The West African Medical Journal and Nigerian Medical Dental Practitioner, Dec 1, 2014
Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop resi... more Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop residues by affecting the activities of residue decomposers or by forming protein complexes. A laboratory microcosm incubation study was conducted to assess the effect of three concentrations of ferulic, vanillic and tannic acids on N 2 O emissions and inorganic N dynamics in a tropical soil amended with cowpea residue. The results show that N 2 O emission and mineral N concentrations in the sole cowpea amended soils were significantly higher than in all the polyphenol treatments. Decrease in N 2 O emissions and N concentrations showed a direct relation with the polyphenol concentrations. However, at the same concentration, the polyphenols did not differ significantly in their ability to decrease N 2 O emissions and N concentrations even though tannic acid showed the highest numerical decrease. The tannic acid lowered N mineralisation and N 2 O production through protein binding while ferulic and vanillic acids decreased N 2 O production through N immobilisation by stimulating microbial activity. It is concluded that the addition of polyphenols to tropical soils amended with cowpea residue is likely to lower N 2 O emissions and inorganic N concentration, but the magnitude of reduction will depend on the type and concentration of the polyphenol compounds added.
Soil organic matter is important because it impacts all soil quality functions. Much less informa... more Soil organic matter is important because it impacts all soil quality functions. Much less information is available on the dynamics of the residual carbon and nitrogen content and their distribution in continuously cropped arable fields.
The immediate supply of K by soils to growing plants derives mainly from the K that is labile whe... more The immediate supply of K by soils to growing plants derives mainly from the K that is labile whereas the long term K nutrition of plants depends on the non-labile K. The dynamic relationship between these forms of K constitutes the dynamics of K in soils. Most Ghanaian farmers grow root and tuberous crops which have high K requirements. Knowledge of K dynamics in soils is therefore essential for K management to sustain crop production and management of agro-ecological environments in Ghana. Quantity-Intensity isotherms provide a better overview of K dynamics in soils. Therefore, Quantity/Intensity (Q/I) curves were used in this study to evaluate the dynamics of K in ten soil series representing the major agro-ecological zones of Ghana. K dynamics in the soils were found to be influenced by some soil properties. Significant correlations were found between soil properties and Q/I parameters; and among equilibrium solution parameters and Q/I parameters. There was no significant variat...
ABSTRACT In the face of climate change, quantification of the emission of nitrous oxide from soil... more ABSTRACT In the face of climate change, quantification of the emission of nitrous oxide from soils in relation to sufficient N availability for crop uptake has assumed much significance. This study used the 15N stable isotope technique, under controlled laboratory conditions, to quantify the interactive effect on and relative contributions of the component species to N2O emission and mineral N dynamics in a tropical luvisol incorporated with different rates of cowpea-maize residue mixtures. The results show that increasing the maize residue proportion in the mixture significantly decreases N2O emission compared to the sole cowpea incorporation but increases mineral N concentration compared to sole maize residue incorporation. It is concluded that mixing low C:N ratio cowpea residue with high C:N ratio maize residue has potential for N management in tropical legume-cereal intercropping systems with the view to minimizing N2O emission while making N available for crop uptake.
A study was conducted to determine the distribution of forms of K (water soluble K, exchangeable ... more A study was conducted to determine the distribution of forms of K (water soluble K, exchangeable K, non exchangeable K, and total K) of potassium in some Ghanaian soils occurring along toposequence using standard laboratory procedures. The soils were the Edina, Atabadzi, Benya, Udu and Kakum series (Acrisols), which form the Edina catena. The concentrations of total K in the soils ranged from 0.64 to 2.37 (cmol (+) kg-1) with Kakum series showing the lowest (P < 0.05) value. Water soluble K and exchangeable K concentrations in the soils ranged from 0.05 to 0.25 c mol (+) kg-1 , and 0.26 to 0.89 cmol (+) kg-1 , respectively, with the Kakum series again showing the lowest values (P < 0.05) for both K forms. The Edina series, occurring at the summit of the catena, showed the highest concentrations of both water soluble and exchangeable K. In the study non-exchangeable K concentrations measured in the soils varied between 0.20 and 1.25 cmol (+) kg-1. The study showed that exchangeable K constituted the highest proportion of the total K measured in the soils, while the proportion of water soluble K in the total K measured was the lowest. Pooling all the data obtained in the study, water soluble K and exchangeable K concentrations positively correlated with organic matter, cation exchange capacity and percentage bas saturation.
