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Numerous methods for estimating soil saturated hydraulic conductivity exist, which range from direct measurement in the laboratory to models that use only basic soil properties. A study was conducted to compare laboratory saturated hydraulic conductivity (K sat) measurement and that estimated from empirical models. Soil samples for the study were collected from four sites at varying depths (15cm, 30cm, 45cm and 60cm) at the Faculty of Agriculture Teaching and Research Farm, University of Maiduguri. The K sat value for each sample was determined in the laboratory using the falling head permeameter method. Soil physical properties (bulk density, porosity, gravimetric water content, % sand and % silt) required by the models were also determined. A refined Kozeny-Carman model and model developed from multiple regression analysis were used to predict K sat which were compared with the results obtained from laboratory measurement. The developed model predicted values of 0.0065, 0.0010, 0.0965 and 0.0048cm/s at 15cm, 30cm, 45cm and 60cm, respectively, that is closer to the value of K sat measured in the laboratory (0.0061, 0.0054, 0.0050 and 0.0048cm/s at 15cm, 30cm, 45cm and 60cm, respectively) while Kozeny-Carman model predicted a value of 0.2208, 0.2161, 0.2020 and 0.1974cm/s at 15cm, 30cm, 45cm and 60cm, respectively, that is far above the one measured in the laboratory. Therefore, K sat estimating models could not fit for all locations very well.

Field experiment was carried out during the wet season of 2012 at the Teaching and Research Farm of Faculty of Agriculture, Adamawa State University, Mubi (Lat.10° 15II N and Long.13° 16II E, altitude of 696 m above sea level) and a Community based Demonstration Farm in Gombe (Lat.11° 30” N and Long.10° 20” E, altitude of 340 m above sea level). Both locations were situated in the Northern Guinea Savanna agro-ecological zone of Nigeria. The study was carried out to determine the level of correlation between weed parameters, growth and yield attributes of maize as affected by pendimethalin application. Treatments which consisted of six different rates of pendimethalin (1.0, 2.0, 3.0, 4.0, 5.0, 6.0kg a.i.ha-1) + two control checks (weed free and weedy check) were placed in the main plots as main treatment while maize cultivar SAMMAZ 17 was placed in the sub-plots as sub-treatments in a split plot design and replicated three times. Pendimethalin was pre-emergence- applied a day after sowing (DAS). Weed free check plots (control) were kept weed free by regular weeding. Similarly, all agronomic practices were adequately carried out except those under study. Data collected on weed cover score (WCS), weed fresh weight (WFW), weed dry weight (WDW), days to 50% emergence (D50E), crop injury score (CIS), crop vigour score (CVS), establishment count (EC), plant height (PH), leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), days to 50% tasseling (D50T), 1000 grain weights (1GWTs) and grain yield (GY) were analyzed using Minitab Version 11 Statistical Software. Results revealed that WCS was significantly higher and strongly correlated with WFW, WDW but was strong and negatively associated with GY of maize in both Mubi and Gombe. D50E, D50T and LAI were positive but contributed weakly to the GY of maize in Mubi. Similarly, D50E, D50T, PH and LAI had same pattern of behavior as the former in Gombe. EC was negative and also contributed weakly to the grain yield of maize in both locations. PH, CVS, CGR, 1GWTs were positive and strongly associated with GY of maize in Mubi. The same trend was also observed for all parameters except PH which though positive it was weakly associated to the final GY of maize in Gombe. Pendimethalin did not posed any significant effect on the post- physico-chemical properties of the soils at the two experimental sites, except in soil-pH, organic carbon, available phosphorus, total nitrogen, magnesium, potassium and sodium in Mubi and available phosphorus, total nitrogen, Calcium, Magnesium and Potassium in Gombe. These soil properties were significantly influenced by rates of soil applied Pendimethalin compared to the control checks.

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