Effect of Variety and Storage on the Tuber Quality of Potatoes Cultivated in the Eastern Highlands of Ethiopia

Eight potato varieties: five improved and released by Haramaya University and three from smallholders potato farmers variety (eastern Hararghe, Oromia, Ethiopia) were planted following cultural practices in RCBD with three replications to assess tuber quality and storage performance differences. Tubers were harvested in 2011. After curing at 15-18oC and relative humidity of 75-82% for one week, the tubers were separately stored at 8-160C and relative humidity of 69-83% for 20, 40, and 60 days in a ventilated storehouse in CRD with three replication per treatment. The results showed significant differences (P< 0.05) due to variety. Storage duration significantly reduced dry matter, specific gravity and amylose contents with no significant changes in ash, crude fibre, potassium and phosphorus contents. The highest dry matter, specific gravity, and amylose contents were obtained for the improved variety Chala whereas the lowest was for the farmers’ variety Jarso. The highest crude protein content was recorded for the farmers’ variety Mashenadima and the lowest was for the improved variety Zemen. The results revealed that potato tubers with superior physicochemical qualities, most of which are released varieties retained their qualities after storage for longer durations, whereas those with lower qualities could be stored only for shorter durations

Evaluation of soil solarisation and bio-fumigation for the management of bacterial spot of tomato

Soil-borne plant pathogens cause heavy losses to all major crops, leading to reductions in both yield and quality. Soil solarisation and bio-fumigation offer disease management options that are safe and reduce the use of pesticides for soil-borne plant pathogens. Mustard plant releases antimicrobial hydrolysis products, notably isothiocyanates when used as a bio-fumigant. Bacterial spot of tomato caused by Xanthomonas campestris pv. vesicatoria (Xcv) can survive in soil and plant debris, which serve as a primary inoculum for infecting the next tomato crop. An experiment was carried out with the objective of evaluating effects of soil solarisation and the use of Ethiopian mustard (Brassica carinata A. Braun) as a bio-fumigant to control bacterial spot disease and on yield of tomato. The treatments consisted of six types of potted soil medium (solarised at Haramaya and Dire Dawa, bio-fumigated, biofumigated as well as solarised at Haramaya and Dire Dawa, and untreated control as non-solarised non-biofumigated pots). Treated tomato seeds were planted and fruit yields were compared among treatments. Potted soil was inoculated with the pathogen, Xcv, belonging to T2P2 race group. The total microbial and Xcv counts were done before as well as after setting up the experiment. The results revealed that solarisation reduced the population of Xcv from 10.68 to 8.79 CFU g-1, total bacterial population from 11.27 to 9.86 CFU g-1, and total actinomycete counts from 11.69 to 9.44 CFU g-1 while bio-fumigation had a non-significant effect on Xcv and total microbial counts. None of the treatments exhibited a significant effect on fungal counts. The fruit yield of tomato grown on biofumigated as well as solarised soil was the highest (91.18 t ha-1) as compared to the other treatments. It can, therefore, be concluded that solarisation and bio-fumigation cannot be used as a bio-rational option for effective management of Xcv on tomato but the two methods could be used to increase tomato yield in the presence of the pathogen.Key words: bio-fumigation, solarisation, bacterial leaf spo

Effect of combined application of organic-P and inorganic-N fertilizers on yield of carrot

A study was undertaken to assess the effect of combined application of organic-P and inorganic-N fertilizers on yield and yield components of carrot (Daucus carota L.). The field experiment was conducted at Kombolcha ATVET College, South Wollo, Ethiopia. Seeds of carrot were sown on raised beds of a black clay soil. “Orga “and urea were used as sources of phosphorus and nitrogen, respectively, for the fertilizer treatments. The rates of fertilizers used in the experiment were, 309 kg“orga” ha-1 combined with six rates of urea (0, 68.5, 267.2, 274,342.5 and 411 kg urea ha-1). The field experiment was laid out in a randomized complete block design with seven fertilizer treatments,replicated five times. Yield and yield components of carrot were significantly influenced by the preharvest combined application of “orga” and urea treatments. Pre-harvest application of 309 kg “orga”ha-1 combined with 274 kg urea ha-1 increased yield of carrot by 46% compared to the control treatment. The values of yield components of carrot were also increased in response to the increased rate ofcombined “orga” and urea fertilizer application. The result showed that the combined application of 309 kg ha-1 “orga”and 274 kg ha-1 urea resulted in the maximum yield of carrot

Synthesis and characterization of Fe-Al-Mn nanocomposite sorbent for phosphate sorption-desorption study

