Department of Soil Science

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    An Evaluation Of Alkaline Hydrolyzable Organic Nitrogen As An Index Of Nitrogen Mineralization And Availability In Biochar-Manure Compost Amended Soils
    (University of Ghana, 2021-09) Zoglie, E.M.
    The ability to predict the amount of plant-available nitrogen (N) organic amendments can supply through mineralization are required to improve their efficient use as sources of N fertilizers. This study compared a rapid alkaline hydrolysis of organic nitrogen (ON) method for evaluating the chemical index of N mineralization in soils to the standard long-term biologically based aerobic incubation method in three contrasting soils amended with 12 different biochar-manure composts (BMCs) of varied C/N ratios. The cumulative N mineralized/hydrolyzed from the biological and chemical hydrolysis methods were fitted to the first-order exponential equation to determine the potentially mineralizable N (No) and an analogous “potentially hydrolyzable N (Nmax)” for the BMCs. Furthermore, the study also assessed the suitability of the alkaline hydrolysis method as a soil fertility index by comparing the results with actual N uptake by maize in a pot experiment. The results showed that the biological and chemical estimated No and Nmax values differed significantly among the BMCs, suggesting that the chemical composition of the BMCs affected their reactivity and decomposability. It was also observed that the No and Nmax values were positively and significantly correlated (p ≤ 0.01). The correlation between Nmax and actual N uptake by maize was also significant (p ≤ 0.05). These results indicated that the rapid chemical hydrolysis method can be interpreted broadly for both mineralization process and soil fertility assessment. It was concluded that the rapid chemical hydrolysis method offers a time-effective surrogate approach for N mineralization and N supplying capacity of soil organic amendments.
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    Biochar Impact On The Water Relations Of Nerica Rice Grown On A Compacted Rhodic Kandiustalf
    (University of Ghana, 2021-09) Adesoyin, A.E.
    ABSTRACT Soil compaction has become a major challenge in tropical agriculture due to the increasing use of heavy agricultural machinery for tillage. Soil compaction sets in a spiral of soil degradation processes through reduced infiltration increased runoff and soil erosion. Ultimately, soil and crop productivity are impaired. Several remedial measures have been proposed to minimize soil compaction-induced degradation. Among these is biochar application to soils. Though the impact of biochar on enhancing soil physical properties is increasingly reported in the literature, data in Ghana continue to be scant and research also continues to lag on this front. The focus of this was three-fold. First, the impact of biochar application on compacted soils with regard to their physical and hydraulic properties such as the bulk density, moisture characteristic, runoff and infiltration, was investigated using laboratory studies. Second, the growth, yield and water use efficiency of upland rice (Nerica 14) under a range of biochar-amended compacted soils were studied under greenhouse conditions. For laboratory and greenhouse studies, the soil used was Toje series (Rhodic Kandiustalf). In a final study, two (2) biochar-modified runoff models were assessed for their suitability in predicting runoff from biochar-amended compacted Toje series. The laboratory study was a Completely Randomized Design (CRD) in factorial arrangement with three (3) compaction levels (Field D1= 1.3 Mg/m3; medium D2 = 1.5 Mg/m3 and high bulk density D3 = 1.7 Mg/m3), rice husk biochar at 3 rates (B0, B10 and B20 corresponding to 0, 10 and 20 ton/ha, respectively) was used. The treatment units which were in PVC pipes of 20 cm height and 16 cm diameter were irrigated from a rainfall simulator. Data were collected on the infiltration and saturated hydraulic conductivity. The variation of bulk density with biochar application was also determined. The soil moisture characteristic (SMC) was determined on samples of the various treatments using the Haines equipment and the dominant soil pore size was derived from the SMC. In the case of the greenhouse study, a similar experimental arrangement was used but with the PVC column heights of 40 cm. In addition, Nerica rice was planted and intermittently irrigated until maturity. There were 3 levels of irrigation (low: seasonal irrigation = 338.5 mm; medium = 419 mm and high = 569.5 mm). Both biochar application rate and bulk density and their interactions showed significant effects on the pore size and saturated hydraulic conductivity (Ksat). The dominant pore size increased from 0.0075 cm for the very high compacted soil (D3) at 0 ton/ha biochar application to 0.015 cm for low compacted soil (D1) at 20 ton/ha biochar application. Similarly, the Ksat was lowest (0.78 cm/h) for D3 with no biochar application and highest for D1 with 20 ton/ha biochar application. The increased pore size for the low density and high biochar application may explain the high Ksat values since according to Poiseuille’s Law, the water flow rate is proportional to the 4th power of the pore radius. It was observed that biochar application significantly reduced the bulk density. Soil compaction also significantly impacted infiltration parameters. Data analysis based on Horton’s (1948) infiltration model showed that the highest value for the initial infiltration rate, io = (134.7 cm/s) was observed for D1 with 20 ton/ha biochar application rate and least (7.7 cm/s) for D3 at 0 ton/ha biochar application rate. With respect to Philip’s (1957) infiltration equation, the sorptivity, S, was highest (12.1 cm/min 0.5) forD1 at 20 ton/ha biochar and least for D3 (2.06 cm/min 0.5) at 0 ton/ha biochar. The biochar-induced parameters used to predict the runoff using the modified Horton and Philip’s equations predicted the laboratory determined infiltration into compacted soils (R2 = 0.75). The greenhouse results showed that biochar application reduced the bulk density, offsetting the soil compaction effect on plant growth as well as the runoff, drainage and evapotranspiration Components of the water balance. The actual seasonal evapotranspiration (ETa) was reduced with increasing soil bulk density for each water regime. The highest yield was recorded for the treatment Combination of the high-water regime, 10 ton/ha biochar application and bulk density, D1. In general, the grain yield response to soil compaction was in the D1 > D2 > D3. The Water Use Efficiency (WUE) decreased with increasing density levels except for D2. Biochar had only a small significant effect on the WUE of the compacted soils. The input of the biochar and soil compaction modified ETa in the Doorembos and Kassam (1979) yield production function showed that rice yields under varying soil compaction and biochar application could be satisfactorily predicted (R2 = 0.67; Willmott d-index (0.89). Runoff was well predicted using the models of Ive et al. (1976) and the USDA Natural Resource Conservation Service (NRCS, 1972) Curve Number (CN) that were modified to respond to soil compaction and biochar application, for the laboratory studies. Overall, the performance of the two modified models was acceptable with R2 > 74% and Willmott index d > 0.67. In general, it can be concluded that the soil compaction problems induced by tillage can be effectively addressed by biochar application.
