Browsing by Author "Danso, E.O."
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Item Assessing the impact of industrial and urban wastes on the irrigation water quality of three streams in a semi-arid coastal savannah catchment in Ghana(Journal of Food, Agriculture and Environment, 2013-02) Danso, E.O.; Abenney-Mickson, S.; Sabi, E.B.; Osae, S.K.; Akiti, T.T.Anthropogenic disturbances have had and continue to have an impact on the aquatic ecosystem of Ghana. The purpose of the study was to investigate the impact of anthropogenic activities on the irrigation water quality of three streams in southern Ghana. In the present study, the chemical quality of three streams under different (industrial and urban) land use within the same catchment in Ghana was examined using standard methods of Environmental Protection Agency (EPA) and American Public Health Association (APHA) to evaluate the effects of human activities on irrigation water quality. Analyses showed that all the streams were neutral to slightly alkaline. Relatively high concentration of salinity (ECw) and Sodium Absorption Ratio (SAR) were found in streams in industrial and high density residential areas. In addition, the mean values of major cations (Na+, K+, Ca2+ Mg2+) and anions (SO4 2-, Cl-HCO3 -) were high in industrial and high density residential areas. Trace metal (Fe2+, Mn2+ Zn2+Cu2+, Cr3+, Pb2+, Cd2+) concentrations were generally low and did not show any trend under different types of land uses. The results showed that all the three streams were generally unsuitable for irrigation and should be used with caution.Item Effect of rice straw biochar and irrigation on growth, dry matter yield and radiation-use efficiency of maize grown on an Acrisol in Ghana(journal of agronomy and crop science, 2019-11-18) Danso, E.O.; Yakubu, A.; Arthur, E.; Sabi, E.B.; Abenney-Mickson, S.; Andersen, M.N.In order to determine whether the current low productivity associated with rainfed cultivation on degraded soils in Ghana can be improved by biochar amendment and irrigation, field experiments with maize were conducted over two seasons in 2017 and 2018. Rice straw biochar at rates of 0 t/ha (B0), 15 t/ha (B15) and 30 t/ha (B30) was combined with irrigation regimes of full irrigation (I100), deficit irrigation (I60) and no irrigation (I0). The I100 treatment was irrigated to field capacity every 3–4 days according to time domain reflectometry measurements while the I60 treatment received 60% of the irrigation amount given to I100 but with the same irrigation frequency. The I0 treatment was not irrigated. In both seasons, the B30 treatment recorded the highest total dry matter yield (TDMY), intercepted photosynthetically active radiation (IPAR) and radiation-use efficiency (RUE) and these were significantly (p ≤ .05) higher than B0 except for RUE in 2017. Irrigation regimes did not significantly affect TDMY, IPAR and RUE in 2017 but compared to I100, I0 significantly reduced TDMY, IPAR and RUE in the relatively dryer 2018 season. Measured ratio vegetation indices differentiated biochar treatments earlier in the 2018 season than during 2017 and increase of leaf chlorophyll content indices with biochar rate in both seasons indicated that biochar amendment improved nitrogen uptake. Our study demonstrated that rice straw biochar is capable of increasing TDMY, IPAR and RUE of maize grown on degraded soils in Ghana. The study further showed that TDMY, IPAR and RUE of deficit irrigated maize for two seasons were similar to the counterpart fully irrigated maize and may be a viable water management option for farmers in Ghana to save irrigation water resourcesItem Heat tolerance in field grown tomatoes (Lycopersicon esculentum Mill.) under semi-arid conditions of west Africa(Acta Horticulturae, 2013-01) Kugblenu, Y.O.; Danso, E.O.; Ofori, K.; Andersen, M.N.; Abenney-Mickson, S.; Sabi, E.B.; Plauborg, F.L.; Abekoe, M.K.; Jørgensen, S.T.; Jensen, C.R.; Ofosu-Anim, J.One major reason for extremely low production of tomato in Ghana is that the length of the growing season last only for a few months due to the high temperature influx during the remaining months. The temperatures recorded during these months are above the optimum for tomato flowering and fruiting and this consequently affects yield. To solve this problem a number management practices