Agronomy

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EFFECT OF INTRA-ROW SPACING ON GROWTH PERFORMANCE AND YIELD OF ONION (Allium cepa L.) VARIETIES AT MIZAN-AMAN, SOUTHWESTERN ETHIOPIA
(Hawassa University College of Agriculture, 2016) DIRO BUZAYO TOLESSA
Onion is among the most important vegetable crops produced in Mizan-Aman for home consumption and as income sources. However, lack of site based varieties and inappropriate planting density have been the major bottlenecks of onion production and productivity in the area, since there are no recommended spacing and variety for that area specifically. Rather farmers use to practice non-uniform plant spacing. This study was thus conducted at Mizan ATVET College in 2015/2016 with the objective of investigating the effect of intra-row spacing on growth performance and yield components of onion varieties. Three varieties (Adama Red, Bombay Red and Melkam) were evaluated under four different intra-row spacings (6, 10, 14 and 18 cm) and constant inter-row spacing of 20 cm by using randomized complete block design replicated three times. Data on days to maturity, growth performance and yield were recorded and subjected to analysis of variance using SAS version-9 software. Results of the study indicated that, intra-row spacing and variety had significant effect on plant height, leaf number per plant, leaf length, days to maturity, bulb diameter and length, bulb dry matter, total bulb yield as well as, marketable and unmarketable bulb yield. Closer intra-row spacings enhanced early maturity, while wider spacing delayed maturity. The maximum plant height, leaf length and leaf number were recorded in 10 cm intra-row spacing. Bombay Red variety was early maturing with the highest mean value for growth and yield parameters. It had the highest total bulb and marketable bulb yield than Melkam and Adama Red onion varieties specially when planted at 10 cm intra-row spacing. Bombay Red with 10 cm intra-row spacing also gave highest total bulb and marketable bulb yield. The correlation values also confirmed the significant and positive association between growth parameters and bulb yield. Based on the result of this study, higher onion yield with better quality was attained when Bombay Red variety was planted with 10 cm intra-row spacing under Mizan-Aman condition, for recommendation, although additional verification trial is needed to substantiate the result.
GROWTH, SYMBIOTIC AND YIELD PERFORMANCE OF SOYBEAN (Glycine max L.) VARIETIES IN RESPONSE TO Bradyrhizobium INOCULATION AND PHOSPHORUS APPLICATION AT ASSOSA, WESTERN ETHIOPIA
(Hawassa University College of Agriculture, 2017) TESFAYE TEKOLA SEIFU
This research was conducted during 2016 main cropping season on field at Assosa, in Benishangul Gumuz Regional State with the objectives of investigating growth, symbiotic and yield performance of three soybean (Glycine max L.) varieties in response to Bradyrhizobium inoculation and P fertilizer application. The treatments studied included three P levels (0, 10 and 20 kg P ha -1 ), two inoculation levels (uninoculated and inoculated with Bradrhizobium strain; MAR-1495) and three soybean varieties (Gizo,Belessa-95 and Local) in randomized complete block design with factorial arrangement using three replications. The results revealed that Bradyrhizobium inoculation with MAR-1495 significantly (P<0.01) increased most of the parameters studied as compared to the control. Inoculation with strain MAR-1495 significantly (P < 0.01) increased nodule number, nodule dry weight, shoot dry weight, root dry weight, leaf area, grain yield, and above ground total biomass as compared to the control. Application of P at 20 and10 kg ha -1 significantly increased nodule number, nodule dry weight, and root dry weight, shoot dry weight, leaf area, above ground total biomass and grain yield. There was significantly (P < 0.01) cultivars effect for most of studied parameters; Belessa-95 variety had better responded on nodule number, nodule dry weigh, grain yield and above ground total biomass as compared to Gizo and Local varieties. The highest grain yield was recorded from Belessa-95 variety 3.29 ton ha -1 from combined application of 20 kg P and Bradyrhizobium inoculation. Nodule number plant -1 was positively and significantly correlated with most of growth parameters, yield and yield components. It could, thus, be deduced that use of MAR-1495 Bradyrhizobium strain and Belessa-95 variety with application of 20 kg P markedly increased the productivity of the crop at Assosa area, however economic analysis revealed that the highest net return was obtained from application of 10 kg P and Bradyrhizobium inoculation with strain MAR-1495. The use of MAR-1495 strain and Belessa-95 variety with application P at 10 kg ha -1 could be recommended, but verification of the results on different farmers’ field could be required before wide use of this study.
EFFECTS OF SEEDLING AGE AND VARYING RATES OF PHOSPHORUS ON GROWTH AND YIELD PERFORMANCE OF ONION (Allium cepa L.) UNDER IRRIGATION IN ALAGE DISTRICT, CENTRAL RIFT VALLEY OF ETHIOPIA
(Hawassa University College of Agriculture, 2017) TILAYE ANBES WASIE
Onion is an important cultivated crop used as a condiment as well as a source of income for many farmers in Ethiopia. However, the yield of the crop is constrained by a number of factors among which inappropriate transplanting age and poor fertilizer management practices are important factors. Therefore, a field experiment was conducted at Alage Agricultural Technical and Vocational Education and Training College (Alage) campus, Central Rift Valley of Ethiopia, during 2016/17 season to determine the effect of seedling age and phosphorus rate on growth and yield performance of onion. The treatments comprised of three seedling ages (6, 7 and 8 weeks of seedling age) and four phosphorus rates (0, 46, 92 and 138 kg ha -1 ). The experiment was laid out in randomized complete block design (RCBD) with four replications. The result showed that seedling age and phosphorus rate significantly affected plant height, leaf length, days to maturity, fresh bulb weight, bulb dry matter fraction, bulb length, marketable bulb yield, total bulb yield, harvest index, medium and large sized bulb yield. Among these parameters, marketable bulb yield, total bulb yield and harvest index were also significantly affected by the interaction of seedling age and phosphorus rate. On the other hand, leaf number per plant, bulb diameter, bulb dry weight, total biomass yield, small bulb sized yield, under sized bulb yield and unmarketable bulb yield were only influenced by the main effect of phosphorus rate. In this study result, transplanting at 8 weeks of seedling age fertilized with 138 kg P 2O5 ha -1 recorded the highest total bulb yield (50.6 t ha -1 ) and marketable bulb yield (48.33 t ha -1 ), but no significant difference was showed with that obtained at 92 kg P 2O5 ha -1 with the same seedling age. Treatment combinations of seedling age at 6 weeks and no P (control) produced the lowest amounts of total bulb yield (24.27 t ha -1 ) and marketable bulb yield (21.63 t ha -1 ). The partial budget analysis revealed that the highest net benefit with low cost of production was obtained in response to the application of 92 kg P2O5 ha -1 and the transplanting age of 8 weeks. The marginal rate of return for this treatment was 5657% which is found to be economically feasible for producing onion in the study area.