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    A Greenhouse Investigation and Modelling the Effects of Extreme Temperature and Moisture Stress on Growth, Development and Yield of Soybean (Glycine max (L.) Merrill).
    (University of Ghana, 2019-07) Ogunkanmi, L. O.
    Climate change is a major stressor that would adversely affect tropical agriculture, which is largely rainfed. Available evidence shows that associated with climate change is an increasing trend in temperature and in some locations, decline in rainfall leading to repeated droughts during the growing season. In this study, the effects of increased temperature and drought on soybean, a C3 plant, was investigated under greenhouse conditions. An understanding of how soybean would respond to climate change effect is a major key to improving food security for the global population and continues to be of research interest. This research was conducted in a greenhouse in the year 2018 with the purpose of determining the effect of climate variables such as temperature, relative humidity (RH), vapour pressure deficit (VPD) and soil water (W) on the phenology, biomass and grain yield of the plant. The research also aimed at developing and testing a simple temperature and water stress model for simulating the effect of these climate variables on the growth and yield of soybean. The experiment was set in a Split Plot Design with three average environmental conditions as main plots: E1 (36 oC, RH = 55 %), E2 (34 oC, RH = 57 % ) and E3 (33 oC, RH = 44 %) resulting in VPD values of 2.7, 2.5 and 3.0 kPa for E1, E2 and E3, respectively. Additionally, there were three water treatments: W1 (near saturation), W2 (Field capacity) and W3 (Drought) and two soybean varieties (Afayak and Jenguma) were used in the study. These treatments were replicated nine times. The results showed that high temperature environment (E1) accelerated soybean development particularly towards flowering. The days from emergence to flowering were 37, 38 and 40 for Afayak (V1) for environments E1, E2, and E3, respectively. In the case of Jenguma (V2), the days from emergence to flowering were 39, 40 and 41 for E1, E2 and E3, respectively. The cumulative evapotranspiration (ET) were 224, 208 and 185 mm for the environments E1, E2 and E3, respectively. Biomass and yield were drastically reduced under the combined effect of high temperature (E1) and drought (W3) compared to combined ambient temperature (E3) and well-watered condition (W1). The water treatment W3 (drought) had the lowest mean pod weights of 1.29, 1.54 and 3.35 g/plant for E1, E2 and E3 respectively, while W1 (near saturation) had the highest mean pod weight. The interactive effect of environment and drought treatment (W3) was most severe under E1 and E2 giving relatively lower grain yield of 0.45 and 0.53 g/plant compared to the ambient environment E3 which had mean weight of 1.54 g/plant. The varieties differed statistically in their responses to drought in both E1 and E2 environments with Jenguma significantly having higher yields than Afayak. The model developed performed quite well, correctly predicting the time-course of the total dry weight (TDW) of both soybean varieties under the range of temperature and soil water conditions. The final seed weights were also well predicted. In general, the agreement between the predicted and observed TDW was good, with R2= 0.74 and Willmott d -index =0.9. It was concluded that increasing environmental stresses associated with climate change would adversely affect the productivity of soybean in general, but some varieties may be more resilient. Breeding efforts should be directed to improving not only drought but also temperature tolerance.
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    Monitoring Phosphorus Nutrition of Maize on Four Landform Technologies in The Vertisols of the Accra Plains
    (University of Ghana, 1997-04) Abunyewa, A.A.
    A field trial was started in August 1994, during the minor cropping season to investigate the efficiency of tour Landforms in the production of maize with special emphasis in phosphorus (P) management in Vertisols at three localities in the Accra Plains of the Coastal Savanna zone of Ghana. The four Landforms were: Flat, Ridged, Ethiopian and Cambered beds. Generally, the soils were low in available P. Raising available P levels in the soil by the addition of fertilizer led to significant increase in dry weight of maize in all the Landforms. On the Cambered bed, however, raising the fertilizer above 50 % of the recommended rate did not cause significant yield increase. The Landforms had significant influence on P uptake and dry matter production. In all instances, the raised beds, i.e. Ridged (R), Ethiopian (EB) and Cambered (CB) significantly outperformed the Flat (F) bed in terms of P uptake and dry matter production. Among the raised beds, the Cambered bed had significantly higher dry matter yield than the Ridged and Ethiopian beds. The relative agronomic efficiency (RAE) of the four landforms were in the order of CB > EB = R> F (P < 0.05). Unlike the Ridged and the Ethiopian beds, the RAE of the Cambered bed at 50 % fertilizer application was higher than the 100 % fertilizer application. Soil organic P formed about 25 % of the total P and this value did not change significantly throughout the growing season. Calcium bound phosphate (Ca-P) was the dominant inorganic P and constituted about 78 % of the active inorganic P in the soils. Iron bound phosphate (Fe-P) was the least and constituted 2 % of the total active inorganic P. The two inorganic P fractions significantly correlated with P uptake and dry matter production. Though both Ca-P and Aluminium bound phosphate (Al-P) did not change significantly during the maize growing period, the Fe-P on the other hand reduced to about one-half its initial value. Generally, increase in fertilizer application increased P uptake, with the highest P uptake on the CB and least on the F. A significant Landform x fertilizer interaction was observed for dry matter production when 50 % fertilizer application on the CB out yielded 100 % fertilizer on the F. Generally, there was negative soil available P balance in all the Landforms and at all the rates of fertilizer application at the end of the season.
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    The Influence of Rice Husk Biochar and Nitrogen Sources on the Growth of Lowland Rice on an Eutric Gleysol from Walewale
    (University Of Ghana, 2018-07) Ahmed, G.
