Yam Storage Research Articles

Effect of tillage, fertilizers and storage structures on quality shelf life of white yam (Dioscorea rotundata Poir) in south west Nigeria

This study examined the effect of tillage, fertilizers and storage structures on quality shelf life of white yam in South West Nigeria. The study was a factorial experiment consisting of Tillage, Fertilizers and Storage Structure. The tillage system involved Heap Tillage (HT) and Ridge Tillage (RT), while Fertilizers involved Poultry Manure (PM), N15P15K15 (NPK) and Control (CLT) and two types of Storage Structures namely; Traditional Barn (TB) and Open Sided Storage Structure (OSSS) were combined to form the treatments. The experiment was a 2x3x2 factorial combination arranged in a Randomised Complete Block Design (RCBD). The treatments were replicated three times for each location respectively. A total of 72 ridges and 144 heaps were used to make a population of 288 plants per location. The tubers were weighed to ensure uniformity before planting. The plot size was 18mx18m square with a pathway of 1.0m between blocks making a total of 324 square metres. At harvest, the tubers were weighed immediately. They were then kept separately in the two storage structures namely: Traditional Barn (TB) and the Open Side Storage Structure (OSSS) for a period of 3 months. After the 3rd months of storage, the tubers were examined and data collected. The weight of each tuber from each storage structure was taken periodically to evaluate the weight loss and assess the keeping quality periodically. The findings of this study demonstrated the significant influence of tillage, fertilizers, and storage structures on the quality, shelf life, nutrient use efficiency, and nutrient composition of white yam. Excessive fertilizer application was found to increase rotting and deterioration levels. Hence, farmers and stakeholders should carefully consider fertilizer application rates to minimize post-harvest losses and enhance food security. Further investigations are needed to explore the underlying mechanisms responsible for the observed effects and to optimize fertilizer management practices for yam storage. Organic fertilization enhances the nutrient use efficiency and nutritional quality of yam, while appropriate storage structures, play a crucial role in preserving the quality and extending the shelf life of the harvested tubers. Based on the result of the study, open sided storage should be considered by producers of yams for storing their harvested tubers due to the facts that, it performed well in minimizing nutrient lost, weight loss and decay to considerable level and prevented pests/rodents attack on yam tubers.

The microbiome and typical pathogen multiplication, qualities changes of baoxing yam at different storage temperatures

The microbial community structure, pathogenic and spoilage microorganism of yam during storage processing were very important to the quality of yam. In this study, the yams after harvesting were treated by lime-mud coating, and stored at different temperatures (1 °C, 4 °C, 8 °C, and 15 °C). Microbial structures and pathogenic species in yam were explored by high-throughput sequencing, and key microbial communities were identified based on significant correlations with quality-related physiochemical attributes. Results suggested that yam had better quality characteristics under 8 °C storage condition. Firmicutes, Proteobacteria were the dominant bacterial community in yam. Ascomycota and Basidiomycota were the predominate fungal in yam. Penicillium and Bacillus were the main cause of corruption at the incision site of yam. Most of the endophytic bacteria were negatively correlated with the quality of yam, while most of the bacteria at the incision site were positively correlated with the quality of yam. The main negative effects of fungi on the quality of yam were Penicillium, Chordomyces and others dominant fungal genus. Hence, the growth control of such flora during yam storage helped to prolong the storage time of yam.

Transcriptomic analysis of Chinese yam (Dioscorea polystachya Turcz.) variants indicates brassinosteroid involvement in tuber development.

