COMMUN. SOIL SCI. PLANT ANAL., 32(11&12),1959-1967 (2001) IRRIGATED COTTON LINT YIELDS AS AFFECTED BY PHOSPHORUS FERTILIZER AND LANDSCAPE POSITION K. F. Brooson/'* A. B. Onken, 1 J. D. Booker/ R. J. Lascano, l T. L. Provin,2 and H. A. Torbere lTexas A&M University, Texas Agricultural Experiment Station, Lubbock, TX 79401 2Texas A&M University, Texas Agricultural Extension Service, College Station, TX 77843 3USDA-ARS, Grassland Soil & Water Research Laboratory, Temple, TX 76502 ABSTRACT Phosphorus (P) is the second most limiting nutrient in cotton (Gossypium hirsutum L.) production after nitrogen. Response to P fertilizer, however, is often hard to predict in the Southern High Plains, even with soil test-based applications. Landscape position has a strong influence on yields and perhaps on fertilizer response as well. The objective of this 5-year study (1994-1998) was to determine P fertilizer response in irrigated cotton in different landscape positions. We used an 825-m transect of end to end 15-m plots across a broad swale in an Amarillo fine sandy loam in Lamesa, TX that included three landscape positions, sideslope, bottoms1ope and drainageway. A randomized complete block design was used with 11 replicates and 5 Prates (0, 22.4, 33.6, *Corresponding author. 1959 Copyright © 200 I by Marcel Dekker. Inc. www.dekker.com