EFFECT OF NITROGEN SOURCES ON GROWTH, YIELD AND YIELD COMPONENTS OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES AT MESKAN, SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2019) MESERET SHIFA
Common beans (Phaseolus vulgaris L.) are an important cash crop and protein source for farmers in many parts of Ethiopia. However, lacks of adequate information on the use of nitrogen source fertilizers are the major yield limiting factors for common bean production in the study area. Thus, the field experiment was conducted at Meskan District in 2018 cropping season to evaluate the effect of nitrogen sources on growth, yield and yield components of common bean varieties; and to identify economically appropriate combination of nitrogen sources that give optimum yield of major common bean varieties. Factors studied includes four common bean varieties (Hawassa Dume, Gegeba, Rori and Ibado) and four level of N sources (T1= Control; T2=Rhizobium inoculated; T3=46 kg N ha -1 , T4= 46 kg N ha -1 + Rhizobium inoculated). The treatments were arranged using randomized complete block design in factorial arrangements with three replications. Results revealed varietal differences on growth, yield and yield components. The highest pod number plant -1 (29.1), seed number pod -1 (5.6) and grain yield (2.7 t ha -1 ) were recorded from variety Hawassa Dume. Similarly, nitrogen sources had significant effect on growth, yield and yield components. Significantly, higher number of pods plant -1 (27.5), seeds pod -1 (5.6), and grain yield (2.7 t ha -1 ) were recorded from combined application of Rhizobium inoculation+46kg N ha -1 . There was significant interaction effect of N sources with varieties on nodule number, root dry weight and straw yield, where by the highest nodule number plant -1 (40), root dry weight (11.6 ) and straw yield (4.5 t ha -1 ) were recorded from combined application of Rhizobium strain HB-429 and 46 kg N ha -1 with variety Hawassa Dume except number of nodule plant -1 . Grain yield was positively and significantly correlated with phenological, growth, nodulation, yield and yield components except maturity date. Partial budget analysis of the study revealed that the highest net return (32,748 ETB ha -1 ) was obtained from Hawassa Dume variety with combined application of inoculation and 46 kg N ha -1 . Based on the results of this study, it can be concluded that combined application of Rhizobium inoculation with 46 kg N ha -1 found to be appropriate for common bean variety Hawassa Dume in the study area. However, the result of the present study need to be evaluated and reconfirmed on farmers field across season and areas in order to reach to a conclusive recommendation.
GROWTH AND YIELD OF ONION (Allium cepa L.) AS AFFECTED BY VARIABLE RATES OF POULTRY MANURE AND MINERAL NITROGEN FERTILIZER AT ALAGE, CENTRAL RIFT VALLEY OF ETHIOPIA
(Hawassa University College of Agriculture, 2019) NEJEHA REDY ALEMAR
Onion is one of the important vegetable crops produced in many home gardens and in some extent commercially in different parts of Ethiopia. However, the average yield of the crop is low compared with the world average yield. Declining soil fertility and lack of information on appropriate fertilizer type and rates are the most important factors attributing for the low yield of onion in Ethiopia. Therefore, the field experiment was carried out at Alage Central Rift Valley of Ethiopia, during 2018/19 cropping season, with the objectives of assessing the growth, yield and quality response of onion to the variable rates of poultry manure and mineral nitrogen fertilizer. The experiment comprising of three nitrogen levels (0, 46 and 92 kg ha -1 ) and four levels of poultry manure (0, 5, 10 and 15 t ha -1 ) were laid out in randomize complete block design with three replications. Data on plant growth, yield and quality components were collected and subjected to ANOVA using SAS (9.2 version) software. The main effects of poultry manure and nitrogen fertilizer significantly affected the leaf length, leaf number, days to maturity, bulb length, unmarketable bulb yield and bulb dry matter content, except total bulb yield and marketable bulb yield. Plant height, bulb diameter and harvest index were significantly affected by the interaction of poultry manure and nitrogen fertilizer levels. Application of poultry manure at the rate of 15 t ha -1 recorded the highest total bulb yield (63.33 t ha -1 ) and marketable bulb yield (62.52 t ha -1 ), but statistically there were no x significant difference between 15t ha -1 and 10t ha -1 poultry manure application. Lower amount of total bulb yield (53.44 t ha -1 ) and marketable bulb yield (52.40 t ha -1 ) were obtained from the control plot as compared to the maximum yields obtained from other treatments. Marketable bulb yield was positively and significantly correlated with most of the growth parameters. The results of partial budget analysis showed that 15 t ha -1 poultry manure application gave the highest marginal rate of returns. Since, the highest bulb yield and maximum marginal rate of returns are obtained at 15 t ha -1 poultry manure application, this rate can be recommended for onion production in the researched area, and areas having similar agro-ecologies. However, as the research is conducted for a single season and location, repeating the experiment over location and year will be required to give a conclusive recommendation.
RESPONSE OF MALT BARLEY (Hordeum vulgare L.) TO DIFFERENT RATES OF NPSB AND UREA FERTILIZERS IN BULE HORA WOREDA, GUJI ZONE, OROMIA REGIONAL STATE
(Hawassa University College of Agriculture, 2020) ASHENAFI TADESSE FOLLA
Malt Barley (Hordeum vulgare L.) is one of major crops grown in Bule Hora woreda,oromia region South western Ethiopia. The soil in the area is poor in most of the available nutrients due to intensive soil erosion and long history of cultivation. Therefore, a field experiment was carried out in 2019 cropping season to evaluate response of malt barley to the different rates of NPSB and N fertilizer. The treatments consisted of four levels of NPSB (0, 50, 100, and 150 kg NPSB ha -1 ) and four levels of N (0, 23, 46, 69 kg N ha -1 ). The experiment was laid out in three replication of the randomized complete block design in a factorial arrangement. The results revealed that the interaction effect had a highly significant (p<0.001) on Days to heading, Days to physiological maturity, thousand kernel weight, grain yield and Hectoliter weight. The main effect N fertilizer had a significant effect on spike length, number of tiller per plant, number of spikelet per spike and protein content. Blended NPSB also had significant (p<0.05) effect on number of effective tiller, above ground biomass. Plant height had significantly (p<0.05) by blended NPSB and N fertilizer The highest yield (3691kgha -1 ) was recorded from the interaction effect of 150 kg NPSB ha -1 and 69kg N ha -1 . The partial budget analysis also indicated that the best treatments were interaction of 150 kg NPSB ha -1 and 69kg N ha -1 , which gave net benefits of 63203 ETB ha -1 with acceptable marginal rate of return (5776%). Therefore, it could be concluded that application of 150 kg blended NPSB ha -1 with 69kg N ha -1 fertilizer rates were economically profitable yield and the application of 23kg N ha -1 acceptable for grain quality for malt barley production in the study area.
EFFECTS OF IRRIGATION FREQUENCY ON YIELD RESPONSE OF TWO COMMONLY GROWN TOMATO VARIETIES AT SHASHOGO WOREDA OF SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2020) GETAHUN LENDABO HELAMO
Tomato is one of the most important vegetable crops widely grown in Ethiopia. It has many nutritional values and considered as high value cash crop in the country. However, its productivity among small scale growers is far below its potential. This is partly due to lack of access and awareness to improved cultivars and agronomic packages. The objective of the study was to identify the response of two tomato cultivars under different irrigation intervals and to determine the optimum irrigation interval. The design was randomized complete block with factorial arrangement of two varieties (variety Galilea and variety Roma VF) and three irrigation intervals (4, 6, and 8 days), with three replications. The experiment was conducted from December 2018 to April 2019, at Shashogo Woreda of Southern Ethiopia. A Data were recorded on Phenological, growth and yield characteristics. Varieties differed significantly (P<0.05) in all characteristics, except in number of primary branches and fruit set percentage. Variety Roma VF was earlier by 8 and 13 days in days to first harvest and days to 50% maturity respectively than variety Galilea. Whereas variety Galilea had significantly (P<0.05) higher number of secondary branches per plant, clusters per plant, flowers per cluster, fruits per cluster, fruits per plant, marketable fruit yield and total fruit yield than Roma VF. Similarly, irrigation interval of 6 days resulted in higher values in all these characters than irrigation interval of 4 and 8 days. The highest net benefit of ETB 682,584 was obtained from Variety Galilea under irrigation interval of 6 days. Hence, economically attractive combination is to grow variety Galilea under irrigation interval of 6 days. Growing Roma VF under irrigation interval of 6 days might be considered when earliness is needed to meet special market demands.