    Soil nutrient depletion in lowland rice growing ecologies in Northern Ghana is one of the major causes of low rice yields. Most nutrients applied to enhance the fertility of soil are lost through leaching due to the low CEC of the soils caused mainly by low organic matter and low colloidal clay content of the soils. The application of biochar has been found to improve soil fertility through its enhanced nutrient retention leading to increased nutrient uptake and consequently increased crop yield. The study therefore focused on assessing the potential of using rice husk biochar in combination with different sources and levels of nitrogen on productivity of a soil from lowland rice ecology. The hypothesis was that rice husk biochar in combination with inorganic or organic N will improve the growth and yield of rice and chemical properties of a typic Eutric Gleysol. Soil samples used for the study were collected from a lowland rice growing field in Walewale and some physical and chemical properties of the soil were determined before applying the soil amendments. A pot experiment involving twelve treatments were laid out in a complete randomized design with three replications. Two biochar application rates of 0 t/ha and 50 t/ha were combined factorially with three different rates of nitrogen at 0 kg/ha, 50 kg/ha and 100 kg/ha from two different sources viz, sulfate of ammonia and cowdung. Growth parameters such as weekly plant height and weekly tiller number were monitored one week after transplanting to harvesting. After harvest, the grain yield, straw yield and plant nutrient concentrations were determined. Residual soil analysis was carried out after harvest. The results of the study showed that grain and dry matter yield, N uptake and residual soil total N and C were influenced by amendment with biochar at 50 tons/ha. The combination of biochar at 50 tons per ha with inorganic nitrogen at 100 kg/ha produced the highest grain yield/pot and the highest nitrogen use efficiency (NUE).
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    Phosphorus Fractions of Biochar-Amended Plinthalqualf under Clean and Waste Water Irrigation Regimes in Northern Ghana
    (University Of Ghana, 2018-07) Obodai, M.S.
    The reactive nature of phosphorus leads to the formation of insoluble Fe, Al and Ca bound phosphate compounds in highly weathered tropical soils, thus limiting P availability for plant uptake. Biochar with its heterogeneous surface properties can influence phosphorus dynamics in tropical soils. To examine phosphorus fractions in a biochar-amended Plinthaqualf, samples were taken from low yielding soils in northern Ghana that had three cycles of vegetable production under clean and waste water irrigation regimes for two seasons. Sampling was done from irrigated soils amended with (i) biochar (B) at application rate of 20 tonnes per hectare, (ii) inorganic fertilizer (Ammonium sulphate-(NH₄)₂SO₄) according to normal agricultural practice (IF-NAP), (iii) a combination of biochar (B) plus (NH₄)₂SO₄) and a control (soil) inclusive. Phosphorus fractionation of the control soil and soil amended plots (B, (NH₄)₂SO₄, and B + (NH₄)₂SO₄) was assessed by a modified Hedley’s method. Water was used as an initial extractant before the resin was applied to ascertain the amount of water leachable P in the soils. The interaction of the amendments [biochar (B), (NH₄)₂SO₄ and (B + (NH₄)₂SO₄)] was assessed, and it showed an increase in the most labile Pi or available Pi (H2O-P, + Resin-P + NaHCO3-P) as well as moderately labile P (NaOH-Pi) fractions in the soils, thus, making P more available for plant uptake. There were significant correlations (p < 0.05; p < 0.01) among P fractions expressing a continuum among the P fractions, The P fractions were also related to the chemical properties of the soil and amended soils. The study showed that the water leachable P highly correlated (p< 0.01) with soil organic carbon, available P and total P at probabilities of 0.43, 0.42 and 0.70, respectively and forms about 24% on the average of total available P fraction of the soil. The study also showed that waste water irrigation regime gave a marginal P increment compared to the clean water irrigation, especially in the biochar treatment plots. Inference from the results of the study showed that all three amendments; biochar (B), (NH₄)₂SO₄ and (B + (NH₄)₂SO₄) significantly (p < 0.005) improved soil fertility parameters especially, P availability. However, B+(NH₄)₂SO₄ performed much better in the release of most labile P and that it could be used to improve the bioavailability of P in acidic soils such as those used in the study. High amount of water leachable P implies a possible loss of about a fourth of the soil available P if irrigation was done beyond field capacity or water saturation point of the soil. It is therefore, recommended that drip or sprinkle irrigation at reduced amounts is adopted to possibly forestall about a quarter (24%) of the available P that could be lost through the current mode of irrigation. It is also recommended that fortified biochar (B+(NH₄)₂SO₄) should be applied to improve P status of highly weathered soils (e.g. Plinthaqualfs) of northern Ghana. Further studies on application of P sources B, (NH₄)₂SO₄ and B+(NH₄)₂SO₄ should be conducted at different rates to ascertain optimum P application. In addition, the high correlations between water leachable P and the total P and also the available P could be exploited to bypass the use of expensive chemicals through modelling of a mathematical relation.
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    Evaluation of the Quality of an Acrisol under Three Land Use Systems in the Southern Savanna Zone of Ghana.
    (University of Ghana, 2017-07) Agbezorli , A-E.
    A Ferric Acrisol (Toje series) under three land use systems namely, natural fallow (forest), a Leucaena leucocephala woodlot and a cultivated plot were studied. Soils from profiles and surface horizons were evaluated to determine the effect of management systems on variability in soil properties and soil quality. A combination of field study and laboratory analyses was carried out. In all, 15 profile samples and 75 grid samples taken from a 12 m x 12 m area at intervals of 3 m each between grid points were collected for analysis on selected physical and chemical properties. Another 30 grid samples were collected for the determination NH4+ -N and NO3- -N. Aggregate stability used, as a physical quality indicator, revealed that aggregates of the forest soil were the most stable followed by the woodlot as a result of organic matter addition from litter fall from the trees. Organic matter build up was in the order forest fallow> woodlot> cultivated (organic carbon content of 16.7 g/kg, 8.6 g/kg and 7.0 g/kg, respectively). Generally, all the soils had higher organic matter content in the surface horizons which decreased decreasing with depth in the profile. The cultivated soil had a soil quality index (SQI) of 33.3% which implied that its quality was 66.7% less than the maximum quality. The SQI of the woodlot was 50% which was more than the cultivated soil by 16.6%. The forest soil had an SQI of 61.1%, which was 27.8 higher than that of the cultivated soils. All the soils had low nutrient levels due to the presence of low activity clays inherent in them. The study revealed that the natural fallows (forest soils) had higher soil quality as well as lowest variability in soil properties.
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    Using Dssat-Ceres Maize Model to Estimate District-Level Yields in Northern Ghana
    (University Of Ghana, 2016-07) Masika, D.