In this work, we evaluated the potential application of a ternary nanosorbent for predicting phosphate desorption kinetics from soil. Accordingly, ternary mixed oxide nanosorbents with Fe:Al:Mn mole ratios of 3:3:1; 6:3:1 and 2:4:1 were prepared using simultaneous oxidation and coprecipitation methods. The adsorbents were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, scanning electron microscope (SEM) coupled with EDX (energy dispersive X-ray) and Furrier transform infrared spectroscopy (FT-IR). The results indicated that the as-synthesized ternary oxides were either amorphous or crystalline depending on the composition from which the composite was formed, with specific surface area ranging from 41.2 to 243 m2g-1. Among the three proportions considered, the one with Fe:Al:Mn in 3:3:1 mole ratio exhibited the highest surface area and was selected for P sorption-desorption studies. Phosphate removal gradually decreased with the increasing of pH from 4 to 10.5. Adsorption isotherms on the adsorbent at pH 6.5 followed the order: Freundlich > Temkin > Dubinin-Radushkevich > Langmuir. At 35 °C, the maximum adsorption capacity for the adsorbent was found to be 49.95 mg g-1. The effect of coexisting anions on phosphate sorption followed the order: SiO32- > CO32– > SO42– > NO3- and this is closely correlated with charge-to-radius ratios of the anions. The kinetic data were described better by the pseudo-second-order adsorption model. The as-obtained nanocomposite sorbent with good specific affinity towards phosphate is a promising adsorbent for soil P desorption studies.               KEY WORDS: Nanostructure, Phosphate, Desorption kinetics, Ternary oxide, Adsorption isotherm Bull. Chem. Soc. Ethiop. 2018, 32(3), 421-436.DOI: https://dx.doi.org/10.4314/bcse.v32i3.

Effects of nitrogen, phosphorus and vermicompost fertilizers on productivity of groundnut (Arachis hypogaea L.) in Babile, Eastern Ethiopia

ArticleThough groundnut (Arachis hypogaea L.) is a main cash crop for smallholder farmers in several districts of eastern Ethiopia, its yield is very low. Farmers apply little or no fertilizers to grow the crop possibly because no generic or recommended fertilizers rates available for farmers. Therefore field experiments were conducted for two consecutive cropping seasons in Babile district, to prove the hypothesis that one of the major factors that severely reduce the yield of the crop was lack of nutrients in the soil with the objective of investigating the effects of applying mineral NP fertilizers and vermicompost on the productivity of improved groundnut variety ‘BaHa-Gudo’. The experiment was 3 × 3 × 3 factorial with three replications laid down in a randomized complete block design comprising nitrogen (0, 23 and 46 kg N ha-1 ), phosphorus (0, 46 and 92 kg P2O5 ha-1 ) and vermicompost (0, 2.5 and 5 t vermicompost ha-1 ). The data on crop growth, nodulation and yield were collected and subjected to analysis of SAS 9.2 software. Means separation were made using Duncans Multiple Range Test (DMRT) at 5% level of significance. The results revealed that growth, yield attributes, and yields were significantly (P < 0.01) affected by the main and interactions effect of the treatments. The pod yield obtained from combined application of 46: 46 kg N: P2O5 ha-1 and 2.5 t vermicompost ha-1 exceeded the pod yield produced from nil application of fertilizers by about 100%. The economic analysis also indicated that the highest marginal rate of return (671%) and net benefit ($ 1,830) ha-1 were obtained from combined application of 46: 46 kg N: P2O5 ha-1 and 2.5 t vermicompost ha-1 . From the results it could be concluded that applying the aforementioned doses of fertilizers combination would enable farmers increase productivity of groundnut so as to enhance farmers’ income and livelihoods

Household Fertilizers Use and Soil Fertility Management Practices in Vegetable Crops Production: The Case of Central Rift Valley of Ethiopia

