How does tillage intensity affect chemical soil health indicators? A United States meta‐analysis

Abstract

AbstractTillage intensity can affect chemical soil health indicators either positively or negatively depending on inherent soil properties and management practices. Soil chemical data (total N, P, K, Ca, Mg, and pH) from four depth increments within 196 published studies were compiled and subjected to a meta‐analysis comparing chisel plow (CP), no‐till (NT), and perennial systems (PER) with moldboard plowing (MP). Overall, CP did not affect soil chemical indicators when compared to MP, but converting from MP to NT increased total N, P, and K concentrations within the top 15 cm. Below that depth, Ca and Mg concentrations were lower under NT than MP but total N, P, and K were not significantly different. Topsoil total N response to NT was moderated by soil order and cropping system, with the largest increase in total N found in Ultisols, Inceptisols, Alfisols, and Mollisols under more diversified cropping systems including those with cover crops. The greatest topsoil P increase in response to NT was found under long‐term experiments (>5‐yr) and on fine‐textured soils. Phosphorus changes in studies on coarse‐textured soils, with short‐term duration, and manure applications were generally neutral. Perennial systems had lower soil P and K but higher total N content in the surface layer as compared to MP. The positive response to PER systems was most notable in Alfisols, Mollisols, and Ultisols and under long‐term PER management. Finally, we demonstrate that these chemical indicators respond to tillage and cropping systems over a wide range of conditions, showing utility for soil health assessment.