Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: November 21, 2000
Publication Date: N/A
Interpretive Summary: As pressure to reduce water use from non-agricultural sectors increases, exploring alternative approaches to improve cotton plant water efficiency becomes even more important. Active leaf transpiration is necessary for normal physiological plant processes and is necessary for adequate yields. Our approach was to reduce leaf heat load by reducing the total solar incident irradiation on the leaf by application of a particle film to the upper leaf surface. A particle film has the advantage over an anti-transpirant by not interfering with stomatal closure and the regulation of internal leaf temperature. In this study, we evaluated the effect of a particle film, 'Surround', under two soil moisture regimes with the intent of improving cotton plant water status, and thus reducing transpiration rates necessary for leaf cooling. Results indicate that the particle film significantly reduced plant canopy temperatures, improved plant water use, and modestly improved lint yields, when compared to unsprayed plants. Because of untimely rains, we were not able to control and maintain soil moisture differences between water regimes in order to determine if particle film applications would have greater potential under reduced soil moisture or dryland conditions.
Technical Abstract: Cotton (Gossypium hirsutum, L.) was planted in Weslaco, TX, into a Raymondville clay loam soil on 8 March 2000 in order to evaluate the potential use of multiple applications of a 6% (w:v) particle film, 'Surround', to plants grown under two soil moisture regimes. Treatments were evaluated for their effect on soil and plant water status, plant canopy temperatures, and agronomic performance. 'Surround' applications reduced mid-day canopy temperatures typically 1.5 C and reduced leaf transpiration rates 13% compared to unsprayed plants. Sprayed plants had slightly improved light penetration through the canopy (P=0.13), higher canopy reflectance, and lighter leaf objective color attributes, as determined by 'L', '-a', hue angle and chroma values. Leaf chlorophyll (mg/g dw) was not affected by spraying, but leaf area (P=0.10) and plant height (P=0.07) were slightly reduced in plants given particle film applications. Raw lint yields were increased 24% when 'Surround' was applied (P=0.12). There were no differences in soil moisture between sprayed and unsprayed plants, but there was more soil moisture in the high soil moisture regime in the 0 to 25-cm depth on the second and last three of the eight measurement dates compared to the same depth in the low soil moisture regime. Five inches of rainfall during the establishment of the two water regimes negated most other soil moisture profile differences.