A laboratory microcosm incubation was conducted to study the influence of mixed cowpea-maize resi... more A laboratory microcosm incubation was conducted to study the influence of mixed cowpea-maize residues on N 2 O emission and N mineralization in a tropical acrisol. The soils were incorporated with different ratios of cowpea:maize mixtures on weight basis: 100:0, 75:25, 50:50, 25:75 and 0:100, and a control treatment in which there was no residue incorporation. The results show that N 2 O and CO 2 emissions were higher in the sole cowpea treatment (100:0) than the sole maize treatment (0:100) and the control. However, cowpea-maize residue mixtures increased the proportion of N lost as N 2 O compared to the sole treatments. This interactive effect was highest in the 75:25 treatment. The 50:50 treatment showed moderate N 2 O emission compared to the 100:0, 75:25 and 25:75 treatments but with corresponding steady N mineralization and appreciable mineral N concentration. It is concluded that mixing cowpea-maize residues might increase the proportion of N lost as N 2 O in a tropical acrisol. However, compared to the other residue mixture treatments, mixing cowpea-maize residues in equal proportions on weight basis might offer a path to reducing N 2 O emissions while maintaining a steady N mineralization without risking good N supply in acrisols. The study therefore offers potential for mitigating greenhouse gas emissions while maintaining soil fertility in tropical acrisols.
Nitrous oxide emissions are usually increased following incorporation of crop residues or inorgan... more Nitrous oxide emissions are usually increased following incorporation of crop residues or inorganic N fertiliser into soil, but the effect of combining these inputs at different proportions on N dynamics and N O emissions has 2 yet to be adequately examined. The interactive effect of combining crop residues barley (Hordereum vulgare) and clover (Trifolium pretense) and inorganic N fertiliser (NH NO ) on N O emission and mineral N dynamics under 74
Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop resi... more Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop residues by affecting the activities of residue decomposers or by forming protein complexes. A laboratory microcosm incubation study was conducted to assess the effect of three concentrations of ferulic, vanillic and tannic acids on N 2 O emissions and inorganic N dynamics in a tropical soil amended with cowpea residue. The results show that N 2 O emission and mineral N concentrations in the sole cowpea amended soils were significantly higher than in all the polyphenol treatments. Decrease in N 2 O emissions and N concentrations showed a direct relation with the polyphenol concentrations. However, at the same concentration, the polyphenols did not differ significantly in their ability to decrease N 2 O emissions and N concentrations even though tannic acid showed the highest numerical decrease. The tannic acid lowered N mineralisation and N 2 O production through protein binding while ferulic and vanillic acids decreased N 2 O production through N immobilisation by stimulating microbial activity. It is concluded that the addition of polyphenols to tropical soils amended with cowpea residue is likely to lower N 2 O emissions and inorganic N concentration, but the magnitude of reduction will depend on the type and concentration of the polyphenol compounds added.
