Effect of Clay Amendment and Strategic Deep Tillage on Soil Water Dynamics and Plant Growth Under Controlled Environments.

Abstract

Strategic deep tillage (SDT) practices, such as soil mixing following the application of soil amendments, are promising approaches to alleviate topsoil water repellence and other subsoil constraints and improve crop productivity. However, there is a lack of knowledge on the effect of SDT on soil water dynamics, especially under water-limited environments. This study evaluates the effects of clay incorporation, soil inversion and deep soil mixing on soil water infiltration, surface evaporation rates, soil water storage and subsequent impacts on the below and aboveground growth of wheat (Triticum aestivum L. var Scepter) in controlled environments. Results show that soil mixing significantly improved water infiltration compared to an untreated control. Clay incorporation exhibited the highest bare soil surface evaporation rates immediately and two years post-tillage, leading to substantial water losses under warm and dry ambient conditions. Despite improving soil water storage in deeper layers, high evaporation rates in clay-incorporated soils negatively impacted wheat growth, with reduced shoot biomass and root length density. Conversely, soil inversion and mixing-only treatments demonstrated balanced improvements in water infiltration, soil water use, and wheat shoot biomass. These findings underscore the trade-offs associated with SDT practices, particularly in managing soil water loss and crop productivity in water-limited environments. This study also highlights the need for the careful selection of SDT for soil amelioration strategies tailored to soil types and climatic conditions to enhance agricultural productivity and sustainability.