Integrated soil nutrient management option for sustainable yam production

A study was conducted at the on-station in Fumesua (Forest) and Ejura (Forest-Savannah transition) of Ghana to evaluate integrated soil nutrient management approach on soil and yam productivity. A split-factorial design with two preceding systems (Pigeon pea and Yam) as main plot treatments and a factorial of poultry manure (0, 3 and 6 t ha-1) and chemical fertilizer (0, 15 - 15 - 20, and 30 - 30 - 40 kg ha-1 N-P2O5-K2O) as subplot treatments. The results of the study revealed significant (P < 0.05) interaction between preceding system, poultry manure and chemical fertilizer on fresh tuber yields. When yam followed pigeon pea as preceding crop, tuber yields were higher, and yields from 3 t ha-1 poultry manure and 15 - 15 - 20 kg ha-1 N-P2O5-K2O were similar to yields when manure and chemical fertilizer were doubled to 6 t ha-1 and 30-30-40 kg ha-1 N-P2O5-K2O. Also when yam followed pigeon pea, the cost benefit ratio showed that Gh 1.00 farmer investment in yam production resulted a profit of Gh 1.65 and Gh 2.22 in addition to the Gh 1.00 invested capital for both Fumesua and Ejura communities respectively. The study suggests integrated nutrient management approach with preceding systems such as pigeon pea (16,667 plants ha-1) and 3 t ha-1 poultry manure would reduce the chemical fertilizer requirement to a third for sustainable yam production on continuously cropped fields.Key words : Integration, legumes, climate change, Ghana

Enhancing productivity of farmer-saved seed yam in Ghana: Positive selection and neem leaf powder factors

Recycling of diseased and pests infested seed yam ( Dioscorea spp.) has resulted in drastic yield reductions in yam production. The objective of this study was to determine the effect of positive selection on the quality of farmer-saved seed yam and also evaluate the effect of neem leaf powder in managing plant parasitic nematodes damage to yam. Two farming systems namely; Positive selection (PS) and Farmer practice (FP) and two soil amendment regimes; neem leaf powder at 20 g stand-1 (NA20) and no neem amendment (NA0) were tested on one variety of yam (Dente). A 2 x 2 x 1 factorial study, mounted on a randomised complete block design in a split plot arrangement was conducted in four replications. Positive selection occupied main plots; while Farmer practice occupied sub-plots. The study was conducted in eight communities located in two municipalities of Ghana, during 2015-2017. Parameters evaluated included Yam Mosaic Virus incidence and severity, incidence and severity of nematode cracks and galling on yam tubers, plant establishment and yield of yam. It was observed that Yam Mosaic Virus (YMV) disease incidence decreased from 38% in 2016 to 31% in 2017 in PS plots as a result of using virus-free planting materials. However, in FP plots, it increased from 67% in 2016 to 72% in 2017. Neem leaf powder amendment resulted in significantly (P< 0.05) low tuber galling (7%) compared with 40% in unamended plots. Similarly, PS plots yielded 7.7 t ha-1 compared to 5.9 t ha-1 in FP fields. In conclusion, Positive selection out-yielded FP by 30.5%; while PS-neem leaf powder interaction resulted in 38.5% over and above FP without neem amendment.Le recyclage des semences d\u2019igname ( Dioscorea spp.) contamin\ue9es par des maladies et des parasites a entra\ueen\ue9 une r\ue9duction drastique du rendement de la production d\u2019igname. L\u2019objectif de cette \ue9tude \ue9tait de d\ue9terminer l\u2019effet de la s\ue9lection positive sur la qualit\ue9 des semences d\u2019igname conserv\ue9es par les agriculteurs et \ue9galement d\u2019\ue9valuer l\u2019effet de la poudre de feuilles de neem dans la gestion des dommages caus\ue9s par les n\ue9matodes parasites des plantes. Deux syst\ue8mes agricoles \ue0 savoir; S\ue9lection positive (PS) et pratique paysanne (PF) et deux r\ue9gimes d\u2019amendement du sol; De la poudre de feuille de neem \ue0 20 g du stand-1 (NA20) et aucun amendement de neem (NA0) ont \ue9t\ue9 test\ue9s sur une vari\ue9t\ue9 d\u2019igname (Dente). Une \ue9tude factorielle de 2 x 2 x 1, mont\ue9e sur une dispositif en\ua0blocs al\ue9atoires complets dans un arrangement en parcelles divis\ue9es, a \ue9t\ue9 men\ue9e en quatre r\ue9p\ue9titions. S\ue9lection positive occup\ue9e parcelles principales; tandis que la pratique paysanne occupait des sous-parcelles. L\u2019\ue9tude a \ue9t\ue9 men\ue9e dans huit communaut\ue9s situ\ue9es dans deux municipalit\ue9s du Ghana en 2015-2017. Les param\ue8tres \ue9valu\ue9s comprenaient l\u2019incidence et la gravit\ue9 du virus de la mosa\uefque de l\u2019igname, l\u2019incidence et la gravit\ue9 des fissures de n\ue9matode et le grippage des tubercules de l\u2019igname, l\u2019\ue9tablissement de la plante et le rendement de l\u2019igname. Il a \ue9t\ue9 observ\ue9 que l\u2019incidence de la maladie caus\ue9e par le virus de la mosa\uefque \ue0 l\u2019igname (YMV) avait diminu\ue9 de 38% en 2016 \ue0 31% en 2017 dans les parcelles PS gr\ue2ce \ue0 l\u2019utilisation de mat\ue9riel de plantation d\ue9pourvu de virus. Cependant, dans les parcelles de PF, il est pass\ue9 de 67% en 2016 \ue0 72% en 2017. L\u2019amendement de poudre de feuille de Neem a entra\ueen\ue9 une r\ue9duction significative du galles des tubercules (P <0,05) (7%) par rapport \ue0 40% dans les parcelles non modifi\ue9es. De m\ueame, les parcelles de PS ont produit 7,7 t ha-1, contre 5,9 t ha-1 dans les champs de PF. En conclusion, la s\ue9lection positive a eu un rendement sup\ue9rieur de 30,5% \ue0 celui de la PF; tandis que l\u2019interaction de la poudre de feuille PS-neem a eu pour r\ue9sultat 38,5% de plus que FP sans amendement de nee