The effects of stand-age of Acacia sp on plant litter turnover and decomposition, soil physical p... more The effects of stand-age of Acacia sp on plant litter turnover and decomposition, soil physical properties and nutrient elements were studied in revegetated gold-mined soils. Litter in the 3-and 6-year plantation soils were significantly lower (P < 0.05) than the forest soil, whilst 9-and 12-year old revegetated soils had litter significantly higher (P < 0.05) than the forest soil. Biomass decomposition constants measured in all treatments were statistically similar, ranging from 1.03 in the forest soil to 0.94 in the revegetated treatments. Total N concentrations were higher in the forest, 12-year and 9-year revegetated treatments and varied from 0.20% to 0.50%. Organic carbon concentrations followed the increasing trend 3-year < 6-year < 9-year < 12-year < forest. Exchangeable K concentrations measured in all the soils were lower than 0.6 cmol kg,-1. Field moisture capacity (12.6 – 20.3 %) and infiltration rates (25.2 – 31.1 cm h-1) in the 3-year, 6-year and 9-year stands were significantly lower than in the forest and 12-year stand whilst soil bulk density values were higher in the 3-year, 6-year and 9-year than in the forest and 12-year stands. The study indicates that after 12 years of revegetation with Acacia sp, soil physical characteristics such as bulk density, moisture holding capacity and infiltration rates improved to levels comparable to those found under un-mined soils and that revegetation is a good strategy for restoring the fertility of gold-mined soils.
Emissions of N 2 O were measured following addition of 15 N-labelled residues of tropical plant s... more Emissions of N 2 O were measured following addition of 15 N-labelled residues of tropical plant species [Vigna unguiculata (cowpea), Mucuna pruriens and Leucaena leucocephala] to a Ferric Luvisol from Ghana at a rate of 100 mg N ⁄ kg soil under controlled environment conditions. Residues were also applied in different ratio combinations with inorganic N fertilizer, at a total rate of 100 mg N ⁄ kg soil. N 2 O emissions were increased after addition of residues, and further increased with combined (ratio) applications of residues and inorganic N fertilizer. However, 15 N-N 2 O production was low and short-lived in all treatments, suggesting that most of the measured N 2 ON was derived from the applied fertilizer or native soil mineral N pools. There was no consistent trend in magnitude of emissions with increasing proportion of inorganic fertilizer in the application. The positive interactive effect between residue-and fertilizer-N sources was most pronounced in the 25:75 Leucaena:fertilizer and cowpea:fertilizer treatments where 1082 and 1130 mg N 2 ON ⁄ g residue were emitted over 30 days. N 2 O (log e) emission from all residue amended treatments was positively correlated with the residue C:N ratio, and negatively correlated with residue polyphenol content, polyphenol:N ratio and (lignin + polyphenol):N ratio, indicating the role of residue chemical composition in regulating emissions even when combined with inorganic fertilizer. The positive interactive effect in our treatments suggests that it is unlikely that combined applications of residues and inorganic fertilizer can lower N 2 O emissions unless the residue is of very low quality promoting strong immobilisation of soil mineral N.
The possibility of growing duckweed (Lemna minor) on anaerobic digester effluent and its nitrogen... more The possibility of growing duckweed (Lemna minor) on anaerobic digester effluent and its nitrogen and phosphorus acquisition potential was studied. Duckweed was cultured for 21 days on an anaerobic digester effluent using two methods: static aeration (SAT) and normal batch reactor (NBR) techniques, respectively. The treatments involved pure effluent and 1/10, 1/25 and 1/50 effluent dilutions, respectively. Fifty duckweed fronds were grown in the anaerobic digester effluent for 21 days. At the end of the growth period, phosphate levels, total ammonium nitrogen (TAN) and total oxidized nitrogen (TON) contents of the growth media were determined. Total nitrogen concentration and orthophosphate P content in the duckweed were also determined. The results obtained indicated that duckweed was capable of growing on the anaerobic digester effluent provided its TAN content did not exceed 42 mg N l -1 . Nitrogen uptake by the duckweed from the effluent ranged between 53 and 115.7 mg l -1 whereas P uptake varied from 1.40 to 8.4 mg P l -1 . The relative growth rate of duckweed in the anaerobic digester effluent was observed to be comparable to literature value of 0.22 mg day -1 . The results have demonstrated that duckweed has the potential to recover N and P from anaerobic digester effluent.
