Soil properties influencing stability of structure of B-horizons of ultisols in semiarid Nsukka, eastern Nigeria

摘要

The argillic B-horizons of some ultisols are dense, often limiting root growths and developing some poor physical properties. Knowledge of the soil properties that influence this poor structural development is needed for better management of the soils. Ten Bt-horizons from different soil profiles were sampled for determination of soil structural properties. The aim was to determine the influence of measurable soil properties and soil aggregate stability indices on the stability of B-horizons. The soils are generally sandy clay loams, acidic and low in basic cations. Principal component analysis (PCA) showed that soil properties that are related to mean-weight diameter (MWD) of the B-horizons are: saturated hydraulic conductivity (Ksat); organic matter content; pH; sand content; bulk density; clay content; water-dispersible clay (WDC); clay dispersion ratio (CDR); silt content; exchangeable Mg2+, K+ and Na+; and CEC. The PCA also revealed that component de. ning variables (CDV) could be extracted from the variables to predict the MWD. The CDV that explained about 89% of the total variation in MWD (R-2 = 0.89; SE = 0.014) were Ksat, sand, WDC, Mg2+, and K+. The prediction model should be applied with caution as limited data were used in developing it. Amelioration of the chemical soil properties by different soil amendment strategies is suggested.