Department of Soil Science, Institute for Agricultural Research, Ahmadu Bello University, P.M.B. 1044, Samaru, Zaria, Nigeria
Abu, S.T., Department of Soil Science, Institute for Agricultural Research, Ahmadu Bello University, P.M.B. 1044, Samaru, Zaria, Nigeria
This paper presents findings of comparative evaluation of selected soil physical quality (SPQ) indicators, obtained from fields subjected to: >50 years of cultivation of three perennial pasture grasses (i) Digitaria smutsii (DS), (ii) Brachiaria decumbens (BD), and (iii) Andropogon gayanus (AG); (iv) >50 years of continuous cultivation (CC) of cereals-legumes; and (v) >20 years of natural fallow (NF). The study was aimed at identifying the land-use system having optimal values for SPQ. Fields under CC had the highest bulk density, and the lowest total porosity (PORt) and macroporosity (PORp), field capacity (FC), and available water capacity (AWC). Perennial pasture grasses fields had significantly higher organic carbon, PORt, FC, AWC, and saturated hydraulic conductivity, and, hence, had better SPQ than CC fields and, in some instances, NF fields. The usefulness of ratios FC/PORt≤0.66 and ACt/PORt≤0.34 as additional indicators for assessing soil response to land-use systems was not proven in this study, and therefore, further studies should be conducted on the subject matter. Pasture grasses improved SPQ values relative to continuous cereal-legume cropping and fallow. The SPQ under CC and NF fields might be best improved by applying organic matter. Journal compilation © CSIRO 2013.
Available water capacities; Comparative evaluations; Continuous cultivation; Natural fallow; Perennial pastures; Saturated hydraulic conductivity; Soil physical quality; Soil physical quality indicators; Land use; Soils; Cultivation; available water capacity; bulk density; cropping practice; cultivation; fallow; field capacity; hydraulic conductivity; land use; organic carbon; pasture; porosity; soil quality