Dioscorea is an important but underutilized genus of flowering plants that grows predominantly in tropical and subtropical regions. Several species, known as yam, develop large underground tubers and aerial bulbils that are used as food. The Chinese yam (D. polystachya Turcz.) is one of the few Dioscorea species that grows well in temperate regions and has been proposed as a climate-resilient crop to enhance food security in Europe. However, the fragile, club-like tubers are unsuitable for mechanical harvesting, which is facilitated by shorter and thicker storage organs. Brassinosteroids (BRs) play a key role in plant cell division, cell elongation and proliferation, as well as in the gravitropic response. We collected RNA-Seq data from the head, middle and tip of two tuber shape variants: F60 (long, thin) and F2000 (short, thick). Comparative transcriptome analysis of F60 vs. F2000 revealed 30,229 differentially expressed genes (DEGs), 1,393 of which were differentially expressed in the growing tip. Several DEGs are involved in steroid/BR biosynthesis or signaling, or may be regulated by BRs. The quantification of endogenous BRs revealed higher levels of castasterone (CS), 28-norCS, 28-homoCS and brassinolide in F2000 compared to F60 tubers. The highest BR levels were detected in the growing tip, and CS was the most abundant (439.6 ± 196.41 pmol/g in F2000 and 365.6 ± 112.78 pmol/g in F60). Exogenous 24-epi-brassinolide (epi-BL) treatment (20 nM) in an aeroponic system significantly increased the width-to-length ratio (0.045 ± 0.002) compared to the mock-treated plants (0.03 ± 0.002) after 7 weeks, indicating that exogenous epi-BL produces shorter and thicker tubers. In this study we demonstrate the role of BRs in D. polystachya tuber shape, providing insight into the role of plant hormones in yam storage organ development. We found that BRs can influence tuber shape in Chinese yam by regulating the expression of genes involved cell expansion. Our data can help to improve the efficiency of Chinese yam cultivation, which could provide an alternative food source and thus contribute to future food security in Europe.

Antifungal Mechanism of Cinnamon Essential Oil against Chinese Yam-Derived Aspergillus niger

Chinese yam with damaged outer skin can be easily oxidized and infected by spoilage fungi. To find preservatives in the storage of the Chinese yam, Aspergillus niger 103 was isolated, identified, and determined as the dominant spoilage fungus in Chinese yam according to Koch’s postulates. Then, the strain was used as a model to screen antifungal agents and study antifungal mechanisms in this study. We found that cinnamon essential oil was the best antifungal agent, and the minimum concentration against Aspergillus niger 103 was 25 μg/mL. The storage life of Chinese yam could significantly extend by 27.66 days by spraying with cinnamon essential oil (25 μg/mL). To further explore the antifungal mechanism of cinnamon essential oil against Aspergillus niger 103, alkaline phosphatase activity and electrolyte content in the fungal solution were measured. The alkaline phosphatase activity and electrolyte content of the fungal solution with cinnamon essential oil were significantly increased than those without cinnamon essential oil, which showed that the cinnamon essential oil could destroy the integrity of the cell wall and cell membrane of Aspergillus niger 103, and disrupted cellular homeostasis of Aspergillus niger 103.

ANTIFUNGAL ACTIVITY OF SELECTED CHEMICAL AGENTS AGAINST PHYTOPATHOGENIC ISOLATED FUNGI SPORES.

Postharvest deterioration has been a major problem associated with yam storage for both famers and traders and it is caused mostly by micro-organisms especially fungi. During the storage of yam, many organisms such as Aspergillus flavus, Aspergillus niger, Penicillium citrinum and Rhizopus stolonifer are often reported to cause rotting of the stored yams. The aim of this research is to find out the antifungal effect of some commonly used anti-dermatophytic agents,(Fluconazole, Terbinafine Hcl, Ketoconazole, Sodium propionate and Griseofulvin) on the above named isolated fungi spores. This was carried out using zone of inhibition, MICs, MFCs, FICs and FFCs to measure the antifungal activities of the test antifungal agents against the isolated phytopathogenic fungi spores. These agents were found to have fungitoxic effects on the test organisms in the order of: Terbinafine Hcl > Fluconazole > Ketoconazole > Sodium propionate > Griseofulvin. This work indicated that the test antifungal agents were able to inhibit the fungi spores that are widely reported to be associated with yams rot when stored. The observation in this study showed that a good and efficient fungicide against the test organisms that are known to cause yam rot during storage can be effectively arrested with combination of these fungicides.

Storage Practices, Incidence and Economic Losses Caused by the Yam Scale Insect, Aspidiella Hartii Cockerell in Nasarawa State, Nigeria

