Extreme rainfall shifts the drivers of Zea mays yield across a tillage-intensity gradient

Jacob R. Hopkins and Alison E. Bennett. Applied Soil Ecology, Volume 216, December 2025, 106566. DOI: 10.1016/j.apsoil.2025.106566

Abstract

Tillage effects on soils vary in their intensity of disturbance within a soil system. There are clear trade-offs between tillage methods, thus farmers must navigate a complex balance between the appropriate level of disturbance to produce soil conditions that facilitate plant growth while minimizing the long-term loss of soil related ecosystem services and effects of drought and extreme rainfall. This balance is exemplified in agricultural systems of the Midwestern US where climate models predict increases in intermittent drought and extreme rainfall events. Here we tested how tillage effects on soil abiotic and biotic characteristics influenced the yield of Zea mays under high rainfall conditions. We found that as tillage intensity increased the relative yield benefits provided by soil abiotic vs. biotic characteristics increased. Specifically, lower intensity tillage methods like no-till (yield: 11.3 Mg/ha) and chisel till (yield: 12.5 Mg/ha) favored bacterial, fungal, and AM fungal taxa that were more beneficial to yield, while moldboard plowing (yield: 12.2 Mg/ha) benefited yield through increases to soil packed bulk density. While decreasing tillage intensity promoted positive effects of soil nutrient retention and soil microbes on yield, the lower soil packed bulk density in no-till plots reduced yield due to poor drainage (10 % yield decrease). Thus, there are complex interactions between tillage, climate, and soils that influence yield, and intermediate intensity tillage methods like chisel till may provide a useful balance between no-till and moldboard plowing with changing precipitation regimes.