Tolessa Debele - Academia.edu (original) (raw)

Papers by Tolessa Debele

Review of Weed Research in Maize in Ethiopia

... REVIEW OF WEED RESEARCH IN MAIZE IN ETHIOPIA Kassa Yihun, Tolessa Debele, Tolera Abera and Gi... more ... REVIEW OF WEED RESEARCH IN MAIZE IN ETHIOPIA Kassa Yihun, Tolessa Debele, Tolera Abera and Giref Sahile EARO, PO Box 2003, Addis Ababa, Ethiopia INTRODUCTION Maize is one of the important cereal crops in Ethiopia, and grows in practically all parts of the ...

Low availability of soil phosphorus (P) is one of the major limiting factors for soybean producti... more Low availability of soil phosphorus (P) is one of the major limiting factors for soybean production on acidic soils of the tropics. The objectives of this study were to assess the interaction of soybean genotypes (G) with levels of P, and identify genotypes that are responsive to high P and tolerant to low P conditions. A total of 36 soybean genotypes were evaluated under three levels of P (0, 100, and 200 kg ha -1 ) in three locations (L) ofWestern Ethiopia in split plot design with P levels as main plots, and genotypes as subplots. The individual locations analysis, revealed that the genotypes X phosphorus interaction for grain yield was significant (P<0.05) at Assosa. The genotypes showed highly significant differences for most of the studied traits in all the locations. The combined analysis revealed that there was significant G, and LXG interactions for mostof the traits. Essex-1, IAC 11 and AGS-3-1 were the best performing genotypes on 200 kgha -1 P; while IAC 11, AA-7138, ...

Response of soybean (Glycine max L.) genotypes to levels of phosphorus for rooting and nodulation characteristics on acidic soils of Western Ethiopia

Dense and deep root systems are desirable traits in maintaining the tolerance of soybeanto advers... more Dense and deep root systems are desirable traits in maintaining the tolerance of soybeanto adverse edaphic factors; while high and effective nodulation are important inimproving soil fertility. The study was conducted to assess the response of soybeangenotypes to varying phosphorus (P) levels for important root and nodulationcharacteristics across three locations of Western Ethiopia (Jimma, Assossa, and Mettuexperimental sites), which are soil acidity prone areas. Treatments were laid out in split-plot design, where levels of P and genotypes (G) were main plots and sub-plots,respectively. The study comprised of 36 soybean genotypes and three levels of P (0, 100,and 200 kg ha -1 of P in the form of TSP). The results revealed that G X P interactionswere significant for number of nodules and total nodule weight at Jimma, and Assossa;while root weight and root volume were significant at Mettu. Genotypes showedsignificant difference for all the parameters, except for number of nodules an...

Information on traits relationship, genetic variation and gains from selection for symbiotic and ... more Information on traits relationship, genetic variation and gains from selection for symbiotic and agronomic characters in chickpea (Cicer arietinum L.) are limited. An experiment was undertaken at two locations (Ginchi and Ambo) in Ethiopia in 2009/2010 to assess the relationship, genetic variation and genetic gain from selection for attributes of symbiotic and agronomic significance. The difference technique with genetically non-nodulating chickpea reference was employed to estimate the amount of symbiotic nitrogen fixation. Significant positive correlations were found between a number of symbiotic and agronomic traits. Grain yield was positively associated with fixed nitrogen assimilation efficiency (r = 0.39), shoot (r = 0.31), grain (r = 0.93), and above ground biomass nitrogen yields (r = 0.77) and NHI (r = 0.52). Grain yield was also positively influenced by agronomic characters including grain filling period (r = 0.38), pod (r = 0.57) and seed numbers (r = 0.59), shoot (r = 0....

