<p> Understanding the variability of physico-chemical properties of soil along a toposequence is essential for smallholder farming communities. However, these resource constraint farmers in Ghana’s Moist Semi-D...<p> Understanding the variability of physico-chemical properties of soil along a toposequence is essential for smallholder farming communities. However, these resource constraint farmers in Ghana’s Moist Semi-Deciduous Forest (MSDF) zone poorly understand how slope positions affect soil properties. Therefore, soil variability assessment along a toposequence was carried out on Bekwai-Nzima/Oda compound association. From the summit to valley bottom slope positions, soil samples were taken at two depths (0 - 20 and 20 - 50 cm). As shown by the coefficient of variation, topsoil (0 - 20 cm) had the highest variation compared to the subsoil (20 - 50 cm). The variations observed in most soil attributes (clay, silt, pH, CEC, SOC and TN) for the 0 to 20 and 20 to 50 cm depths were between eroded (summit and upper slopes) and depositional (lower slope and valley bottom) zones. The highly variable soil attributes were silt, TN, Av. P, and Av. K. However, bulk density and sand were the least variable irrespective of soil depth or toposequence. Pearson correlation analysis indicated a significant correlation (p < 0.05) between most soil attributes at the 0 - 20 and 20 - 50 cm depths at different slope positions. Principal component (PC) analysis indicated that the first four PCs explained more than 80% and 70% of the total variation for the 0 - 20 and 20 - 50 cm soil depths, respectively. Statistically, our results revealed a significant effect of slope position on soil properties (p < 0.05) and topography influenced soil characteristics and development. Soil pH, sand, silt and clay contents were less affected by slope gradient, which confirms the inherent nature of these highly weathered tropical soils. The findings of this study can serve as a reference for the formulation of soil management strategies for smallholder farm communities. </p>展开更多
Land-use conversion and unsustainable farming practices are degrading native forest ecosystems of Ghana’s humid savannah agro-ecological zone. This study assessed the impact of land-use change on soil C and N stocks ...Land-use conversion and unsustainable farming practices are degrading native forest ecosystems of Ghana’s humid savannah agro-ecological zone. This study assessed the impact of land-use change on soil C and N stocks in different land-use systems and soil types. A total of eighty (80) composite soil samples at two depths (0 - 20 cm and 20 - 50 cm) were sampled from five land use types (Forest, Woodland savannah, Grassland, Fallow and Cropland) for laboratory analyses. Particle size distribution, bulk density, pH, SOC and TN were determined using standard procedures. Results of the study indicated that C and N stocks were significantly lower in croplands (p < 0.05) compared to other land-use systems. There were significant interactions (p < 0.05) within land-use systems, soil types, and soil depth for soil C and N stocks. Acrisol and associated soils had the highest C and N stocks. A strong positive significant correlation (p < 0.05) was observed between C and N stocks with an R<sup>2</sup> value of 0.85 and 0.93 for the 0 - 20 and 20 - 50 cm depth, respectively. Soil C and N stocks in the study area were estimated to be 34.56 kg/m<sup>2</sup> and 4.63 kg/m<sup>2</sup> for soil types and 26.89 kg/m<sup>2</sup> and 3.39 kg/m2 for land use types, respectively for the 0 to 50 cm soil depth. Our findings indicated that the conversion of native forest to arable land has significantly reduced soil C and N stocks in the top 50 cm (0.50 m) soil layer by 50.77% and 47.77%, respectively. Therefore, we conclude that land-use change, soil type, and soil depth influenced soil C and N stocks of land-use systems in the humid savannah agro-ecological zone of Ghana.展开更多