    Maize farmers accrue low yields due to poor weather, lack of certified seeds and farm inputs. The crop cutting method used by MoFA in yield estimation is tedious, labour intensive and most information are not adequately captured for decision making and policy. This study explores an additional method of scaling farmer-level yield to Tolon District level yield. The DSSAT-CERES maize model was used to simulate farmer-level yields where weather, soil and crop management data from selected sites in Tolon District were used. The simulated farmer-level yields were compared to the observed yields using a 1:1 plot, R2 (0.82) and Wilmott-d index (0.95). The validation confirmed the goodness of fit. To estimate the district yields, an aggregation procedure was used. Three different fertilizer rates and three sowing dates were interrelated then obtained as a weighted sum of management categories. The probability distribution of the District-level simulated yield was compared with the observed using cumulative frequency distribution. The trends agreed well. Analysis of the long-term climate in Northern Ghana showed that the frequencies of hot/dry regimes increased in the more recent periods. The validated model was used to investigate the usefulness of improved management such as addition of 3,000 kg/ha of farm yard manure to improve fertility, reduce run off and increase the water holding capacity of soil to increase yield. The results showed the mean District yield of 1935 kg/ha and 1482 kg/ha with application of high inputs (HI) under improved and under normal management respectively. Mean yield of 1386 kg/ha and 1190 kg/ha were obtained for improved and for normal management respectively with application of medium inputs (MI). Under low inputs (LI), the mean yields of 415 kg/ha and 225 kg/ha were obtained for improved and for normal management respectively. The District yield under improved management practices were 30.6% higher than under normal management. The yield gain is attributed to addition of appropriate inorganic fertilizers. Information on climate variability are crucial guiding principles for all stakes in sustainable future planning to enhance food security.
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    Biochar as A Liming Agent and Phosphorus Source to Enhance the Growth of Soya Bean in Two Acid Soils.
    (University of Ghana, 2017-07) Manso, E.F.
    Unavailability and high cost of conventional liming materials have contributed largely to low food production in acid soils of Ghana. Biochar produced from agricultural waste materials have high concentration of basic cations and available P that could be exploited for use as liming material and/or P source. However, the biochar type that will provide a conducive soil pH vis-à-vis P availability for food crop production in acid soils of Ghana has received little attention. Consequently, two typical acid soils, Ankasa series (Plinthic Acrudox) and Tikobo series (Typic Hapludult) were amended with corn cob and rice husk biochar types charred at 500 and 700 oC at a rate of 80 tons/ha in a screen house experiment to ascertain the efficacy of the biochar types as substitutes for agricultural lime and sources of P. The Ca equivalent of the biochar types from CaCO3 was amended to the soils to serve as a realistic control. The amended soils in addition to their un-amended counterparts were all kept at 80% field capacity in a completely randomized design in the screen house to allow for pH equilibration amidst weekly pH and bi-weekly exchangeable Al and basic cations monitoring. After pH equilibration, inoculated soya bean seeds were sown at stake. Nitrogen was applied at rates of 0 kg/ha and 10 kg/ha. Phosphorus was applied at zero and the biochar P equivalent from triple super phosphate was applied to the non-biochar-amended soils. Extra 30 kg P/ha from TSP was applied to some of the biochar amended soils to ascertain if any, the combined effect of synthetic P and biochar on growth and nodulation of soya bean. At flower initiation, crops were harvested, nodules counted, root volume, shoot and root dry matter and P uptake were determined. Results showed that corn cob charred at 700 oC was able to raise pH from 4.2 to 5.2 in Ankasa Series and from 4.9 to 6.2 in Tikobo Series within a six-week incubation and equilibraation period. Rice husk charred at 700 oC was able to raise pH from 4.2 to 5.0 Ankasa Series and 4.9 to 5.8 in Tikobo Series within the incubation period. All the biochar types reduced Al concentration from 0.4 cmol/kg to undetectable levels in the Tikobo Series with the element being reduced from 1.31 cmol/kg to 0.45 cmol/kg in the rice husk and corn cob at 700 oC biochar amended Ankasa soils within the six-week equilibration period. Soya bean nodulated in the rice husk biochar charred at 700 oC amended Tikobo Series without any form of synthetic fertilization. There was no nodulation in the Ankasa series. Shoot P uptake of soya bean was 1.5 and 1.4 times more in Ankasa and Tikobo Series, respectively when amended with rice husk biochar charred at 700 oC than the same soils amended with conventional lime and equivalent biochar P from triple super phosphate. Apparent nutrient recovery efficiency was higher in biochar amended soils than the CaCO3 amended soils. The biochar amended soils showed an increase in organic carbon contents. The residual total P increased from 101.4 mg/kg to 257.8 mg/kg when rice husk biochar charred at 700 oC was applied to Tikobo Series whilst there was an increase from 164.0 mg/kg to 344.9 mg/kg when corn cob biochar charred at 500 oC was added to Ankasa Series. There was high increase in residual available P after amending the soils with the liming materials. The study concludes that corn cob and rice husk biochar can be used as liming materials and P source in acid soils, particularly Tikobo Series for growth of soya bean.
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    Selection of Cowpea (Vigna Unguiculata (L). Walp) For High Yield under Low Soil Phosphorus Conditions
    (University of Ghana, 2018-04) Souleymane, A.