EFFECT OF ALTERNATE FURROW IRRIGATION UNDER DIFFERENT MOISTURE REGIMES ON WATER USE EFFICIENCY, GROWTH, YIELD AND YIELD COMPONENTS OF COMMON BEAN (Phaseolus vulgaris L.) AT ALAGE, CENTRAL RIFT VALLEY OF ETHIOPIA
(Hawassa University College of Agriculture, 2020) HUNDE HAYILE TOLOSA
The farmers use common traditional irrigation methods which at times lead them to over irrigate, resulting in high water losses and low irrigation efficiency. Under such conditions understanding and application use of deficit and alternate furrow irrigation systems on crop production would enhance food security through improved water use. Thus, this study evaluated that the effect of alternate furrow irrigation under different moisture regimes on water use efficiency, growth, yield and yield components of common bean, during 2019 at Alage ATVET College. The experiment was laid out in factorial combination of two factors, following randomized complete block design in split plot arrangement with three blocks consisting twelve treatments; four irrigation levels (100% ETc (I 0 ), 80% ETc (I 1 ) 60% ETc (I 2 ) and 40% ETc (I 3) as the main plot and three irrigation methods (fixed alternate furrow irrigation (FAFI), variable alternate furrow irrigation (VAFI) and conventional furrow irrigation (CFI)) as the sub plot. This experiment showed that deficit irrigation (DI) and AFI significantly (P<0.01) affected days to physiological maturity, No of nodules plant -1 , grain yield, CWUE and IWUE. DI also significantly (P<0.05) influenced days to 50% flowering, stand count, plant height, No of branch, shoot dry weight, nodule dry weight, No of pods plant -1 , No of seeds pod -1 , pod length, 100-seed weight and HI. The interaction effect of DI and AFI also significantly (P<0.05) influenced the biological yield. Maximum (5.16 t ha -1 ) and minimum (3.38 t ha -1 ) biological yield was recorded at I0 and I 3 respectively with combination of FAFI and CFI, in that order. The highest grain yield was obtained under I 0 (2.45 t ha -1 ) and the lowest (1.34 t ha -1 ) was at I 3 . On the AFI, the maximum grain yield (2.11 t ha -1 ) was obtained under FAFI and the minimum (1.78 t ha -1 ) was under CFI. The uppermost CWUE (1.03 kg m -3 ) was recorded at I 3 followed by I 2 (0.92 kg m -3 ) and the smallest was at I0 (0.70 kg m -3 ) followed by I1 (0.77 kg m -3 ). The maximum CWUE (0.92 kg m -3 ) was recorded under FAFI followed by VAFI (0.86 kg m -3 ) and CFI (0.79 kg m -3 ). The partial budget analysis showed that I 0 , I 1 and I 2 gave marginal rate of return above the acceptable threshold value with additional investment advantages for the later. However, there was significant yield difference between I 0 and I 1 ; farmers can save 20% of the irrigation water in the expenditure of the reduced yield (0.33 ton ha -1 ). The highest net benefit was obtained from FAFI, thus the farmers option allows for FAFI at which high yield was recorded. Generally this analysis indicates that farmers at study area and related agro-ecology can use I 0 (100% ETc) in order to maximize their income from increased investment, but if there is lack of adequate irrigation water they can use I 1 (80% ETc) in order to save and use irrigation water more economically.
PERFORMANCE EVALUATION OF MUNG BEAN (Vigna radiata(L.) Wilczek) VARIETIES UNDER VARIABLE PHOSPHOROUS FERTILIZER RATES AT ALAGE, CENTRAL RIFT VALLEY OF ETHIOPIA
(Hawassa University College of Agriculture, 2020) HABTAM TILAHUN ASRATIE
Mung bean is an important pulse crop in Ethiopia. However, lack of adapted high yielding varieties and poor soil fertility, especially low levels of nitrogen and phosphorus, have been demonstrated to be important constraints for the production of the crop. Field experiment was conducted during the 2019 belg season to determine the Performance Evaluation of Mung Bean (Vigna Radiata(L.) Wilczek) Varieties Under Variable Phosphorous Fertilizer Rates at Alage Agricultural Technical and Vocational Education Training college Experimental field. The treatments consisted of factorial combinations of four mung bean varieties ( Boreda-1, N26, NVL-1 and shoa robit local) and four phosphorus fertilizer rates (0, 23, 46 and 69 kg P2O5 ha-1 ) laid out in Randomized Complete Block Design with four replications. Data were collected on plant height , number of nodules plant-1 , nodules dry weight plant-1 , root dry weight plant-1 , shoot dry weight plant-1 , number of branches plant-1 ,number of pods plant-1 , number of seeds pod-1 , hundred seeds weight, grain yield, harvest index, biological yield, days to flowering and maturity. The variety Boreda-1 showed the best performance in number of pods plant-1 , number of seeds pod-1 ,and grain yield whereas NVL1 gave the lowest performance.Variety Boreda-1 also gave the highest gross benefit of 47624.22 ETB and the highest net benefit of 46749.22 ETB. But the lowest gross return and net return were obtained from variety NVL-1 ,with 40044.38 ETB and 39169.38 ETB, respectively. The increasing rates of phosphorous fertilizer showed substantial improvement in nodules dry weight plant-1 , shoot dry weight plant-1 , plant height, grain yield, and biological yield up to fertilizer rates of 46 kg P2O5 ha-1 . Application of 46 kg P2O5 ha-1 recorded the highest gross income of 47053.13 ETB and net return of 45003.13 ETB and the lowest values were recorded from the control; which were 40280.63 ETB and 40280.63 ETB in that order. From the study,the interaction of variety Boreda-1 with phosphorous fertilizer rates of 46 Kg P2O5 ha-1 recorded highest gross income of 50321.25 ETB and net return of 47396.25 ETB .While, the lowest was recorded from the interaction of variety NVL-1 with phosphorous fertilizer rates of 0 Kg P2O5 ha-1 with a gross income of 36303.75ETB and net return of 35428.75 ETB. Accordingly,variety Boreda-1 and application of 46 kg P2O5 ha-1 ,can be used to improve productivity of mung bean in the study area.
