Organic materials are important resources for the improvement of soil physical and chemical properties. This study was carried out to examine the impact of tillage and organic matter on some soil structural indices. The study was designed in a split-plot Randomized Complete Block with four replications. Hoe tillage and no-tillage were assigned to the main plot, whilst the subplot comprised cowpea residue, cattle manure, maize residues, elephant grass and control (no organic residue applied). The soil physical parameters measured were bulk density, total porosity, volumetric water content and aggregate stability. Bulk density was lower in the 2013 minor season than in the 2014 major season for all the treatments (1.34 Mg m -3 -1.51 Mg m -3 ). Porosity ranged from 42.98-49.28% in the second season (2013 minor season). The cattle manure treated plots produced the highest volumetric water content of 20.25% and the control gave the lowest value of 16.20% at the end of the last growing season (2014 major season). The highest aggregate stability (74.91%) was recorded on cattle manure plots whilst the control gave the lowest value (71.11%). Crop residues were identified to be good source of organic material for the improvement of soil physical properties.

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Aims: Direct methods of measuring saturated hydraulic conductivity (K s ), either in situ or in the laboratory, are time consuming and very expensive. Several Pedotransfer functions (PTFs) are available for estimating K s , with each having its own limitations. In this study, the performances of four popular PTFs were evaluated on different soil classes in the semi deciduous zone of Ghana. The PTFs considered herein were Puckett et al. (1985), Campbell and Shiozawa (1994), Puckett (1994), andFerrer-Julià et al. (2004). In addition, five local data derived PTFs were used to study the possibility of using local datasets to validate PTF accuracy. Materials and Methods: A total of 450 undisturbed soil cores were collected from the 0 -15 cm depth from three benchmark soils, namely, Stagni-Dystric Gleysol (SDG), Plinthi Ferric Acrisol (PFA) and Plinthic Acrisol (PA). The K s of samples were measured by the falling-head permeameter method in the laboratory. Sand, silt and clay fractions, bulk density, organic matter content, and exchangeable calcium and sodium were measured and used as input parameters for the newly derived PTFs. Accuracy and reliability of the predictions were evaluated by the root mean square error (RMSE), coefficient of correlation (r), index of agreement (d), and the Nash-Sutcliffe efficiency (NSE) between the measured and predicted values from both tested and newly derived PTFs. The relative improvement (RI) of the newly derived PTFs from this study over the existing ones were also evaluated. Results: The newly derived PTFs in this study had higher prediction accuracy with r, d, RMSE and NSE ranging from 0.80 -0.99, 0.79 -0.94, 0.14 -1. 74 and 0.84 -0.98, respectively, compared with 0.32 -0.45, 0.27 -0.50, 4.00 -4.90 and 0.41 -0.47 for the tested PTFs. The relative improvement of the newly derived over the tested PTFs ranged from 56.50 -95.71% in the SDG, 70.73 -96.89% in the PFA, and 65.37 -95.81% in the PA. Generally, RI was observed to be highest for Model 1 in the SDG, and Model 4 in both PFA and PA, and lowest for Model 5 in all three soils. It was observed that the inclusion of exchangeable calcium and sodium as predictors increased the predictability of the newly derived PTFs.

The main objective of this study was to improve the growth of oil palm seedlings by using microbe plus to enhance phosphorous availability from rock phosphate under oil palm nursery was evaluated at Oil Palm Research Institute of Ghana, Kade-Kumasi. The study consisted of 16 treatments replicated 3 times in a 4 × 4 factorial experiment arranged in Randomize Complete Block Design. The factors tested were: Phosphate fertilizers (Phosphate only, triple superphosphate, super rock phosphate and Togo rock phosphate) and microbe plus rates (0, 50, 100 and 150%). Data was collected on leaf area, leaf area index and dry matter production. All data obtained were subjected to analysis of variance (ANOVA) using GENSTAT Version 11.1 (2008). The results showed that the P fertilizers and microbe plus applied alone or their interactions had no significant (P=.05) effect on leaf area and leaf area index values, however, dry matter produced was significantly (P=.05) different from each other. TSPMP150 treated seedlings produced significantly (P=.05) the highest dry weight; 42% increase over the control (No phosphate and microbe plus). The complementary use of microbe plus with triple superphosphate or Senegal rock phosphate proved to be the best options in terms of the parameters measured than the triple superphosphate. Microbe plus can therefore be used in combination with rock phosphate to improve phosphate availability. Field experiment is suggested to validate the effect of microbe plus and these rock phosphates on the performance of oil palm, whereas, additional studies with different application rates, both at nursery and at the field, are recommended.