    Nitrogen (N) and phosphorus (P) are among the main edaphic factors that limit crop production in Sub-Saharan Africa (SSA). As a nitrogen fixing legume, cowpea production is not significantly affected by N, but P deficiency in soils. Two hundred (200) cowpea genotypes composed of both landraces and improved varieties were screened in the field under low P soil conditions in order to (i) determine genetic variability and heritability of traits associated with low P tolerance, (ii) assess the genotype by environment interactions for yield and its components under low P conditions, (iii) identify superior cultivars for use as varieties and/or as parents in improvement programs and (iv) determine the effects of planting date on the cycle and yield of local cowpea varieties in Niger. A participatory rural appraisal (PRA) was conducted to obtain farmers‘ knowledge and perceptions on low soil fertility and preference for cowpea varieties. The PRA results revealed that 11, 49 and 40 % of respondents claimed that their farms are respectively very low, low and high in fertility. About 75 % of farmers indicated that their cowpea production was low. Drought and low soil fertility were identified as the major production constraints. In terms of varietal preferences, early maturity and high yield potential were the traits preferred by farmers. High diversity with regards to yield and yield related traits under low soil P conditions was detected in the evaluated germplasm. High estimates of heritability, genetic variance, phenotypic variance as well as GCV and PCV were obtained in rainy season in comparison to dry season. The mean number of days to flowering, days to 50 % maturity, plant height, fodder yield, harvest index and hundred seed weight were the most highly heritable traits with 92.51 %, 85.02 %, 70.56 %, 80.6 %, 80.72 % and 71.94 % broad-sense heritability estimates, respectively. Grain yield was positively correlated with shoot dry weight, plant height and shoot color ; it was however negatively correlated with days to flowering and days to 50 % maturity. Genotype x Environment interaction was only significant for days to flowering, days to 50 % maturity and University of Ghana iii fodder yield. The contribution of genotypes to the variation was high regarding fodder yield and days to flowering, but medium with regard to grain yield. Genotypes with high grain and fodder yield under low P soil conditions were detected; nevertheless, only G150 was stable across the test environments. The largest contribution of genotypes to traits variation was observed in fodder yield (46.76 %) while the smallest was in shoot dry weight (1.5 %). Genotypes were also responsible for a significant variation with regard to days to flowering (21.57%) as well as grain yield (15.06 %). The environment was the main cause of the variability detected in shoot dry weight, plant height, days to 50 % maturity and grain yield with 82.45 %. 72.04 %. 58.69 % and 36.55 %, respectively. The GEI part of the variation was high in days to flowering (36.85 %). fodder yield (22.73 %) and days to 50 % maturity (18.66 %). The G x E interaction although not significant for grain yield, contributed considerably (15.85 %) to the yield variation. Planting date had a significant effect on yield and yield related traits of local cowpea cultivars in Niger. Significant reduction in days to flowering and days to 50 % maturity with subsequent decrease in grain and fodder yield was observed when varieties were planted late. The first planting dates recorded the highest mean grain yield in both 2016 and 2017 while the lowest belonged to last planting dates. G56 and G34 were the best and worst performing genotypes with respectively 40.47 and 1.78 g grain yield per plant across the test environments. Superior genotypes in terms of fodder yield were G35, G78 and G74 with 178.50, 173.63 and 167.37 g per plant, respectively. Cultivars tolerant to both low P soil conditions and striga were also identified.The population developed for recurrent selection and QTL detection is at F2 generation. Candidate Genotypes for release as variety were identified.
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    Using Biochar To Reduce Leaching And Enhance Nitrogen Uptake In Two Ghanaian Soils
    (University of Ghana, 2016-12) Egyir, M.
    In recent times the use of biochar as soil amendment has been proposed as one of the ways for reducing nitrogen leaching particularly in sandy soils because it has the potential to retain cations and anions. Three different biochar types (sawdust, rice husk and corn cob) pyrolysed at 400°C were tested in the laboratory to investigate their retention capacity for NO3- and NH4+. One hundred and fifty grams (150 g) of each biochar was packed into acrylic cylinders to create biochar column. The soluble cations in these biochar types were then leached out completely. Three nitrogen fertilizer solutions (ammonium sulphate, potassium nitrate and ammonium nitrate) prepared at 1.36 g N per litre were allowed to pass through the column and leachate collected to determine NO3-N and NH4+N. Results from the column leaching experiment showed that the sawdust biochar had superior retention capacity for NO3- and NH4+. This could be due to its relatively higher surface area when compared to the other biochar types. In another experiment in the screen house, the sawdust and rice husk biochar types were applied at 0, 20 and 40 t/ha and treated with different N sources (cow dung and ammonium sulphate; 265 N kg/ha) in two soils, Keta series (Quartzi Psamment) and Nyankpala series (Plinthic Acrisol) and maize was grown for five weeks. During the growth period the treated soils were leached at 14 and 28 days after planting to determine the quantity of available nitrogen (N) leached out. Biochar amendment of the soils reduced leaching of NO3-N and NH4-N, indicative of their ability to retain N in the soils. The amendment also enhanced dry matter production and N uptake by maize, therefore biochar amendment is recommended for reducing leaching. It was also recommended that the experiment should be conducted under field condition.
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    Effect of Different Marinades on Quality Characteristics of Chevon Jerky
    (University Of Ghana, 2017-07) Arthur, G.M.
    This study was carried out to investigate the effect of different marinades on quality characteristics of chevon jerky. Chevon (Hindquarter muscle) was treated with marinades containing different levels of vinegar (0, 2.5% or 5% v/v) and papain (0, 0.004g/0.04gw/v). A 3x3 factorial design which composed of nine treatments with three replicates was used. Chevon was cut into 1.5cm x 1.5cm cubes and samples were marinated for 12h and dried in an oven for 10h at temperature of 65oC. Sensory and microbial characteristics, drying rate and rehydration ratio were determined. The samples for sensory analysis were vacuum packaged after drying and stored at room temperature. Due to the risk of mould growth on samples from treatments containing papain only (T2 and T3) after 15d of storage in a preliminary work, sensory evaluation was conducted on samples stored for 1d and 15d. Panelists were presented with randomly coded cooked samples and the tenderness, chewiness, juiciness; flavour and overall liking of the samples were evaluated using 8 point hedonic scale. The result of sensory properties showed that out of the nine treatments tested, papain (0.04g) was effective in tenderising the chevon jerky compared with all the other treatments. Samples were ranked as very tender to extremely tender while samples treated with vinegar (5%) was ranked as moderately tough to slightly tough. Samples from control (T1) obtained the highest acceptability score of 52.78% and was ranked as ―very like to extremely like‖ whereas papain 0.004g +vinegar 2.5% (T5) was the least scored 38.88% and was ranked as ―slightly like to moderately like‖. No significant (p > 0.05) differences were observed among treatments for chewiness, juiciness and flavour. However, juiciness improved with longer storage time at 15d. Samples evaluated at 1d were rated as ―extremely dry to very dry‖ (24.69%) but were ranked as ―very juicy to extremely juicy‖ (24.08%) at 15d. Samples for microbial test were also vacuum packaged and stored at room temperature. Additionally, microbial quality analysis was conducted at 1d, 15d and 30d of storage and the effects of the nine treatments on the growth of four different microbes (total plate count, Staphylococcus aureus, E.coli, yeast and mould) during storage were investigated. As storage period increased from 15 to 30d total plate count increased from1.59 to 1.93log cfu/g, while E.coli count declined from 0.19 to 0.09log cfu/g. Additionally, Staphylococcus count decreased from 1.96 to 0.00log cfu/g and lastly as storage period progressed from 15d to 30d yeast and mould count declined from 1.17 to 0.30log cfu/g. Drying rate was determined by change in % moisture content per unit time during drying for 10h. The analysis showed that all the test samples recorded lower moisture content compared to that of the control (T1) after drying. Samples from vinegar (2.5%) recorded the least (1.71%) moisture content whereas the highest (3.61%) was observed in control (T1) samples. Rehydration studies were carried out on sample (1.5cm x 1.5cm) to distilled water ratio of 1:40 for 300min under ambient condition. As rehydration time progressed from time 0 to 300min there was an increase in weight among all test samples. Samples from control (T1) recorded the least moisture uptake of 9.83 whereas samples from vinegar 2.5% (T4) recorded the highest moisture uptake (19.94) after rehydration. Overall, the results of this study indicate that although overall likeness score favoured the control treatment, it is possible to improve meat toughness using papain to produce meat with acceptable sensory attribute than vinegar. Also, the drying process resulted in a jerky product with low moisture content which inhibited microbial growth; however, vinegar can be used in jerky production to add flavour to the product.