Large areas of farms are covered by variety of vegetable crops in the Central Rift Valley of Ethiopia. With a view to improve current vegetable production fertilizer use efficiency, survey has been conducted through collections of baseline information to describe household fertilizer uses and soil fertility management in vegetable production system using descriptive statistics. Multistage samplings were made to select  representative growers in the six districts of East Showa zone. Based on field observations and group discussions, vegetable growers grouped their farm land into four local categories. The survey revealed that tomato growers apply variable rates of urea and DAP fertilizers for tomato cultivation. Survey results indicated that highest 43.61% of onion growers apply 200 kg of DAP fertilizer on their onion field, while 30.85% of growers apply 300 kg DAP per ha, another 39.35% apply, 400 kg and above DAPfertilizer, still 8.5% of onion growers apply 600 kg DAP fertilizer on their onion farm. This survey indicated that fertilizers were not wisely used in the vegetable crops production systems and the applications are in excess rate, which could leads to pollution of the environment from over dose application and from runoff in to the water bodies and leaching in to the ground water with economic loss. Most of the tomato and onion growers use three splits application of UREA and DAP mainly at transplanting, at first and second cultivation for both crops as top-dressing. The survey results indicated that 54.44% of onion growers apply an average of 230.35 kg ha-1 DAP at transplanting, while 46.53% apply an average of 188.29kg ha-1 DAP at second split application, and finally 17.82% apply an  average of 119.44 kg ha-1 DAP at last third split applications. This is the first document come across that vegetable growers in the CRV area apply DAP fertilizer as much as three splits. This indicates that there are no  systems of updating of frontline development workers; poor extension services with shallow development workers knowledge made the growers totally depend on their own innovations for vegetable production

Irrigation Water Management Practices in Smallholder Vegetable Crops Production: The Case of the Central Rift Valley of Ethiopia

Smallholder irrigated vegetable production in the Central Rift Valley region of Ethiopia is instrumental in ensuring the year-round availability of fresh vegetables in the local market in the country. However, a number of  problems constrain irrigated vegetable production in the region. Therefore, asurvey was conducted with the objectives of assessing smallholder  irrigated vegetable production practices and identifying factors associated with problems of irrigation water management. The survey was conducted in December 2011. A multistage purposive sampling procedure was  employed to select sample districts, peasant associations, and sample respondents that grew vegetables using small-scale irrigation. Key  informants were interviewed and group discussions were conducted with smallholder vegetable farmers. Data were collected on household irrigation knowledge, experiences, skills, irrigation water sources as well as on  irrigation water management practices such as methods, time, depth and frequency of irrigation. Data were also collected on supplemental irrigation practices under rain-fed vegetable production. In addition, household perceptions on the environmental impacts of irrigation, on-farm irrigation water related challenges, and related information were also recorded. About 16.5% of the respondents indicated that their knowledge and skills on irrigation water management practices were mainly drawn from experiences of trial and error.About 38.1% of the respondents indicated that they  irrigated their vegetable fields both in the morning and the afternoon  whereas 35.1% replied that they irrigated only in the afternoon. A large number of the respondents (89.6%) replied that they determined irrigation intervals based on specific crop needs. About 90.9% of the respondents replied that they applied enough irrigation water up to the point where the water level reached the furrow basin head. The survey result also indicated that 51.7% of the respondents practiced supplemental irrigation when shortage of moisture occurred in the soil during the rainy season as well at the end of the rainy season. One hundred percent of the respondents replied that they faced problems commonly related with the use of  irrigation, namely, soil salinity, waterlogging, soil erosion and degradation, sedimentation, and build-up of pests and diseases. In conclusion, the survey results revealed that extension services on irrigation water  management were almost non-existent, and the smallholder vegetable farmers managed irrigation water merely by intuition.Therefore,  participatory on-farm irrigation research and extension on irrigation water management practices should be formulated to generate appropriate technologies for enhanced and sustainable irrigated vegetable production in the region

Histone H3 Localizes to the Centromeric DNA in Budding Yeast

During cell division, segregation of sister chromatids to daughter cells is achieved by the poleward pulling force of microtubules, which attach to the chromatids by means of a multiprotein complex, the kinetochore. Kinetochores assemble at the centromeric DNA organized by specialized centromeric nucleosomes. In contrast to other eukaryotes, which typically have large repetitive centromeric regions, budding yeast CEN DNA is defined by a 125 bp sequence and assembles a single centromeric nucleosome. In budding yeast, as well as in other eukaryotes, the Cse4 histone variant (known in vertebrates as CENP-A) is believed to substitute for histone H3 at the centromeric nucleosome. However, the exact composition of the CEN nucleosome remains a subject of debate. We report the use of a novel ChIP approach to reveal the composition of the centromeric nucleosome and its localization on CEN DNA in budding yeast. Surprisingly, we observed a strong interaction of H3, as well as Cse4, H4, H2A, and H2B, but not histone chaperone Scm3 (HJURP in human) with the centromeric DNA. H3 localizes to centromeric DNA at all stages of the cell cycle. Using a sequential ChIP approach, we could demonstrate the co-occupancy of H3 and Cse4 at the CEN DNA. Our results favor a H3-Cse4 heterotypic octamer at the budding yeast centromere. Whether or not our model is correct, any future model will have to account for the stable association of histone H3 with the centromeric DNA