Papers by Veronica N E Uzokwe
Freely nodulating soybean genotypes vary in their phosphorus (P) uptake and P-use efficiency (PUE... more Freely nodulating soybean genotypes vary in their phosphorus (P) uptake and P-use efficiency (PUE) in low-P soils. Understanding the genetic basis of these genotypes' performance is essential for effective breeding. To study the inheritance of PUE, we conducted crosses using two high-PUE genotypes, two moderate-PUE genotypes and two inefficient-PUE genotypes, and obtained F 1 , F 2, BC 1 and BC 2 populations. The inheritance of PUE was evaluated using a randomized complete block design. A generation mean analysis of phenotypic data showed that PUE was heritable, with complex inheritance patterns and the presence of additive, dominance and epistatic gene effects. Seed P, shoot P, root P, P-incorporation efficiency and PUE were largely quantitatively inherited traits. There were dominance, additive 9 additive and dominance 9 dominance gene effects on PUE, grain yield, shoot dry weight, 100-seed weight, root dry weight and shoot dry matter per unit P for populations grown under low-P conditions. Dominance effects were generally greater than additive effects on PUE-related indices. These PUE indices can be used to select P-efficient soybean genotypes from segregating populations.
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An experiment was carried out to examine the effectiveness of four different composts formulated ... more An experiment was carried out to examine the effectiveness of four different composts formulated from poultry (PM) and cowdung (CD) manures as primary constituents and two bulking agents namely sawdust (SD) and sorted refuse (SR) on some yield components of maize for two cropping seasons.
All compost mixtures were fortified with rock phosphate and urea. The compost treatments (PM/SD, PM/SR, CD/SD and CD/SR at ratio 3:1) were applied at 2.5 tonnes/ha, replicated three times with NPK (15:15:15) fertilizer applied at 300 kg/ha as reference treatment and a control (no compost, no
fertilizer), all arranged in a randomized complete design. The results showed that the composts significantly increased (P<0.05) all the maize yield components measured for the two cropping seasons. The PM/SD and PM/SR produced a higher grain yield of 3326 and 3218 kg/ha, respectively, for the
first cropping season and 1603 and 2423 kg/ha, respectively, for the second season compared to the cowdung-based composts, i.e. CD/SD and CD/SR with a range of 3073 and 3044 kg/ha and 1440 and 2051 kg/ha grain yield for the first and second seasons respectively. The sawdust-bulking agent
performed better in the first cropping season producing a mean grain yield of 3200 kg/ha compared to
sorted refuse with 3131 kg/ha. The study showed that types of bulking agent and animal manure used determined plant refuse to fortified composts.
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Aforestation is a key forest policy in Nigeria and it usually goes with arable farming. This pape... more Aforestation is a key forest policy in Nigeria and it usually goes with arable farming. This paper describes existing forest policies in Onigambari forest reserve, Oyo State, Nigeria and further examines the socio-economic/demographic characteristics of farming households as they affect poverty status of the households in the study area. Two-stage random sampling technique was employed in sampling the respondents. Structured questionnaires were used to collect data on the socio-economic/demographic characteristics as well as agricultural output/input used by the farming households in 2002/2003 planting season. Logit model and scale rating were employed in analysing the data. The study revealed that the main features of existing forest policies are reservation, management, and protection of forest resources. A poverty line of N1540 (one thousand five hundred and forty Nigeria Naira equivalent to $25USD) per month was obtained and 46% of the households were poor. Logit model showed that, age, marital status and occupational level of household head, household size and farm income were significant at between 1% (p<0.01) and 5% (p<0.05) confidence limit. The scale rating identified lack of financial resources, limited technical skill, information barriers and lack of infrastructure, in order of importance as constraints to agricultural production in the study area. It is, therefore, recommended that there is need to improve upon infrastructures in the study area to reduce farming household poverty.