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    Assessment Of Crude Oil Degradation And Hydrocarbon Utilizing Bacteria Associated With Some Beach Soils In Ghana
    (University of Ghana, 2017-07) Andoh-Payin, K.
    Ghana discovered oil in 2007 at Cape Three Point in the Western Region. It experienced its first low-based mud oil spillage in 2009 and 2010. Ghana is therefore exposed to possible oil spillage due to oil production in commercial quantities. It is against this background that the present study is aimed to assess the degradation along the coast and identify hydrocarbon utilizing bacteria (HUB) associated with some beach soils. The beach soils were taken from eight coastal towns; Aflao, Anloga, Ada, Accra, Winneba, Cape Coast, Takoradi and Axim. The soils were contaminated with crude oil at 10 g oil /kg soil and incubated under room temperature for a period of 60 days. The contaminated soils were sampled at ten (10) days interval for HUB population and quantity of crude oil degraded. The results showed a cumulative significantly (p < 0.05) increase in the amount of crude oil degraded with time in all the soils. There was variation in degradation potential along the coast. Ada showed significantly (p < 0.05) highest degradation potential followed by Anloga. However, Takoradi and Axim soils showed the least degradation potential but was significantly (p < 0.05) lower than the others. The hydrocarbon utilizing bacteria genera associated with the soils are Bacillus, Pseudomonas, Staphylococcus and Yersinia. The dominant HUB identified was Bacillus. Further research work should be conducted to determine the diversity of HUB and enhancement of oil degradation along the coast.
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    Characterization Of The Geophagic Materials And Their Overlying Rocks And Soils From Anfoega, Ghana
    (University of Ghana, 2016-07) Badu, J.K.
    Geophagy is the deliberate consumption of earth and clay deposits by animals, including man. It is a special type of pica, which is defined as the craving and subsequent consumption of non-food substances. This study was conducted to examine the physical, chemical and mineralogical properties of the geophagic materials and their overlying rocks and soils from four sites at Anfoega in order to determine possible relationships among them and the potential human health risk associated with the consumption of the geophagic materials. The four sites were Tokorme 1, Tokorme 2, Tokorme 3 and Wuve. Soil samples and geophagic materials from the selected sites were subjected to the following laboratory analyses: colour, particle size distribution, pH, electrical conductivity, cation exchange capacity, organic carbon content and X-ray defractometry. The rock samples and geophagic materials were also subjected to petrographic and x-ray analysis. Whereas the pH of the soils from Tokorme 1, Tokorme 3 and Wuve ranged from slightly acidic to moderately acidic, that of Tokorme 2 was moderately acidic in the surface soils but strongly acidic in the lower layers. The pH of the geophagic materials was strongly acidic. While the soil samples generally contained high amounts of sand, the geophagic materials contained high amounts of clay. With higher amounts of clay, the CEC of the geophagic materials ranged from 18.0 to 23.2 cmolc kg-1 which was higher than that of the soil samples (5.3 to 22.6 cmolc kg-1). The thin sections of the rocks showed very high amounts of quartz and small amounts of feldspars and sericite. The thin sections of the geophagic materials on the other hand, revealed the presence of large amounts clay and some quartz, feldspars and sericite. The x-ray diffractograms showed that the soils, rocks, and geophagic materials were dominated by SIALIC minerals mainly quartz, kaolinite, muscovite and iii feldspar. The mineralogy of the soils indicated that they were derived in-situ from the underlying sandstones. The results also showed that the high amounts of SIALIC minerals in the geophagic materials was accumulated through leaching of the overlying sandstone. The health risk index analysis of the geophagic materials calculated based on consumption of 70 g of clay per day were all less than 1.0. This result indicates that the geophagic materials were safe for human consumption. Also, the microbial analysis of the geophagic materials showed high levels of bacteria load in the processed fresh, processed dry, powdered and smoked samples. However, no coliform group was detected. The microbial results showed that although the geophagic materials were naturally safe for consumption, processing them could introduce harmful micro-organisms.
