|Terra, J - INIA, URUGUAY|
|Delaney, D - AUBURN UNIVERSITY|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 2, 2000
Publication Date: January 4, 2000
Citation: Prior, S.A., Reeves D.W., Terra, J.F., and Delaney, D.P. 2000. Effects of conventional tillage and no-tillage on cotton gas exchange and water relations: Standard row vs. ultra-narrow row system. In 2000 Proc., Beltwide Cotton Production Research Conferences, San Antonio, TX pp. 1433-1435. National Cotton Council, Memphis, TN. Interpretive Summary: Crop production in the U.S. is often limited by available soil water. Adoption of no-tillage farm practices can lead to more crop residue on the soil surface which can enhance soil water storage. Our goal was to evaluate cotton gas exchange during reproductive growth as affected by tillage practice (conventional tillage vs. no-tillage) and row spacing (standard 40 in vs. ultra-narrow row). During early reproductive growth, standard row cotton had higher rates of photosynthesis and transpiration since soil water was not limiting. Latter in reproductive growth, cotton under no-tillage exhibit higher rates (both row systems) compared to plants under conventional tillage. These results indicate that no- tillage systems that maintain surface residue can conserve water needed during the critical period of boll filling.
Technical Abstract: The availability of soil water to crops is considered to be the major limitation to crop production in the U.S. Use of conservation tillage systems enhances soil residue cover, water infiltration and reduces evaporative soil water loss. Our objective was to measure cotton (Gossypium hirsutum L.) leaf level photosynthesis, stomatal conductance, transpiration, and water use efficiency during reproductive growth under different row spacing and tillage conditions on a Norfolk loamy sand (Typic Kandiudults; FAO classification Luxic Ferralsols) in east-central Alabama. The study used a split-plot design replicated four times with row spacing (standard 40 in row and ultra-narrow row) as main plots and tillage systems (conventional and no-tillage) as subplots. These results indicate that cotton grown with standard row spacing can maintain a higher rate of photosynthesis when soil water was not limiting during the early stages of reproductive growth. At latter stages, no-tillage management may aid in conserving soil water needed during critical reproductive stages such as boll filling when demand for water is high.