Journal of Horticulture, 2021

A field experiment to evaluate blended fertilizer types and validation of soil fertility map base... more A field experiment to evaluate blended fertilizer types and validation of soil fertility map based on fertilizer recommendation was conducted at 10 sites on-farmers’ fields in Lemu Bilbilo and Asasa districts during 2014 and 2015 cropping seasons. The experiment was conducted to compare the effects of multi-nutrient blends that included macro- and micro-nutrients (N, P, K, S, B, and Zn) among each other and against the conventional N and P rate recommendation from Urea and DAP fertilizers. The experiment consisted of six treatments viz. recommended NP and five different types of blended fertilizers laid out in randomized complete block design (RCBD) with three replications. The P and S containing fertilizers were drilled along seed line at planting while N was split applied in such a way that half was applied at planting and the remaining half was applied at tillering stage. All management practices in respect of sowing, seed rate, weed control, pest and disease control were done ac...

1 Integrated soil Fertility Management, Soil Science Department, Sokoine University of Agricultur... more 1 Integrated soil Fertility Management, Soil Science Department, Sokoine University of Agriculture, P. O. Box 3000, Chuo Kikuu,

Effects of Water Regime and Reaction of Soil on Properties of Newly—Formed Humic Substances

The effects of soil water regime and soil reaction on nitrogen distribution and fractional compos... more The effects of soil water regime and soil reaction on nitrogen distribution and fractional composition of newly-formed humus (decayed products) and the structural characteristics of the newly-formed humic acids (HAs) were studied in an incubation experiment, with the following results obtained:1. The humus newly formed under submerged conditions was higher in the relative content of α-amino acid-N and the humic acid/ fulvic acid (HA/ FA) ratio than that under upland conditions. The HAs extracted from the former were also higher in C / O ratio, aromaticity and the contents of methoxyl groups and lignin-like components, but lower in the content of carboxyl groups than the HAs from the latter.2. Under upland conditions, the C / organic N ratio and the relative content of mobile HA of newly-formed humus were lower, but the HA / FA ratio was higher in the CaCO3-amended treatment than in non-amended treatment. The presence of CaCO3 also resulted in a decrease of C / N ratio of HA and a sl...

Optimum design by computer of power electronic transformers and d.c. chokes

Ethiopian Journal of Agricultural Sciences, 2017

Assessment of the genetic variability of soybean genotypes under low soil phosphorus (P) conditio... more Assessment of the genetic variability of soybean genotypes under low soil phosphorus (P) conditions provides an understanding of the genetic potential of the genotypes to improve the crop for low P tolerance. The study was designed objectively to estimate the extent of genetic variability of soybean genotypes for low P tolerance. Thirty six soybean genotypes that were introduced from various sources were grown in simple lattice design with three replications at three locations in Western Ethiopia characterized by P-deficient-acidic soils. It was revealed that weight of 100 seeds; plant height, root and biomass fresh weight exhibited relatively high heritability and genetic advance on low P soils. Principal component analysis also revealed that the first five principal components (PCs) accounted for more than 85% of the total variation. The first principal component that contributed for 37.7% of the total variation was influenced by root fresh weight, tap root length, root volume, fr...

Effect of Tillage Systems and Residue Management on Penetrometer Resistance of Nitisols under Maize Production in Western Ethiopia

Penetrometer resistance is one of soil physical properties influenced by tillage systems and crop... more Penetrometer resistance is one of soil physical properties influenced by tillage systems and crop residue management. Therefore, a field experiment was conducted to determine integrated effects of tillage systems and crop residue management on penetrometer resistance of Nitisols under maize production at five locations in western Ethiopia. Three tillage systems (minimum tillage with residue retention = MTRR, minimum tillage with residue removal = MTRV and conventional tillage = CT) and three N fertilizer levels (69, 92 and 115 N ha-1) were combined in complete factorial arrangement. The experiment was laid out in a randomized complete block design with three replications. The experimental plots were kept permanent for five cropping seasons to observe carry-over effects on soil penetrometer resistance. Tillage systems and depth intervals had significant (P<0.05) influence on penetrometer resistance of Nitisols at all five locations. Maize grain yield was significantly (P<0.05) ...