RESPONSE OF BARLEY (Hordeum vulgare L.) GENOTYPES TO INORGANIC FERTILIZER TYPES UNDER ACIDIC SOIL OF HAGERESELAM, SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2020) HAILU HAMESO
Barley is one of the most important cereal crops in the world. It is a staple food grain, especially for Ethiopian highlanders. However, the barley productivity is commonly influenced by different biotic and abiotic factors. Soil acidity is one of the main environmental factors affecting growth and crop yield. Field experiment was conducted on acidic soil of Hagereselam, southern Ethiopia in 2019 cropping season to evaluate the performance of barley genotypes in terms of yield and yield components under different inorganic fertilizer types. The experiment was laid out in Randomized Complete Block Design with factorial arrangement with three replication and consisted of four fertilizer types (control, NP, NPS and NPSB) and four barley genotypes (217176b, 240478, 234911b and 208855b) and one barley variety (HB- 1307) as a check. Both main and interaction effects influenced days to physiological maturity, plant height, number of effective tillers m -2 , above ground total biomass and grain yield. However, days to heading, spike length, number of grain per spike, 1000 grain weight, straw yield and harvest index were only affected by main effects. Barley Genotype 217176b with NPSB fertilizer exhibited the highest grain yield of (4.9 ton ha -1 ). However, it did not significantly differ from the yield obtained from the same genotype under NP (4.72 ton ha -1 ) and genotype 240478 with NPSB fertilizer application (4.58 ton ha -1 ). The lowest yield was recorded from genotype 208855b with control fertilizer. Genotypes 217176b and 240478 were categorized as efficient and responsive to fertilization under the evaluation. The highest marginal rate of return (MRR %), 3745.35, recorded from the application of recommended rates of NPSB fertilizer for genotype 217176b. Greater net benefits with more than the minimum acceptance value of 100% of MRR were obtained for the same genotype with NP. Similarly economically acceptable performances were obtained for genotype 240478 either with NPSB or NP fertilization. Given the fact that grain yield performance between the two genotypes in combinations either with NPSB or NP is not statistically significant, either of the two genotypes with the NPSB or NP fertilizer can be recommended for barley production in acidic soils of Hagereselam and acidic soils of similar agro-ecologies in the highlands of Ethiopia. Further studies that are replicated at least over seasons are needed to investigate response of the two promising barley genotypes to application of inorganic fertilizers under acidic soil conditions in order to come up with a conclusive recommendation.
GROWTH, SYMBIOTIC AND YIELD RESPONSES OF SOYBEAN (Glycine max L.) VARIETIES TO BRADYRHIZOBIUM INOCULATION AND PHOSPHORUS APPLICATION AT ALAGE, CENTRAL RIFT VALLEY OF ETHIOPIA
(Hawassa University College of Agriculture, 2021) AYANA YADETA GEMEDA
Soybean (Glycine max L.) is one of the most important food legumes of great nutritional value that has the highest protein content (40%) of all food crops and is equivalent to the protein of animal product. However, in Ethiopia its productivity is constrained mainly by low soil fertility and lack of improved varieties. A field experiment was conducted during 2020 belg cropping season at Alage Central Rift Valley of Ethiopia with the objective of evaluating the effects of Bradyrhizobium japonicum strain inoculation and P fertilizer rates on growth, symbiotic and yield response of soybean varieties. The treatments studied includes four P levels (0, 10, 20 and 30 kg P ha-1 ), two inoculation levels (un-inoculated and inoculated with Bradyrhizobium strain; TAL-379) and two soybean varieties (Afgat and Nova) in randomized complete block design with factorial arrangement with three replications. The results revealed that the main effect of varieties were significantly (P≤ 0.01) influenced most of measured parameters. The results also revealed that inoculation of soybean varieties with Bradyrhizobium strain TAL-379 significantly (P≤ 0.01) influenced days to maturity, nodule number, nodule dry weight, shoot dry weight, root dry weight, pod number plant-1 , hundred seed weight, grain yield, above ground biological yield and harvest index. Conversely, days to emergence, days to flowering, plant height and seed number pod-1 was not statistically affected by inoculation of strain TAL-379. The effect of P fertilizer was also significant for most of studied parameters except branch number and harvest index. The interaction effect of varieties x strain, strain x P, and varieties x P caused significant variation on days to maturity, number of nodule, nodule dry weight, shoot dry weight, root dry weight, pod plant-1 , hundred seed weight, grain yield and above ground biological yield. Hence, the use of Afgat variety with Bradyrhizobium strain TAL-379 inoculation significantly gave the highest grain yield (2.99 t ha-1 ) followed by the interaction of Afgat variety with the supply of 20 kg P ha-1 (2.89 t ha-1 ). Grain yield was positively and significantly correlated with most of studied parameters. From the economic point of view the partial budget analysis of the study treatments revealed that the highest net return (63750 ETB ha-1 ) was gained from Bradyrhizobium strain TAL-379 inoculation followed by application of 20 kg P ha-1 and Afgat variety. Thus, it could be recommended that the use of Afgat variety, Bradyrhizobium strain TAL-379 and application of 20 kg P ha-1 to get higher yield and profit of this crop at Alage Central Rift Valley of Ethiopia. However, verification of the result on farmers’ fields across season and areas could be required before wide use of this study to put the recommendation in firm ground
EFFECTS OF INOCULANT AND NPS FERTILIZER ON NODULATION, GROWTH AND YIELDS OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES AT BILATE ZURIA DISTRICT, SIDAMA REGIONAL STATE, ETHIOPIA
(Hawassa University College of Agriculture, 2021) ENJAMO NAGESSO SATO
Common bean (Phaseolus vulgaris L.) is a major grain legume grown and consumed in subSaharan Africa, including Ethiopia. It is the most important food legume, fodder and cover crop. However, its cultivation is globally constrained mainly by low soil fertility and lack of improved agronomic practices. Four common bean varieties (Ibaddo, Hawassa Dume, Omo95 and Nasir were studied under three nutrient conditions (0kg ha-1 ,100 kg ha-1 NPS, Inoculation by strain HB-429) in three replication of randomized complete block design (RCBD) during the 2019 main cropping season (June to September). The objectives of the study were investigating the response these varieties to the three nutrient statuses in nodulation, growth, yield and yield components and investigating the variety X inoculant/fertilizer interaction in the same traits. There were significant differences between the four varieties in all traits (nodulation, growth, yield and yield components). Ibaddo had the highest grain yield (2.81 t ha-1 ) while Hawassa Dume had the highest mean in yield (2.53 t ha-1 ). The three fertilizer levels also differed significantly in all traits, 100 kg ha-1 NPS giving the highest means in all traits, while the control (no fertilizer application) had the lowest mean in all traits. Inoculation by rhizobium strain had intermediate mean of all traits. The variety X inoculant/fertilizer interaction was also significant for all traits except for nodule dry weight, leaf area index, shoot dry weight, grain yield, above biological yield and harvest index. Omo95 variety had the lowest means in all traits except leaf area index, plant height, number of primary branches where ranks first, second and third. The highest net return (48325 ETB ha-1 ) with acceptable marginal rate return (5993%) was obtained from Hawassa Dume variety with 100 kg NPS ha-1 followed by Hawassa Dume variety with strain HB-429 inoculation had net return of 41337 ETB ha-1 with 4895% marginal rate of return. This implies that the grower on the study area can gate additional benefit of 59.93 and 48.95 ETB for every 1 ETB expense by growing Hawassa Dume with the application of 100 kg NPS ha-1 and strain HB-429 inoculation, in that order. Moreover, the highest net benefits (37763.5) with MRR (%) of 3084 ETB and net benefits of 3935ETB with MRR (%) obtained from variety Ibaddo and Nasir grown with strain HB-429 and 100 kg NPS ha-1 fertilizer application. Therefore, use of both Hawassa Dume and Nasir varieties with 100 kg NPS ha-1 and Hawassa Dume and Ibaddo grown with strain HB-429 found to be economically feasible at the study area. However, verification of the result on farmers’ fields across season and similar areas could be required before wide use of this study to put the recommendation in firm ground.
