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101.

Grassland silage management is generally semi-organised with no conscious attempt to re-use wheel ways as with arable fields. The total number of machine passes can be 15 or more with normal traffic (NT) systems resulting in potentially large areas of a field suffering from direct damage to the crop and soil. Literature suggests there can be grass dry matter yield reductions of 5 to 74% under NT through compaction and sward damage, with a mean of 13% in the UK. Commercially available grass forage equipment with widths of 3 to 12 m set up for controlled traffic farming (CTF) could reduce trafficked areas (which is typically 90% to 80% for NT) to 40% to 13% for CTF. This study compared grass dry matter yield between CTF and NT for a three-cut silage system based on a 9 m working width in a permanent silage field in the southwest of Scotland, UK in 2015. Results showed a 13.5% (0.80 t ha?1) increase in yield for CTF for the 2nd and 3rd cuts combined. The CTF trafficked area covered was 57% less than the NT system (30.4% compared to 87.4%) over the three silage cuts. An economic analysis based on a 13% increase in dry matter yield (for 2- and 3-cut systems) and a reduction in trafficked area from 80% (for NT) to between 45% and 15% (for CTF), increased the yield by between 0.53 t ha?1 and 1.36 t ha?1 for 2- and 3-cut systems, respectively with an equivalent grass value of between £38 ha?1 and £98 ha?1. Introducing CTF for a multi-cut grass silage system is cost-effective by increasing yields due to a reduction in compaction and sward damage.

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102.
BACKGROUND: The excellent fungicidal activity of [1,2,4]triazolo[1,5‐a]pyrimidines suggested the search for further analogues with improved properties. RESULTS: A series of novel trisubstituted pyrido[2,3‐b]pyrazines has been designed and prepared as 6,6‐biheterocyclic analogues of related 5,6‐bicyclic [1,2,4]triazolo[1,5‐a]pyrimidines. Their fungicidal activity was evaluated against the plant pathogens Puccinia recondita Rob. ex Desm. f. sp. tritici (Eriks.) CO Johnston (wheat brown rust), Mycosphaerella graminicola (Fuckel) Schroter (Septoria tritici Rob., leaf spot of wheat) and Magnaporthe grisea (Hebert) Barr (Pyricularia oryzae Cav., rice blast). Structure–activity relationship studies revealed the advantage of a fluoro substituent in position 6 and of a secondary amine in position 8. CONCLUSION: 8‐Amino‐7‐aryl‐6‐halogen‐substituted pyrido[2,3‐b]pyrazines have been prepared as 6,6‐biheterocyclic analogues of similarly substituted triazolopyrimidine fungicides. A concise four‐step synthesis route has been worked out to prepare these novel compounds from commercially available starting materials. [(R)‐(1,2‐Dimethylpropyl)]‐[6‐fluoro‐7‐(2,4,6‐trifluorophenyl)pyrido[2,3‐b]pyrazin‐8‐yl]amine showed excellent activity against three economically important phytopathogens. Copyright © 2009 Society of Chemical Industry  相似文献   
103.
This paper contributes to the limited literature on open government initiatives at the subnational level in developing countries. It examines the motivations of actors in a local government authority to utilize the capabilities of various stakeholders to overcome constraints in cocreating an action plan for open government reforms. This empirical analysis utilized qualitative fieldwork conducted in Sekondi‐Takoradi Metropolitan Assembly, Ghana's third largest local government. The findings demonstrate that a confluence of citizen demand for openness, and willingness within the governance stakeholders, are motivating the pursuit of open government reforms. Viewed through an open innovation framework, we argue that achieving good governance through information transparency, public participation, and accountability reforms is hindered by the institutional environment. Ghana's subnational governments need national level commitment to provide the resources, mandate, and authority to become truly “open.”  相似文献   
104.
The phosphorus (P) release characteristic of Ogun rock phosphate (OPR) acidulated with cashew nutshell liquid (CNSL), an industrial waste, was studied under laboratory conditions for ten weeks. The results showed that the acidulation of phosphate rock with cashew nutshell liquid at a ratio of 4 to 1 released the highest quantity of available P. There was a general increase in the amount of P extracted from the phosphate rock under the influence of cashew nutshell liquid and this was more spontaneous in alkaline media. The peak of phosphorus release occurred at the 56 days of incubation following a form of stoichiometric order. We found the use of the cashew nutshell liquid in this regard as a win-win approach to not only recycle a major waste of cashew processing industries, which will help to maintain a healthy environment, but to deploy the complementary use of this waste in crop production.  相似文献   
105.
Forests in Africa support the livelihoods of millions of people through provision of timber and non-timber forest products, food and nutrition, energy and payment of environmental services. However, mismanagement of forests has resulted in deforestation and forest degradation, thereby contributing to the increased emission of carbon dioxide into the atmosphere. This special issue highlights some of the research outcomes presented at a pre-congress workshop organised by the African Forest Forum and partners at the 2015 World Forestry Congress. In this issue, the main drivers of land degradation are highlighted vis-à-vis population growth, agricultural expansion, climate variability, drought and energy needs. Promising traditional management practices are identified including age-old farmer-managed natural regeneration and exclosures. In addition, research presented indicates that age-old systems such as native non-browse shrubs in Ethiopia are important in that they facilitate regeneration of late-successional tree species. Furthermore, opportunities for using forests to mitigate climate change are highlighted with a case study on the economics associated with carbon markets. The issue also highlights the methodological challenges of quantifying carbon in African forests. The effect of climate change on threatened forest species and biodiversity in general is discussed, and the associated human disturbances impacting on the population structure of a threatened species, e.g. Afzelia africana in West Africa, is presented. The important role of non-timber forest products in income generation for the rural communities and the associated challenges of commercialisation is emphasised with examples from two important tree species: shea (Vitellaria paradoxa) and baobab (Adansonia digitata). Finally, the issue covers a people-centred approach in tree planting and management where studies demonstrated that there are still problems of poor participation of local communities due to poor implementation of enabling policies, lack of involvement in initial planning and subsequent lack of clear benefit-sharing mechanisms.  相似文献   
106.
The strobilurin fungicides   总被引:5,自引:0,他引:5  
Strobilurins are one of the most important classes of agricultural fungicide. Their invention was inspired by a group of fungicidally active natural products. The outstanding benefits they deliver are currently being utilised in a wide range of crops throughout the world. First launched in 1996, the strobilurins now include the world's biggest selling fungicide, azoxystrobin. By 2002 there will be six strobilurin active ingredients commercially available for agricultural use. This review describes in detail the properties of these active ingredients--their synthesis, biochemical mode of action, biokinetics, fungicidal activity, yield and quality benefits, resistance risk and human and environmental safety. It also describes the clear technical differences that exist between these active ingredients, particularly in the areas of fungicidal activity and biokinetics.  相似文献   
107.