The aim of the study was to characterize humus system of natural and artificial products. Humus systems from leonardite, lignite biotransformed with Trichoderma sp. （Plantagra）, plant materials after pyrolisis （cha...The aim of the study was to characterize humus system of natural and artificial products. Humus systems from leonardite, lignite biotransformed with Trichoderma sp. （Plantagra）, plant materials after pyrolisis （charcoal） and composts are compared. Humus systems are characterized by Kononova-Belchikova＇s method, and heavy metals content was measured by atomic absorption spectroscopy （AAS）. Humic acids from the International Humic Substances Society （IHSS） collection are the standards for humus substances quality of compared products. Data obtained for leonardite indicate that the studied substances from factory, Izmir, Turkey contain humic acids over 94%. Compared to the standard, heavy metals content in these materials demonstrate high amounts. Organic carbon content in the composts is very low compared to the leonardite materials and IHSS collection, where the heavy metals content is lower. Biotransformed lignite is characterized with lower content of organic carbon, but humic acids are with high degree of humification. Results obtained show that the fourth studied humus systems may be used in agriculture on base of the high humic acids content. It is recommended to measure heavy metals content before applying the materials in agriculture.展开更多
The ever-increasing human population has resulted in political pressure to increase crop production. Currently, smallholder farmers are expected to be environmentally considerate, adapt to extreme climatic conditions ...The ever-increasing human population has resulted in political pressure to increase crop production. Currently, smallholder farmers are expected to be environmentally considerate, adapt to extreme climatic conditions and deal with financial instability. Despite these recent developments, farmers and their farming activities in these rural environs of developing countries need to improve household food and income security on a sustainable basis. A minimum data set selected from extensive data was used to determine indicators for soil sustainability assessment. This method involved expert opinion and statistical data reduction techniques. The results indicated that SOC, MBC, BS, EC, Spo and sand were the most important variables selected as MDS using PC analysis. Forest and Grassland had a high sustainability index (SI) while Savannah woodland, Fallow and Cropland were rated not sustainable (NS). For Cumulative rating using the total dataset (CR-TDS), Forest had a high sustainability index (HS), Savannah woodland and Grassland were sustainable (S) compared to Fallow and Cropland, which were sustainable with high input (SWHI). Also, for cumulative rating using the minimum dataset (CR-MDS), Forest, Savannah woodland and Grassland had high sustainability (SH) indices compared to Fallow and Cropland, which were considered sustainable with high input (SWHI). Sustainability index (SI) and Cumulative rating (CR) using the total dataset (CR-TDS) had a strong correlation (R<sup>2</sup> = 0.91, p < 0.05) compared to SI versus CR-MDS (R<sup>2</sup> = 0.44, p < 0.05) and CR-TDS versus CR-MDS (R<sup>2</sup> = 0.60, p < 0.05). These methods consider that these management goals dictate soil functions affecting the selection of indicators. Using PCA and variance analysis, silt, clay, EC, SOC, MBC and CEC relating to soil texture and fertility were identified as the most influential (sensitive) indicators for soil sustainability assessment. The selected soil attributes can serve as target indicators for soil fertility restoration, erosion control and management in the Nkoranza district. Therefore, a farm-level sustainability index for small-scale and commercial farms is proposed based on readily available data for the Savannah Transition Agro-ecozone of Ghana.展开更多
Phytoextraction has been introduced as a new technology to clean up soils contaminated with heavy metals as the use of conventional methods to clean up the soil is very expensive and destructive to the ecosystem. Howe...Phytoextraction has been introduced as a new technology to clean up soils contaminated with heavy metals as the use of conventional methods to clean up the soil is very expensive and destructive to the ecosystem. However, using plants to clean up contaminated soils takes a considerable period before the contaminants are removed from the soil by the plants. This has necessitated the use of amendments to enhance phytoextraction in order to shorten the period of contaminants removal by plants. In view of this, a