EFFECTS OF SEED AND BLENDED FERTILIZER RATES ON YIELD AND YIELD COMPONENTS OF BREAD WHEAT (Triticum aestivum L.) AT DUNA DISTRICT, HADIYA ZONE, SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2021) BIRHANU ARASO LATEBO
Bread wheat is one of the major staple and strategic food security crops in Ethiopia. However, the production and productivity of the crop are far below the global average. This is partly due to the low soil fertility and poor crop management practices including the use of suboptimal seed and fertilizers rates. Hence, this experiment was conducted to assess the effect of seed and blended fertilizer (NPSB) rates on the growth and yield of bread wheat; and determine the economically feasible seed and NPSB fertilizers rates for wheat production in the study area. Treatments consisting of four levels of seed rates (80, 100, 120, and 140 kg ha1 ) and four levels of blended NPSB fertilizers (0, 50, 100, and 150 kg ha-1 ), was laid out in a Randomized Complete Block design in factorial combinations with four replications. Data were collected on phenology, growth, and yield parameters and subjected to ANOVA using SAS software version 9.0. Results revealed that the days to heading, days to physiological maturity, plant height, spike length, thousand kernels weight, straw yield, and above-ground dry biomass were significantly (p<0.01) affected by the main effect of seed and NPSB fertilizer rates. The longest days to heading, days to physiological maturity, and spike length were recorded at 80 kg ha-1 seed rate. The maximum thousand kernels weight was obtained from the 120 kg ha-1 seed rate. However, the tallest plant height, straw yield, and above-ground dry biomass were recorded at 140 kg ha-1 seed rate. The tallest plant height, spike length, number of kernels spike-1 , thousand kernels weight, straw yield, and above-ground dry biomass were obtained from 150 kg ha-1 NPSB rate. However, the longest days to heading and days to physiological maturity were recorded from the control. The treatment interactions significantly (p<0.05) affected the number of total tillers, number of productive tillers, grain yield, and harvest index. The highest number of total and productive tillers were recorded at the combination of 140 kg ha-1 seed rate with 150 kg ha-1 NPSB fertilizer rate. However, the highest grain yield and harvest index were recorded from the combination of 120 kg ha-1 seed and 150 kg ha-1 NPSB fertilizer rates. Grain yield was strongly and positively correlated with plant height, number of total tillers, number of productive tillers, number of kernel spike-1 and above-ground dry biomass. As per the partial budget analysis the highest net benefit of 81,914 ETB ha-1 was obtained from the combined application of 120 kg ha-1 seed rate with 150 kg ha-1 NPSB fertilizer with a MRR of 988.2%. Hence, the combination of 120 kg ha-1 seed and 150 kg ha-1 NPSB fertilizer rates are profitable than other combinations, therefore this combination can be recommended for wheat production in the Duna District and areas sharing similar agro-ecology.
EVALUATION OF THE GROWTH, PHYSIOLOGICAL AND YIELD PERFORMANCE OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES UNDER SOIL MOISTURE STRESS CONDTITIONS
(Hawassa University College of Agriculture, 2021) MITIKE MULATU ALEMU
Common bean is one of the most important food crops, with significant economic importance and it is suitable for food security due to its short growing cycle and adaptability to different cropping systems. However, its average yield reported at the national levels remains far below the potential due to various biotic and abiotic constraints among which is moisture stress. The study was conducted to evaluate the effects of moisture stress on growth, physiological and yield and yield components of common bean varieties. A pot experiment was conducted under lath house from June to September 2020, at Hawassa University College of agriculture. Seven common bean varieties viz. Gofta, Fedis, Awash-2, Tinike, Awash-1, Dursitu and Nasir were grown under three irrigation intervals/moisture level viz. watered every day (waterlogging stress), watered every four days (control) and watered every eight days (moisture deficit), in factorial combination using Completely Randomized Design with three replications. The main and interaction effects were significant on Days to flowering, physiological maturity, plant height, leaf number, Shoot fresh weight, Shoot dry weight, root length, Transpiration rate, photosynthesis rate, stomata conductance, water use efficiency, stomata number, stomata width and length, chlorophyll concentration, Proline content, Length of pod, pods plant-1 , seeds pod-1 and yield gram-1 plant-1 . However, branch number and Internode length, leaf relative water content, hundred seed weight, total biomass (biological yield), straw yield and harvest index were significantly affected by main effects of moisture levels and varieties but chlorophyll fluorescence was affected by only moisture levels. Moisture stress significantly reduced growth, stomata conductance, photosynthesis, yield and yield components. Varieties performed differently in response to moisture stress. The highest hundred seed weight, biological yield, and straw yield were recorded for Awash-1 and Tinike varieties, respectively in control moisture stress. The highest yield was recorded from the variety Awash-1 and Gofta irrigated every 4 days of interval ( control); whereas the lowest yield was recorded from Fedis variety treated with daily irrigation ( water logging). Also Awash - 2 varieties is relatively better compared to the Tinike, Fedis, Dursitu and Nasir on yield and yield parameters at all moisture levels. Varieties Gofta, Awash-2 and Awash-1 appeared to be moisture stress-tolerant duo to maximum proline accumulation mechanism, high water use efficiency, low transpiration rate and better photosynthesis and yield performance by using different mechanisms.
RESPONSE OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES TO DIFFERENT RATES OF PHOSPHORUS FERTILIZER AT NEGELLE BORENA, SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2021) GADISA BEYENE FUFA
Even though its production and demand is highly increasing in Ethiopia due to its fast maturity and nutritional value, Common bean productivity is constrained by soil phosphorus along with proper use of variety. In view of this problem, a field experiment was conducted at Negelle Borena, Southern Ethiopia under rain fed in 2020 cropping season to determine the optimum phosphorus rate needed to get the highest and economically feasible yield of Common bean variety. The experiment was designed in factorial combinations of five levels of Phosphorus (0, 23, 46, 69 and 92 kg ha-1 ) and three haricot bean variety (Hawassa Dume, Omo-95 and Nassir) in a Randomized Complete Block Design with three replications. Data on days to flowering, days to maturity, number of nodules plant-1 , number of leaves plant-1 , plant height, number of primary branches plant-1 , number of pod plant-1 , number of seed pod-1 , hundred seed weight, above ground biomass, grain yield and harvest index were recorded and subjected to analysis of variance using SAS software. The results revealed that both P rates and common bean variety had significant effect on days to flowering, days to maturity, number of leaves plant-1 , number of primary branches plant-1 , number of pods plant-1 , number of seeds pod-1 , total above ground biomass, hundred seed weight and grain yield.The interaction effect of phosphorus fertilizer rate and Common bean variety significantly influenced total of nodule number and effective nodules number plant-1 . All parameters tested were positively correlated except days to 50% flowering, days to maturity and leaves number plant-1 was Negatively correlated but plant height was not siginificant with grain yield . The highest grain yield (2.38 tons ha-1 and 2.11 tons ha-1 ) was recorded from 46 kg P ha-1 rate and Hawassa Dume Common Beanvariety, respectively.The highest net return (37,630 ETB ha1 ) with acceptable marginal rate return (1140.54 %) was obtained from Hawassa Dume variety with 46 kg P2O5 ha-1 application. This implies that the growers at the study area can get additional benefit of 11.4054 ETB for every 1 ETB expense by this treatment, followed by Hawassa Dume variety with 23 P2O5 kg ha-1 supply having a net return of 27,080ETB ha-1 . The lowest net economic return was recorded in the Omo-95 variety with zero-P application (17,550Birr ha-1 ). Thus, it can be concluded that application of 46 kg P ha1 and Hawassa dume haricot bean variety were found superior both in productivity and economically at Negelle Borena area.