By collecting more data at a higher resolution and by creating the capacity to implement detailed crop management, autonomous crop equipment has the potential to revolutionise precision agriculture (PA), but unless farmers find autonomous equipment profitable it is unlikely to be widely adopted. The objective of this study was to identify the potential economic implications of autonomous crop equipment for arable agriculture using a grain-oilseed farm in the United Kingdom as an example. The study is possible because the Hands Free Hectare (HFH) demonstration project at Harper Adams University has produced grain with autonomous equipment since 2017. That practical experience showed the technical feasibility of autonomous grain production and provides parameters for farm-level linear programming (LP) to estimate farm management opportunities when autonomous equipment is available. The study shows that arable crop production with autonomous equipment is technically and economically feasible, allowing medium size farms to approach minimum per unit production cost levels. The ability to achieve minimum production costs at relatively modest farm size means that the pressure to “get big or get out” will diminish. Costs of production that are internationally competitive will mean reduced need for government subsidies and greater independence for farmers. The ability of autonomous equipment to achieve minimum production costs even on small, irregularly shaped fields will improve environmental performance of crop agriculture by reducing pressure to remove hedges, fell infield trees and enlarge fields.

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108.
The limb blastemal cells of an adult salamander regenerate the structures distal to the level of amputation, and the surface protein Prod 1 is a critical determinant of their proximodistal identity. The anterior gradient protein family member nAG is a secreted ligand for Prod 1 and a growth factor for cultured newt blastemal cells. nAG is sequentially expressed after amputation in the regenerating nerve and the wound epidermis-the key tissues of the stem cell niche-and its expression in both locations is abrogated by denervation. The local expression of nAG after electroporation is sufficient to rescue a denervated blastema and regenerate the distal structures. Our analysis brings together the positional identity of the blastema and the classical nerve dependence of limb regeneration.  相似文献   
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