The West African Medical Journal and Nigerian Medical Dental Practitioner, Dec 1, 2014
Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop resi... more Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop residues by affecting the activities of residue decomposers or by forming protein complexes. A laboratory microcosm incubation study was conducted to assess the effect of three concentrations of ferulic, vanillic and tannic acids on N 2 O emissions and inorganic N dynamics in a tropical soil amended with cowpea residue. The results show that N 2 O emission and mineral N concentrations in the sole cowpea amended soils were significantly higher than in all the polyphenol treatments. Decrease in N 2 O emissions and N concentrations showed a direct relation with the polyphenol concentrations. However, at the same concentration, the polyphenols did not differ significantly in their ability to decrease N 2 O emissions and N concentrations even though tannic acid showed the highest numerical decrease. The tannic acid lowered N mineralisation and N 2 O production through protein binding while ferulic and vanillic acids decreased N 2 O production through N immobilisation by stimulating microbial activity. It is concluded that the addition of polyphenols to tropical soils amended with cowpea residue is likely to lower N 2 O emissions and inorganic N concentration, but the magnitude of reduction will depend on the type and concentration of the polyphenol compounds added.
Soil organic matter is important because it impacts all soil quality functions. Much less informa... more Soil organic matter is important because it impacts all soil quality functions. Much less information is available on the dynamics of the residual carbon and nitrogen content and their distribution in continuously cropped arable fields.
The immediate supply of K by soils to growing plants derives mainly from the K that is labile whe... more The immediate supply of K by soils to growing plants derives mainly from the K that is labile whereas the long term K nutrition of plants depends on the non-labile K. The dynamic relationship between these forms of K constitutes the dynamics of K in soils. Most Ghanaian farmers grow root and tuberous crops which have high K requirements. Knowledge of K dynamics in soils is therefore essential for K management to sustain crop production and management of agro-ecological environments in Ghana. Quantity-Intensity isotherms provide a better overview of K dynamics in soils. Therefore, Quantity/Intensity (Q/I) curves were used in this study to evaluate the dynamics of K in ten soil series representing the major agro-ecological zones of Ghana. K dynamics in the soils were found to be influenced by some soil properties. Significant correlations were found between soil properties and Q/I parameters; and among equilibrium solution parameters and Q/I parameters. There was no significant variat...
ABSTRACT In the face of climate change, quantification of the emission of nitrous oxide from soil... more ABSTRACT In the face of climate change, quantification of the emission of nitrous oxide from soils in relation to sufficient N availability for crop uptake has assumed much significance. This study used the 15N stable isotope technique, under controlled laboratory conditions, to quantify the interactive effect on and relative contributions of the component species to N2O emission and mineral N dynamics in a tropical luvisol incorporated with different rates of cowpea-maize residue mixtures. The results show that increasing the maize residue proportion in the mixture significantly decreases N2O emission compared to the sole cowpea incorporation but increases mineral N concentration compared to sole maize residue incorporation. It is concluded that mixing low C:N ratio cowpea residue with high C:N ratio maize residue has potential for N management in tropical legume-cereal intercropping systems with the view to minimizing N2O emission while making N available for crop uptake.
A study was conducted to determine the distribution of forms of K (water soluble K, exchangeable ... more A study was conducted to determine the distribution of forms of K (water soluble K, exchangeable K, non exchangeable K, and total K) of potassium in some Ghanaian soils occurring along toposequence using standard laboratory procedures. The soils were the Edina, Atabadzi, Benya, Udu and Kakum series (Acrisols), which form the Edina catena. The concentrations of total K in the soils ranged from 0.64 to 2.37 (cmol (+) kg-1) with Kakum series showing the lowest (P < 0.05) value. Water soluble K and exchangeable K concentrations in the soils ranged from 0.05 to 0.25 c mol (+) kg-1 , and 0.26 to 0.89 cmol (+) kg-1 , respectively, with the Kakum series again showing the lowest values (P < 0.05) for both K forms. The Edina series, occurring at the summit of the catena, showed the highest concentrations of both water soluble and exchangeable K. In the study non-exchangeable K concentrations measured in the soils varied between 0.20 and 1.25 cmol (+) kg-1. The study showed that exchangeable K constituted the highest proportion of the total K measured in the soils, while the proportion of water soluble K in the total K measured was the lowest. Pooling all the data obtained in the study, water soluble K and exchangeable K concentrations positively correlated with organic matter, cation exchange capacity and percentage bas saturation.
