ABSTRACT Small farmers in semi-arid areas of eastern Kenya produce green grams and pigeon peas for both subsistence and income. Because of this, it was important for a detailed investigation on the difficulty of raising marketed surplus (produce) of green grams and pigeon peas. The literature with respect to how small farmers differed in the uses of the produce and the determinants of marketed surplus is sparse. The objectives of the study therefore were to assess the differences in farm retention (for self-consumption, seed and payments in kind) and marketed surplus and to determine the factors affecting marketed surplus. Survey research design was selected for making the observations. Sampling of the households was done using a multistage technique. There were 364 households selected in two agro-ecological zones, each with 182 respondents. Data collection was done using a well-structured questionnaire. Data analysis was done using the IBM SPSS Statistics 21. One-way analysis of variance results indicated that farmers of green grams and pigeon peas differed significantly in the produce consumed, marketed and used as seed and in-kind transactions. Green grams farmers differed significantly at F(3, 1 452) = 11.420, p = 0.000, whereas pigeon peas small farmers at F(3, 1 452) = 21.680, p = 0.000. Multiple linear regression analysis results showed factors influencing farmers in marketed produce of green grams as area cultivated, yield and region of production at p = 0.01. Seeds and in-kind transactions showed positive effect at p = 0.05, whereas access to market information at p = 0.1. The factors influencing farmers on marketed production of pigeon peas were seeds and in-kind transactions and the price of output (p = 0.01). The study concluded that the design of policy interventions therefore needed to take account of small farmer variations and the factors influencing the marketed production of green grams and pigeon peas.
A two–year experiment was carried out to determine the effects of tillage (heap and level, hoe plough and herbicide-based zero tillage) and weed control methods (no weeding, hoe weeding at 25 days after transplanting (DAT), hoe weeding at 25 and 45 DAT, application of post-emergence herbicide propanil plus 2,4-D (Orizo Plus, Proficol Calle, Baranquilla, Colombia) at 25 DAT followed by hoe weeding at 45 DAT, and Orizo Plus® at 25 and 45 DAT) on weed infestation and performance of lowland rice in Badeggi, Nigeria. Reduced weed density and biomass, taller rice plants, and higher panicle and paddy yield were recorded in most heap and level treatments. Two hoe weedings only and Orizo Plus® at 25 DAT followed by one hoe weeding resulted in significantly lower weed density and biomass, more panicles and significantly higher paddy yield. Hoe plough in combination with two hoe weedings had the lowest weed density. Zero tillage planting in combination with two hoe weedings produced weed biomass comparable to heap and level in combination with the application of Orizo Plus® at 25 DAT followed by one hoe weeding. These results suggest that hoe plough followed by hoe weeding at 25 and 45 DAT, or heap and level tillage followed by application of Orizo Plus® at 25 DAT and hoe weeding at 45 DAT effectively controlled weeds and increased plant height, panicle number and paddy yield of transplanted rice.
Many rural dwellers in tropical regions depend on non-timber forest products (NTFPs) for their livelihood and income requirements. However, the link between the economic benefits of NTFPs and their resource base (including local availability and sustainability) and sources are poorly understood. Understanding the dependence on NTFPs requires an economic valuation to improve on sustainable utilization and planning of NTFP resources in the forest. Further, NTFPs are undervalued and not be included in the national accounts therefore lowers overall contribution of forests to the GDP. The current study, therefore, estimated the value NTFPs from The South Nandi forest reserve, using a combination of methods. Twenty-two NTFPs and associated plant species used were cited in Focused Group Discussion, but it was firewood, grazing and medicinal plants that were mostly utilized. The collection of NTFPs took 54.5% of the households’ productive time suggesting high dependence on them. The economic value of NTFP extraction household−1 yr−1 was US$ 579.51. The annual firewood extraction was 7 285.4 ± 1 586.9 kg household−1 and households spent an average of 2.9 ± 1.2 hours to collect a headload of firewood. The net economic value for grazing cattle in the forest yr−1 household−1 ranged from US$ 11.6 to US$ 205.0. NTFPs contributed between 32.7% and 48.7% to households’ income confirming the importance of NTFPs to their livelihoods. This forest should be managed based on the principles of sustainable forest management for continued provision of these benefits.