RESPONSE OF MUNGBEAN (Vigna radiata (L.) Wilczek) VARIETIES TO DIFFIRENT RATES OF NPSB FERTILIZER RATESAT ZALA DISTRICT, SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2021) HABTAMU HARINGO
Mungbean (Vigna radiata L.) is the sixth exportable pulse crop in Ethiopia and is a useful protein source for consumers in semi-arid and arid areas of the country. However, its current national productivity is 1.003ton ha-1 , which is much lower than its potential due to the unavailability of balanced nutrients in the soil. Therefore, thisstudy was carried out to evaluate the response of Mungbean varieties toNPSB fertilizer rates. The experiment was conductedin Zala woreda, during the main cropping season of 2021.The experiment was laid out using RCBD in a factorial arrangement with three replications. There was a total of sixteen treatments from a factorial combination of four fertilizer rates (0, 50,100 &150 kgha1 ) and four varieties of Mungbean (Borda,Rasa (N26),NVL-1 & Gofa local).The results revealed that fertilizer had a significant (P<0.05) effect on days to flowering, days to physiological maturity, plant height, brunch number, nodule number, pod number per plant, seed number per pod, thousand seed weight, grain yield, above ground dry biomass, and strow yield. Varieties also had a significant (P<0.05) effect on days to physiological maturity, branch number, pod number per plant, seed number per pod, thousand seed weight, grain yield and harvest index.The interaction of NPSB fertilizer application with verities also had a significant(P<0.05) effect on days to flowering, days to physiological maturity, number of seeds per pod, thousand seed weight, grain yield, dry above ground biomass and harvest index.The highest yield (2.5tonha-1 ) resulted from the interaction effect of the150kg NPSB with the Boreda Varity application. The partial budget analysis also indicated that the best treatments were interaction of the 150kgha-1NPSB with Borda and Rasa (N-26), which gave the first and second highest net benefits of 126126 and 96600 ETB ha-1 , respectively, with an acceptable marginal rate of returns. Therefore, mung bean producers can use the NPSB mixed fertilizer at the rate of 150kg ha-1 and Boreda Variety in the Zala district of the Gofa Zone and other similar areas to increase their productivity.
GENETIC, MORPHOLOGICAL, AND AGRONOMIC EVALUATION OF COWPEA (VIGNA UNGUICULATA (L.) WALP.) GENOTYPES UNDER MOISTURE LIMITED AREAS OF SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2022) YASIN GOA CHONDIE
Cowpea (Vigna unguiculata (L.) Walp.) is a legume predominantly grown in lowland areas of Ethiopia for grains, income source, feed, and to a lesser extent as a vegetable crop. However, several biotic and abiotic constraints and lack of improved varieties suited to different agro-climatic conditions limit its production. Therefore, the objectives of this dissertation work were to: i) Assess farmers’ perceived production constraints, farmers’ perceptions, farmers traits of preferences, and the production systems of cowpea in southern Ethiopia ii) Estimate the genetic diversity among cowpea genotypes based on morpho-agronomic traits iii) Assess the magnitude of genotype by environment interaction and yield stability of cowpea genotypes and thereby identify broad and/or narrowly adapted genotypes for production in south Ethiopia and; iv) Assess and select superior cowpea variety/varieties that meet farmers’ needs and preferences using farmers’ participatory variety selection (PVS). The study was conducted in southern Ethiopia from 2016 to 2018. Firstly, a participatory rural appraisal (PRA) approach was undertaken in the year 2016 in Konso, Kindo koyisha, Humbo, and Gofa districts, to identify farmers perceived cowpea production constraints, farmers' perceptions, farmers’’ traits of interest, and its importance in production systems. Semi-structured interviews, focused group discussions and discussions with key informants were used for data collection. Descriptive statistics, cross-tabulations and chi-square tests were used to analyze the data. The results revealed that the majority of farmers (92.7%) grow local landraces in the area and 12 production constraints were identified and prioritized. Diseases and insect pests, drought, lack of improved varieties, poor access to extensions, poor access to credit services, low soil fertility, farmland shortage, sub-optimal agronomic practices, and storage pests (mainly weevils) were some of the factors limiting cowpea production in south Ethiopia. The criteria used by farmers to select cowpea varieties included high grain and aboveground biomass yield, early maturity, resistance to diseases and insect pests, resistance to drought, good taste, seed color, large seed size, short cooking time, resistance to storage pests (weevils), resistance to shattering, marketability, leaf shedding, and suitability to XXI intercropping of the variety. This study implies that different types of varieties need to be developed for different areas. A field experiment was conducted at the Gofa research station during the 2016/17 main cropping season using 36 cowpea genotypes arranged in a simple lattice design. The Shannon diversity index ranging from 0.633 to 0.953 with a mean of 0.84 revealed a high degree of variation in qualitative traits of cowpea genotypes. Cluster analysis based on 14 quantitative traits grouped the 36 cowpea genotypes into six clusters, indicating that agro-morphological diversity exists. Clusters III and IV were found to be promising for yield and its major component traits, while the genotypes in Cluster VI had genotypes for earlier flowering and maturity. Therefore, clusters III, IV, and VI genotypes could be used directly in multi-location trials for their suitability to be released for successful cowpea production or could be source materials for obtaining desirable new recombinants for early maturity and higher yield in south Ethiopia. Thirdly, twenty cowpea genotypes were tested at Gofa, Kucha, and Humbo in Meher seasons of 2016 and 2017 (E1 to E6) and Belg seasons of 2017 and 2018 (E7 to E12) to investigate the influence of genotype by environment interaction and yield stability on cowpea genotypes. The experiments were laid out in a Randomized Complete Block Design (RCBD) with three replications. Environment, Genotype, and GEI effects were highly significant (P<0.001) for the grain yield indicating differences between genotypes and variation of the environments. Additive Main Effects and Multiplicative Interactions (AMMI) and Genotype plus Genotype by Environment interaction (GGE) biplot), AMMI stability value (ASV), and Genotype Selection Index (GSI) were used for stability analysis. AMMI and GGE biplot, ASV and GSI indices identified G16 (IT-89KD), and G14 (IT93K293-2-2) as the highest yielding with better stability across environments, suggesting that it can be recommended for all cowpea growing areas of southern Ethiopia with weather conditions similar to the areas used in this study. The advanced lines, G12 (IT96D-604), G13 (93K-619-1), G20 (IT97K-569-9), and G15 (IT99K-1060) had higher grain yields than the checks and were suggested for further inclusion in the breeding program to boost cowpea production. Lastly, PVS was designed to assess and select superior cowpea varieties that meet farmers’ needs and preferences using farmers’ participation. In this study, eight cowpea varieties were laid out in an RCBD using three replications at Gofa research station and across three selected kebeles at three villages from each kebele(site) comprising a total of nine farmers' fields during the 2016 and 2017 main cropping XXII seasons.Combined mean values showed that Brazil-3 (1.65 t/ha), Brazil-2 (1.62 t/ha), Kenketi (1.53 t/ha), and bole (1.52t/ha) were high-yielding varieties with a yield advantage of 3.9 to 12.2% more than a check variety white wonderer trailing. These varieties also got high farmers' overall preference. Therefore, considering data on farmer preferences and field performance, two released varieties, kenekti and Bole, were selected as farmers’ first choice and can be recommended for further demonstration, popularization, and dissemination on farmers’ fields, while the two Brazilian varieties, Brazil-2 and Brazil-3 are preferred as the second category of choice by farmers must be registered according to national regulations of the country. Overall, this study documented the present cowpea production constraints, farmers’ perceptions, and farmer-preferred traits; indicated the presence of considerable genetic diversity among tested genotypes; identified cowpea genotypes with farmers' preferred traits. Also, advanced lines with high yields across environments were identified that can be recommended for release. In general, the research serves as the basis for designing further research and development programs by using the expressed farmers’ concerns and the identified promising genotypes to enhance sustainable cowpea production by smallholder farmers in southern Ethiopia and similar areas.