Agronomic management is one of the important inputs for getting high potential yield and net retu... more Agronomic management is one of the important inputs for getting high potential yield and net returns in hybrid maize production. The experiments were conducted on farmers’ field to examine the effect of four maize varieties and three nitrogen fertilizer rates interactions in mid-altitude of western Ethiopia in 2013 and 2014 cropping seasons. The N fertilizer application significantly increased grain yield of the all maize varieties. Furthermore, the interaction of the maize varieties with the N fertilizer rates were significantly affected the yield and yield components of the maize varieties. Application of half and full recommended N fertilizer increased the grain yield by 31 and 41 % as compared to the control treatment. The maize varieties with the higher grain yield also produced higher aboveground biomass. The N up take of the maize varieties ranged from 225 to 357 kg ha and the higher agronomic efficiencies of the maize varieties were obtained by applying half of the 1 recomme...

Effects of soybean precursor crop and nitrogen rates on subsequent maize grain yield and nitrogen use efficiency at Bako, West Ethiopia

Maintaining soil fertility using legumes precursor crop and minimum nitrogen, is ofparamount impo... more Maintaining soil fertility using legumes precursor crop and minimum nitrogen, is ofparamount importance for of sustaining maize production. A study was carried out atBako Agricultural Research Center to assess the effects of soybean precursor crop andnitrogen rates on subsequent maize grain yield and nitrogen use efficiency. Maizevarieties planted were significantly varied following soybean precursor crop.Significantly higher mean grain yield and dry biomass of maize were harvested fromBH-661 varieties planted following soybean precursor crop indicating variations ofmaize varieties in yielding potential following soybean. Application of nitrogenfertilizer following soybean precursor crop was significantly affected mean grain yieldof maize. Significantly higher mean grain yield of maize was produced from maizeplanted with application of half and full recommended rate of nitrogen fertilizerfollowing soybean precursor crop showing importance of nitrogen application incropping sequence....

From sonochemical and shielding experiments towards improved ultrasound-assisted chemistry

Legumes like faba bean (Vicia faba L.) and soybean (Glycine max L.) is able to fix 20–60 kg N ha ... more Legumes like faba bean (Vicia faba L.) and soybean (Glycine max L.) is able to fix 20–60 kg N ha 1 under tropical environments, but these amounts are significant for the succeeding cereal to meet the N requirement for economically attractive mean yields. Density of rhizobium population, intrinsic antibiotic resistance and nodulation and seed yield of faba bean and soybean from soil before and after planting in western Ethiopia was studied. The highest population of rhizobia was found from fields planted with faba bean without rhizobium inoculation in two farm fields and with rhizobium inoculation in one farm fields indicating the variations of effective local rhizobium strains in the soil due to faba bean plantation in the field. Faba bean planted with application of nitrogen fertilizer was produced lower rhizobium population density. Inoculation of different strains of rhizobia was produced considerable variation in population density of rhizobia in soybean. Knowing farm history be...

Conservation agriculture for sustainable maize production in Ethiopia

This experiment was conducted to determine the optimum levels of nitrogen (N) and phosphorus (P) ... more This experiment was conducted to determine the optimum levels of nitrogen (N) and phosphorus (P) fertilizer formaize production; and to see the interaction between different levels of N and P fertilizer on the growth andperformance of maize (Zea mays L.) BH-660 variety at Nedjo. The experiment had two factor: 5 levels of N (0,46, 92, 138, and 184 kg ha-1) and 5 levels of P (0, 23, 46, 69 and 92 kg ha-1) arranged in Randomized CompleteBlock Design (RCBD) with three replications. The sources of N and P were urea (46% N) and triple superphosphate (TSP) (46% P2O5), respectively. The main effects of N and P brought significant effect on thousandgrain weight. The interactions of N and P also significantly affected grain, and biomass yield; and harvest index.The highest grain yield (5497.5 kg ha-1) and biomass yield (16521 kg ha-1) were recorded at the highest rates ofN/P (184/92 kg ha-1).Key words: nitrogen, phosphorus, maize NP interaction, Nedjo.