may be undertaken such has growing heat tolerant tomato varieties or providing shade to mitigate the devastating effect of high temperatures. Therefore the present study was conducted outside the normal growing season from June to October, which has a mean temperature of 23°C. Heat tolerant tomato cultivars were grown from April to July with a mean temperature of 25°C to evaluate their performance under these conditions and to assess the effect of shading on the production of one of the genotypes. Fruiting percentage was significantly lower in exotic hybrids compared to a local variety. Different genotypes showed no differences in the production of viable pollen. Shading decreased final shoot and root biomass by 67 and 47%, respectively, whiles fruit yield was not affected. Also among cultivars yields were similar.Item Impact of rice straw biochar and irrigation on maize yield, intercepted radiation and water productivity in a tropical sandy clay loam(Field Crops Research, 2019-09-28) Danso, E.O.; Yakubu, A.; Darrah, Y.O.K.; Arthur, E.; Manevski, K.; Sabi, E.B.; Abenney-Mickson, S.; Ofori, K.; Plauborg, F.; Andersen, N.M.Continuous cultivation of staple crops to feed a growing population in the semi-deciduous agro-ecological zone of eastern Ghana (SDAG) has led to degraded soils and decreased crop yields. Biochar constitutes a potential remedy as it is often reported to improve soil health and increase crop yield of infertile soils. We thus conducted an experiment over two seasons to evaluate the impact of rice straw biochar on yield, radiation interception and water productivity of maize grown in the SDAG. The biochar was incorporated into the soil at rates of 0, 15 and 30 t ha−1 under irrigated and non-irrigated conditions. Maize grain yield (GY), accumulated intercepted photosynthetic active radiation (IPAR) and water productivity (WP) were compared among treatments. Regardless of season, the highest GY, IPAR and WP were achieved in plots amended with 30 t ha−1 biochar. A biochar rate of 30 t ha−1 increased grain yield by 17% and 36% and IPAR by 19% and 25% in 2017 and 2018 seasons, respectively, compared to a no biochar control. For both seasons, maize GY for the 15 t ha−1 treatment was statistically similar to that of 0 t ha−1 treatment whether irrigated or not. Irrigation increased grain yield by 9% and IPAR by 3% in 2017 and with 30% and 17%, respectively, in the dryer 2018 season. The effects of biochar and irrigation were additive. Water productivity from the 30 t ha−1 treatment was significantly higher in the non-irrigated than in the irrigated plots. Overall, in the SDAG, a biochar soil amendment rate of 30 t ha−1 might be a viable solution for farmers to increase yield and enhance water productivity of maize. Future studies should focus on the effect of biochar on the soil and crops over a longer time span in order to recommend viable management options to the farmers in SDAG.Item Response of Okra to Different Irrigation and Fertilization Methods in the Keta Sand Spit of Southeast Ghana(University of Ghana, 2014-07) Danso, E.O.; Abenney-Mickson, S.; Sabi, E.B.; Plauborg, F.; Abekoe, M.K.The sandy soil in the Keta Sand Spit, Southeast Ghana is infertile but is used for intensive vegetable cultivation. The vegetable production systems are managed with large amounts of irrigation water and fertilizers on sandy soils with low inherent water and nutrient retention capacities. The long term sustainability of a shallow groundwater lens which is used for irrigation in the area is threatened by several consecutive years of over withdrawal. Also, the shallow groundwater which is the primary irrigation water resource is prone to salinization from the Keta Lagoon, the Atlantic Ocean and brackish water underneath. There is excess input of phosphorus into the soil, through the continuous application of animal manure as the sole plant nutrient over the years. To ensure the sustainability of vegetable production at the Keta Spit, introduction of water saving irrigation systems and improved irrigation and fertilizer management schemes are important. Thus, the main aim of the study was to explore the productivity of drip irrigation compared with sprinkler and the traditional bucket irrigation in the Keta Sand Spit. Okra (Abelmoschus esculentum L) is widely grown in Southeast Ghana