The study focuses on the impacts of climate variability and change on maize yield in Mt. Darwin District. The rainfall and temperature data for the period under study that is from 1992 to 2012 were obtained from Meteorological Services Department of Zimbabwe at daily resolution while crop yield data were obtained from Department of Agricultural, Technical and Extension Services (AGRITEX) and Zimbabwe Statistics Agency (ZIMSTAT) at seasonal/yearly resolution. In order to capture full rainfall seasons, a year was set to begin on 1 June and end on 31 July the next year. Yearly yield, temperature and rainfall data were used to compute time series analysis of rainfall, temperature and yield. The relationship between temperature, rainfall, quality of season (start, cessation, dry days, wet days and length) and yield was also investigated. The study also investigated the link between meteorological normal and maize yield. The study revealed that temperature is rising while rainfall is decreasing with time hence increasing risk of low maize yield in Mt. Darwin. Correlation between maize yield was higher using a non-linear (R 2 = 0.630) than a linear regression model (R 2 = 0.173). There was a very high correlation between maize yield and number of dry days (R = −0.905) as well as between maize yield and length of season (R = 0.777). We also observed a strong correlation between percentage normal rainfall and percentage normal maize yield (R 2 = 0.753). This was also agreed between rainfall tessiles and maize yield tessiles as 50 % of the seasons had normal and above normal rainfall coinciding with normal and above normal maize yield. Of the 21 seasons considered, only one season had above normal rainfall while maize yield was below normal. The study concluded that there is a strong association between meteorological normal and maize yield in a rain-fed agricultural system. Climate information remains crucial to agricultural productivity hence the need to train farmers to access the information and use it for the benefit of their activities.
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Siambabala Bernard Manyena Emmanuel Mavhura Chipo Muzenda Elias Mabaso 《Global Environmental Change》2013,23(6):1786-1794
Disaster research and scholarship is now advocating a shift from focusing on the hazard event to processes that generate vulnerability and loss of resilience to disasters. Disaster legislations are among prominent instruments that can highlight the tensions as well as challenges that are being encountered towards this change in focus. Using textual analysis, this paper presents a study that investigated whether five post-2002 disaster legislations have shifted emphasis from the hazard to the vulnerability and resilience paradigms. The five examples illustrate that while there is a slight change, at least in rhetoric, from response to a prevention focus, disaster legislations largely promote a centralised institutional framework, with inadequate resource commitments and limited participation from vulnerable communities. Consequently, while generalisations simply cannot be made without a wider analysis of many more examples from different countries, the five disaster legislations appear to re-emphasise the response focus with less attention on the processes that reduce vulnerability and enhance resilience. The conclusion is that while the rhetoric has changed, the disaster legislations have not significantly moved from the hazard to vulnerability and resilience focus suggesting that reduction of losses and damages to disasters remains a big challenge 相似文献
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Mushore Terence Manatsa Desmond Pedzisai Ezra Muzenda-Mudavanhu Chipo Mushore Washington Kudzotsa Innocent 《Theoretical and Applied Climatology》2017,129(3-4):1167-1173
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Remote sensing is useful for water quality assessments but current remote sensing applications favour parameters that are easy to detect such as chlorophyll-a. An assessment of the utility of Landsat 8 for detecting nutrients was conducted in Mazvikadei reservoir in Zimbabwe. The main objective was to determine whether nutrients often overlooked by remote sensing and yet are the main determinants of water quality can be remotely sensed. Sampling targeted ammonia, nitrates and reactive phosphorus from May to October 2015. In situ nutrient concentrations were regressed against reflectance derived from Landsat 8 imagery. Strong negative relationships were found between ammonia and the near-infrared band in July (R2 = 0.80, p < 0.05) as well as between nitrates and the blue band (R2 = 0.67, p < 0.05) in June. Overall, the results suggest that the cool dry season is the optimum time to use Landsat 8 for monitoring nutrients in tropical lakes. 相似文献
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S. O. Masebinu E. T. Akinlabi E. Muzenda A. O. Aboyade 《International Journal of Environmental Science and Technology》2018,15(1):231-242
This paper presents a methodology to assess the technical and economic viability of grid-tied battery energy storage for a student residence under a time-of-use tariff structure. Battery as a storage medium can take advantage of the price arbitrage between peak and off-peak period under favourable conditions. To investigate the impact of different pricing regimes, summer rate was implemented, and the results were compared with that of winter rate on yearly basis. At base case conditions, neither a prevailing summer nor winter pricing tariff favours the use of battery energy storage. A 0.4656 R/kWh price differential between peak and off-peak period for a summer pricing regime was not sufficient for the battery energy storage system to break even. Implementing a year-round winter pricing regime with a price differential of 2.1171 R/kWh between peak and off-peak period requires a minimum of 866 battery cycle life to break even. Probabilistic analysis using Monte Carlo simulation indicated that to make battery energy storage system attractive, at least 110% increase in the peak price of electricity for summer is needed. The study concluded that the price differential among the different time-of-use tariff regimes impact on the extent of profitability of using battery energy storage. 相似文献
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利用1993年2月—2006年6月沂源县气象资料和苹果冻害资料,在对沂源有代表性的乡镇果园及果农进行实地调查的基础上,选择相应果园进行冻害防御技术研究,确定了沂源县苹果冻害发生的主要类型,提出了苹果抗冻技术措施,从而为苹果安全生产、防止冻害提供技术保障。 相似文献
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