Root growth and mineral nutrition of cotton cultivars as affected by liming

Cotton root growth is under genetic control but can be decreased by soil fa ctors as Al toxicity and low Ca levels. Lime was applied to a Dark-Red Lato sol (sandy loam) with 10% of base saturation. to raise base saturation to 3 0, 50 and 70%, in order to study the effects of liming on root growth and m ineral nutrition of cotton (Gossypium hirsutum L., v. latifolium Hutch), cv . IAC 20, IAC 22 e CNPA-ITA 90 cultivares. The experiment was conducted in pots with 4 L of soil, under greenhouse conditions, up to 37 days after pla nt emergence in a 3 x 4 factorial design with four replications in randomiz ed blocks. Liming was necessary in order to get a good cotton root growth. The IAC 22 cv. showed roots more tolerant to low soil base saturation than cv. IAC 20 and cv. CNPA-ITA 90. Maximum root growth was observed when the s oil base saturation was around 50%. CNPA-ITA 90 showed a higher K absorptio n and was more tolerant to high Mn levels, showing a decrease in dry matter production at the highest soil base saturation.