Evaluation of DSSAT model to predict sorghum yields under Conservation Agriculture in the Pandamatenga vertisols of Northern Botswana

Abstract

This study was conducted at Pandamatenga of Chobe District in northern Botswana. The main aim of the study was to evaluate the Decision Support System for Agrotechnology Transfer (DSSAT) model in the prediction of sorghum yields under Conservation Agriculture (CA) technologies. A field experiment was conducted at the Pandamatenga Agricultural Research station during the 2015-2017 growing seasons. A randomized complete block design was used for the on-station field experimentation. The design had trial plots with four treatments, namely No Tillage (NT), No Tillage + Mulch (NT+M), Minimum Tillage (MT), and Broad Bed and Furrow (BBF), with four replicates rotated between sorghum cowpea. Sorghum grain yield results were analyzed using the Statistical Analysis Software (SAS version 9.2). Analysis of variance and means were separated using Duncan’s multiple range test at 5% confidence level. The DSSAT model was evaluated using the experimental data and weather data for the growing periods. The model was further used to test these CA technologies in terms of sorghum grain yield in the future. The DSSAT crop model provided reasonable predictions of sorghum grain yield under NT, MT, NT+M, and BBF on vertisols of Pandamatenga. The model furthermore predicted that sustained NT+M practice by smallholder rainfed farmers in Pandamatenga would increase sorghum grain yield production in the future.