Soil Physical Properties and Hydraulic Conductivity of Compacted Sandy Clay Loam Planted with Maize Zea Mays

Abstract

Land degradation from soil compaction has a major influence on the hydraulic conductivity, total porosity (PT), micro porosity (MIC), macro porosity (MAC), roots growth and grain yield. Field experiment was conducted in a tilled and compacted sandy clay loam soil under different machinery passes to determine compaction effects on soil bulk density, total porosity (PT), micro-porosity (MIC), macro-porosity (MAC), hydraulic conductivity and growth characteristics of maize. Four plots; A, B, C and D, each of area 5 x 10 m² were used. Plot A was tilled with a tractor-mounted disc plough and the remaining three plots; B, C and D were subjected to 5, 10 and 15 passes, respectively of heavy duty Mercy Fergusson tractor model 4355 (3.82 Mg ). Compacted plots progressively increased in bulk density between 1.63g  to 1.90 g, while total porosity decreased from 38 to 28.3 % in plots under 5 and 15 traffic passes, respectively. Soil micro-porosity decreased from 9.6 % to 7.84 % and from 17 % to 9.17 % in the soil superficial layer (0-10 cm) and at the 10-20 cm layer, respectively while the macro porosity ranged from 28.64 % to 20.45 % and 24.3 % to 19.12 %  in the 0 - 10 and 10 - 20 cm soil layers, respectively. At suction of 2 cm s^-1, tilled plot had the highest cumulative infiltration rate of 3.42 cm s^-1 and hydraulic conductivity of 9.09 x 10^-3. Results show that different machinery passes poses different restrictions to rooting depths of maize.