The green seeker sensor reading of normalized difference vegetation index (NDVI) is highly relate... more The green seeker sensor reading of normalized difference vegetation index (NDVI) is highly related with leaf N content in quality protein maize (Zea mays). Mean yield components of quality protein maize were significantly affected by application of nitrogen rate in 2013 and 2014 cropping seasons. Increasing N rate from 0 to 100 kg ha increased significantly all parameters of quality protein maize varieties. Significantly a taller 1 plant height, higher leaf area and leaf area index was recorded from 50-100 kg N ha than other treatments. 1 Higher correlation between NDVI reading and leaf area were observed, with correlation coefficients of 0.46 and 0.47 at V4 and V6 growth stage in 2013 cropping season resulted in a good correlation between NDVI and leaf area. N application rates produced significantly higher increase up to 50-100 kg ha and small increase after 1 suggesting that the rate supplied sufficient N for maximum yield of maize. Significantly higher mean grain yield of qualit...

The well-known 1-2-3 Conjecture asserts that the edges of every graph without isolated edges can ... more The well-known 1-2-3 Conjecture asserts that the edges of every graph without isolated edges can be weighted with 1, 2 and 3 so that adjacent vertices receive distinct weighted degrees. This is open in general, while it is known to be possible from the weight set {1, 2, 3, 4, 5}. We show that for regular graphs it is sufficient to use weights 1, 2, 3, 4. Moreover, we prove the conjecture to hold for every d-regular graph with d ≥ 10 8 .

Clinical and Experimental Medicine, 2019

Conservation Agriculture (CA) can be a possible technique to mitigate reduction in soil quality, ... more Conservation Agriculture (CA) can be a possible technique to mitigate reduction in soil quality, reduce runoff and soil erosion, and increase in situ soil moisture conservation, thereby improve crop yield. The objective of this study was to test and validate beneficial CA practices for sustainable wheat production and enhance small-scale farmers know how and skill for adoption. Three CA technology verification trials were conducted during 2013-2016. The first trial compared CA with conventional agriculture (CVA) on-farmers fields in Sinana IP sites during 'meher' or big rainy season in 2013-2016. In CA verification, soil disturbance was restricted to the absolute minimum; viz. the soil was disturbed only to place the seed in the soil at the time of sowing. In contrast, in CVA the soil was plowed four times with the local oxen-plow 'maresha' prior to sowing to obtain a suitable seedbed. Weed control in the CA was done by applying roundup at the rate of 3 L/ha prior to planting while Pallas 45OD at 0.5 L/ha and 2,4-D at 1 L/ha were used as post-emergence application. The recommended weed control practice was used for conventional agriculture viz. twice hand weeding at tillering and booting stages. During 'belg' (small rainy season faba bean was used as cover or break crop in early 2014 and 2015. The second CA verification trial was initiated with the introduction of zero tillage planter at Kulumsa Research Center involving zero tillage CA, minimum or reduced tillage CA and CVA in 2016. The third trial was conducted in low rainfall areas in which CA, CA coupled with tie ridge and CVA were compared at Dhera in 2014. Results of the first trial indicated that at the initial year CVA gave more wheat yield than CA. The benefits of CA has increased progressively over years and on average CA yielded 12.5% more wheat yield than CVA. Similarly, zero tillage CA increased wheat grain yield by 7.1% and 11.6% as compared with conventional and reduced tillage, respectively. In arid and semi-arid areas, CA coupled with tieridge significantly increased wheat grain yield as compared to conventional agriculture. Thus, CA could be more applicable to moisture stress /erratic rainfall areas as compared to high rainfall areas and wheat farmers in drought prone regions could possibly adopt CA technology.