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    Aspergillus Niger Mediated Phosphocompost and Maize Production in a Greenhouse
    (University Of Ghana, 2014-07) Nyamedi, I.M
    Generally, soils in coastal savanna in Ghana are low in phosphorus (P) which affects crop growth and yield. Most phosphate rock deposits in West Africa are not reactive and therefore their direct applications do not promote readily P availability to crops. Co-composting organic waste and phosphate rock and using phosphorus solubilizing micro-organisms (PSMs) are some of the options currently attracting the attention of scientists. A study was conducted to (1) evaluate the effectiveness of Aspergillus niger, a phosphorus solubilizing microbe, in solubilizing P in phosphate rock during co-composting with organic waste (citrus waste (CW) or rice straw (RS) and (2) to evaluate the growth, dry matter production and P uptake of maize to phospho-compost application. The phospho-compost was prospered at the University of Ghana Forest and Horticulture Research Center, Okumaning near Kade. The organic waste feed stocks used were: citrus waste and rice straw. The composition of each composting pile was in the ratio of 24:3:1 w/w of feed stock, Togo phosphate rock and urea. The results showed that citrus waste feedstock was more effective than rice straw in solubilizing the P in rock phosphate. Inoculation with A. niger was not very effective in solubilizing the rock phosphate to release P to the test crop. Available P increased from week one to week four and decreased from week five to week six. During the initial days of composting, the pH of the CW compost pile with A. niger inoculation decreased from 4.6 to 2.9, while without A. niger, the pH decreased from 4.9 to 3.5. Similarly, the pH of the RS compost pile with A. niger inoculation decreased from 7.1 to 4.1, while without A. niger the pH decreased from 7.2 to 5.2. However from week5- week6 the pH increased in all the compost piles. The phospho-composts produced were evaluated using maize (Zea mays) as test crop in a pot experiment. The soil used was Toje series (Rhodic Kandiustalf). Four P rates, 0, 60, 120, and 180 kg P/ha as phospho-composts were applied per pot to a Toje series soil (Rhodic Kandiustalf). A water soluble P source Triple super phosphate (TSP) and RP with A. niger were applied at a single rate of 60 kg P/pot as control. The results suggested that A. niger + RP did not have significant effect on the vegetative parameters (plant height, girth, leaf area, dry matter yield, and plant P and Ca and Mg uptake). The CW-derived phospho-compost was more effective in promoting maize DMY compared to RS derived-compost and TSP at 60 kg P/ha, whilst the RS-derived compost was more effective at higher rate (180 kg P/ha). No significant difference in dry matter production was observed between phospho-compost inoculated with or without A. niger. At 60 kg P/ha, the trend in DMY was: CW-based phospho-compost without A. niger = CW based phospho-compost with A. niger > RS based-phospho-compost without A. niger = RS based phospho-compost with A. niger> TSP > RP with A. niger> Control. At 120 kg P/ha, the trend was: CW based phospho-compost without A. niger > RS based phospho-compost without A. niger = RS based phospho-compost with A. niger> CW based phospho-compost with A. niger. At 180 kg P/ha, the order in DMY was: RS based phospho-compost with A. niger> RS based phospho-compost without A. niger = CW based phospho-compost with A. niger> CW based phospho-compost without A. niger). P uptake followed similar trend as the DMY, and P uptake at 60 kg P/ha, was CW based phospho-compost with A. niger = CW based phospho-compost without A. niger> RS based phospho-compost without A. niger = RS based phospho-compost with A. niger = TSP > RP with A. niger> Control. No significant difference in shoot P uptake was observed between CW based phospho-compost with and without A. niger at 60 kg P/ha. The relative agronomic efficiency (RAE) for CW based phospho-compost without A. niger at 60 kg P/ha and 120 kg P/ha was 2.5 fold better than TSP. Similarly, the RAE of RS based phospho-compost with A. niger at 180 kg P/ha was 1.9 times higher than that of TSP. Further research should be conducted on the CW based phospho-compost which has proven to be more effective in promoting DMY and improved P uptake in maize
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    Adsorptive Characteristics of Phosphorus on Four Biochar Types
    (University Of Ghana, 2014-07) Tetteh, J.L
    Biochar prepared from cocoa pod, sawdust, rice straw and husk wastes may provide new low cost technology for environmental management with emphasis on P removal from waste water to minimize eutrophication and to enhance P availability in tropical soils. To achieve this, the sorption characteristics of the biochar types would have to be understood. In this study, laboratory experiments were conducted to investigate the P adsorptive characteristics on four biochar types derived from cocoa pod, sawdust, rice husk and straw. Batch sorption experiment was conducted to investigate the time for maximum adsorption by shaking at two (2) hours intervals between 2 to 24 hours. X-ray diffractograms of the various biochars were obtained to help elucidate possible mechanisms of adsorption. Effect of pH on adsorption was also studied for initial pH ranging between 2 and 12 and initial P concentrations between 0.4 mM and 1.6 mM. Results from the research revealed that six (6) hours of shaking time was sufficient to achieve maximum adsorption onto the various biochars. Optimum pH for adsorption occurred at equilibrium pH of 5.7 for rice husk, 6.2 for sawdust, 6.7 for cocoa pod and 7.2 for the rice straw biochar. The isotherms indicated that the amount of P adsorbed increased with increasing equilibrium P concentrations. Increases in equilibrium pH above 7.2 led to decreases in adsorption for all the biochar types. Rice husk and sawdust biochar types were found to have the highest affinity for P with estimated maximum adsorption of 7300 mg/kg P. Phosphate adsorption mechanism varied with biochar type. Surface precipitation of P by Ca and Mg was proposed as an important mechanism of P adsorption on the sawdust biochar. Magnesium precipitation of P was also proposed as a mechanism of P removal by the rice husk biochar. Both electrostatic attraction and ligand exchange reactions by periclase (MgO) with P could be the main mechanisms of adsorption on cocoa pod, rice straw and sawdust biochar types. Phosphorus adsorption via ligand exchange and or electrostatic attraction could have accounted for P removal by the rice husk biochar.
