Soil moisture and quality effects of tillage on South Texas Victoria clay

No-tillage is increasingly recommended as a practice supporting sustainable agriculture. The intention of this study was to find the mechanism behind yield improvements under no tillage that had been recorded in an on-going experiment of no-tillage versus conventional tillage on Victoria (fine, smectitic, hyperthermic Sodic Haplusterts) clay in South Texas. It was hypothesized that yield increases under no-tillage occurred due to improvements of soil quality or moisture relative to conventional tillage. A neutron probe was used to measure soil water content. Soil quality was quantified using the Cornell soil health assessment. Inconsistent results were obtained regarding soil moisture. Soil quality was not improved under no-tillage. The work described here took place during years of unusually wet or average rainfall, in contrast, to preceding years which were relatively dry (and were the years in which yield increases under no tillage were recorded). Because soil quality was not seen to increase with no-tillage, it was hypothesized that no-tillage only brings about soil moisture increases during dry years. It is recommended that monitoring activities continue so that the effect of tillage on soil moisture during dry years is captured