AGRO-MORPHOLOGICAL VARIABILITY, GENOTYPE BY ENVIRONMENT INTERACTION, NUTRIENT AND LAND-USE EFFICIENCY, AND NUTRITIONAL PROFILE OF OAT (Avena sativa L.) GENOTYPES IN ETHIOPIA
(Hawassa University College of Agriculture, 2024) GEZAHAGN KEBEDE BUNARE
Agro-morphological variability, genotype by environment interaction, nutrient and land-use efficiency, and nutritional profile of oat (Avena sativa L.) genotypes in Ethiopia Oat (Avena sativa L.) is one of the useful annual cereal crops grown at higher altitudes in the tropics and temperate regions. It is a dual-purpose crop cultivated for fodder and grain production in the central highlands of Ethiopia. This crop is mainly cultivated for fodder production and the grain is also used for human food and animal feed in Ethiopia. Oat generally produces high amounts of fodder which has better nutritional quality and it can be used as a green feed and the excess production can be conserved as hay and silage to utilize during the feed scarcity period. Despite its significance, oat production, and productivity are highly influenced by genetics, environments, agronomic management, and their interactions. Therefore, developing high-yielding oat varieties with stable performance under diverse environmental conditions and improving the productivity of oat through various agronomic management are the major research areas for oat improvement in Ethiopia. However, studies on agromorphological based genetic diversity and yield stability of oat genotypes under diverse environmental conditions and the optimum nutrient requirements of oat for higher yield and nutritional quality under sole and mixed cultures with vetch have not been well studied and properly documented in the country. Thus, the overall aim of this study was to enhance the productivity of oat genotypes through proper exploitation of genetic variability and agronomic management under different environments and management conditions. The first experiment was conducted using 120 oat genotypes using a randomized complete block design with three replications at Holetta and Ada-Berga research stations in the 2020/2021 cropping season. The objectives of this study were to estimate the extent of agro-morphological based genetic variability, heritability, and genetic advance in oat genotypes, to investigate the phenotypic and genotypic relationships between the studied quantitative traits, to determine the direct and indirect effects of measured quantitative traits on fodder and grain yields, and to evaluate the genetic variations using cluster, genetic divergence, and principal component analyses for oat yield improvement. The results revealed that moderately high to very high heritability (62.9– 86.4%) coupled with high to moderate genetic advance as percent of mean (16.0–26.1%) were recorded for forage dry matter yield (FDMY), number of leaves at forage harvest (NLFH), stem dry matter yield (SDMY), forage yield production rate (FYPR), grain yield (GY), panicle length at grain harvest (PLGH), number of spikes per panicle (NSPP), and harvest index (HI). This result demonstrated that the selection of oat genotypes based on these traits could be effective for yield improvement. The genotypic and phenotypic correlation and path coefficient analyses indicated that the FYPR had a significant positive association and high direct effect on FDMY and also the biological yield production rate (BYPR) and HI had a significant positive association and high direct effect on GY. This indicated that selection based on FYPR and BYPR/HI would simultaneously improve the FDMY and GY in oat genotypes, respectively. The multivariate analysis revealed that the studied genotypes grouped into four clusters with the intra and inter-cluster genetic distances ranging from 2.3 to 4.3 and 11.7 to 63.2, respectively. The principal component analysis showed that traits such as FYPR, BYPR, PLGH, FDMY, and xxxi number of spikelets per panicle (NSLPP) contributed more for the first component whereas HI, GY, NLFH, and plant height at grain harvest (PHGH) had a high contribution for the second component. The presence of genotype by environment interaction (GEI) complicates the selection of genotypes with high yielding coupled with stable performance across environments. Twenty-four oat genotypes were selected and sown during the 2020/2021 cropping season at Holetta (E1), Ada-Berga (E2), Ginchi (E3), Jeldu (E4), D/Zeit (E5), Kulumsa (E6), Bekoji (E7), Kuyu (E8), and D/Markos (E9) agricultural research stations using a randomized complete block design with three replications. Thus, the second experiment aimed to assess the magnitude of GEI and to evaluate the fodder and grain yield stability performance of oat genotypes using univariate and multivariate statistical models. The additive main effects and multiplicative interaction (AMMI) analysis of variance for fodder yield showed that the total variation was highly contributed by the environment (E) main effect followed by GEI and genotype(G). Moreover, the GGE biplot analysis for fodder yield showed that G6 was the ideal genotype while G2, G3, G10, and G23 were desirable genotypes. Among environments, E7 was an ideal environment whereas E1 and E8 were favorable environments. The results of univariate stability analysis indicated that selection of oat genotypes using genotypic superiority index (Pi), yield stability index (YSI), coefficient of determination (R2 ), and coefficient of variation (CVi) stability parameters would be effective for fodder yield improvement. Similarly, the AMMI analysis of variance for grain yield showed that the E main effect was the highest contributor to the total variation followed by G and GEI. Based on the GGE biplot analysis for grain yield, G19 was an ideal genotype while G8, G11, G12, G14, G17, and G22 were desirable genotypes. Moreover, the ideal environment was E2 whereas E1, E4, and E5 were favorable environments. The univariate stability analysis for grain yield indicated that high grain yield-producing oat genotypes had stable performance using the stability parameters of Pi , the Perkins and Jinks adjusted linear regression coefficient (Bi), and YSI. The yield and nutritional quality of oat can be improved through the application of optimum fertilizer at the right time. Oat can be cultivated using the blanket recommended fertilizer rate in Ethiopia. Thus, the optimum fertilizer rate for fodder and grain production of oat has not been well studied and documented in the country. Therefore, this study aimed to assess the effect of fertilizer rates on agro-morphological traits, nutrient uptake and use efficiency, nutritive value, and economic feasibility of oat varieties at Holetta. The study was carried out during the 2020/2021 and 2021/2022 cropping seasons using a factorial arrangement of eight levels of the blanket recommended fertilizer (0, 25, 50, 75, 100, 125, 150, and 175%) and three oat varieties (CI-8251, SRCPX80Ab2291, and Sorataf) in a randomized complete block design with three replications. The results showed that variety, fertilizer, and year had significant effects on FDMY. The FDMY of oat varieties increased with increasing fertilizer rates and the highest (15.9 t/ha) yield was obtained from the application of 175% (71.8 kg N + 35 kg P/ha) fertilizer. Among oat varieties, the highest FDMY was obtained from CI-8251 (forage type oat) followed by SRCPX80Ab2291 (dual type oat) and Sorataf (grain type). The number of tillers per plant (NTPP), yields of morphological fractions (leaf, stem, and grain), FYPR, nutrient concentration, and uptake had significant positive associations with fertilizer levels and FDMY. However, all the nutrient use efficiencies