Yam (Dioscorea species) is an annual root-tuber crop with social and economic significance in terms of food security, cash returns and human health, which has social and economic importance in terms of food, cash and medicine. Insect pests present major constraints to production, storage and marketing resulting in yield and revenue reduction, and deterioration of tuber quality in storage. This study was thus designed to assess yam storage practices by the farmers and the prevalence and economic impacts of the yam scale insect, Aspidiella hartii in selected locations of Nasarawa state, Nigeria. A multi-stage sampling technique was used to select 60 yam farmers from the study area. The first stage involved random selection of four Local Government Areas (LGAs) out of the five in the study area. The second stage was the purposive selection of three villages from each of the selected LGAs while the 3rd stage was random selection of five yam farmers from each of the 12 selected villages who were interviewed using a pretested structured questionnaire. Data collected were analyzed using descriptive statistics. Results showed that the common yam storage structures were open sheds, under tree canopies, and field barns with varied dimension of 5-10 m2. Most respondents (98.3%) affirmed the presence of the yam scale insects on stored yams on those stored in the open, barns and stores, with increased incidence with extended duration in storage. Significant reduction of 36% – 50% in the market value of yam due to infestation of the yam scale insect was reported under all storage conditions. Many respondents (60%) recognized misuse and abuse as consequences of pesticide application thus, creating the need for farmers to adopt more environmentally friendly storage practices for management of the yam scale insect in the study area.

Characterization and evaluation of sodium alginate-based edible films by incorporation of star anise ethanol extract/hydroxypropyl-β-cyclodextrin inclusion complex

The star anise ethanol extract (SAEE)/hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex in sodium alginate-based composite films was evaluated for its effect on the storage of fresh-cut Chinese yam. The effect of inclusion complex on rheological, mechanical, color, optical, and thermal properties of the composite films were characterized in this study. The introduction of inclusion complex has significant effects on the mechanical, color, and rheological properties of produced films. With addition of SAEE and SAEE/HP-β-CD inclusion complex, the composite films exhibited variable degrees of antioxidant and antibacterial activities. Particular finding is that inclusion complex-based films presented higher antimicrobial activity against Rhizopus stolonifera. Meanwhile, the release study revealed that mechanical property, solution polarity, matrix structure, and light exposure affected the release efficiency of active substances from the composite films. Also, the addition of inclusion complex improved the thermal stability. Consequently, composite films incorporating the SAEE/HP-β-CD inclusion complex could serve as alternative material for coating fresh-cut Chinese yam.

Storage of Fresh Yam (Dioscorea alata L.) under Controlled Conditions

Freshly harvested "Florido" yam tubers (a highly desirable variety of the species D. alata) were subjected to a temperature of around 32° C. (90° F.) and a relative humidity of 90 percent. Wounded tissues were suberized in about 4 days. This curing may be accomplished either in controlled environmental rooms or under tropical prevailing ambient conditions. The formation of the cork tissue during suberization protects tubers from infection by microorganisms if stored under reduced temperatures. Cured and uncured tubers were stored in a properly ventilated Forma Scientific room at 16° C. ± 1° (59° to 62.9° F.), and a relative humidity of 70 percent. Uncured samples suffered high losses due to physiological breakdown as well as markedly higher weight losses than similarly handled cured ones which showed no signs of internal decay during the storage period. Cured tubers kept under conditions noted above, at temperatures below those prevailing in tropical areas, had the dormant period lengthened by 4 additional months. High-quality tubers can be provided by this means for the fresh market and for processing during the off-season. Although the yam tubers hardened slightly during storage, weight losses were kept at a fairly low level and the palatability of the tubers remained very high, as determined by sensory evaluation.

Calcium Nitrate Fertilization Effect on Anthracnose Caused by Colletotrichum Gloeosporioides Penz., Tuber Rot By Rhizopus Stolonifer Ehrenb. and Yield in Dioscorea Alata Variety Atoroku After Fallow

