, including uncertainty analysis associated with model parameters, the optimal root depth for our environment in the southeastern USA under rainfed conditions, was between 110 and 140cm to maximize final biomass yield. The simulated hypothetical 120cm root depth sweet sorghum had final biomass yields up to 48.2% higher than the simulated widely grown cultivar ‘M81 E’ in rainfed systems and would require up to 32% less irrigation to meet actual evapotranspiration demand. These results highlight the importance of breeding for deeper rooted sweet sorghum cultivars along with optimized sowing dates for higher biomass yields. However, model simulations also indicated that, even with optimal rooting depth and density, irrigation would be needed to maximize final biomass yields.

Keywords: Water; CERES; Modeling; Root length density; Irrigation; Rainfed (search for similar items in EconPapers)
Date: 2017
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378377416304747
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:181:y:2017:i:c:p:47-55

DOI: 10.1016/j.agwat.2016.11.023

Access Statistics for this article

Agricultural Water Management is currently edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Bibliographic data for series maintained by Catherine Liu ().