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With larger planting areas being used in greenhouses, evaluating crop evapotranspiration in a gre... more With larger planting areas being used in greenhouses, evaluating crop evapotranspiration in a greenhouse has garnered
greater attention. Currently, calculating the reference crop evapotranspiration for a greenhouse crop through using the
Penman-Monteith formula recommended by FAO is difficult because the wind speed in a greenhouse is approximate
zero. In order to calculate reference crop evapotranspiration in a greenhouse by the Penman-Monteith modified formula,
a simplified model for calculating reference crop evapotranspiration in a greenhouse was proposed based on the energy
balance equation, which was the correlative function between reference crop evapotranspiration and radiation and
temperature. The model’s parameters were obtained through meteorological data taken from the inside of a greenhouse
in 2011. Then, the model was validated by using meteorological data within the greenhouse in 2012, and the fitted value
of the model agreed with the calculated value of the formulas with a determination coefficient (R2) of 0.9554. This
model is an easy means of calculating the reference crop evapotranspiration in a greenhouse because less meteorological
factors are needed. Furthermore, the model provides a theoretical basis for crop irrigation in greenhouses.
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Cassava (Manihot esculenta Crantz) production is constrained by many factors, including the viral... more Cassava (Manihot esculenta Crantz) production is constrained by many factors, including the viral cassava mosaic disease (CMD). This study was conducted to explore the potential of intercropping cassava with legumes to reduce CMD effects on cassava production. Local (Lyongo Kwimba) and improved (Suma) cassava varieties were intercropped with three types of grain legumes (groundnut, Arachis hypogea L. var. Upendo; cowpea, Vigna unguiculata (L.) Walp. var. Vuli; and green gram, Vigna radiata (L.) R. Wilczek var. Imara). Monocrops of cassava with and without NPK fertilizer were included as controls. The experiment was established using a randomized complete block design with four replications in a split-plot arrangement for three seasons. Cassava varieties intercropped with cowpeas, green gram, and groundnuts and cassava monocrops with and without NPK fertilizer constituted the main plot and sub-plots, respectively. Whitefly population counts and CMD severity and incidence were measured at regular intervals. Cropping system had a significant effect (P < 0.05) on whitefly populations and CMD severity. Small whitefly populations (0e7.5 individuals per leaf) and low CMD severity (1e2.4 on a 5-point scale) were recorded in improved and local cassava varieties intercropped with green gram. The local cassava variety intercropped with green gram showed low CMD incidences (0%e40%) in all seasons. Generally, growing cassava with green gram proved effective in reducing whitefly populations and CMD incidence and severity. Intercropping cassava with grain legumes may improve cassava production and food security in CMD-prone areas of the Lake Zone of Tanzania and areas with similar environments.
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The continuous increase in global population and simultaneous decrease in good-quality water reso... more The continuous increase in global population and simultaneous decrease in good-quality water resources emphasize the need of conjunctive use of groundwater and surface-water resources for irrigation. The optimal allocation of water resources can be achieved by employing an appropriate optimization technique. This paper presents an overview of the different programming techniques used for the conjunctive use planning and management of irrigated agriculture. Past papers on the applications of different programming techniques for the conjunctive use of different water sources are grouped into four categories: linear programming, nonlinear programming, dynamic programming, and genetic algorithms. Conclusions are provided based on this review, which could be useful for all stakeholders.
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A B S T R A C T Sustainable agriculture requires the careful optimization of the use of organic a... more A B S T R A C T Sustainable agriculture requires the careful optimization of the use of organic amendments to improve soil fertility while minimizing any harmful environmental effects. To understand the events that occur in soil after the addition of different organic amendments, we evaluated the nitrogen (N) mineralization dynamics in soil after adding organic amendments, and evaluated changes in the microbial population. The four organic amendments were fresh dairy cattle manure, fresh white clover, vegetable, fruit, and yard waste compost, and poplar tree compost. The N mineralization potential of each organic amendment was determined by analyzing total mineral nitrogen during a 97-day laboratory incubation experiment. Soils amended with clover released 240 mg N g À1 soil during the 97-day incubation, more than twice as much as that released from soils amended with manure or composts (76–100 mg N g À1 soil). At the end of the incubation, the net N mineralization in clover-amended soils was 54%, more than five times higher than that in soils