Calcium nitrate soil amendment fertilization effects on anthracnose disease caused by Collettrichum gloeosporioides, tuber rot by Rhizopus stolonifer and yield were determined in Dioscorea alata variety Atoroku (a local variety from South West Nigeria). The field design was RCBD (randomized complete block design) with 3 treatments and 3 replicates. The 3 treatments were calcium at 0, 2 and 4 kg ha–1 from calcium nitrate (analar grade) applied at 3 MAP (months after planting). N in the experimental site was below the critical determined for optimum yam production in South West Nigeria, but Ca, Mg and K were above the critical. At 4 MAP, shoot number (mean, 3.68) was comparable/similar across treatments, but shoot length (3.43 m) was higher in the 2 kg ha–1 treatment than others. At 5 MAP the control and 2 kg ha–1 calcium fertilized plants had higher shoot number, a mean of 5, than the 4 kg ha–1 calcium fertilized plants, whereas shoot length had become similar in the treatments. Tubers were inoculated and incubated for two weeks with Rhizopus stolonifer, an economic yam storage pathogen in Nigeria, after the 5MAP and 6MAP harvests. There were no significant differences in weight loss or infection in the incubated tubers at 5MAP. Weight loss of 11.01% in the 2 kg ha_1 incubated calcium-fertilized tubers were significantly higher than in the control (3.20%) and the 4 kg ha_1 treatment (1.90%) at 6MAP. However infection was significantly lower in the 2 kg ha_1 (0.78%) and 4 kg ha_1 (0.86%) calcium-fertilized tubers than the control (2.25%) at 6MAP. Calcium nitrate at 2 kg ha_1 and 4 kg ha_1 soil amendment may be used in smallholder farmers plots to reduce infection in D. alata variety Atoroku tubers if the six months after planting is desired for income as is the practice for white guinea yam 6MAP milk harvest in Nigeria. Anthracnose severity scored at 8MAP was moderately susceptible in the 4 kg ha_1 treatment (3.17), control (2.83) and the 2 kg ha_1 treatment (2.75) and were not significantly different from one another. Reduction of anthracnose may be further determined with one or two foliar sprays in addition to the 3MAP calcium nitrate soil amendment, as well as leaf calcium analysis to ascertain the optimum concentration commensurate to anthracnose resistance. Shoot number per plant at 8MAP was in the range 2.07 to 2.54 with no significant differences among the three treatments. Tuber number per plant was also not significantly different and was 3.55, 4.27 and 3.18 in the 0, 2 and 4 kg ha_1 treatments. Plant weight above the mound of 4.78 kg and tuber weight of 5.35 kg in the 4 kg ha_1 treatment at 8MAP harvest was significantly higher than the control (3.25 kg and 3.55 kg respectively), and the 2 kg ha_1 treatment (3.05 kg and 3.25 kg respectively), whereas both were similar in the control and the 2 kg ha_1 treatment. The 8MAP yield of 3.55 kg, 3.25 kg and 5.35 kg in the 0, 2 and 4 kg ha_1  treatment is the equivalent of 35.5, tons ha_1, 32.5 tons ha_1 and 53.5 tons ha_1 and are higher than the expected 15 to 25 tons ha_1 with 400 kg (8 bags) NPK 15-15-15 (ICS-Nigeria) and also in the range of the estimated potential of 30 to 75 tons ha_1 (Zinsou, 1997; Diby et al., 2004). Calcium nitrate soil amendment at 4 kg ha_1 is recommended for increase in yield in Dioscorea alata variety Atoroku after fallow in South West Nigeria or areas of similar soils.

Post-Harvest Loses and Socioeconomic Sustenance of Yam Farmers in Southern Agricultural Zone of Nasarawa State

Aims: The study determined the effect of post-harvest losses of yam on the socio-economic sustenance of farmers in Nasarawa State Nigeria. It also described the socio-economic status of farmers; determined the average quantities of yam lost for the years in review (2014-2018).
 Study Design: The study employed the use of cross sectional design.
 Place and Duration of Study: The study was conducted in Nasarawa state, Nigeria between October 2019 to June 2020.
 Methodology: Using the multistage sampling technique, data for the study were collected from a sample of three hundred and eighty seven (387) respondents.
 Results: That majority of the respondents (322) 83%, were male, and within the age range of 31-40 years 158(41%) followed by the age bracket of 41-50: 97(25%); 323(84%) of the respondents were married with average household size of 8.0 persons per household while 87% of the respondents have had one form of formal education or the other.
 The Ordinary Least Square result of the effect of postharvest losses on the socioeconomic sustenance of the respondents revealed that the coefficient of simple determination (r2) was 0.850which implies that 85.00% of the variations in the socioeconomic sustenance of the respondents was explained by the independent variable included in the model (post-harvest losses) while 15.00% unexplained was due to error. F-prob. value of 0.0000 was observed from the analysis which is less than 0.05, indicating that the variables included in the estimated regression model were correct and significant at 1% significant level. The coefficient of post-harvest losses with the value of (-4.327) was statistically significant and negatively related to the socioeconomic sustenance of the respondents at 1 percent.
 Conclusion: The study concluded that there is a relationship between the post-harvest losses and socioeconomic sustenance of farmers. Therefore, the relevant government and agricultural agencies, Non- Governmental Organizations (NGOs), Community Based Organizations (CBOs) as well as individuals need to strengthen their effort toward reducing post-harvest losses of yam by educating through demonstration and encouraging farmer to use modern technologies and materials in yam storage.

