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1 Miezah, K.; Ofosu-Anim, J.; Budu, G. K. O.; Enu-Kwesi, L.; Cofie, Olufunke. 2008. Isolation and identification of some plant growth promoting substances in compost and co-compost. International Journal of Virology, 4(2):30-40. [doi: https://doi.org/10.3923/ijv.2008.30.40]
(Location: IWMI HQ Call no: e-copy only Record No: H042260)
(0.42 MB)
In this study, plant growth hormones in compost or co-compost prepared from human excreta and/or municipal solid waste were extracted and identified. Water (deionized) or 80% methanol (chilled) extracts were prepared from the composts for the isolation and identification of plant growth substances. The methanolic extracts of plant growth hormones fraction was further partitioned into cytokinin (fraction) using ethyl acetate and n-butanol; auxins (fraction) using diethyl ether and gibberellins (fraction) using sodium hydrogen carbonate and n-butanol. Five different concentrations of standard plant growth hormones; Benzyl Amino Purine (BAP), Gibberellic Acid (GA3) and Indole-3-Acetic Acid (IAA) were prepared and used in a bioassay test to compare the effects and concentration of the extracted plant growth hormones from the compost and co-compost. The presence of some plant growth hormones in the extracted samples from compost or co-compost was confirmed using the relative fluidity, (Rf) values of the co-chromatography using a standard hormone and the extracted plant growth hormones. The results indicated the presence of plant growth substances such as IAA, GA3 and cytokinins. In co-compost, the concentration of hormone were found to be 68.3 to 345.1 mg kg-1, 61.9 to 185.8 mg kg-1 and 250.4 to 312.7 mg kg-1 for auxins, cytokinins and gibberellins, respectively. Whereas in compost 42.0 to 248.8 mg kg-1, 33.1 to 198.3 mg kg-1 and 10.1 to 200.2 mg kg-1 of auxins, cytokinins and gibberellins, respectively were found.
2 Adamtey, Noah; Cofie, Olufunke; Ofosu-Budu, G. K.; Ofosu-Anim, J.; Laryea, K. B.; Forster, D. 2010. Effect of N-enriched co-compost on transpiration efficiency and water-use efficiency of maize (Zea mays L.) under controlled irrigation. Agricultural Water Management, 97(7):995–1005. [doi: https://doi.org/10.1016/j.agwat.2010.02.004]
(Location: IWMI HQ Call no: IWMI 631.7.2 G200 ADA Record No: H042817)
(0.58 MB)
Population growth, urban expansion and economic development are increasing competition for water use between agriculture and other users. In addition, the high rate of soil degradation and declining soil moisture in the Sub-Saharan African Region have called for several crop production management and irrigation options to improve soil fertility, reduce water use by crops and produce ‘more crops per drop of water’. Notwithstanding this, considerable variations exist in the literature on water-use efficiency, WUEcwu (economic yield per water used) for maize (Zea mays L.) across climates and soil management practices. Different views have been expressed on the effect of different rates of nitrogen (N) application on transpiration efficiency, TE (biomass produced per unit ofwater transpired). The objectives of the study were to assess the effect of different rates of N-enriched municipal waste co-compost and its derivatives on TE, WUEcwu and yield of maize (Z. mays L.) in comparison to inorganic fertiliser. The greenhouse pot experiment was conducted in Accra, Ghana on a sandy loam soil (Ferric Lixisol) using a split plot design. The main plot treatmentswere soil (S), dewatered faecal sludge(DFS), municipal solidwaste compost (C),co-compost from municipal solid waste and dewatered faecal sludge (Co), compost enriched with (NH4)2SO4 (EC), co-compost enriched with (NH4)2SO4 (ECO), (NH4)2SO4 and NPK15–15–15 + (NH4)2SO4. The sub-plot treatments were different rates of application of nitrogen fertiliser applied at the rate of 91, 150 and 210 kg N ha1 respectively. Maize cv. Abelehii was grown in a poly bag filledwith 15 kg soil. Eight plants per treatment were selected randomly and used for the collection of data on growth parameters forth-nightly. At physiological maturity two plants per treatment were also selected randomly from each treatment plot for yield data. The results showed that TE of maize (Z. mays) varied for the different treatments and these are 6.9 Pa in soil (S) alone to 8.6 Pa in ECO. Increase in N application rate increased TE at the vegetative phase for fast nutrient releasing fertilisers (DFS, ECO, EC, NPK + (NH4)2SO4, (NH4)2SO4) and at the reproductive phase for slow nutrient releasing fertilisers (C and CO). Water-use efficiency increased significantly as rate of N application increased. Treatment ECO improved crop WUEcwu and was 11% and 4 times higher than that forNPK + (NH4)2SO4 or soil alone; and 18–36% higher than those for DFS and CO. Treatment ECO used less amount of water to produce drymatter yield (DMY) and grain yield (GY) that was 5.2%and 12.6%, respectively, higher thanNPK + (NH4)2SO4. Similarly, the DMY and GY for ECO was 8.9–18.5% and 23.4–34.7%, respectively, higher than DFS and CO. High nutrient (N and K) uptake, TE, and low leaf senescence accounts for 83% of the variations in DMY whereas WUEcwu accounts for 99% of the variations in GY. Thus, the study concluded that different sources of fertiliser increased TE and WUEcwu of maize differently as N application rate increases.
3 Lente, I.; Keraita, Bernard; Drechsel, Pay; Ofosu-Anim, J.; Brimah, A. K. 2012. Risk assessment of heavy-metal contamination on vegetables grown in long-term wastewater irrigated urban farming sites in Accra, Ghana. Water Quality, Exposure and Health, 4(4):179-186. [doi: https://doi.org/10.1007/s12403-012-0077-8]
Risk assessment ; Heavy metals ; Contamination ; Vegetable growing ; Urban agriculture ; Wastewater irrigation ; Public health ; Sampling ; Indicators / Ghana / Accra
(Location: IWMI HQ Call no: e-copy only Record No: H045012)
(0.48 MB)
Assessment was done of heavy-metal contamination and its related health risks in urban vegetable farming in Accra. Samples of irrigation water (n = 120), soil (n = 144) and five different kinds of vegetable (n = 240) were collected and analyzed for copper, zinc, lead, cadmium, chromium, nickel and cobalt. All water, soil and vegetable samples contained detectable concentrations of each of the seven heavy metals except for irrigation water which had no detectable chromium, cadmium and cobalt. All heavy-metal levels were below permissible limits except lead on vegetables which was 1.8–3.5 times higher. Health risk assessments showed for all elements that normal consumption of each of the vegetables assessed poses no risk. The highest hazard index obtained was 42 % for wastewater irrigated cabbage. Though within permissible limits, cabbage and ayoyo had the highest potential risk. Compared with previous studies on the same sites, the data show that the risk from heavy metals is less significance than that from pathogen contamination which has positive implications for risk mitigation.
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