Effect of pesticide application rate on yield of vegetables and soil microbial communities

Lindane is listed among the Prior Informed Consent (PIC) pesticides, and agricultural uses of lindane have been banned in 52 countries due to its hazardous nature. However, lindane is still widely used in vegetable cultivation in Ghana. The effect of increasing rates of application of lindane (156.0, 244.0 and 312.0 g ha-1), unden (propoxur) (125.0, 187.5 and250.0 g ha-1), dithane and karate (166.6, 209.8 and 333.3 g ha-1) on garden eggs, okro and tomatoes was studied to find out if it has any advantage that makes its use attractive to farmers despite its ban. Yields of garden eggs were suppressed by all the rates of lindane applied. In tomatoes, lower rates of lindane increased yields whereas the higherrates suppressed yields lower than the control. In okro yields were higher than the control at all levels of lindane applied though yield increments were low. Unden application had the highest effect on garden egg yields followed by tomatoes and least on okro. In the garden egg and tomato treatments, increasing concentration of unden resulted in decreasing yields though yields were higher on the control plots. The optimum unden rate for garden egg and tomato was U20 (i.e. 125.0 g ha-1). Increasing rates of unden on okro did not have any significant effect. Pesticide applicationhad a higher effect on fungal population (50-70% reduction) than on bacterial population in the soil (23.0–38.4% reduction). Dithane suppressed bacteria most whereas karate suppressed fungal population most. Lower levels of chloride residues in tomato fruits corresponded to lower rates of lindane application. Lindane did not have any advantage over the other pesticides as it caused the least increase in yield. It is recommend that farmers are educated on the adverse effects of lindane use, and government enforces the restriction on lindane importation and use in agriculture

Decomposition and Fertilizing Effects of Maize Stover and Chromolaena odorata on Maize Yield

La qualité, le niveau de la décomposition et l'effet fertilisant de Chromolaena odorata et le maïs étaient déterminés dans l'expériment du terrain comme l'application de la superficie ou enterrés dans les sacslitières. Des études sur l'effet du matériau des plantes avec les qualités variantes (Maïs et C. odorata) appliquées uniquement (10 mg ha-1) et mélangées sur le graine du maïs et le rendement de la biomasse étaient également entamées sur la série du sol “Asuansi” (ferric Acrisol).Le contenu total de l' azote des résidus est entre 0.85% en maïs et 3.50% en C. odorata. Dans le cas de la carbon organique, c'est entre 34.90% en C. odorata et 48.50% en maïs. Dans le cas du phosphore, c'est entre 0.10% en maïs et 0.76% en C. odorata. Dans la saison sèche, le niveau de la décomposition (K) était 0.0319 jour-1 pour C. odorata et 0.0081 pour le maïs. Dans la saison sèche c'était 0.0083 pour C. odorata et 0.0072 jour-1 pour le maïs. L'enterrement du matériau des plantes a réduit la période de la vie moitié (t ) de 18 à 10 jours 50 pour C. odorata et 45 à 20 jours pour le maïs. Dans le cas de C. odorata unique, (10 mg ha-1) on a obtenu 2556 kg ha-1 de rendement de la graine par rapport à 2167 kg ha-1 pour le maïs. Le mélange des résidus du maïs et les résidus de C. odorata ont amélioré le contenu nutritif ainsi que les nutriments relâchés par le mélange aboutissant en rendement plus élevé dans le mélange que le traitement unique. Il est recommandé qu'on utitise C. odorata comme l'engrais végétal, le paillis ou le matériau compostage pour augmenter la fertilisation du sol.The quality, rates of decomposition and the fertilizing effect of Chromolaena odorata, and maize stover were determined in field experiments as surface application or buried in litter bags. Studies on the effect of plant materials of contrasting qualities (maize stover and C.odorata) applied sole (10 Mg ha-1) and mixed, on maize grain and biomass yield were also conducted on the Asuansi (Ferric Acrisol) soil series. Total nitrogen content of the residues ranged from 0.85% in maize stover to 3.50% in C. odorata. Organic carbon ranged from 34.90% in C. odorata to 48.50% in maize stover. Phosphorus ranged from 0.10% in maize stover to 0.76% in C. odorata. In the wet season, the  decomposition rate constants (k) were 0.0319 day-1 for C. odorata, and 0.0081 for maize stover. In the dry season, the k values were 0.0083 for C. odorata, and 0.0072 day-1 for maize stover. Burying of the plant materials reduced the half-life (t ) periods from 18 to10 days for C. odorata, and 45 to 20 days for 50 maize stover. Maize grain yield of 2556 kg ha-1 was obtained in sole C. odorata (10 Mg ha-1) compared with 2167 kg ha-1 for maize stover. Mixing of maize stover and C. odorata residuesimproved the nutrient content as well as nutrient release by the mixtures resulting in greater maize grain yields in the mixtures than the sole maize stover treatment. It is recommended that C. odorata be used as green manure, mulching or composting material to improve soil fertility