Predictive Modelling of Peroxidase, Polyphenol Oxidase and Catalase in Post-Harvest White Trifoliate (D. Dumetorum Var.) Yam Tubers

The enzymes peroxidase (EC 1.11.1.7), polyphenol oxidase (EC 1.10.3.1) and catalase (EC 1.11.1.6) are fundamental in the development of Dioscorea dumetorum yam tissues. Enzymological studies on activities of peroxidase, polyphenol oxidase and catalase in white trifoliate yam tubers stored for three (3) days under room temperature (28±2°C) and 72-85%RH, and at refrigeration (5±1°C) and 85-100%RH conditions were fitted in a second order polynomial model. The model showed that at day three (3) of yam storage, a 750units activity of peroxidase relates to 1200units of polyphenol oxidase activity in white trifoliate yam tubers stored at 28±2°C and 72-85%RH. Similarly, day three (3) of yam storage, a 7.5 units of catalase activity relates to 1000units of peroxidase activity in white trifoliate yam tubers stored at 28±2°C and 72-85%RH. Also, day three (3) of yam storage, a catalase activity of 2 units corresponded to 400 units for both peroxidase and polyphenol oxidase activities in white trifoliate yam tubers at 5±1°C and 85-100%RH. This data describes the mechanism of association of these enzymes as may be linked to the production of biomolecules that affect biochemical changes and physical properties in post-harvest white trifoliate yam tuber.

Thin‐layer drying kinetics of yam slices, physicochemical, and functional attributes of yam flour

AbstractThis study aimed to investigate the effect of temperature (50–80°C) on the drying behavior of yam slices and to evaluate the physicochemical and functional properties of yam flour. The results revealed that higher temperature enhanced the drying rate and moisture diffusivity (2.01 × 10−10–4.25 × 10−10 m2 s−1) and the drying process occurred entirely in the falling rate period. Twelve thin‐layer drying models were employed to fit the drying data using statistical parameters; coefficient of determination (R2), root mean square error, chi‐square (χ2), sum of squares residual, and mean bias error. The results suggested that logarithmic for 50°C (R2 =0 .9990) and parabolic for 60–80°C (R2 =0 .9977–0.9991) were the best models that can adequately explain the drying behavior of yam slices. Different physicochemical and functional properties of yam flour were significantly affected by the drying temperatures. However, the developed yam flour exhibited a satisfactory range of nutritional contents, such as protein (4.79–5.97%), fat (0.59–0.74%), ash (5.57–6.60%), fiber (0.83–1.96%), starch (65.59–73.93%), carbohydrate (85.69–87.53%), and total phenolics (10.68–11.88 mg Gallic Acid Equivalent/100 g (GAE/100 g). Therefore, the drying kinetic results and the physicochemical quality of developed yam flour could be useful for its industrial production.Practical ApplicationsYam is one of the leading root crops in the world and used as staple food in many countries. Postharvest storage and transport of the raw yam are one of the main problems in developing countries. The objective of this study was to investigate the effect of drying temperature on the thin‐layer drying kinetics of yam slices and to evaluate a suitable drying model for describing the drying process together with the food compositions, total phenolics, and other functional and color characteristics. This study revealed a useful outcome that could convince the food producers for industrial production and consumers to consider the yam flour as a suitable alternative to rice, wheat, or corn flour for the formulation of high‐quality health food products, such as bakery, confectionery, snack, noodle, soup, and other products.

Recovery of Yam Soluble Protein from Yam Starch Processing Wastewater

Over the past two decades, many studies have shown that the yam storage protein dioscorin, which is abundant in the wastewater of starch processing, exhibits many biological activities both in vitro and in vivo. In the present study, the acid-precipitation method was optimized using Box-Behnken design (BBD) combined with response surface methodology (RSM) for the recovery of yam soluble protein (YSP) from wastewater. The experimental yield of YSP reached 57.7%. According to relative quantitative proteomics (LC-MS/MS), the crude YSP was mainly composed of 15 dioscorin isoforms, which was further verified by anion-exchange and size-exclusion chromatography. YSP was found to be rich in glutamic acid and aspartic acid, and the eight essential acids made up approximately 33.7% of the YSP. Moreover, the YSP demonstrated antioxidant activity, including scavenging DPPH, hydroxyl and superoxide anion radicals, and the possible structure-activity relationships were discussed. These results indicated that YSP produced by acid precipitation may be used as a protein source with antioxidant properties.