A laboratory microcosm incubation was conducted to study the influence of mixed cowpea-maize resi... more A laboratory microcosm incubation was conducted to study the influence of mixed cowpea-maize residues on N 2 O emission and N mineralization in a tropical acrisol. The soils were incorporated with different ratios of cowpea:maize mixtures on weight basis: 100:0, 75:25, 50:50, 25:75 and 0:100, and a control treatment in which there was no residue incorporation. The results show that N 2 O and CO 2 emissions were higher in the sole cowpea treatment (100:0) than the sole maize treatment (0:100) and the control. However, cowpea-maize residue mixtures increased the proportion of N lost as N 2 O compared to the sole treatments. This interactive effect was highest in the 75:25 treatment. The 50:50 treatment showed moderate N 2 O emission compared to the 100:0, 75:25 and 25:75 treatments but with corresponding steady N mineralization and appreciable mineral N concentration. It is concluded that mixing cowpea-maize residues might increase the proportion of N lost as N 2 O in a tropical acrisol. However, compared to the other residue mixture treatments, mixing cowpea-maize residues in equal proportions on weight basis might offer a path to reducing N 2 O emissions while maintaining a steady N mineralization without risking good N supply in acrisols. The study therefore offers potential for mitigating greenhouse gas emissions while maintaining soil fertility in tropical acrisols.
Nitrous oxide emissions are usually increased following incorporation of crop residues or inorgan... more Nitrous oxide emissions are usually increased following incorporation of crop residues or inorganic N fertiliser into soil, but the effect of combining these inputs at different proportions on N dynamics and N O emissions has 2 yet to be adequately examined. The interactive effect of combining crop residues barley (Hordereum vulgare) and clover (Trifolium pretense) and inorganic N fertiliser (NH NO ) on N O emission and mineral N dynamics under 74
Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop resi... more Polyphenols can influence the rate of N 2 O emission and N mineralization in leguminous crop residues by affecting the activities of residue decomposers or by forming protein complexes. A laboratory microcosm incubation study was conducted to assess the effect of three concentrations of ferulic, vanillic and tannic acids on N 2 O emissions and inorganic N dynamics in a tropical soil amended with cowpea residue. The results show that N 2 O emission and mineral N concentrations in the sole cowpea amended soils were significantly higher than in all the polyphenol treatments. Decrease in N 2 O emissions and N concentrations showed a direct relation with the polyphenol concentrations. However, at the same concentration, the polyphenols did not differ significantly in their ability to decrease N 2 O emissions and N concentrations even though tannic acid showed the highest numerical decrease. The tannic acid lowered N mineralisation and N 2 O production through protein binding while ferulic and vanillic acids decreased N 2 O production through N immobilisation by stimulating microbial activity. It is concluded that the addition of polyphenols to tropical soils amended with cowpea residue is likely to lower N 2 O emissions and inorganic N concentration, but the magnitude of reduction will depend on the type and concentration of the polyphenol compounds added.
