Journal of Agriculture and Rural Development in the Tropics and Subtropics (JARTS)
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The Role of Bio-productivity on Bio-energy Yields
Get PDFThe principal photosynthetic pathways convert solar energy differently depending on the environmental conditions and the plant morphotype. Partitioning of energy storage within crops will vary according to environmental and seasonal conditions as well. Highest energy concentration is found in terpens like latex and, to a lesser extent, in lipids. Ideally, we want plant ingredients with high energy content easily amenable to ready-to-use bio-fuel. Generally, these crops are adapted to drier areas and tend to save on eco-volume space. Competition with food crops could be avoided by fetching energy from cheap agricultural by-products or waste products such as bagasse in the sugar cane. This would in fact mean that reducing power of agricultural residues should be extracted from the biomass through non-photosynthetic processes like animal ingestion or industrial bio-fermentation. Conversion and transformation efficiencies in the production chain are illustrated for some relevant crops in the light of the maximum power theorem
Local Productive Arrangements for Biodiesel Production in Brazil – Environmental Assessment of Small-holder’s Integrated Oleaginous Crops Management
Get PDFSustainability assessments were carried out in small-holders’ farms in four territories where productive arrangements have been organized for production of minor oleaginous crops under the Brazilian biodiesel program. The study aimed at checking local impacts of the biodiesel productive chains at the rural establishment scale, and promoting the environmental performance of the selected farms, henceforth proposed as sustainable management demonstration units. Assessments were carried out with the APOIA-NovoRural system, which integrates 62 objective and quantitative indicators related to five sustainability dimensions: i) Landscape Ecology, ii) Environmental Quality (Atmosphere, Water and Soil), iii) Socio-cultural Values, iv) Economic Values and v) Management and Administration. The main results point out that, in general, the ecological dimensions of sustainability, that is, the Landscape Ecology and Atmosphere, Water, and Soil quality indicators, show adequate field conditions, seemingly not yet negatively affected by increases in chemical inputs and natural resources use predicted as important potential impacts of the agro-energy sector. The Economic Values indicators have been favorably influenced in the studied farms, due to a steadier demand and improved prices for the oleaginous crops. On the other hand, valuable positive consequences expected for favoring farmers’ market insertion, such as improved Socio-cultural Values and Management Administration indicators, are still opportunities to be materialized. The Environmental Management Reports issued to the farmers, based on the presented sustainability assessment procedures, offer valuable documentation and communication means for consolidating the organizational influence of the local productive arrangements studied. These productive arrangements were shown to be determinant for the selection of crop associations and diversification, as well as for the provision of technical assistance and the stabilization of demand - conditions that promote value aggregation and income improvements, favoring small-holders’ insertion in the market. More importantly, these locally organized productive arrangements have been shown to strongly influence the valorization of natural resources and environmental assets, which are fundamental if sustainable rural development is to take place under the emerging agro-energy scenario
Effects of Biomass Ashes on Plant Nutrition in Tropical and Temperate Regions
Get PDFThe drastic rise of prices for commercial fertilizers is one of the main obstacles to increase the productivity in crop production, mainly in poor countries. The search for alternatives therefore becomes very important. The reutilization of residues from bionergy processes for plant nutrition is an important concern to save fertilizers and to implement nutrient cycling in agriculture. For this study ashes derived from bioenergy production were investigated. The effect of sugar cane ash (SCA) on lettuce and cucumber was investigated in Cuba and the effects of ashes from wood (WA), poultry litter (PLA), and rape meal (RMA) on ryegrass and oil radish were investigated in Germany. Special attention was given to phosphorus (P) availability. Positive yield effects and an increased plant P uptake were found when ashes were applied (mainly SCA and RMA). Investigation regarding the effect of PLA on soil P pools showed that the ash application may also result in an increase of readily available P contents in soil. Furthermore, an increased plant uptake of potassium was found. The results indicate that ashes derived from the energetic use of biomass may provide a suitable source for plant nutrition