Evaluation of efficacy of false yam (Icacina oliviformis) as surface protectant against rot pathogens of white yam (Dioscora rotundata Poir)

Rots in yam tubers are the dominant cause of postharvest losses. Therefore, studies were con­ducted to identify the rot-causing organisms in yam and to evaluate the efficacy of false yam (Icacina oliviformis) plant extracts as surface protectants in the storage of yam. The experiment was laid out in a completely randomized design (CRD) design with five treatments (fruit, root and leaf extract of false yam, Mancozeb and tap water) replicated three times. Two concen­trations (50% and 100%) of each extract were also tested. Species were identified based on the structural features, the characteristics and properties of the spore and mycelium. A spore suspension of yam rot fungi was sprayed on healthy yam tubers that had been pretreated with the extracts. Results showed that fungi isolated from rotted yams were Aspergillus niger, A. fla­vus and Penicillium sclerotigenum. Leaf extracts (both 50% and 100%) had the highest growth inhibitions on all the three fungi isolated in vitro. Tubers treated with root and leaf extracts of false yam had a decreased tuber rot lengths of 1.80 mm2 and 2.17 mm2, respectively. The leaves and roots of false yam can be used as a surface protectant of yam in place of Mancozeb. Keywords: Icacina oliviformis; Dioscora rotundata; Mancozeb; Pathogenicity; Aspergillus spp.

Enhancing the food security status of yam (Dioscorea spp.) for smallholder farmers through an improved farm-gate storage structure in Ghana

Yams (Dioscorea spp.) are a good source of food in Ghana. This study investigated the storage of seven (7) key yam varieties in an improved farm-gate yam storage structure. Seven freshly harvested key yam varieties identified as Pona, Lariboko, Dente, Mutwumudoo, Serwah, Matches and Akaba were used in a Complete Block Design technique of 3 blocks and stored in an improved farm-gate yam storage structure for 146 days. Formation of buds, pests and diseases, wholesomeness, regeneration of sprouts, temperature and relative humidity were monitored. After the storage period, mean number of buds formed varied between 1.3 and 2.7. Matches, Mutwumudoo and Dente yam varieties recorded the highest number of buds compared to Pona, Laribokor and Serwah, which recorded a mean of 1.3, 1.4 and 1.5 buds, respectively. Pona and Lariboko yam varieties were more highly susceptible to pests and diseases than Matches, Akaba, Dente and Serwah. Wholesome tubers were higher in Serwah, Matches, Akaba, Mutwumudoo and Dente varieties than Pona and Lariboko yam varieties, as the former were less attacked by pests and diseases. Serwah yam variety was observed to store best among the seven (7) key yam varieties even though regeneration of buds observed in Serwah yam variety was the highest.

Impact of Yam Postharvest Activities on Standard of Living of Yam Farming Households in North-East Zone of Benue State, Nigeria

Aims: The aim of the study was to identify postharvest activities of yam farming households in North-East Zone of Benue State, Nigeria and to assess the impact of losses from the yam postharvest activities on standard of living of yam farming households in North-East Zone of Benue State, Nigeria.
 Study Design: Survey research design was adopted for the study.
 Place and Duration of Study: North-East Zone of Benue State, Nigeria.
 Methodology: The study purposively selected three (3) local government areas (Ukum, Katsina-Ala and Logo) that are most prominent in yam production in North-East Zone of Benue State from where a total sample size of two hundred and four (204) yam farming households were drawn from three local government areas of North-East Zone of Benue state using multi-stage cluster sampling technique.
 Results: Almost all the farmers 99% (202) store their yams and majority of the farmers are also involved in yam marketing. Majority of the famers 84% (172) always need to transport their yams. This could be in order to access distant markets which make for more gain. The few who do not need to transport their produce could be those who sale at farm gates. This could also be the reason why only a few 64% (130) majority take time to sort, grade and clean their produce. With the computed f-statistic value of 512.110 which was significantly higher than the tabulated f-value of 16.26 at 1% level of significance and 5.05 at 5% level of significance, therefore, the null hypothesis was rejected. This implies that, yam loss from yam postharvest activities noted above has a significant negative impact on the standard of living of yam farming households in the study area by reducing their household income (99%), affecting their access to health care services (89%), access to education (64%), access to good housing (84%) and access to sufficient quality food (98%).
 Conclusion: The study thus concludes that, yam loss during postharvest activities such as: yam handling, yam storage, yam transportation, yam sorting / grading / cleaning and yam marketing has significant negative impact on the standard of living of yam farming households in the study area, by reducing their household income, affecting their access to health care services, access to education, access to good housing and access to sufficient quality food. The study recommends communication of knowledge on modern yam storage methods to yam farmers in the study area by agricultural extension agents and building of yam processing factories in the study area so as to add economic value to yam and consequently improve the standard of living of yam farming households in the study area.