Sustainable yam production in Ghana The nonstaking option

A trial was conducted on-station with farmer participation at Fumesua (Forest zone), Wenchi (Forest-Savannah transition zone) and Bodwease (Coastal Savannah zone) from 2000 to 2003 and on-farm during 2002-2003. Two factors, staking and species, with two levels each were assessed using the Augmented RCB design. The objective of this study was to identify genotypes capable of producing high and stable yields under staking and non-staking condition. No significant differences (P>0.05) were observed in disease severity, frequency of hand weeding and yield of D. alata genotypes. Among the D. rotundata genotypes, leaf spot severity was more severe on non-staked genotypes except in TDr95/19177 where no significant differences were observed between the staked and non-staked genotypes. Tuber yield of the genotypes were significantly increased by staking. In Punjo the increase in yield of staked over non-staked plants ranged between 51.3 and 56.5%. Similarly, the yield of non-staked Dorban was increased by staking by 48.1-55.9% and Tela by 44.9-47.6%. Non-staked TDr95/19177 was technically and economically the more efficient system for production followed both staked and non-staked Punjo, Dente and Tela. Generally, cost of yam production was greater in the coastal savannah than the forest and the forest-savannah transition, due to the largest cost of labour and staking

Does alternation increase water productivity when applying partial root-zone drying to tomato?

In developing countries, horticultural production relies on smallholder farmers who cannot access advanced irrigation technologies. In Ghana, tomato production does not match the increasing demand for this crop, especially during the dry season so there is a need to increase irrigated tomato production. Optimal application of low cost irrigation techniques can increase water productivity and therefore the irrigated acreage. Partial root-zone drying (PRD) is a water-saving irrigation technique that applies sub-optimal irrigation to half of the root-zone, while adequately irrigating the remainder. PRD increased water productivity compared to homogeneous drying in different crops including tomato. Although root-to-shoot signaling studies predict that the drying of the irrigated zones need to be alternated to maintain PRD effects, studies on the effects of alternation are scarce. To investigate the optimal PRD application technique in tomato we carried out a field trial in Kumasi (Ghana) on an improved bush-type cultivar (Petomech) where both alternated and fixed PRD alternation at 50% of ETc (crop evapotranspiration) were compared with full irrigation (100% ETc). Irrigation treatments did not affect fruit yield, increasing water productivity. Plant physiological responses to alternation were also assessed in a controlled environment experiment in Lancaster (UK) on a miniaturised, containerised PRD system (75% of ETc) using the dwarf cultivar Micro-Tom. PRD decreased fruit yield by ca 15% regardless of whether it was alternated or not. Whole-plant gas exchange and stem diameter variations did not differ between alternated or fixed PRD, even under high vapor pressure deficit, either during the drying cycles or upon re-watering. Stem growth was reduced early after applying PRD and was not affected by alternation. Contrary to previous reports, these results suggest that alternation has little impact on tomato yield, and so fixed PRD may be more readily assimilated by smallholder farmers

