Response of forage production to drought in silvopastoral systems in Argentina

Abstract

Considering the increment of agricultural and ecological droughts frequency and 19 intensity by climate change, this study aimed to assess the response of annual forage dry matter 20 production (AFP) to drought in 22 sites across Argentina?s silvopastoral systems (SPS) in native 21 forests and forest plantations and compare it to grasslands and treeless pastures. The AFP was 22 evaluated using a one-way ANOVA with a factorial design, considering the productive system 23 (SPS and grassland/treeless pasture) and hydrological condition year (normal and dry) as 24 factors. Mean AFP ranged from 195 kg DM ha-1 yr-1 to 18520 DM ha-1 yr-1. The results showed 25 that AFP varied according to aridity categories, drought intensity, and forage type (grassland 26 and pastures). Under drought intensity ≤35% (normal year), SPS showed higher AFP than 27 grassland/pastures, while severe drought intensities > 35% (dry year) resulted in the opposite 28 response. The relative response (RR) of AFP in SPSs, compared to grasslands/pastures ranged 29 from -225% to +100%, depending on the site and drought intensity. Principal component 30 analysis of the RR in dry years revealed that SPS in semi-arid and semi-humid sites had lower 31 soil carbon and nitrogen concentrations, fewer forage species, and higher AFP values in dry 32 years. Understanding the effect of trees in SSPs during drought events is crucial for enhancing 33 the resilience of livestock production systems to climate change.