ABSTRACT Osyris lanceolata is an evergreen, drought tolerant tropical African tree species belonging to the family Santalaceae. It is endangered, owing to overexploitation for its essential oil used in cosmetics and pharmaceutical industries. The study aimed at determining: (1) the genetic diversity; and (2) the population genetic differentiation in seven key O. lanceolata populations, representing its natural distribution in Kenya. Genotype data for ISSR neutral molecular markers were generated for seven populations of O. lanceolata. The percentage of polymorphic loci (P), ranged from 51% (Wundanyi) to 82% (Gwasii), with a mean of 65%. The mean number of effective alleles (Ne) was 1.430, whereas the Shannon Information Index (I) mean was 0.263. Gwasii population was the most genetically diverse followed by Mt Elgon and least was Wundanyi. The coefficient of differentiation Gst was 0.343. Results of analysis of molecular variance (AMOVA) showed that most of the genetic variation (62%) in O. lanceolata resided within populations. Principal coordinate analysis (PCoA) analysis showed that Baringo population located in the Rift Valley was genetically distinct from the rest of the populations. In conclusion, Gwasii, Mt Elgon and Baringo populations should be delineated for in situ conservation, whereas selection for ex situ conservation should target good trees from all the populations.
ABSTRACT Villagization brings scattered households together into a defined area with the aim of transforming living conditions through providing social and economic services. As the forest in Mengeshi district, southwest Ethiopia, has been destroyed through shifting cultivation, the study aims at assessing the effect of villagization on conserving forest resources. Three sites were selected, these being at Fejeji, Baya and Kumi. A total of 119 households were selected for interviews. Information was collected through structured and semi-structured questionnaires. Six farms and 18 plots were assessed for woody plants. The results show that the most important changes which positively contribute towards forest resources were perceived after villagization. A total of 34 woody species representing 13 families were identified in the abandoned farms. Economically important species including Cordia africana Lam., Pouteria altissima (A.Chev.) Baehni and Diospyros abyssinica (Hiern) F. White that need conservation due to overutilization were recorded across the three sites. The Simpson's diversity index was 0.94 at Fejeji, 0.93 at Baya and 0.88 at Kumi. Villagization has brought about changes in the sources of livelihoods of the households. The forest-based livelihoods have shifted to farming-based livelihoods and the main sources of forest products have shifted from forest to homestead. A paired t-test showed a significant change in the forest product sources implying less pressure on natural forest resources. In general villagization has positive effects towards conserving forest resources in the area.
Pumpkin is becoming an important fruit-vegetable, although its potential remains unexploited in Kenya. This study aimed at enhancing conservation, preservation and production of naturalized pumpkins through the cataloguing of accessions and documentation of indigenous traditional knowledge influencing cultivation and utilization. In 2012 an expedition led to the collection of 155 accessions of Cucurbita moschata (Lam.) Poir., with 70 from Kakamega and 85 from Nyeri. Variegated accessions were significantly (P < 0.05) the most popular and highly utilized, compared to the exotic green-leafed ones. Significantly (P < 0.05) more green-leafed accessions were collected in Nyeri, and variegated in Kakamega. There was significant (P < 0.05) variation in fruit shape and skin colour. Fruit-form ranged from ovate to globose or elliptical, and the predominant skin colour was dark to pale-green. Intercropping was the main cropping system. Food provision and income generation significantly (P < 0.05) influenced cultivation and utilization of the pumpkins. Most variegated accessions were inherited from past generations and have become naturalized. The green-leafed accessions were introduced by farmers and other stakeholders. Fruits and leaves were significantly (P < 0.05) utilized by farmers, compared to seeds and whole plants. The quality of fruits and leaves, cooking method and recipes were significantly (P > 0.05) considered by farmers when selecting accessions to cultivate. These factors were significant (P > 0.05) in sustaining genetic diversity and conservation. Interventions to preserve positive factors and overcome constraining ones should be promoted to enhance growing of naturalised pumpkin for good health and income generation.
Soil quality plays an important role in the assessment of sustainable land-use systems. Assessment of soil quality will always help farmers to apply correct fertilisers in correct proportions to their soil. This will definitely help them achieve maximum yield with minimum expenditure. Not only that, they can conserve their environment. Assessment tools for indexing soil quality at various scales were pursued to show the multiple functions that soils provide as the foundation for sustainable land management. Newly developed soil quality index called Heber soil quality index (HSQI) is widely used to identify and differentiate the various types of soils. In the current investigation, the soil samples were taken in the rice and sugarcane fields from, at least fifteen places of the Thiruvarur district (9.28° N, 79.3 °E) and were categorised as excellent, good or bad for cultivation of the rice and sugarcane on the basis values of Heber soil quality index (HSQI). The HSQI values of all samples ranged from 73.34 to 81.04, which reveals that the quality of soils studied in this investigation is good for the cultivation of rice and sugarcane. The index was found to be time saving and cost effective method of assessing the fertile nature of the soil for the effective cultivation of rice and sugarcane. Soil quality assessment in the light of HSQI is intended to provide a better understanding of the soil resources measures to be taken, to improve the quality of soil system for the better yield of any crop in general and rice and sugarcane in particular processes.