Demonstrating the efficacy of existing yam technologies in the forest-savannah transition zone of Ghana

Open Access ArticleImproved technologies (row planting, ridging, seed treatment, weed management, fertilizer application) with a proven record of sustained productivity for yam production are imperative for food security. This study promotes the efficacy of these existing improved agronomic practices using a farmer-based participatory approach in some selected major yam-growing areas in the forest–savannah transition zone of Ghana. The improved agronomic practice treatment included use of ridging as seedbed, seed treatment before planting, fertilizer application at a rate of 30:30:36 N:P2O5: K2O kg/ha plus 15 kg/ha Mg and 20 kg/ha S as MgSO4 and the use of minimum stakes (trellis; 30-50% fewer stakes used by farmers). This was compared with farmers’ practice, which consisted of mounding, no fertilizer application, and no seed treatment. A significantly (p ≤ 0.01) higher yam yields (more than 60%) were observed for the improved agronomic practice over the farmers’ practice at Ejura, Atebubu, and Kintampo which are major yam-growing communities of Ghana. Sensory evaluation showed that the culinary quality of fertilized yam was as good as unfertilized yam. The contribution of existing improved yam production practices in the selected yam communities of Ghana was quantified in terms of their productivity and economic benefit to smallholder farmers

Influence of Fertilizer Application on Postharvest Storage of Two White yam (Dioscorea rotundata) Cultivars in Ghana