including the Keta Sand Spit area and was therefore used as the model crop. The study was conducted to evaluate the effect of different irrigation and fertilization methods on crop evapotranspiration, yield, nitrogen uptake, crop intercepted solar radiation, radiation use efficiency and water productivity of okra grown in a sandy soil. The basal crop coefficient (K cb ) was related to spectral reflectance measurements. The basal crop coefficient and soil evaporation coefficient (K e ) for drip and sprinkler irrigation were also estimated using FAO-56 methods. There were four seasons of study to determine the okra crop response to the following treatments: 1. sprinkler irrigation with manure spread on the soil (SSM); 2. sprinkler irrigation with manure placed around the plants (SPM); 3. Bucket irrigation with manure spread on the soil (BSM) 4. drip irrigation with manure placed around the plants (DPM) and 5. drip irrigation with fertigation (DFT); i.e. nutrient solution added to irrigation water. Fertigation was done only two times (two weeks after germination and immediately after flowering) during the first and second experiments while weekly fertigation (8 times from two weeks after germination) was done during the third and fourth experiments. Results from the experiments showed that the okra crop did not respond well when fertigation was done only twice (two weeks after germination and immediately after flowering) in the first and second experiments, probably due to nitrogen lost through leaching on the extremely sandy soil. However, a significant improvement on the yield response (P≤0.05) in the fertigated treatment compared to SSM, SPM, BSM and DPM was obtained when fertigation was done weekly for eight weeks. In the third experiment, with similar nitrogen application (89 kg N/ha) for all treatments, the highest yield, N uptake, water productivity (WP) and radiation use efficiency (RUE) were obtained under DFT and these parameters were significantly higher than the other treatments (SSM, SPM, BSM and DPM). Increase in fertilization in the fourth experiment (from 89 kg N ha -1 to 140 kg N ha -1 ) increased yield and WP compared to the three previous seasons, WP for DFT and DPM being significantly higher than for SSM, SPM and BSM. In the four seasons under sprinkler irrigation, yield was higher with manure placed around the plants (SPM) compared with manure evenly spread on the soil (SSM) even though the difference was not significant during the first and last experiments. The optimal crop N-uptake was 125 kg N/ha independent of season and adequate N-supply seemed especially important for ensuring sufficient light interception and radiation use efficiency during the fruiting stage of growth. Simple linear regression equations (R 2 > 0.9) were developed to provide an estimate of K cb during any time of the growth period with the fraction of the photosynthetically active radiation (f PAR ) data from spectrosense measurements. The dual K c values derived from FAO-56 methodology for sprinkler irrigation were K c and K c end : 1.05 whilst for K e 0.85 and K cb end : ini : 0.95, K e mid : 0.05 and K e end ini : 1.10, K c mid : 0.9 0.29, and for K cb ini : 0.15, K cb mid : 0.76 respectively. For drip irrigation the initial, mid and late season K c were 0.48, 0.89 and 0.98 with K e having 0.33, 0.04 and 0.22, and for K cb 0.15, 0.85 and 0.76 respectively. The K c data showed that the evaporative component was high during the initial stage of the growing season, due to the high frequency of irrigation. Seasonal crop water use (ET c ) for sprinkler irrigation were 346 mm, 339 mm, 379 mm, and 346 mm for the four experiments. For drip irrigation these were 233 mm, 236 mm, 269 mm and 233 mm. By adopting drip irrigation for okra, the seasonal crop water use could be reduced by nearly 30 %. From the results it is concluded that: 1. on coarse textured sandy soil drip irrigation with weekly fertigation resulted in significant water savings, yield increase and improvement in WP, RUE and nitrogen uptake compared with sprinkler irrigation combined with farm manure 2. The dual crop coefficient which allowed differentiation between crop transpiration (basal crop coefficient, K cb ) and evaporation from the soil (evaporation coefficient, K e ) should be used for irrigation scheduling in the Keta Sand Spit.