Research was carried out at the farm level to assess plant water status differences between conventionally tilled and reduced-tilled cotton. Also, two non-destructive reflectance/transmittance instruments were evaluated for their correlation potential with plant water stress. In 1998, six farmer co-operators established both conventional and reduced tillage cotton in companion commercial fields in south Texas. Irrigation was used by one-half of the co-operators. Three sub-sampling areas within each tillage system were established for thermocouple and access tube placement. Fields were visited the weeks of 8 June and 29 June. Leaves of plants within the sub-sampling area were evaluated by porometry, non-destructive light measurement, and then sampled leaves/plants were returned to the lab for psychrometric and gravimetric measurements. Edaphic measurements were made at the time of sampling. Results indicate that plant water stress is reduced by both irrigation and reduced tillage. Porometric measurements consisting of leaf transpiration, stomatal conductance, diffusive resistance and leaf temperature, and leaf water potential (LWP) were correlated with light reflectance 'L' values determined non-destructively with a Minolta CR-200. Leaf relative water content was correlated with leaf greenness, 'a' values, and hue (color saturation) but not with leaf porometric values. Non-destructive Minolta SPAD readings were weakly correlated with LWP and plant canopy temperature. Irrigated plants had improved water content, leaf number and area, and yield. Crop leaf area index was greater in no-till compared to conventionally tilled cotton, but mean lint yields were statistically similar (422 vs. 348 kg/ha, respectively). Soil moisture at 25 cm was slightly higher (P<0.14) and mid-day surface soil temperature lower in no-till fields when compared to conventionally tilled fields.