Yam growers across major growing areas are being encouraged to increase tuber yield through the application of fertilizer at the recommended rates and periods. Ghana, the leading exporter of yam in Africa, is currently facing the problem of poor tuber storability. Some actors along the food value chain attribute most storage rots to the application of fertilizer by farmers. This study was conducted to investigate in to the claim that fertilizer application has an effect on the shelf life of white yam tubers. Four fertilizer application models were tested on two white yam cultivars, Serwa and TDr95/19177. No fertilizer application served as the control experiment. Healthy- looking white yam tubers of the two cultivars were randomly selected from a fertilizer application trial at Ejura-Sekyedumasi District in Ashanti Region of Ghana and storage rot experiment conducted at CSIR-CRI(onstation) between January and July, 2015.The experimental design was a Split plot design with three replications. The main plot represented the two cultivars whilst the sub-plot was the fertilizer models. Initial parameters taken were tuber weight, yield and moisture content. Temperature and relative humidity were periodically recorded. Rot assessment were done at 3rd, 4th, 5th and 6th months of storage. Rot analysis parameters taken were tuber weight, number of rotten tubers, rot initiation point, rot type and associated pathogens. Percent incidence and severity were determined and used for the analysis and interpretations. Severity data was subjected to statistical analysis using the Genstat statistical package 9.2, after the results was transformed using the square root transformation. Major fungi identified from rotten tissues over the period were Lasiodiplodia the obromae, Fusarium oxysporum, Penicilliumsp., Rhizopussp., Aspergillus flavus. Fifty-four percent of rotten tubers were the dry rot type. There were similarities in the incidence of rot among all treatments. There was no significant difference in terms of rot severity among the fertilizer application models as well as the control. However, varietal differences and tuber sizes were key factors identified as having effect on storage rots. Further studies on commercial white yam varieties such as Pona and Dente need to be conducted to evaluate the influence of fertilizer application on their shelf lives. .Key words: fertilizer application, storage rots, white yams and shelf life. Influence de l'application d'engrais sur le stockage post-récolte de deux variétés d'igname blanche (Dioscorea rotundata) au GhanaLes producteurs d'igname dans les principales zones de culture sont encouragés à augmenter le rendement des tubercules par l'application déngrais aux taux et périodes recommandés. Le Ghana, qui est le premier exportateur d'igname en Afrique, est actuellement menacé par une faible capacité de stockage des tubercules. Certains acteurs de la chaîne de valeur alimentaire attribuent la plupart des pourritures de stockage à l'application d'engrais par les agriculteurs. Cette étude a été menée pour étudier l'allégation selon laquelle l'application d'engrais a un effet sur la durée de conservation des tubercules d'igname blanc. Quatre modèles d'application d'engrais ont été testés sur deux cultivars d'igname blanche, Serwa et TDr95 / 19177. Aucune application d'engrais n'a servi d'expérience de contrôle. Des tubercules d'igname blanche d'apparence saine des deux cultivars ont été choisis au hasard dans un essai d'application d'engrais dans le quartier d'Ejura-Sekyedumasi dans la région d'Ashanti au Ghana et une expérience de pourriture du stockage a été effectuée à CSIR-CRI (en-station) entre janvier et juillet 2015. La conception expérimentale était une conception de parcelle avec trois répétitions. La parcelle principale représentait les deux cultivars tandis que la sous-parcelle était les modèles d'engrais. Les paramètres initiaux ont été le poids du tubercule, le rendement et la teneur en humidité. La température et l'humidité relative ont été enregistrées périodiquement. L'évaluation de la pourriture a été effectuée aux 3e, 4e, 5e et 6e mois d'entreposage. Les paramètres d'analyse de la pourriture mesurés étaient le poids des tubercules, le nombre de tubercules pourris, le point d'initiation de la pourriture, le type de pourriture et les pathogènes associés. L'incidence et la gravité en pourcentage ont été déterminées et utilisées pour l'analyse et les interprétations. Les données de sévérité ont été soumises à une analyse statistique en utilisant le progiciel statistique Genstat 9.2, après transformation des résultats en utilisant la transformation de la racine carrée. Les principaux champignons identifiés à partir des tissus pourris au cours de la période étaient: Lasiodiplodia l'obromae, Fusariumoxysporum, Penicilliumsp., Rhizopussp., Aspergillusflavusetc. Environ 54% des tubercules pourris étaient des type pourriture sèche. Il y avait des similitudes dans l'incidence de la pourriture parmi tous les traitements. Il n'y avait pas de différence significative en termes de sévérité de pourriture parmi les modèles d'application d'engrais ainsi que le contrôle à P <0,05. Cependant, les différences variétales et la taille des tubercules étaient des facteurs clés identifiés comme ayant un effet sur les pourritures de stockage. D'autres études sur des variétés commerciales d'ignames blanches telles que Pona et Dente doivent être menées pour évaluer l'influence de l'application d'engrais sur leurs durée de conservation.Mots clés: application d'engrais, pourritures de stockage, ignames blanches et durée d

Simulative Evaluation of the Response of Maize and some Dual-Purpose Legumes to Water and Nutrient Amendments

The study evaluated DSSAT's CERES-Maize and CROPGRO models for their effectiveness in simulating the growth of maize, groundnut, and cowpea under dynamic nutrient amendments and water management practices in field experiments. The experiments were laid-out in split-plot with water management (rainfed and irrigated) as main plots and fertilizer (organic and inorganic fertilizer) as sub-plots during the maize trial, while, water management treatment (irrigated and rainfed) was the main plot and variety as the subplot during the cowpea and groundnut trials arranged in three replications. The CERES-Maize model's RMSE-observations standard deviation ratio (RSR) for simulating maize grain yield under irrigated and rainfed were 0.1624 and 0.0317 respectively, while that for the maize biomass under irrigated and rainfed were 0.4027 and 2.1676 respectively. Also, the CROPGRO model's RSR for simulating groundnut grain yield under irrigated and rainfed were 0.1058 and 8.0592 respectively, while that for the groundnut biomass under irrigated and rainfed were 1.1154 and 0.0161 respectively. In addition, the CROPGRO model's RSR for simulating cowpea grain yield under irrigated and rainfed were 8.1625 and 0.1019 respectively, while that for the cowpea biomass under irrigated and rainfed were 0.2677 and 0.2630 respectively. From the results, it was concluded that the CERES-Maize model was more suited to effectively scope alternate management practices under maize production whereas more research is needed to be able to confirm the effectiveness of the model in our environment.Keywords: Crop production, CROPGRO, CERES-Maize, DSSA