Article Plot-Scale Agroforestry Modeling Explores Tree Pruning and Fertilizer Interactions for Maize Production in a Faidherbia Parkland Aynalem M. Dilla 1,2, Philip J. Smethurst 3,*, Neil I. Huth 4 and Karen M. Barry 2 1 Center for Environmental Science, College of Natural and Computational Sciences, Addis Ababa University, Addis Ababa 1000, Ethiopia;
[email protected] 2 Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 98, Hobart, TAS 7001, Australia;
[email protected] 3 Commonwealth Scientific and Industrial Research Organization, Private Bag 12, Hobart, TAS 7001, Australia 4 Commonwealth Scientific and Industrial Research Organization, 203 Tor St, Toowoomba, QLD 4350, Australia;
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[email protected] Received: 16 September 2020; Accepted: 3 November 2020; Published: 4 November 2020 Abstract: Poor agricultural productivity has led to food shortages for smallholder farmers in Ethiopia. Agroforestry may improve food security by increasing soil fertility, crop production, and livelihoods. Agroforestry simulation models can be useful for predicting the effects of tree management on crop growth when designing modifications to these systems. The Agricultural Production Systems sIMulator (APSIM) agroforestry tree-proxy model was used to simulate the response of maize yield to N fertilizer applications and tree pruning practices in the parkland agroforestry system in the Central Rift Valley, Ethiopia. The model was parameterized and tested using data collected from an experiment conducted under trees and in crop-only plots during the 2015 and 2016 growing seasons. The treatments contained three levels of tree pruning (100% pruned, 50% pruned, and unpruned) as 1 the main plots, and N fertilizers were applied to maize at two rates (9 or 78 kg N ha− ) as sub-plots.