pot experiment was conducted to study the effect of various aminopolycarboxylic acids (EDTA, EDDS, NTA dry and NTA liquid) and two commercial fertilizers which are Hortrilon? and Fetrilon? on their ability to solubilize Cd and Zn in contaminated soils. It was observed that the inducing effect of EDTA on the solubility of Cd and Zn persisted throughout the experimental period. Initially, EDDS enhanced the solubility Cd and Zn, however, its effect dissipated with time. The application of both NTA dry (powder) and NTA liquid had a significant effect on the solubility of Zn as a result of the formation of Zn-NTA soluble complexes. Hortrilon? and Fetrilon? solubilized significant concentrations of both Cd and Zn with Hortrilon? having the greatest inducing effect on the solubility of Cd and Zn.展开更多
文摘<p> Understanding the variability of physico-chemical properties of soil along a toposequence is essential for smallholder farming communities. However, these resource constraint farmers in Ghana’s Moist Semi-Deciduous Forest (MSDF) zone poorly understand how slope positions affect soil properties. Therefore, soil variability assessment along a toposequence was carried out on Bekwai-Nzima/Oda compound association. From the summit to valley bottom slope positions, soil samples were taken at two depths (0 - 20 and 20 - 50 cm). As shown by the coefficient of variation, topsoil (0 - 20 cm) had the highest variation compared to the subsoil (20 - 50 cm). The variations observed in most soil attributes (clay, silt, pH, CEC, SOC and TN) for the 0 to 20 and 20 to 50 cm depths were between eroded (summit and upper slopes) and depositional (lower slope and valley bottom) zones. The highly variable soil attributes were silt, TN, Av. P, and Av. K. However, bulk density and sand were the least variable irrespective of soil depth or toposequence. Pearson correlation analysis indicated a significant correlation (p < 0.05) between most soil attributes at the 0 - 20 and 20 - 50 cm depths at different slope positions. Principal component (PC) analysis indicated that the first four PCs explained more than 80% and 70% of the total variation for the 0 - 20 and 20 - 50 cm soil depths, respectively. Statistically, our results revealed a significant effect of slope position on soil properties (p < 0.05) and topography influenced soil characteristics and development. Soil pH, sand, silt and clay contents were less affected by slope gradient, which confirms the inherent nature of these highly weathered tropical soils. The findings of this study can serve as a reference for the formulation of soil management strategies for smallholder farm communities. </p>
文摘Land-use conversion and unsustainable farming practices are degrading native forest ecosystems of Ghana’s humid savannah agro-ecological zone. This study assessed the impact of land-use change on soil C and N stocks in different land-use systems and soil types. A total of eighty (80) composite soil samples at two depths (0 - 20 cm and 20 - 50 cm) were sampled from five land use types (Forest, Woodland savannah, Grassland, Fallow and Cropland) for laboratory analyses. Particle size distribution, bulk density, pH, SOC and TN were determined using standard procedures. Results of the study indicated that C and N stocks were significantly lower in croplands (p < 0.05) compared to other land-use systems. There were significant interactions (p < 0.05) within land-use systems, soil types, and soil depth for soil C and N stocks. Acrisol and associated soils had the highest C and N stocks. A strong positive significant correlation (p < 0.05) was observed between C and N stocks with an R<sup>2</sup> value of 0.85 and 0.93 for the 0 - 20 and 20 - 50 cm depth, respectively. Soil C and N stocks in the study area were estimated to be 34.56 kg/m<sup>2</sup> and 4.63 kg/m<sup>2</sup> for soil types and 26.89 kg/m<sup>2</sup> and 3.39 kg/m2 for land use types, respectively for the 0 to 50 cm soil depth. Our findings indicated that the conversion of native forest to arable land has significantly reduced soil C and N stocks in the top 50 cm (0.50 m) soil layer by 50.77% and 47.77%, respectively. Therefore, we conclude that land-use change, soil type, and soil depth influenced soil C and N stocks of land-use systems in the humid savannah agro-ecological zone of Ghana.