Ridging, a Mechanized Alternative to Mounding for Yam and Cassava Production

A cassava seedbed preparation field study was established at Fumesua in the forest and Ejura in the forest-savanna transition agroecologies of Ghana in 2004/2005. The experimental design was split plot with three seed bed preparation methods as the main plots and three nitrogen rates as sub plots, with basal application of 45-90 kg ha-1 P205 - K20 on the fertilized plots. A similar study was conducted on yam seedbed preparation in 2003/2004, with a 23 factorial design. Cassava and yams on ridges resulted in highest root and tuber yields, on both Lixisols in the coastal and forest-savanna transition and Acrisols in the forest agro-ecologies. However, yam tuber yield on mounds was not statistically different from yields on ridges. Number of roots per plant was identified as a major contributory factor to the yield increase of cassava on ridges. Seed bed preparation method was, however, not an important determinant of cassava root yield at high rates of fertilizer application of 90-45-90 kg ha-1 N-P205-K20. Planting on mounds resulted in slender, cylindrically shaped cassava roots and yam tubers, while ridging produced oblong shaped roots and tubers. Weeding and fertilizer application were easier on manual ridging than on manual mounds. The study points to ridging as a potential option to mounding for cassava and yam production, with the feasibility of mechanization of ridges to reduce drudgery associated with roots and tuber crop production in the West African sub-region

The Effect of Rock Phosphate on Soil Nutrient Dynamics, Growth, Development and Yield of Oil Palm in The Semi-Deciduous Forest Zone of Ghana

Field experiment was conducted at Oil Palm Research Institute, Kusi from 2002 to 2007 to as-sess the effect of Phosphate Rock (PR) on soil nutrient dynamics, growth, development and yield of oil palm. The study was carried out on the soils of Nzema series classified as Ferric Acrisols and Typic Hapludult. The oil palm trees selected were 8 year old tenera (DXP ex OPRI). Each plot measured 17.6 m x 17.6 m and had 6 palm trees. There were four treatments arranged in randomized complete block design with four replicates. The treatments included: 1). TSP - OPRI fertilizer recommendation - 222 kg of AS + 222 kg of TSP + 296 kg of MOP/ha/yr (control); 2). PR1 - PR 715 kg + 222 kg of AS + 296 kg of MOP/ha - Yr 1. PR 358 kg + 222 kg of AS + 296 kg of MOP/ ha – Yr 2. PR 358 kg + 222 kg of AS + 296 kg of MOP/ha – Yr 3; 3). PR2 - PR 1428 kg + 222 kg of AS + 296 kg of MOP/ha applied once in every 5 years; 4). PR3 - PR 142.85 kg/ha +222 kg AS/ ha + 296 kg of MOP/ha applied twice in every 5 years. Application of treatments influenced the soil chemical properties to a varying extent. Gradual increase in soil nutrient lev-els were more pronounced in RP treatments than Triple Super Phosphate (TSP) treatment (control). Soil pH increased from extremely acidic (3.73) to acidic (5.43) for treatment PR2. At the end of the study, available P recorded 9.55 mg/kg. The value is slightly below the medium range of available P for oil palm production. Significant increases were recorded by RP treat-ments for exchangeable Ca, Mg, K and ECEC. The results showed that treatment PR2 was effec-tive and gave the highest oil palm yield of 62.8t/ha with TSP recording 53.7t/ha. For sustained levels of soil nutrients, growth, development and yield of oil palm, PR incorporation should be encouraged.Keywords: Phosphate Rock, nutrient dynamics, oil palm, triple super phosphat

Reviewing the literature on access to prompt and effective malaria treatment in Kenya: implications for meeting the Abuja targets

<p>Abstract</p> <p>Background</p> <p>Effective case management is central to reducing malaria mortality and morbidity worldwide, but only a minority of those affected by malaria, have access to prompt effective treatment.</p> <p>In Kenya, the Division of Malaria Control is committed to ensuring that 80 percent of childhood fevers are treated with effective anti-malarial medicines within 24 hours of fever onset, but this target is largely unmet. This review aimed to document evidence on access to effective malaria treatment in Kenya, identify factors that influence access, and make recommendations on how to improve prompt access to effective malaria treatment. Since treatment-seeking patterns for malaria are similar in many settings in sub-Saharan Africa, the findings presented in this review have important lessons for other malaria endemic countries.</p> <p>Methods</p> <p>Internet searches were conducted in PUBMED (MEDLINE) and HINARI databases using specific search terms and strategies. Grey literature was obtained by soliciting reports from individual researchers working in the treatment-seeking field, from websites of major organizations involved in malaria control and from international reports.</p> <p>Results</p> <p>The review indicated that malaria treatment-seeking occurs mostly in the informal sector; that most fevers are treated, but treatment is often ineffective. Irrational drug use was identified as a problem in most studies, but determinants of this behaviour were not documented. Availability of non-recommended medicines over-the-counter and the presence of substandard anti-malarials in the market are well documented. Demand side determinants of access include perception of illness causes, severity and timing of treatment, perceptions of treatment efficacy, simplicity of regimens and ability to pay. Supply side determinants include distance to health facilities, availability of medicines, prescribing and dispensing practices and quality of medicines. Policy level factors are around the complexity and unclear messages regarding drug policy changes.</p> <p>Conclusion</p> <p>Kenya, like many other African countries, is still far from achieving the Abuja targets. The government, with support from donors, should invest adequately in mechanisms that promote access to effective treatment. Such approaches should focus on factors influencing multiple dimensions of access and will require the cooperation of all stakeholders working in malaria control.</p