Few studies have evaluated improved pigeonpea varieties developed and released in Kenya for soil fertility improvement and contribution to the productivity of cereal-based cropping systems prevalent in marginal areas. A study comprising field and greenhouse experiments was conducted between 2009 and 2013, in order to evaluate improved pigeonpea varieties for nitrogen (N) uptake, biological nitrogen fixation (BNF), response to rhizobia inoculation and their effect on maize yields. Field experiments were conducted in Katumani Research Centre using a split-split plot design, with three pigeonpea varieties, two cropping systems and three crop residue regimes as the main plot, subplot, and sub-subplot, respectively. Greenhouse experiments were conducted at Muguga Research Centre where five pigeonpea varieties were screened for BNF and response to rhizobia inoculation in plastic pots filled with 10 kg of soil and replicated four times in a completely randomized design. Data collected on nitrogen uptake, BNF and maize and pigeonpea yields was subjected to analysis of variance using GENSTAT statistical software. Pigeonpea had significantly (p ≤ 0.05) higher nitrogen uptake compared with maize; Mbaazi II (84–114 kg N ha−1) absorbed more N, followed by Kat 60/8 (29–44 kg N ha−1) and Mbaazi I (20–37 kg N ha−1). All the three pigeonpea varieties fixed 60–70 kg N ha−1, meaning they were all good nitrogen fixers. Mbaazi II fixed significantly (p ≤ 0.05) higher N (70 kg N ha−1) compared with KAT 60/8 (66 kg N ha−1) and Mbaazi I (62 kg N ha−1) when intercropped with maize. Inoculation with rhizobia gave mixed results. Mbaazi II-maize intercrop gave the highest maize (1.9 t ha−1) and pigeonpea (1.4 t ha−1) grain yields and produced sufficient maize stover (2.1 t ha−1) and pigeonpea stalks (2.9 t ha−1).
The litter fall production, decomposition and subsequent nutrient release of Carrisa edulis, Juniperus procera, Maytenus obscura and Olea europaea was monitored in the dry Afromontane forest of Northern Ethiopia by collecting abscised leaves using litter trap with a 192 litter bags in a randomised complete block design and collected monthly for 8 months where leaf mass and nutrient release of carbon (C), nitrogen (N) and phosphorus (P) were monitored. J. procera had the highest litter fall production. C. edulis had the highest leaf mass loss (27%) followed by M. obscura (22%) and the lowest was from J. procera (9%). The leaf of J. procera had significantly higher C content (p < 0.05) than the leaf of the other three species. Leaf of C. edulis N concentration was significantly higher (p < 0.05) than the other species. C. edulis had the fastest litter decomposition rate and the lowest was found in J. procera. High lignin, lignin:N and C:N was found in J. procera followed by O. europaea and were low in C. edulis. The rate of decomposition of J. procera leaves were slower than the other three species. The higher lignin, lignin:N and C:N contents of J. procera leaves contributed to the slower decomposition rate. The litter fall from C. edulis can be a supplemental source of nutrients for fertility maintenance nutrient deficient areas and low organic matter and the leaves of J. procera could be used as mulch to prevent erosion in erosion prone areas.
In most of sub-Saharan African countries, including Rwanda, the predominant agricultural production is from a mixed-crop-livestock farming system, because of small size land holding. The objective ...
Women are taking over the Agriculture sector in sub-Saharan Africa and policies that enhance their empowerment in farming would have positive gains in enhancing food security and transforming lives. Adoption studies have identified gender as one of the factors that determine technology uptake, and this has been linked to women’s access to farming information or lack of it. Technology scaling up systems should utilize pathways that are compatible with the needs of rural women who have to juggle farming with other household chores. Unfortunately, there has been limited effort to evaluate the suitability of the information pathways used to specific gender. This study evaluates the appropriateness of field days with respect to gender of the participants. A total of 2,615 participants were interviewed out of 6,221 who attended field days in Kenya, Uganda and Tanzania. The determinants of level knowledge level gained and willingness to adopt was evaluated using an ordered probit and logit model. Our findings shows that majority of the participants were women (51.3%), middle aged (40-45 years) and with primary level education (54.1% women). The model results shows that women farmers understood more about push-pull (coefficient of ordered probit = -0.112) and were more willing to adopt push-pull (coefficient of logit = -0.367). Age, education, being a push-pull farmer, perception of Striga severity and having a mobile phone were also significant. Our findings demonstrate that field days are appropriate for training farmers especially women who are often disadvantaged in information access.