文摘The aim of the study was to characterize humus system of natural and artificial products. Humus systems from leonardite, lignite biotransformed with Trichoderma sp. （Plantagra）, plant materials after pyrolisis （charcoal） and composts are compared. Humus systems are characterized by Kononova-Belchikova＇s method, and heavy metals content was measured by atomic absorption spectroscopy （AAS）. Humic acids from the International Humic Substances Society （IHSS） collection are the standards for humus substances quality of compared products. Data obtained for leonardite indicate that the studied substances from factory, Izmir, Turkey contain humic acids over 94%. Compared to the standard, heavy metals content in these materials demonstrate high amounts. Organic carbon content in the composts is very low compared to the leonardite materials and IHSS collection, where the heavy metals content is lower. Biotransformed lignite is characterized with lower content of organic carbon, but humic acids are with high degree of humification. Results obtained show that the fourth studied humus systems may be used in agriculture on base of the high humic acids content. It is recommended to measure heavy metals content before applying the materials in agriculture.
文摘The ever-increasing human population has resulted in political pressure to increase crop production. Currently, smallholder farmers are expected to be environmentally considerate, adapt to extreme climatic conditions and deal with financial instability. Despite these recent developments, farmers and their farming activities in these rural environs of developing countries need to improve household food and income security on a sustainable basis. A minimum data set selected from extensive data was used to determine indicators for soil sustainability assessment. This method involved expert opinion and statistical data reduction techniques. The results indicated that SOC, MBC, BS, EC, Spo and sand were the most important variables selected as MDS using PC analysis. Forest and Grassland had a high sustainability index (SI) while Savannah woodland, Fallow and Cropland were rated not sustainable (NS). For Cumulative rating using the total dataset (CR-TDS), Forest had a high sustainability index (HS), Savannah woodland and Grassland were sustainable (S) compared to Fallow and Cropland, which were sustainable with high input (SWHI). Also, for cumulative rating using the minimum dataset (CR-MDS), Forest, Savannah woodland and Grassland had high sustainability (SH) indices compared to Fallow and Cropland, which were considered sustainable with high input (SWHI). Sustainability index (SI) and Cumulative rating (CR) using the total dataset (CR-TDS) had a strong correlation (R<sup>2</sup> = 0.91, p < 0.05) compared to SI versus CR-MDS (R<sup>2</sup> = 0.44, p < 0.05) and CR-TDS versus CR-MDS (R<sup>2</sup> = 0.60, p < 0.05). These methods consider that these management goals dictate soil functions affecting the selection of indicators. Using PCA and variance analysis, silt, clay, EC, SOC, MBC and CEC relating to soil texture and fertility were identified as the most influential (sensitive) indicators for soil sustainability assessment. The selected soil attributes can serve as target indicators for soil fertility restoration, erosion control and management in the Nkoranza district. Therefore, a farm-level sustainability index for small-scale and commercial farms is proposed based on readily available data for the Savannah Transition Agro-ecozone of Ghana.
文摘Phytoextraction has been introduced as a new technology to clean up soils contaminated with heavy metals as the use of conventional methods to clean up the soil is very expensive and destructive to the ecosystem. However, using plants to clean up contaminated soils takes a considerable period before the contaminants are removed from the soil by the plants. This has necessitated the use of amendments to enhance phytoextraction in order to shorten the period of contaminants removal by plants. In view of this, a pot experiment was conducted to study the effect of various aminopolycarboxylic acids (EDTA, EDDS, NTA dry and NTA liquid) and two commercial fertilizers which are Hortrilon? and Fetrilon? on their ability to solubilize Cd and Zn in contaminated soils. It was observed that the inducing effect of EDTA on the solubility of Cd and Zn persisted throughout the experimental period. Initially, EDDS enhanced the solubility Cd and Zn, however, its effect dissipated with time. The application of both NTA dry (powder) and NTA liquid had a significant effect on the solubility of Zn as a result of the formation of Zn-NTA soluble complexes. Hortrilon? and Fetrilon? solubilized significant concentrations of both Cd and Zn with Hortrilon? having the greatest inducing effect on the solubility of Cd and Zn.