amended with composts or manure (4%–9%). Nitrogen was mineralized faster in clover-amended soil (1.056 mg N g À1 soil day À1) than in soil amended with composts (0.361–0.417 mg N g À1 soil day À1). The microbial biomass carbon content was higher in clover-amended soil than in the soils amended with manure or composts. We monitored changes in the microbial population in amended soils by a phospholipid fatty acid (PLFA) analysis. On day 97, there were higher concentrations of total PLFAs in soils with organic amendments (e.g., 14.41 nmol g À1 in clover-amended soil) than in control soil without amendments (9.84 nmol g À1). Bacteria (Gram-positive and Gram-negative), actinomycetes, and fungi were more abundant in clover-amended soils than soils amended with manure or composts. The N mineralization potential varied among the four organic amendments. Therefore, the timing of application and the type of organic amendment should be matched to the nutrient needs of the crop. ã 2016 Z. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
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Crop Protection, 2011
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Crop Protection, 2011
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Other by Veronica N E Uzokwe
Cassava (Manihot esculenta Crantz) production is constrained by many factors, including the viral... more Cassava (Manihot esculenta Crantz) production is constrained by many factors, including the viral cassava mosaic disease (CMD). This study was conducted to explore the potential of intercropping cassava with legumes to reduce CMD effects on cassava production. Local (Lyongo Kwimba) and improved (Suma) cassava varieties were intercropped with three types of grain legumes (groundnut, Arachis hypogea L. var. Upendo; cowpea, Vigna unguiculata (L.) Walp. var. Vuli; and green gram,
Vigna radiata (L.) R. Wilczek var. Imara). Monocrops of cassava with and without NPK fertilizer were included as controls. The experiment was established using a randomized complete block design with four replications in a split-plot arrangement for three seasons. Cassava varieties intercropped with cowpeas, green gram, and ground- nuts and cassava monocrops with and without NPK fertilizer constituted the main plot and sub-plots, respectively. White fl y population counts and CMD severity and incidence were measured at regular intervals. Cropping system had a significant effect (
P<0.05) on white fly populations and CMD severity. Small whitefly populations (0 to 7.5 individuals per leaf) and low CMD severity (1 to 2.4 on a 5-point scale) were recorded in improved and local cassava varieties intercropped with green gram. The local cassava variety intercropped with green gram showed low CMD incidences (0% to 40%) in all seasons. Generally, growing cassava with green gram proved effective in reducing white
fly populations and CMD incidence and severity. Intercropping cassava with grain legumes may improve cassava production and food security in CMD-prone areas of the Lake Zone of Tanzania and areas with similar environments.
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Papers by Veronica N E Uzokwe
All compost mixtures were fortified with rock phosphate and urea. The compost treatments (PM/SD, PM/SR, CD/SD and CD/SR at ratio 3:1) were applied at 2.5 tonnes/ha, replicated three times with NPK (15:15:15) fertilizer applied at 300 kg/ha as reference treatment and a control (no compost, no
fertilizer), all arranged in a randomized complete design. The results showed that the composts significantly increased (P<0.05) all the maize yield components measured for the two cropping seasons. The PM/SD and PM/SR produced a higher grain yield of 3326 and 3218 kg/ha, respectively, for the
first cropping season and 1603 and 2423 kg/ha, respectively, for the second season compared to the cowdung-based composts, i.e. CD/SD and CD/SR with a range of 3073 and 3044 kg/ha and 1440 and 2051 kg/ha grain yield for the first and second seasons respectively. The sawdust-bulking agent
performed better in the first cropping season producing a mean grain yield of 3200 kg/ha compared to
sorted refuse with 3131 kg/ha. The study showed that types of bulking agent and animal manure used determined plant refuse to fortified composts.
greater attention. Currently, calculating the reference crop evapotranspiration for a greenhouse crop through using the
Penman-Monteith formula recommended by FAO is difficult because the wind speed in a greenhouse is approximate
zero. In order to calculate reference crop evapotranspiration in a greenhouse by the Penman-Monteith modified formula,
a simplified model for calculating reference crop evapotranspiration in a greenhouse was proposed based on the energy
balance equation, which was the correlative function between reference crop evapotranspiration and radiation and
temperature. The model’s parameters were obtained through meteorological data taken from the inside of a greenhouse
in 2011. Then, the model was validated by using meteorological data within the greenhouse in 2012, and the fitted value
of the model agreed with the calculated value of the formulas with a determination coefficient (R2) of 0.9554. This
model is an easy means of calculating the reference crop evapotranspiration in a greenhouse because less meteorological
factors are needed. Furthermore, the model provides a theoretical basis for crop irrigation in greenhouses.