except agro-physiological efficiency (APE) had inverse associations with fertilizer levels and FDMY. Similar to FDMY, the GY of oat varied significantly for variety, fertilizer, and year effects. Application of 150% (61.5 kg N + 30 kg P/ha) fertilizer rate produced the highest GY (6.5 t/ha) and grain nutrient uptakeGNU (141.7 kg/ha) while the lowest GY and GNU were recorded from oat sown without fertilizer application. Sorataf (grain type) variety gave the highest GY, GNU, partial factor xxxii productivity (PFP), and agronomic efficiency (AE) compared to forage and dual-type oat varieties. Oat varieties sown with 25% (10.3 kg N + 5 kg P/ha) fertilizer rate produced the highest PFP (346.6 kg/ha) and AE (164.8 kg/ha) while PFP and AE decreased with increasing fertilizer rates. The nutrient concentration and uptake had positive associations with fertilizer level and GY while nutrient harvest index (NHI) and nutrient use efficiency had inverse associations with fertilizer level and GY. The nutritional quality analysis indicated that digestible yield (DY) and total digestible nutrient yield (TDNY) varied significantly with variety, fertilizer, and year effects. Among oat varieties, CI-8251 gave the highest TDNY while SRCPX80Ab2291 gave the highest DY but the Sorataf variety gave the lowest TDNY and DY. Most of the measured nutritional quality parameters varied for the interaction effect of variety by fertilizer by year effect. Sorataf variety sown with 175% fertilizer rate in 2020 gave the highest crude protein-CP (113.9 g/kg DM), crude protein yield-CPY (1.66 t/ha), and digestible crude protein-DCP (68.2 g/kg DM). Application of fertilizer and FDMY had significant positive associations with CP, CPY, DY, DCP, and TDNY. The combined partial budget analysis for the three oat varieties showed that application of 125% (51.3 kg N + 25 kg P/ha ) fertilizer rate produced higher net benefit (83,440 ETB) and marginal rate of return (12,635.6%) from fodder production. On the other hand, the application of 150% fertilizer rate produced the highest net benefit from grain production. Oat can be also cultivated with vetch (annul forage legume) to improve the quantity and quality of feed in the central highlands of Ethiopia. The oat/vetch mixtures are sown with the same blanket recommended fertilizer rate that is used for the production of sole oat in the country. This indicated that the application of fertilizer on oat/vetch mixtures does not depend on the nutrient requirements of oat and vetch for better growth and development under a mixed cropping system. Accordingly, the optimum fertilizer rate for the oat/vetch mixed cropping system has not been well studied and documented in the country. Therefore, this study aimed to investigate the effect of fertilizer rates on agro-morphological traits, nutrient uptake and use efficiency, competitive ability, and economic feasibility of oat under oat/vetch mixed cropping and nutritive value of mixtures at Holetta Agricultural Research Center during the 2020/2021 and 2021/2022 cropping seasons. In this study, the oat/vetch mixture was sown with eight fertilizer rates (0, 25, 50, 75, 100, 125, 150, and 175%) and also sole oat and sole vetch were sown with their recommended fertilizer rate (100%) using a randomized complete block design with three replications. The results showed that fertilizer and year had significant effects on all measured agro-morphological traits, nutrient concentration, and nutrient uptake and use efficiency of oat. Accordingly, all the measured agro-morphological traits increased with increasing fertilizer rates, and the highest values were recorded in the second year. Application of 150% fertilizer rate increased the FDMY of oat/vetch mixtures by 107.4% compared to oat/vetch mixtures sown without fertilizer application. However, the highest nutrient use efficiency was recorded with the application of fertilizer at the rate of 25% while the nutrient use efficiency was the lowest with the highest fertilizer (175%) application rate. The FDMY of oat under oat/vetch mixtures was associated significantly and positively with all measured agro-morphological traits, nutrient concentration, and uptake while it had significant inverse associations with nutrient use efficiencies. The highest net benefit and marginal rate of return were recorded from the application of 150% fertilizer rate. The productivity of oat under oat/vetch mixed cropping was also assessed using different indices. The results showed that over-yielding oat (OYO), land equivalent coefficient (LEC), area-time equivalent ratio (ATER), and land equivalent ratio (LER) were higher in the first year while oat equivalent yield (OEY) and system productivity index (SPI) were higher in the second year. All xxxiii the aforementioned biological efficiency indices increased with increasing fertilizer rates and the highest values were recorded from the application of 150% fertilizer rate. Similarly, all the measured competitive indices such as crowding coefficient of oat (KO), actual yield loss of oat (AYLO), intercropping advantages of oat (IAO), and the competitive ratio of oat (CRO) were higher in the first year. All the values of competitive indices except aggressivity of oat (AO) increased with increasing fertilizer rates and the highest values were recorded from the application of 150% fertilizer. The economic efficiency indices of oat/vetch mixtures showed that the higher values of monetary advantages index (MAI), relative value total (RVT), replacement value of intercropping (RVI), and relative net return index (RNRI) were recorded in the first year. All the values of economic efficiency indices increased with increasing fertilizer rates and the highest values were recorded from 150% fertilizer rate. The nutritive values of oat/vetch mixtures also varied with fertilizer application and year of production. All the measured nutritive values except fiber contents (NDF-neutral detergent fiber, ADF-acid detergent fiber, ADL-acid detergent lignin, HC-hemicellulose, and C-cellulose) were higher in the second year. Application of fertilizer at the rate of 150% gave the highest ash, CPY, digestible dry matter (DDM), dry matter intake (DMI), in-vitro dry matter digestibility (IVDMD), DY, total digestible nutrients (TDN), TDNY, relative feed value (RFV), and relative feed quality (RFQ). On the other hand, oat/vetch mixtures sown without fertilizer gave the highest fiber contents. The person correlation analysis indicated that fertilizer application had significant inverse associations with fiber contents while it had significant positive associations with the remaining measured nutritional quality parameters. In conclusion, oat genotypes such as CI-715, CI-1463, SRCPX80Ab2806, A-505, CI-1480, S-122, Bona-bas, and CI-1674 were selected for fodder yield and grain yield improvement. Based on the AMMI, GGE, and univariate stability parameters, G6 (CI-1512), G9 (CI-1629), G10 (C-12), and G23 (CI-8235) were selected for fodder yield improvement while G8 (SRCPX80Ab2267), G17 (SRCPX80Ab2310), and G22 (SRCPX80Ab2691) were selected for grain yield improvement of oat. Application of 125% (51.3 kg N + 25 kg P/ha) fertilizer rate for fodder production and 150% (61.5 kg N + 30 kg P/ha) fertilizer rate for grain production could increase the respective yield and farm profitability in the study area. Similarly, application of 150% fertilizer rate would increase the fodder yield, competitive ability, and economic profitability of oat under oat/vetch mixtures and nutritive value of mixtures. However, the selected genotypes and fertilizer rates should be verified under diverse environments of oat-growing areas in Ethiopia.