To understand farmers' preference and perceptions of breed attributes, breeding and feeding practices, 419 households in western Kenya were interviewed in a cross-sectional survey. Respondents scored their preference for cattle breeds, traits and breeding methods on a scale of 1 (most preferred) to 5 (least preferred). Preferences were compared using multinomial logistic regression models on weighted scores. The Ayrshire breed was most preferred followed by the Friesian. Using hardship tolerance as a reference trait, the Friesian was preferred 4.86 times more for high milk production and Ayrshire, Jersey and Guernsey breeds 4.61, 4.60 and 4.18 times (p < 0.01) more, respectively, for milk fat content. The Ayrshire was preferred 4.16 times more for its perceived low feed requirement and 1.22 times more (p < 0.01) for resistance to diseases. Friesian was the only breed preferred (3.18 times more) (p < 0.01) for high growth rate of calves. Artificial insemination (AI) was the breeding method of choice, but majority (>68%) of respondents used natural mating, because it was readily available and cheaper. The current study highlights the importance of taking into account farmers' objectives and the production environment when designing breed improvement programmes and recommends packaging of breeding together with feeding interventions.
Nyandarua County has enormous milk production potential and has a large amount of milk, because of large a population of dairy cows coupled with the huge milk market demand from within and without. Despite this potential, milk postharvest losses have posed a major challenge to the dairy sector in the county. The general objective of the current study was to establish causes of losses among milk producers, as well as factors that contribute to the choice of a milk-marketing channel. A total of 188 milk producers were selected through proportionate to size sampling from Nyandarua North subcounty, including the formal and informal milk value chains. A statistical analysis, as well as a quantitative analysis was done with the help of Microsoft Excel, STATA and SPSS Ver. 21. The first step Heckman results indicate that age of household head, gender of household head, education level, breed type, total milk output, feeding system, keeping of records and type of milk container significantly influenced the choice of milk-marketing channel. The second step Heckman results suggest that dairy farming experience, distance to milk collection point, type of breed, total milk output, use of detergent to clean milk containers, feeding system and keeping of production records were significant as far as causes of milk losses among milk producers was concerned. Based on the results of the current study, it is recommended that policy implementers and dairy stakeholders should prioritise efforts to minimise postharvest milk losses considering that the implications of these losses directly affect the economic wellbeing and livelihood of farmers and other dairy chain participants. Milk-marketing channels, both formal and informal, need to be re-evaluated based on returns and convenience with emphasis on proper postharvest milk management and handling. This will reduce on the losses and additional cost incurred by milk producers and transporters resulting to higher economic returns for the respective chain participants in the dairy value chain.
The study was carried out at the Kenya Agricultural and Livestock Research Organisation (KALRO) Centre at Mtwapa to assess the effect of shade on the productivity of a maize–cassava intercropping system and on the contribution of the intercropping system to food and feed during the dry season, as well as to income. Maize and cassava crops were established in two plots measuring one hectare each. One plot was established in the shade to mimic crop production under tree crops, which is characteristic of coastal Kenya. The second plot was established in an open area. There were no significant differences (p > 0.05) between the yields in the shaded and unshaded plots for all cassava products with the exception of cassava leaf yield, which was higher (p < 0.05) in the shade, (1.67 vs 1.25 t ha−1). In contrast, all the maize products differed (p < 0.05) between the shaded and unshaded treatments. Shade reduced maize grain and bran yield by 48% and stover by 29%. It was estimated that the grain yield in the shade (2.38 t ha−1) would feed a family of 10 people and leave a surplus of 1.4 t ha−1 for sale. The marketable cassava in the shaded and unshaded treatments (19 and 22 t ha−1) could be sold for KES 317 720 and KES 323 600, equivalent to US$ 3 488 and US$ 3 553, respectively. The unmarketable cassava roots (8.5 and 9.59 t ha−1), plus the maize bran (0.11 and 0.21 t ha−1) from the shaded and unshaded treatments could be an adequate energy supplement for seven to eight cows (400 kg live weight) annually. Maize stover (1.5 to 2.1 t ha−1) could be fed to 7–9 cows for 53 to 65 days. The cassava leaves would provide protein supplement for one to two cows per year. Maize–cassava intercrop systems would, therefore, contribute to food and feed security and increase incomes in coastal Kenya.