Wounding induces dedifferentiation of epidermal Gata6+ cells and acquisition of stem cell properties

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Decision support tools for site-specific fertilizer recommendations and agricultural planning in selected countries in sub-Sahara Africa

Peer Revie

Effect of Roundup-Salt Mixtures on Weed Control and Soil Microbial Biomass Under Oil Palm

Field experiments were conducted at Oil Palm Research Institute, Kusi from 2002 to 2004 to evaluate the effect of roundup – salt mixtures on the control of weeds and soil microbial biomass. The efficacy of roundup at 0.47 kg a.i./ha mixed with either 0.23 kg/ha of sodium chloride or 0.53 kg/ha of ammonium sulphate or 0.24 kg/ha of urea was compared with roundup at 1.44 kg a.i/ha and manual weeding. The treatments were arranged in randomized complete block design and replicated four times. The roundup and its salt mixtures effectively controlled weeds up to 3 months after treatment (MAT) in both 2002 and 2003 trials. In 2002, roundup with sodium chloride, roundup with ammonium sulphate and roundup with urea maintained a substantial weed control of 77%, 79% and 87% respectively at 3 MAT compared to the 80% and 41% weed control by roundup only and manually weeding. By 3 MAT in 2003, the % weed control for roundup with sodium chloride, roundup with ammonium sulphate, roundup with urea, roundup only and manual weeding were 63%, 60%, 63%, 65% and 43% respectively. These weed control measures were however ineffective in the 2004 trial. The addition of ammonium sulphate or urea to roundup increased soil microbial C accumulation significantly by 115% and 650% respectively while the application of roundup with sodium chloride, roundup only and manual weeding stimulated microbial C accumulation slightly by 57%, 33% and 30% respectively. Microbial P also increased by 267%, 137%, 81%, 75% and 45% following the application of roundup with urea, roundup with ammonium sulphate, roundup only, roundup with sodium chloride and manual weeding respectively. The use of roundup – salt mixtures reduced the annual cost of manual weeding per hectare by 76% (¢1,735,000) and annual cost of applying roundup at the labeled rate also by 47 % (¢480,000). The addition of salts to reduced rate of roundup is therefore a cost efficient strategy to control weeds in oil palm plantations. Journal of the Ghana Science Association Vol. 9 (2) 2007: pp. 61-7

Heritability of antibody isotype and subclass responses to Plasmodium falciparum antigens.

BACKGROUND: It is important to understand the extent to which genetic factors regulate acquired immunity to common infections. A classical twin study design is useful to estimate the heritable component of variation in measurable immune parameters. METHODOLOGY/PRINCIPAL FINDINGS: This study assessed the relative heritability of different plasma antibody isotypes and subclasses (IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE) naturally acquired to P. falciparum blood stage antigens AMA1, MSP1-19, MSP2 (two allelic types) and MSP3 (two allelic types). Separate analyses were performed on plasma from 213 pairs of Gambian adult twins, 199 child twin pairs sampled in a dry season when there was little malaria transmission, and another set of 107 child twin pairs sampled at the end of the annual wet season when malaria was common. There were significantly positive heritability (h(2)) estimates for 48% (20/42) of the specific antibody assays (for the seven isotypes and subclasses to the six antigens tested) among the adults, 48% (20/42) among the children in the dry season and 31% (13/42) among the children in the wet season. In children, there were significant heritability estimates for IgG4 reactivity against each of the antigens, and this subclass had higher heritability than the other subclasses and isotypes. In adults, 75% (15/20) of the significantly heritable antigen-specific isotype responses were attributable to non-HLA class II genetic variation, whereas none showed a significant HLA contribution. SIGNIFICANCE: Genome-wide approaches are now warranted to map the major genetic determinants of variable antibody isotype and subclass responses to malaria, alongside evaluation of their impact on infection and disease. Although plasma levels of IgG4 to malaria antigens are generally low, the exceptionally high heritability of levels of this subclass in children deserves particular investigation