Water deficit effects on sweet corn. II. Canopy development

Abstract

The response of sweet corn canopy development to timing and severity of water deficit was determined in an experiment using a mobile rainshelter. Six irrigation treatments were applied such that plots experienced: (1) no water deficit; (2) full water deficit; (3) moderate pre-silking deficit; (4) severe pre-silking deficit; (5) moderate post-silking deficit; or (6) severe post-silking deficit. Soil moisture content profiles were measured using neutron moisture probes and water deficit was quantified using the concept of ‘potential soil moisture deficit’ (Dp), which was calculated from climatic data. Water deficit reduced leaf area, and the effect varied depending on its timing and severity. Early water deficit reduced the rate of leaf expansion (but not duration of expansion) and, consequently, the maximum area of individual leaves; it therefore reduced the maximum leaf area index (LAI). Moderate post-silking water deficit did not significantly reduce maximum LAI, but it hastened leaf senescence. Severe water deficit late in crop growth reduced canopy development by decreasing maximum LAI and advancing leaf senescence. A model was developed which accounted for these effects. Two measures of Dp were defined which related to both short-term transient responses and those integrated over longer times. The model made it possible to simply and mechanistically describe the effects of water deficit on canopy development.

Effects of increased soil water availability on grassland ecosystem carbon dioxide fluxes

“…Ellipses denote significant treatment effects on ecosystem CO 2 fluxes in a specific month, based on paired t-tests (a = 0.1) experiments (Mamolos et al 2001;Yang et al 2001). Irrigation-delayed senescence also was found in a field experiment with corn in New Zealand (Stone et al 2001). Higher R soil at the irrigated plots in September might have been caused by greater root and soil microbial respiration.…”

Physiological Responses of Selected Vegetable Crop Species to Water Stress

“…The leaf photosynthetic activity of plants can be monitored with measurement of chlorophyll content using a portable chlorophyll meter and chlorophyll fluorescence while the measurement of stomatal conductance indicates the severity of water stress [2,3,14]. Spectral vegetation indices such as the green normalized vegetation index (GNDVI) and the normalized differential vegetation index (NDVI) were used for monitoring the growth of the plant to detect the water stress and for yield prediction [36][37][38][39]. Crop water stress index is determined by an infrared thermometry technique to indicate the change in canopy temperature of plants under water stress conditions.…”

“…The essential defence mechanism against drought operating in the plants is the maintenance of the water status and the reduction of tissue water loss ( Figure 1). (GNDVI) and the normalized differential vegetation index (NDVI) were used for monitoring the growth of the plant to detect the water stress and for yield prediction [36][37][38][39]. Crop water stress index is determined by an infrared thermometry technique to indicate the change in canopy temperature of plants under water stress conditions.…”

Managing drought risk in eucalypt seedling establishment: An analysis using experiment and model

“…Stone et al, 2001). Therefore, the measurements on the various canopy attributes (Table 2) should provide a clear indication of the level of stress across the range of treatments.…”