Caught between Energy Demands and Food Needs: Dilemmas of Smallholder Farmers in Njoro, Kenya
Get PDFSmallholders in rural Kenya, like their counterparts in tropical Africa currently face acute shortage of fuel wood for domestic use. There has been rapid population increase in the last few decades resulting in increased demand for food crops. This has led to the expansion of area under subsistence agriculture eating into indigenous forests, the traditional source of wood fuel. This situation has been compounded by the limited access to alternative sources of domestic energy in rural parts of Kenya. The recent upsurge in the cost of fossil-derived fuels as well as in hydro-generated electricity has left the smallholder farmer with wood as the sole source of fuel. This paper therefore examines the conflicting demands of domestic fuel needs and foods. Key research questions were: What are the household domestic energy demand and constraints? What is the household food demand and constraint among smallholders? How do the smallholders reconcile these competing basic needs? The paper reflects on the constraints of smallholders in their quest to fulfill their food and energy needs. The discussed model is a result based on discussions between the researchers and focus group discussions drawn from smallholder farmers. The primary data gathered from the discussions is augmented by secondary data to draw imperative implications on domestic energy use and food needs. The results indicate an average annual per capita wood fuel demand of 1.99 m3 and a deficit of 8.816 m3 per household. The deficit is usually catered for through purchase of wood fuel from the market, which has an implication on the pressure exerted on the forestry resources. This paper shows that households in Njoro have turned to desperate coping mechanisms and strategies such as use of maize straw, pruning and fallen twigs. The results of this study provide insights on how the dilemma may be resolved in a smallholder setup and suggest local policy options
Comparisons of Production Costs and Profit of Three Different Technology Levels of Papaya Production in Tabasco, Mexico
Get PDFThe survey was carried out from September 2006 to January 2007 in three papaya production sites located in main papaya production zones in Tabasco; SE Mexico. There are differences in size of the cultivated area, in the yield of the papaya as well as in production costs and profit, according to the different technology levels in the farming systems: low, medium and high technology cultivation level. The financial evaluations were carried out in three sites with different productive technologies. The comparison of the agronomic and economic traits results for low technology level in: V AN of 2359.00 USD, BCR in 1.9 and an equilibrium point of 3750.00 USD, TIR of 0.25. In order to avoid loses, a quantity of 10714 kg papaya should be sold. In medium technology VAN is 1605.10 USD, BCR is 1.7, TIR 0.20 and the equilibrium point is 12800.00 USD. 36571 kg of papaya should be yearly sold. In high technology level VAN is 11749.40, BCR is 2.73, TIR 0.43 and the equilibrium point is 12187.50 USD, 34821 kg papaya should be sold yearly. The indicators showed that all three levels are profitable and economically viable
Traits for Screening and Selection of Cowpea Genotypes for Drought Tolerance at Early Stages of Breeding
Get PDFThe association of leaf water content with yield-attributes such as pod setting and number of pods/plant and seed yield in cowpea was examined using midday drop of leaf relative water content (RWC) determined from morning (800 h) and midday (1330 h) measurements of RWC. Midday drop of RWC was significantly correlated to pod setting ratio (R2 = 0.80, P 0.01), number of pods/plant (R2 = 0.87, P 0.01) and seed yield (R2 = 0.37, P 0.05). There was a significant genotypic variation for leaf water potential (LWP) at 800 and 1330 h and for RWC at 1330 h. Significant genotypic differences were also observed in pod setting ratio, number of pods/plant, number of seeds/pod, 1000-seed weight, biomass and seed yield. Pod setting ratio was significantly and positively correlated with number of pods/plant (R2 = 0.80, P 0.01) and seed yield (R2 = 0.38, P 0.05). These results showed that the genotypes with a smaller reduction in midday drop of RWC produced a larger number of pods/plant and consequently had higher seed yield as compared with a larger midday drop of RWC. The results also showed that there was a large genotypic variation in the midday drop of RWC, which was correlated with yield-attributes and seed yield. It may therefore be possible to use midday drop of RWC as a screening and selection trait for drought tolerance of cowpea genotypes
Effect of Inoculation with Rhizobacteria and Arbuscular Mycorrhizal Fungi on Growth and Yield of Capsicum chinense Jacquin
