|Baumhardt, Roland - Louis|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/4/1999
Publication Date: N/A
Technical Abstract: Irrigation of cotton on the Texas High Plains considers rain and the amount of irrigation water available. In many cases, wells have insufficient capacity resulting in deficit irrigation, i.e., application of less water than the crop requires. Late season irrigation of cotton often increases vegetative growth but not lint yield. Our objective was to determine the effect of three irrigation levels (0.1, 0.2, and 0.3 inches/day) on alternate (AFI) and every furrow irrigation (EFI) and three termination dates on lint yield and fiber quality. The termination dates were based on cumulative heat units (HU, base temperature 60 F) from emergence of 1600, 1800, and 2000 HU. Field experiments were conducted in Lubbock, at the Texas A&M Univ. Res. and Ext. Center using Paymaster HS-26 planted on 40-inch bedded rows from 1996 to 1998. Annual rain in 1996 was 14.9", 19.8" in 1997, and 10.5" in 1998. Seasonal cumulative heat units from emergence to first freeze were 2522 in 1996, 2090 in 1997, and 2845 in 1998. Irrigation termination dates for the 1600 HU were 26 July 1996, 2 Sep. 1997, and 29 July 1998; for the 1800 HU were 5 Aug. 1996, 15 Sep. 1997, and 9 Aug. 1998; and for the 2000 HU were 16 Aug. 1996, 4 Oct. 1997, and 21 Aug. 1998. Our results show that AFI versus EFI had no effect on fiber quality and only affected lint yield in 1998 when EFI reduced yield 8%. The low irrigation level reduced lint yield compared to medium and high levels which were similar. Terminating irrigation at the 1800 and 2000 HU did not affect yield but terminating at 1600 HU reduced lint yield 10%. Micronaire increased with termination date, but decreased with increasing irrigation level. Our results show the effects of irrigation level and termination date on lint yield and fiber quality.