EFFECT OF SOIL AND FOLIAR POTASSIUM APPLICATION ON YIELD AND FIBER QUALITY IN COTTON (Gossypium hirsutum L.)

Abstract

Cotton cropping has shifted from traditional southeastern Brazil producing zones to central region savannahs. In this process, significant changes in production technology as well as in the crop environment have occurred, concurrently with a great yield increase. These changes have disrupted the practice of fertilization, creating systems where intensive applications are made, although not properly supported by experimental data. This study aimed to evaluate, in field conditions, the effect of combined soil and foliar spray potassium doses on yield and quality of cotton fiber, in southeastern Goiás State. The trial was conducted in the municipality of Ipameri (16°35'S, 47°02'W, 920 m), during the 2004/2005 growing season. A randomized complete block with split-plot experimental design was used. Five doses were applied to soil (0 kg ha-1, 60 kg ha-1, 120 kg ha-1, 180 kg ha-1, and 240 kg ha-1 K2O), combined with four foliar doses (0 kg ha-1, 7.2 kg ha-1, 14.4 kg ha-1, and 21.6 kg ha-1 K2O). Yield gains were observed for potassium applied both through soil and foliar spraying, without interactions between modes of application. There were no effects of doses and mode of application on the technological cotton fiber quality.

KEY-WORDS: Cotton fertilization; foliar-fertilization.