This study investigates the willingness of the respondents to establish private forest plantations (PFPs) in Oyo State, Nigeria. Two purposively selected and two randomly selected local government areas were used. One hundred and sixty household heads randomly selected were interviewed using the interview schedule and the data analysis was carried out using both descriptive (frequencies, percentages, mean) and inferential (Chi-Square and PPMC) statistics with α0.05. The majority of the respondents were male (89.2%), within 41–50 years (43.9%) and 92.8% were married. About 85.6% have knowledge of private ownership and 91.4% had knowledge on forest plantation establishment. Respondents’ attitude towards PFPs (78.4%) was favourable. A large percentage (96.4%) agreed that involvement in PFPs serves as income generating activity, whereas 58.3% identified government policy on forestry and land tenure system as major constraints to establishing PFPs. There were significant relationships between age (χ2 = 236.256), educational qualification (χ2 = 35.283), primary occupation (χ2 = 62.944) private ownership (r = 0.424), knowledge on forest plantation (r = 0.451), perception (r = 0.230), perceived benefits (r = 0.180), perceived constraints (r = −0.181) and willingness to establish PFPs. Respondents possessed high knowledge and favourable attitude towards PFPs despite the perceived constraints. The state, in collaboration with the Forestry Research Institute of Nigeria (FRIN), should initiate programmes to emphasise benefits of PFPs in order to encourage more participation and government policy on land use decree should be reviewed to promote participation in forest plantation establishment.
Smallholder farmer groups increase market access and reduce transaction costs, but many challenges reduce their performance. A study on how group dynamics and capacity building influence group performance was conducted in Meru, Tharaka Nithi and Uasin Gishu Counties in 2013 with six smallholder dairy groups. Specific objectives were to determine how group dynamics influence group performance, build capacity in the groups and evaluate group performance. Focus group discussions were conducted followed by training based on findings from the discussions. Evaluation was done three months after training. Descriptive analysis was used by adopting the Institutional Analysis and Development Framework to evaluate group performance. The groups had differences in resource endowment, membership, and operating environment. After evaluation, Muchege Hortmil, Ciomburu Arithi and Langas Disabled Self-help Groups had the highest scores, whereas Kapkawa Baitany and Thuita Dairy Self-help Groups, and Chepng’oror Cooperative Society had the least. Awareness of the legal and governance systems after training increased labour division and democracy in Muchege Hortmil and Ciomburu Arithi. Strict enforcement of group rules in Muchege Hortmil improved performance, but the groups faced unfair competition from hawkers. Vulnerabilities reduced performance in Chepng’oror and Kapkawa Baitany, whereas the same vulnerabilities motivated Langas Disabled to improve. The high proportion of inactive members in Thuita reduced performance. Group performance is not so necessarily determined by the group's initial conditions, but by their efforts to organise themselves and learn. Rules are significant in determining group’s performance.
The smallholder direct marketing outlets (private grain traders) serve the smallholder farmers poorly in the rural areas of Kenya, making local markets thin and less competitive. The purpose of this study is to evaluate the diversity and the determinant factors influencing the private grain traders’ performance based on the volumes transacted of green gram and pigeon pea commodities. A multistage stratified random sampling procedure was employed for this study to obtain relevant information on the grain traders in Mwala and Yatta subcounties. One hundred and ten (110) grain traders were sampled in Mwala (38) and Yatta (72) subcounties. Descriptive statistics and a multiple linear regression were used during analysis. The descriptive statistics indicated that the grain traders were diverse in terms of age with majority being 31 to 40 years old, gender in trading found mainly males (54.5%), trader education status with the majority having college education (58.2%), access to credit with large group of traders not accessing (65.5%) and the distribution of the volume purchased of green gram and pigeon peas grain, which indicated high market concentration and the trader inequality. Our model for the trader purchases of green gram and pigeon pea grain was correctly described by the multiple linear regression model. The results obtained from the ANOVA indicated that the overall regression is significant, F(16, 93) = 2 632.316, p < 0.000 for the green gram purchases and F(16, 93) = 660.542, p < 0.01 for the pigeon peas purchases. Grain markets for the green gram and pigeon pea functions poorly, because few traders dominate the markets with high shares in the volumes purchased. Few traders are likely to offer low prices to the smallholder farmers of green gram and pigeon pea. There is a possibility of collusion in the market, owing to few traders in the market.
