Characterization of cotton root growth in relation to plant growth, water management and potassium kinetic uptake parameters

Selecting deep rooting cotton (Gossypium hirsutum L.) cultivars for water deficit stress environments should enhance water uptake from lower in the soil profile. Six cotton cultivars from three maturity groups were evaluate in two water regimes. Maturity differences in shoot parameters were generally found under irrigated (IR) conditions, while maturity differences in root length density (RLD) were found under water deficit stress (NIR) conditions. Total root length (TRL) generally increased in both water regimes up to boll development with maximum values of approximately 162 and 265 cm in the IR and NIR cotton, respectively. Maturity differences in RLD were found at the 20 to 50 cm depth increment in the IR cotton and at 30 to 60 cm depth increment for NIR cotton. As compared to the early and medium maturing cultivars, late maturing cultivars produced 16 to 24% greater RLD at the 20-50 cm depth for the IR cotton and 7 to 33% greater RLD at the 30-60 cm depth for the NIR cotton.;Thirteen eastern Arkansas soils were sampled at 15-cm depth increments to 75-cm and evaluated for the effect of subsoil Al and Ca on root growth of Deltapine smooth-leaf cotton. When averaged over soils, mean total root length (TRL) ranged from 16.8 cm in the 60 to 75-cm soil-depth increment to 58.8 cm in the 0 to 15-cm soil depth. The low TRL deeper in the profile coincided with an increase in Al and decrease in Ca concentration. It would appear that subsoils in eastern Arkansas contain Al concentrations that limit deeper rooting and consideration should be given to amelioration of this soils or selecting cultivars that are Al tolerant.;Two cotton cultivars (DP20 and DP90) were grown hydroponically in a growth chamber to study the influence of foliar K on kinetic uptake parameters that describe K absorption by roots. The I...