Get PDFWe evaluated the effect of two rhizobacteria (Azotobacter chroococcum and Azospirillum brasilense) and a commercial product containing multiple strains of arbuscular mycorrhizal fungi (AMF) and an NPK fertiliser on the growth and yield of habanero chilli (Capsicum chinense Jacquin). All treatments were applied as single or combined inoculants, under nursery and field conditions, in a completely randomised design. The biofertilisers were applied to the roots by coating or dipping, with the inoculants in a solid or liquid support, respectively. At 30 days after inoculation, populations of 2.5×106 to 1.3×106 cfu g soil−1 of A. brasilense and 10.3×105 to 2.6×105 of A. chroococcum were detected in the rhizosphere of the crop. The prevalence of colonisation of plants inoculated with AMF ranged from 35 to 57%, with the greatest values recorded for the treatment involving single biofertilisation by root coating. In the nursery phase, single biofertilisation promoted a higher growth and nutrient content in the crop than combined biofertilisation. However, in the field phase the combined biofertilisation increased the nutrient content of the plant leaves, which was significantly greater than observed in the NPK treatment. The highest yields were recorded for the treatments involving a single inoculation of A. chroococcum and for those with the multi-strain of AMF, with average values of 2.5 and 2.3 kg plant−1 respectively, compared with 1.0 kg plant−1 obtained with the treatment in which NPK fertiliser was applied
Species Richness in Relation to the Presence of Crop Plants in Families of Higher Plants
Get PDFCrop species richness and percentages of cultivated plants in 75 families comprisingmore than 220000 species were analyzed. Three major groups have been made. The first group is including the “big five” families with 10000 and more species in each. The second group comprises 50 families with more than thousand and up to 10000 species and finally the third group contains families with relatively high numbers of crop species. The percentage of cultivated species is various, from 0.16 to 7.25 in group 1, 0 to 7.24 in group 2 and 2.30 to 32.5 in group 3. The results show that there is a positive correlation (r = + 0.56) between number of crop plants and species diversity of the families
Plant Genetic Resources: Selected Issues from Genetic Erosion to Genetic Engineering
Get PDFPlant Genetic Resources (PGR) continue to play an important role in the development of agriculture. The following aspects receive a special consideration: 1. Definition. The term was coined in 1970. The genepool concept served as an important tool in the further development. Different approaches are discussed. 2. Values of Genetic Resources. A short introduction is highlighting this problem and stressing the economic usfulness of PGR. 3. Genetic Erosion. Already observed by E. Baur in 1914, this is now a key issue within PGR. The case studies cited include Ethiopia, Italy, China, S Korea, Greece and S. Africa. Modern approaches concentrate on allelic changes in varieties over time but neglect the landraces. The causes and consequences of genetic erosion are discussed. 4. Genetic Resources Conservation. Because of genetic erosion there is a need for conservation. PGR should be consigned to the appropriate method of conservation (ex situ, in situ, on-farm) according to the scientific basis of biodiversity (genetic diversity, species diversity, ecosystem diversity) and the evolutionary status of plants (cultivated plants, weeds, related wild plants (crop wild relatives)). 5. GMO. The impact of genetically engineered plants on genetic diversity is discussed. 6. The Conclusions and Recommendations stress the importance of PGR. Their conservation and use are urgent necessities for the present development and future survival of mankind
A Survey of Myanmar Rice Production and Constraints
Get PDFAlthough modern high yielding varieties were introduced into Myanmar in the early 1980s, the national average of rice grain yield has stagnated at 3.2-3.4 t ha-1. To identify yield constraints, input intensities and the general practices of rice cultivation in Myanmar, a survey was conducted during the wet seasons of 2001 and 2002. A total of 98 farmers from five townships in Upper Myanmar and 16 in Lower Myanmar representing the most important areas of rice production were questioned on their management practices, yields, and perceived yield constraints over the previous four years. There was a recent decrease in the overall average rate of fertilizer application, an increase in the prevalence of rice-legume cropping systems, and only localized insect pest or disease problems. Additionally, rice yields were found to be higher in Upper Myanmar, likely the results of more suitable weather conditions, better irrigation, and ready market access. Furthermore, a number of critical factors affecting production are identified and possible solutions discussed