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    Evaluation of Sweet Potato (Ipomea Batatas, L.) Cultivars and Advanced Breeding Lines For Resistance to Two Root-Knot .Nematode Species (M. Incognita & M. Javanica)
    (University of Ghana, 1978-05) Bonsi, C.K.; Bobby, R.P; Maloney, M.A.; University of Ghana, College of Basic and Applied Sciences School of Agriculture Department of Soil Science
    Several sweet potato cultivars and advanced breeding lines were screened in both the greenhouse and a heavily nematode infested field for resistance to root-knot nematode species (Meloidogyne incognita and Meloidogvne javanica). Two greenhouse methods, "The Bed Method" and "The Improved Method" were used for indoor investigations. A heavily nematode infested field was used for outdoor investigations. The infestation in the field had been built up over a period of three years. Plants in all investigations were evaluated on a scale of 1-5 based on the percentage number of roots infested using both gall and egg mass indices. Several breeding lines, namely, FH-7-72, TI-1&92, L3-186, TI-15S-76, TI-152-76 and TI-I84-76 were resistant to M. incognita; however only FH-7-72, TI-1892 and L3-186 were comparable to ’Jewel’ in their resistance. ’Carver’ and ’Rojo Blanco’, two newly released cultivars from Tuskegee Institute were intermediate in resistance and susceptibility respectively when inoculated with M. incognita. When plants were screened for resistance to M. .jayanica, TI-1892, ’Carver’, FH-7-72, TI-1895, TI-164-76, TI-152-76,
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    Nodulation and Nitrogen Fixation of Indigenous Rhizobia in Soils Cultivated and Uncultivated With African Yam Bean (Sphenostylis Stenocarpa)
    (University Of Ghana, 2015-10) Agbenyega, H.E.; Asuming-Brempong, S.; Lawson I. Y. D.; University Of Ghana, College of Basic and Applied Sciences, School of Agriculture, Department of Soil Science
    The association between leguminous plants and rhizobia helps to meet the limiting nitrogen in the soil by producing about 40 to 60 million metric tons (Mt) per hectare per year of nitrogen. However, the focus of legume-Rhizobium symbiosis has been on biomass productivity, nodulation and nitrogen fixation of the major and domesticated food legumes whereas little research has been conducted on the indigenous legumes which hold promise in retaining agricultural diversity and achieving food security. Among these are the underutilized, neglected and unknown ones which include African yam bean (Sphenostylis stenocarpa). Further research into this crop is necessary to explore its biological nitrogen fixation and nutritional capabilities. This study was carried out to investigate the nodulation and nitrogen fixing capacity of the indigenous rhizobia in African yam bean (AYB) from some Ghanaian soils (Adenta series, Bekwai series, Nzima series and soils from Akorviefe, Dzolokpuita and Dzologbogame also known as Kuli series) that have been cultivated and uncultivated with African yam bean. Secondly, the study was to assess the response of AYB to inoculation and nitrogen fertilization. Results from Most probable number estimates showed that Bekwai series did not record any African yam bean nodulating rhizobia (0 cells g-1 soil), whereas the other five soils recorded variable numbers of rhizobia. Soils from Akorviefe (Kuli series) recorded the highest African yam bean nodulating rhizobia (290 cells g-1 soil), followed by soil from Dzolokpuita (Kuli series, 140 cells g-1 soil), Adenta series (72 cells g-1 soil) with soil from Dzologbogame (Kuli series) and Nzima series recording the least number (52 cells g-1 soil). The results of symbiotic effectiveness studies showed that there were no highly effective rhizobia present in the soils tested but moderate and ineffective rhizobia strains were observed. Soils not cultivated with African yam bean (Adenta, Toje, Akuse and Haatso) recorded 87% ineffective and 13% moderately effective rhizobia whereas soils cultivated with African yam bean (soils from Akorviefe, Dzolokpuita and Dzologbogame [Kuli series]) recorded 97% ineffective and 3% moderately effective rhizobia. Nitrogen application at the rate of 70 kg N ha-1 had a negative effect on nodule numbers, nodule dry weight and N2 fixation whereas positive effect was observed for total N accumulation and shoot biomass in all the soils. In contrast, inoculum application had a positive effect on nodule numbers, nodule dry weight, N2 fixation, N accumulation and shoot biomass in all the soils used. Cross inoculation results showed that 56%, 33% and 11% of African yam bean rhizobia isolates were able to nodulate cowpea, pigeon pea and soybean respectively. However, 80% of soybean, 40% of cowpea and 0% of pigeon pea rhizobia isolates were able to nodulate African yam bean plant. It can therefore be concluded from this study that nodulation and nitrogen fixation are positively influenced by the indigenous Africa yam bean rhizobia in the various soils.
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    Physico-Chemical Properties and Agronomic Performance of Nerica L19 Rice in Three Salt‒ Affected Soils amended with Gypsum
    (University of Ghana, 2015-07) Louis, S.; Owusu- Bennoah, E.; Tetteh, F. M.; University of Ghana, College of Basic and Applied Sciences, School of Agriculture, Department of Soil Science
    In Ghana approximately 318,000 ha of arable land in the Volta region is affected by salt and excess sodium. This aspect of chemical land degradation has adversely affected agricultural productivity in this part of the country. The application of gypsum (CaS04 (2H2O)) to soils affected by salt is widely used because it is easy to apply, easy to acquire and economical. It is against this background that the physico-chemical properties and agronomic performance of NERICA L19 rice was investigated on three salt-affected soils amended with gypsum. Three profile pits were dug to a depth of 2.0 m from three different salt-affected sites namely Anyako, Anyenui and Atiehife at the Volta region. The soils were sampled and their morphological and physico-chemical properties analysed. Morphological description and classification showed that, the soils, were mainly clayey within the top soil with a high presence of pyrite, rusty root channels and yellowish brown mottles. Two of the soils from Anyako and Anyenui were classified as Oyebi and the other from Atiehife was classified as Ada series respectively. The agronomic performance of NERICA L19 rice was determined in the greenhouse. The soils were treated with different rates of gypsum at 0, 25, 50, 75 and 100 %, respectively and incubated for three days. The soils were leached and planted to NERICA L19 rice which was replicated four times in a completely randomized design. Plant growth parameters such as plant height, number of tillers and number of leaves were recorded at weekly intervals for twenty eight days. At the end of 28 days after transplanting, the rice was harvested and the plant tissue composition as well as the soil chemical composition were determined. Results obtained, showed that EC, SAR and pH decreased as the levels of gypsum application increased compared to the original soils. This indication of soil reclamation, provided a favourable chemical soil condition and corrected nutrient imbalance to support rice growth. The plant tissue had increased concentration of calcium, magnesium, potassium and low level of sodium. Generally growth performance of the three soils observed followed the trend; Atiehifie >Anyenui > Anyako. In conclusion, enhanced rice growth was attributed to the improvement in the chemical properties of the soil. The application of gypsum at the rate of 1.39×104, 1.40×104 and 1.35×104 kg/ha, was recommended for Anyako, Anyenui and Atiehifie soils respectively.