The effects of stand-age of Acacia sp on plant litter turnover and decomposition, soil physical p... more The effects of stand-age of Acacia sp on plant litter turnover and decomposition, soil physical properties and nutrient elements were studied in revegetated gold-mined soils. Litter in the 3-and 6-year plantation soils were significantly lower (P < 0.05) than the forest soil, whilst 9-and 12-year old revegetated soils had litter significantly higher (P < 0.05) than the forest soil. Biomass decomposition constants measured in all treatments were statistically similar, ranging from 1.03 in the forest soil to 0.94 in the revegetated treatments. Total N concentrations were higher in the forest, 12-year and 9-year revegetated treatments and varied from 0.20% to 0.50%. Organic carbon concentrations followed the increasing trend 3-year < 6-year < 9-year < 12-year < forest. Exchangeable K concentrations measured in all the soils were lower than 0.6 cmol kg,-1. Field moisture capacity (12.6 – 20.3 %) and infiltration rates (25.2 – 31.1 cm h-1) in the 3-year, 6-year and 9-year stands were significantly lower than in the forest and 12-year stand whilst soil bulk density values were higher in the 3-year, 6-year and 9-year than in the forest and 12-year stands. The study indicates that after 12 years of revegetation with Acacia sp, soil physical characteristics such as bulk density, moisture holding capacity and infiltration rates improved to levels comparable to those found under un-mined soils and that revegetation is a good strategy for restoring the fertility of gold-mined soils.
Emissions of N 2 O were measured following addition of 15 N-labelled residues of tropical plant s... more Emissions of N 2 O were measured following addition of 15 N-labelled residues of tropical plant species [Vigna unguiculata (cowpea), Mucuna pruriens and Leucaena leucocephala] to a Ferric Luvisol from Ghana at a rate of 100 mg N ⁄ kg soil under controlled environment conditions. Residues were also applied in different ratio combinations with inorganic N fertilizer, at a total rate of 100 mg N ⁄ kg soil. N 2 O emissions were increased after addition of residues, and further increased with combined (ratio) applications of residues and inorganic N fertilizer. However, 15 N-N 2 O production was low and short-lived in all treatments, suggesting that most of the measured N 2 ON was derived from the applied fertilizer or native soil mineral N pools. There was no consistent trend in magnitude of emissions with increasing proportion of inorganic fertilizer in the application. The positive interactive effect between residue-and fertilizer-N sources was most pronounced in the 25:75 Leucaena:fertilizer and cowpea:fertilizer treatments where 1082 and 1130 mg N 2 ON ⁄ g residue were emitted over 30 days. N 2 O (log e) emission from all residue amended treatments was positively correlated with the residue C:N ratio, and negatively correlated with residue polyphenol content, polyphenol:N ratio and (lignin + polyphenol):N ratio, indicating the role of residue chemical composition in regulating emissions even when combined with inorganic fertilizer. The positive interactive effect in our treatments suggests that it is unlikely that combined applications of residues and inorganic fertilizer can lower N 2 O emissions unless the residue is of very low quality promoting strong immobilisation of soil mineral N.
The possibility of growing duckweed (Lemna minor) on anaerobic digester effluent and its nitrogen... more The possibility of growing duckweed (Lemna minor) on anaerobic digester effluent and its nitrogen and phosphorus acquisition potential was studied. Duckweed was cultured for 21 days on an anaerobic digester effluent using two methods: static aeration (SAT) and normal batch reactor (NBR) techniques, respectively. The treatments involved pure effluent and 1/10, 1/25 and 1/50 effluent dilutions, respectively. Fifty duckweed fronds were grown in the anaerobic digester effluent for 21 days. At the end of the growth period, phosphate levels, total ammonium nitrogen (TAN) and total oxidized nitrogen (TON) contents of the growth media were determined. Total nitrogen concentration and orthophosphate P content in the duckweed were also determined. The results obtained indicated that duckweed was capable of growing on the anaerobic digester effluent provided its TAN content did not exceed 42 mg N l -1 . Nitrogen uptake by the duckweed from the effluent ranged between 53 and 115.7 mg l -1 whereas P uptake varied from 1.40 to 8.4 mg P l -1 . The relative growth rate of duckweed in the anaerobic digester effluent was observed to be comparable to literature value of 0.22 mg day -1 . The results have demonstrated that duckweed has the potential to recover N and P from anaerobic digester effluent.
Uploads
Papers by Kwame Frimpong