Other by Veronica N E Uzokwe
Vigna radiata (L.) R. Wilczek var. Imara). Monocrops of cassava with and without NPK fertilizer were included as controls. The experiment was established using a randomized complete block design with four replications in a split-plot arrangement for three seasons. Cassava varieties intercropped with cowpeas, green gram, and ground- nuts and cassava monocrops with and without NPK fertilizer constituted the main plot and sub-plots, respectively. White fl y population counts and CMD severity and incidence were measured at regular intervals. Cropping system had a significant effect (
P<0.05) on white fly populations and CMD severity. Small whitefly populations (0 to 7.5 individuals per leaf) and low CMD severity (1 to 2.4 on a 5-point scale) were recorded in improved and local cassava varieties intercropped with green gram. The local cassava variety intercropped with green gram showed low CMD incidences (0% to 40%) in all seasons. Generally, growing cassava with green gram proved effective in reducing white
fly populations and CMD incidence and severity. Intercropping cassava with grain legumes may improve cassava production and food security in CMD-prone areas of the Lake Zone of Tanzania and areas with similar environments.
All compost mixtures were fortified with rock phosphate and urea. The compost treatments (PM/SD, PM/SR, CD/SD and CD/SR at ratio 3:1) were applied at 2.5 tonnes/ha, replicated three times with NPK (15:15:15) fertilizer applied at 300 kg/ha as reference treatment and a control (no compost, no
fertilizer), all arranged in a randomized complete design. The results showed that the composts significantly increased (P<0.05) all the maize yield components measured for the two cropping seasons. The PM/SD and PM/SR produced a higher grain yield of 3326 and 3218 kg/ha, respectively, for the
first cropping season and 1603 and 2423 kg/ha, respectively, for the second season compared to the cowdung-based composts, i.e. CD/SD and CD/SR with a range of 3073 and 3044 kg/ha and 1440 and 2051 kg/ha grain yield for the first and second seasons respectively. The sawdust-bulking agent
performed better in the first cropping season producing a mean grain yield of 3200 kg/ha compared to
sorted refuse with 3131 kg/ha. The study showed that types of bulking agent and animal manure used determined plant refuse to fortified composts.
greater attention. Currently, calculating the reference crop evapotranspiration for a greenhouse crop through using the
Penman-Monteith formula recommended by FAO is difficult because the wind speed in a greenhouse is approximate
zero. In order to calculate reference crop evapotranspiration in a greenhouse by the Penman-Monteith modified formula,
a simplified model for calculating reference crop evapotranspiration in a greenhouse was proposed based on the energy
balance equation, which was the correlative function between reference crop evapotranspiration and radiation and
temperature. The model’s parameters were obtained through meteorological data taken from the inside of a greenhouse
in 2011. Then, the model was validated by using meteorological data within the greenhouse in 2012, and the fitted value
of the model agreed with the calculated value of the formulas with a determination coefficient (R2) of 0.9554. This
model is an easy means of calculating the reference crop evapotranspiration in a greenhouse because less meteorological
factors are needed. Furthermore, the model provides a theoretical basis for crop irrigation in greenhouses.
Vigna radiata (L.) R. Wilczek var. Imara). Monocrops of cassava with and without NPK fertilizer were included as controls. The experiment was established using a randomized complete block design with four replications in a split-plot arrangement for three seasons. Cassava varieties intercropped with cowpeas, green gram, and ground- nuts and cassava monocrops with and without NPK fertilizer constituted the main plot and sub-plots, respectively. White fl y population counts and CMD severity and incidence were measured at regular intervals. Cropping system had a significant effect (
P<0.05) on white fly populations and CMD severity. Small whitefly populations (0 to 7.5 individuals per leaf) and low CMD severity (1 to 2.4 on a 5-point scale) were recorded in improved and local cassava varieties intercropped with green gram. The local cassava variety intercropped with green gram showed low CMD incidences (0% to 40%) in all seasons. Generally, growing cassava with green gram proved effective in reducing white
fly populations and CMD incidence and severity. Intercropping cassava with grain legumes may improve cassava production and food security in CMD-prone areas of the Lake Zone of Tanzania and areas with similar environments.