Infestation by insect pests is a serious problem in legume up scaling activities and a threat to future production in Kenya. The survey aimed at determining incidence and severity of insect pests of common beans in different districts and agro-ecological zones of western Kenya. Foliage beetle incidence was highest in the hot and drier LM3 (72.6%) and LM4 (92.1%) zones during the long and short rains, respectively. Leaf hopper incidence was highest in LM4 (26.8%) and (59.3%) whereas bean fly incidence was highest in UM3 (12.4%) and LH1 (2.9%). Whitefly incidence was highest in LM3 (13.0%) and LM2 (17.9%) and aphid incidence was highest in LM1 (16.5%) and UM1 (40.8%). Plant bug incidence was highest in LM1 (16.5%) and LM2 (5.8%). Flower thrips incidence was highest in LM2 (20.7%) and (34.2%) in both seasons. Bean flies (7.2%) and Spodoptera (2.9%) incidences were higher during the long rains. Foliage beetle incidence (52.7%), aphids (22.6%), leaf hopper (27.9%) and flower thrips (17.8%) were higher during the short rains. Whitefly (7.9%), thrip (9.7%) incidences and foliage beetle severity (2.1) were lower on improved cultivars in LM2 areas in Homa Bay. Intercropping reduced aphid incidence (18.3%) and severity (1.3) in UM1 areas in Vihiga district. Inorganic fertiliser reduced bean fly (3.8%) and thrips (11.8%) incidences in UM1 areas in Vihiga and in LM2 areas in Siaya districts, respectively, compared with fields without fertiliser. The result is important in the development of strategies in bean insect pest management and control.
This paper looks at the role of gender and other socioeconomic factors in the adoption of the contagious bovine pleuropneumonia (CBPP) vaccine in response to three research questions: What gender and socioeconomic factors affect the adoption of the CBPP vaccine? How do they affect the adoption? What can be done to enhance the adoption of CBPP? Answers to these questions were obtained through a review of literature on CBPP and technology adoption studies.The review revealed that technology adoption, including vaccine technology adoption, is gendered, with women tending to adopt less than men, especially in terms of consumer associated drivers.CBPP vaccine adoption can be enhanced through one or a combination of up to four strategies, which include: price reduction and provision of subsidies by government and philanthropic projects especially in times of enhanced and unpredicted demand; convincing, evidence-based, demonstration of benefits of vaccination over its alternatives using methods such as return on investment for every dollar used; gender sensitive advocacy strategies and messages; and carrying out human and livestock vaccination campaigns, simultaneously, in pastoral communities living in marginal areas.
The potato (Solanum tuberosum L.) is an important cash and food security crop in the eastern highlands of Ethiopia. However, the yield of the crop is constrained by low soil fertility and poor agronomic practices. Therefore, the field experiment was conducted at the main campus of Haramaya University and at Hirna Research substation during the 2015 main cropping season. The objective of the experiments was to elucidate the effect of seed tuber planting depth and nitrogen fertiliser rate on yield-related traits and yield of the crop. The treatments consisted of four seed tuber planting depths (5, 10, 15 and 20 cm) and five rates of nitrogen (0, 46, 92, 138 and 184 kg N ha−1). The experiment was laid out as a randomised complete block design with three replications. The results of the experiment at both locations revealed that the main effect of nitrogen application rate influenced total dry weight, unmarketable tuber yield, the percentage of small-sized and medium-sized tubers. Nitrogen rate and seed tuber planting depth also interacted to influence unmarketable tuber yield, the percentage of medium and large-sized tubers produced, and tuber starch content. The main effects of seed tuber planting depth significantly influenced total dry biomass, unmarketable tuber yield, total tuber yield, marketable tuber yield, the percentage of small-sized tubers produced and tuber starch content. Increasing seed tuber planting depth generally enhanced the aforementioned parameters. However, for most parameters, the highest values were obtained already at the seed tuber planting depth of 10 cm. The optimum total and marketable tuber yields of 26.93 t ha−1 and 26 t ha−1 for Haramaya and 34.57 t ha−1 and 32.65 t ha−1 for Hirna were obtained in response to planting seed tubers at the depth of 10 cm.
