691 research outputs found

    The role of cattle manure in enhancing on-farm productivity, macro- and micro-nutrient uptake, and profitability of maize in the Guinea savanna

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    An on-farm trial was conducted in the northern Guinea savanna of Nigeria, over a period of five years, with the objectives of quantifying the effects on maize of applying cattle manure in combination with synthetic fertilizer with regard to soil characteristics, yield, plant nutrition and profitability. Maize grain yield was significantly increased by the annual application of cattle manure, compared to maize receiving an equal amount of N through synthetic fertilizer, but only from the third year of the experiment. The application of manure resulted in higher soil Kjel N, Bray-I P and exchangeable K values, and an increased N utilization efficiency by maize, suggesting that yield-limiting factors other than N deficiencies were of lesser importance than in the treatment receiving sole inorganic fertilizer. Nutrients other than N applied via the manure, particularly P, K and/or B, may have contributed to the higher grain yields in treatments receiving manure. A partial budgeting analysis revealed that, over a 5-year period, investments in the application of manure, in combination with synthetic fertilizer, resulted in higher margins than the application of fertilizer alone. However, analyses of marginal rates of return of changes from low urea N to high urea N or additional manure applications suggested that it was more profitable to invest in additional urea than in organic manure in the first two years of the experiment. The results suggested that manure applications, even when applied at relatively high rates, did not serve as a quick fix to on-farm soil fertility problems, but over a longer period, manure applied in combination with synthetic fertilizers did provide a significant and profitable contribution to enhanced cereal production

    Ultrafast-pulse diagnostic using third-order frequency-resolved optical gating in organic films

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    We report on the diagnostic of ultrafast pulses by frequency-resolved optical gating (FROG) based on strong third-harmonic generation (THG) in amorphous organic thin films. The high THG conversion efficiency of these films allows for the characterization of sub-nanojoule short pulses emitting at telecommunication wavelengths using a low cost portable fiber spectrometer

    Does crop-livestock integration lead to improved crop production in the savanna of West Africa?

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    Integrated crop-livestock farming in the Guinea savanna of West Africa is often assumed to lead to synergies between crop and livestock production, thereby improving the overall productivity and resilience of agricultural production. Whether these synergies actually occur remains poorly studied. On-farm trials were conducted in northern Nigeria over a period of four years to assess the agronomic and economic performance of maize-legume systems with and without the integration of livestock (goats). Groundnut-maize rotations with livestock achieved the highest carry-over of nutrients as manure from one season to the next, covering approximately one-third of the expected N, P and K uptake by maize and reducing the demand for synthetic fertilizers. However, the advantage of lower fertilizer costs in rotations with livestock was offset by higher labour costs for manure application and slightly lower values of maize grain. Overall, no clear agronomic or economic benefits for crop production were observed from the combined application of manure and synthetic fertilizer over the application of synthetic fertilizer only, probably because the amounts of manure applied were relatively small. Legume-maize rotations achieved higher cereal yields, a better response to labour and fertilizer inputs, and a higher profitability than maize-based systems with no or only a small legume component, irrespective of the presence of livestock. Livestock at or near the farm could nevertheless make legume cultivation economically more attractive by increasing the value of legume haulms. The results suggested that factors other than crop benefits, e.g. livestock providing tangible and non-tangible benefits and opportunities for animal traction, could be important drivers for the ongoing integration of crop and livestock production in the savann

    Determinants of adoption and intensity of use of balanced nutrient management systems technologies in the northern Guinea savanna of Nigeria

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    As part of a major effort to address soil fertility decline in West Africa, a project on Balanced Nutrient Management Systems (BNMS) has since 2000 been implemented in the northern Guinea savanna (NGS) of Nigeria. The project has tested and promoted two major technology packages, including a combined application of inorganic fertilizer and manure (BNMS-manure) and a soybean/maize rotation practice referred to as BNMS-rotation. This study employed Tobit model to examine factors that influence the adoption and intensity of utilization of BNMS technologies in the NGS of Nigeria. Results showed that less than 10% of the sample households adopted at least one of the two components of the technology package by the end of 2002. However, by 2005 the adoption of BNMS-rotation had reached 40% while that of BNMS-manure had reached 48%. A number of factors such as access to credit, farmers’ perception of the state of land degradation, and assets ownership were found to be significant in determining farmers’ adoption decisions on BNMS-manure while off-farm income was found to be significant in determining farmers’ adoption decisions on BNMS-rotation. Extension services and farmer-to-farmer technology diffusion channels were the major means of transfer of BNMS technologies.Adoption, BNMS-manure, BNMS-rotation, Northern Guinea Savanna (NGS)., Agricultural and Food Policy, Community/Rural/Urban Development, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Health Economics and Policy, Institutional and Behavioral Economics, International Relations/Trade, Livestock Production/Industries, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies, Research Methods/ Statistical Methods,

    PND10 Faster Cognitive Decline is Associated With Decreasing Survival in Patients With Alzheimer'S Disease

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    Physical realization of coupled Hilbert-space mirrors for quantum-state engineering

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    Manipulation of superpositions of discrete quantum states has a mathematical counterpart in the motion of a unit-length statevector in an N-dimensional Hilbert space. Any such statevector motion can be regarded as a succession of two-dimensional rotations. But the desired statevector change can also be treated as a succession of reflections, the generalization of Householder transformations. In multidimensional Hilbert space such reflection sequences offer more efficient procedures for statevector manipulation than do sequences of rotations. We here show how such reflections can be designed for a system with two degenerate levels - a generalization of the traditional two-state atom - that allows the construction of propagators for angular momentum states. We use the Morris-Shore transformation to express the propagator in terms of Morris-Shore basis states and Cayley-Klein parameters, which allows us to connect properties of laser pulses to Hilbert-space motion. Under suitable conditions on the couplings and the common detuning, the propagators within each set of degenerate states represent products of generalized Householder reflections, with orthogonal vectors. We propose physical realizations of this novel geometrical object with resonant, near-resonant and far-off-resonant laser pulses. We give several examples of implementations in real atoms or molecules.Comment: 15 pages, 6 figure
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