Poultry Manure and NPK 15 15 15 Fertilizer Application and their Residual Effect on White Yam (Dioscorearotundata) Storage in the Forest Derived Savanna Ecological Zones of Edo State, Nigeria

Field experiments were conducted in Igueben, located in the forest derived savanna ecological zone of Edo state. In 2012 and 2013 cropping seasons to determine the effect of poultry manure, NPK 15 15 15 fertilizer and their combinations on the storage of white yam (Dioscorearotundata). The treatments consisted of four levels of poultry manure, 0,4,8 and 12 tons/ha and three levels of NPK fertilizer 0, 100 and 200kg/ha. The treatments were replicated three times and were fitted into randomized complete block design. The poultry manure was applied by broadcasting 2 weeks before planting while the NPK fertilizer was applied during planting. The tubers were carefully harvested after 7months of planting and stored in a barn. Tubers were observed and determined for duration of dormancy, weight loss and the number of tubers that rotted. Result showed that tuber weight loss and rot increased significantly with high levels of poultry manure NPK fertilizer and their combinations. The period of dormancy reduced as level of treatment increased it was concluded that the application of combination of low rate of chemical fertilizer with poultry manure boost yield and storage of white yam. Consequently a combination of 100kg NPK 15 15 15/ha with 12 tonspm/ha is recommended for yam farmers for good storage in the forest derived savanna ecological zone.

Effect of yam storage techniques usage on farm income in Kwara State, Nigeria

Yam is an important tuber crop in Nigeria. However, its availability is affected by rate of deterioration arising from poor postharvest handling. Hence, farmers use various techniques to minimize the loss. Therefore, this study examined the effect of the usage of various yam storage techniques on farm income in Kwara State, Nigeria. Data were collected from 180 respondents and analyzed with descriptive statistics, Tobit regression, weight index, and bivariate correlation. Data analysis reveals that yam barn storage technique was ranked first in terms of level of usage by the farmers with the highest average weight index (AWI=2.54) while, open sided shelve was the least (AWI=0.594). However, in terms of level of awareness, the heap on the floor technique was ranked first by the respondents. The Tobit regression analysis indicates that extension service and crop yield had a positive and significant effect on the usage of yam storage techniques, while access to credit had a negative significant effect. The bivariate correlation reveals that; there is a positive significance between usage intensity and farm income of the farmers. It is therefore recommended that extension agents should actively disseminate information on improved storage techniques to yam farmers in the study area as well as the need to use such techniques. Keywords: storage technique, postharvest loss, yam barn, usage, awareness

Factors Affecting the Adoption of Chemical Use in Yam Storage among Farmers in Orire Local Government Area of Oyo-State, Nigeria

Yam as a staple food in Nigeria has lot of importance, hence it has been imperative to know different ways of preserving this tuber. The study aimed at looking at the factors that affected the adop...

West African yam food technologies: prospects and impediments to change

Yam is an important commodity for more than 350 million people in West Africa because of its food, monetary and cultural values. The commodity is expensive compared with alternative starchy staples such as maize and cassava because of low technologies used in its production and postharvest handling. Yam storage techniques are rudimentary and redundant but vary from place to place depending on a range of circumstances including agro-ecology. Yam food is prepared mostly from fresh tuber by simple methods that have not changed over time and consumption is also simple because those yam foods can be eaten straight without a condiment. Compared with cassava the relative long postharvest shelf life; relative ease of food preparation from fresh tuber; and non-conventional uses of yam constitute disincentives for yam processing. Processed yam food is inferior substitute for the yam’s fresh alternative; at the same time processed yam product is more expensive than processed cassava and grain products that are its substitutes.