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Abstract. Soil structural indices have a significant effect on the nutrients retention and crop yield. Studies on soil structure indices in the semi-arid zone are minimal despite their importance in controlling water and water transmission, root elongation and erosion. A study was conducted in the area of Hadejia to evaluate the influence of tillage systems (TS) and sampling depths on some selected soil structure indices. The TS were four (4); conventional tillage (CT), reduced tillage (RT), zero tillage (ZT) and chisel plough (CP), while the sampling depths were two – 0-15cm and 15-30cm. Randomised complete block design (RCBD) was used in factorial arrangement. The result showed that the soil is sandy loam in texture irrespective of the TS. Lower dispersion ratio (DR) was observed in ZT with greater aggregate silt + clay (ASC) and water stability index (WSI) which differed significantly (p<0.01) from one another. Pearson’s correlation and simple linear regression analysis revealed a significant (p<0.01) positive and negative relationships between organic matter (OM) content of the soil with ASC, WSI and DR, respectively. Negative correlation of OM with DR stressed the significance of OM in decreasing DR of the soil which further explains lower DR by ZT because of greater OM content (p<0.05). Sodium (Na), sodium absorption ratio (SAR) and exchangeable sodium percentage (ESP) were in the order of RT>ZT>CT>CP with RT having the highest that differed significantly (p<0.05) from other TS. Lower values in CT and CP could be a result of leaching due to the lower surface residues relative to conservational tillage systems. Conclusively, the best tillage systems to improved soil structural indices are conservation tillage (ZT and RT) systems, particularly ZT.

The study was conducted to determine the effects of different tillage practices on some physical and hydraulic properties of soils in Hadejia Local Government Area of Jigawa state during the 2017 cropping season. The field experiment was laid in a Randomized Complete Block (RCB) Design in factorial arrangements with 4 treatments for tillage practices-TP (Zero tillage-ZT, Minimum tillage-MT, Conventional tillage-CT and Deep tillage-DT) and sampling depth-SD (5 cm, 15 cm, 25 cm and 35 cm) all were in four replicates. Data collected were analyzed using the generalized linear model of Statistical Analyses System (SAS 9.4) for the ANOVA. The results showed that there were significant differences (p<0.05) in the main effect of TP and SD as well as in the interaction effect between TP and SD on soil bulk density (Bd), saturated hydraulic conductivity (Ksat), volumetric moisture content (VWC) at different soil water potentials and plant available water (PAW). Greater Bd and Ksat were observed in DT which differed significantly (p<0.05) from other TP while the lowest was found in ZT with 6.5% reduction than DT. The result further showed no significant difference in terms of PAW (p>0.05) between the TP at the average depth of 15 and 25 cm, but they (TP) differed significantly at the average depth of 5 and 35 cm with the highest in ZT. Higher soil moisture content retained at all soil water pressure was found in ZT which differed significantly (p<0.01) form other TP. The research concluded that the best TP to be adopted in Hadejia in terms of improvement in physical and hydraulic properties is ZT practice.

Different tillage practices are being employed by the farmers of Jigawa state, and as such, there is a need to determine its influence on some physical and chemical properties, so that farmers will base their choices on scientific facts rather than assumptions. An experiment was conducted to investigate the effects of three tillage practices (TP) on soil properties in Federal University Dutse, Teachings and Research farm, Jigawa State. The TP adopted are conventional tillage (CT), reduced tillage (RT) and zero-tillage (ZT). Samples were collected at a depth of 0 -20 cm for the chemical and other physical properties determination, while core samplers were used for bulk density (Bd) determination. All data collected were analyzed using Statistical Analysis Software (SAS and analysis of variance (ANOVA) was used to determine the significant tillage effect on the parameters measured at 5% level of significance and the means were separated using Least Significance Difference (LSD). The results showed that the soil texture of the study area was sandy loam. ZT differed significantly from other TP with higher Bd value of 1.51 Mg m-3, lower porosity (42.7%), and lower moisture content (10.3). ZT also had higher organic carbon (OC), total nitrogen (TN), available phosphorus (AP), exchangeable acidity (0.48 cmol+ kg-1) and bases and most importantly higher CEC (7.5 cmol (+) kg-1) which differed significantly from other tillage practices and the lowest of the most parameters were found in RT. Conclusively, ZT is the best TP to be used by the farmers because of the im- proved physical and chemical parameters and been not only economically sus- tainable but also socially and environmentally friendly.