Soil and Plant Water Evaporation from Strip‐Tilled Cotton: Measurement and Simulation

Abstract

It is estimated that 20% of cotton producers in the Texas High Plains use the strip tillage practice of planting cotton (Gossypium hirsutum L.) in residues of chemically terminated winter wheat (Triticum aestivum L.). The effect of the residue on water use partitioning between soil (Es) and crop (Ec) evaporation has not been reported. This study tested the hypothesis that the cumulative evapotranspiration (Et), of crop ina strip tillage system and in conventional tillage are similar, and that the residue modifies the components of total Et by reducing Es and increasing Ec. Winter wheat was planted in the fall of 1990 and was chemically terminated in the spring of 1991 in an Olton soil (fine, mixed, thermic Aridic Paleustoll) at Lubbock, TX. The plot was divided into a wheat‐stubble and a conventional treatment. Residue on half of the plot was left as stubble and residue on the other half was shredded and incorporated. Both plots were planted with cotton on 20 May 1991. Measurements included soil water and temperature profiles, soil evaporation, weather, and crop phenology and lint yield. Input values obtained from these data were used in the energy and water balance model (ENWATBAL) to calculate the daily and seasonal water lost to Es and Ec for 100 d. Calculated daily Es varied <1 SD from measured values. Measured mean total Et were similar, i.e., 305 ± 20 mm for conventional and 304 ± 41 mm for cotton in the wheat stubble. Simulated Et was within 10% of the measured value. The ratio of total Ec to Et was 0.50 in the conventional and 0.69 in the wheat stubble cotton. The more efficient use of Et in the wheat stubble increased lint yield by 35%. The Ec water use efficiency was not modified by the wheat stubble and was 3.8 g lint kg−1 of transpired water. The modified version of ENWATBAL was adequate to calculate the daily and seasonal water use of a cotton crop in a terminated wheat stubble, and the results support our hypothesis. The Et water use efficiency was increased by the wheat residue without additional input of water.

Adubação verde e sistemas de manejo do solo na produtividade do algodoeiro

“…Dessa forma, alguns estudos indicam que plantas de algodão cultivadas sob sistema de plantio direto apresentam maior eficiência no uso da água do solo e maior taxa de transpiração, se comparadas às cultivadas em sistema convencional de preparo do solo (Lascano et al, 1994). Essa maior taxa transpiratória pode causar grande resfriamento das folhas por evaporação, possibilitando a diminuição da temperatura do dossel (Pettigrew & Jones, 2001).…”

Evaporation Research: Review and Interpretation

“…Other E and T Partitioning Lascano et al (1994) reported a 100-day E reduction of 39% for a stubble/no-till treatment verses a conventional tillage treatment for cotton on an Olton sandy clay loam soil in Lubbock, Tex. (Table 10).…”

“…In 1982, there were 56 mm of light rain, and in 1984 there were 70 mm of heavier rain (Table 9). Lascano et al (1994) reported the cumulative lOa-day soil evaporation for the two treatments. These treatments were con ventional tillage and stubble/no-till (NT) treatments for cotton on an Olton sandy clay loam soil in Lubbock, Tex.…”

No-tillage and high-residue practices reduce soil water evaporation

“…In our studies, coupling notillage with high-residue preservation practices could reduce soil water evaporative losses during the summer season by about 4 inches (10.2 centimeters), or 13%, assuming a seasonal evapotranspiration demand of 30 inches. In Texas, a study of strip-till cotton grown in wheat residues, compared to cotton under conventional tillage, showed decreased soil water evaporation, increased crop transpiration and an increase in water use efficiency of 37% (Lascano et al 1994). …”