Tillage and residue management effects on irrigated maize performance and water cycling in a semiarid cropping system of Eastern Colorado

Abstract

Residue removal from maize (Zea mays) fields offers an opportunity to increase farmer profits, but potential tradeoffs for water dynamics and crop performance merit further evaluation. This study, established in 2014, compared the effects of two tillage practices (no-till and conventional) and two residue management practices (harvested vs. kept in place) on maize grain yields, water infiltration, evapotranspiration, and soil physical attributes. On average, maize grain yields under limited irrigation increased with residue retention by 1.1 Mg ha−1 year−1 between 2016 and 2018, but tillage had no significant effect. Total infiltration (over 30 min) was higher with residue retention. Neither tillage nor residue management had a significant impact on evapotranspiration during the vegetative growth stage. However, there was a significant residue by tillage interaction where vegetative evapotranspiration was reduced by no-till and residue retention. Conversely, penetrometer resistance was significantly reduced by both tillage and residue retention. Volumetric water content in the soil profile at planting was higher with residue retention. These results suggest that plots with residue removal would on average require 60 mm year−1 of additional irrigation to attain the same yields as fields with residue retention. In summary, our findings suggest that high rates of crop residue removal under limited irrigation in a semiarid environment can negatively affect water conservation and yields, and that tradeoffs surrounding residue export need to be fully considered in land management and policy decisions.