scholarly journals Exploring Niches for Short-Season Grain Legumes in Semi-Arid Eastern Kenya — Coping with the Impacts of Climate Variability

2017 ◽  
Vol 8 ◽  
Author(s):  
Anne Sennhenn ◽  
Donald M. G. Njarui ◽  
Brigitte L. Maass ◽  
Anthony M. Whitbread
Keyword(s):  
Climate Variability ◽  
Grain Legumes ◽  
Short Season ◽  
Semi Arid

scholarly journals Understanding growth and development of three short-season grain legumes for improved adaptation in semi-arid Eastern Kenya

2017 ◽  
Vol 68 (5) ◽  
pp. 442 ◽  
Author(s):  
A. Sennhenn ◽  
D. M. G. Njarui ◽  
B. L. Maass ◽  
A. M. Whitbread
Keyword(s):  
Resource Use ◽  
Growth Habit ◽  
Farming Systems ◽  
Grain Legumes ◽  
Resource Use Efficiency ◽  
Growing Period ◽  
Plant Densities ◽  
Use Efficiency ◽  
Short Season ◽  
Semi Arid

Short-season grain legumes play an important role in smallholder farming systems as source of food and to improve soil fertility through nitrogen fixation. However, it is not clearly understood how these diverse legumes contribute to the resilience of such systems in semi-arid environments. We describe the growth, development and resource-use efficiency (focusing on radiation, RUE) of three promising short-season grain legumes: common bean (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp.) and lablab (Lablab purpureus (L.) Sweet). Two field experiments were conducted during the short rains of 2012–13 and 2013–14 in Eastern Kenya. In the first experiment, the legumes were grown at three plant densities (low, medium, high); in the second experiment, they were subjected to three water regimes (rainfed, partly irrigated, fully irrigated). Phenological development was monitored and biomass accumulation, leaf area index and fractional radiation interception were measured repeatedly during growth; grain yield was measured at maturity. Harvest index and RUE were calculated from these data. Common bean had the shortest growing period (70 days), the most compact growth habit and relatively high RUE but limited grain yield (1000–1900 kg ha–1), thereby proving more suitable for cultivation in areas with restricted cropping windows or in intercropping systems. Cowpea had a longer growing period (90 days) and a spreading growth habit leading to high light interception and outstanding grain yields under optimal conditions (1400–3050 kg ha–1). Lablab showed stable RUE values (0.76–0.92 g MJ–1), was relatively unaffected by limited water availability and had a comparatively long growing period (100 days). Lablab grain yields of ~1200–2350 kg ha–1 were obtained across all water regimes, indicating a high potential to cushion climatic variability. Planting density strongly influenced the production success of cowpea and lablab, with high plant densities leading to vigorous growth habit with low podset establishment. Such information on temporal and spatial differences in growth, development and resource-use efficiency is highly valuable for crop-modelling applications and for designing more resilient farming systems with short-season grain legumes.

Forecasting the impacts of climate variability: lessons from the rainfed corn market in Ceará, Brazil

2008 ◽  
Vol 13 (2) ◽  
pp. 201-227 ◽  
Author(s):  
ARIASTER B. CHIMELI ◽  
FRANCISCO DE ASSIS DE SOUZA FILHO ◽  
MARCOS COSTA HOLANDA ◽  
FRANCIS CARLO PETTERINI
Keyword(s):  
Climate Variability ◽  
Developing Economies ◽  
Arid Zone ◽  
Well Being ◽  
Policy Makers ◽  
Local Climate ◽  
The World ◽  
Forecast Models ◽  
Climatic Impacts ◽  
Semi Arid

ABSTRACTA number of studies show that climatic shocks have significant economic impacts in several regions of the world, especially in, but not limited to, developing economies. In this paper we focus on a drought-related indicator of well-being and emergency spending in the Brazilian semi-arid zone – rainfed corn market – and estimate aggregate behavioral and forecast models for this market conditional on local climate determinants. We find encouraging evidence that our approach can help policy makers buy time to help them prepare for drought mitigating actions. The analysis is applicable to economies elsewhere in the world and climatic impacts other than those caused by droughts.

scholarly journals CLIMATE VARIABILITY AND CHANGE: FARMER PERCEPTIONS AND UNDERSTANDING OF INTRA-SEASONAL VARIABILITY IN RAINFALL AND ASSOCIATED RISK IN SEMI-ARID KENYA

2011 ◽  
Vol 47 (2) ◽  
pp. 267-291 ◽  
Author(s):  
K. P. C. RAO ◽  
W. G. NDEGWA ◽  
K. KIZITO ◽  
A. OYOO
Keyword(s):  
Climate Variability ◽  
Crop Production ◽  
Smallholder Farmers ◽  
Crop Productivity ◽  
General Tendency ◽  
Climate Variability And Change ◽  
Negative Impacts ◽  
Probabilistic Nature ◽  
Semi Arid

SUMMARYThis study examines farmers’ perceptions of short- and long-term variability in climate, their ability to discern trends in climate and how the perceived trends converge with actual weather observations in five districts of Eastern Province in Kenya where the climate is semi-arid with high intra- and inter-annual variability in rainfall. Field surveys to elicit farmers’ perceptions about climate variability and change were conducted in Machakos, Makueni, Kitui, Mwingi and Mutomo districts. Long-term rainfall records from five meteorological stations within a 10 km radius from the survey locations were obtained from the Kenya Meteorological Department and were analysed to compare with farmers’ observations. Farmers’ responses indicate that they are well aware of the general climate in their location, its variability, the probabilistic nature of the variability and the impacts of this variability on crop production. However, their ability to synthesize the knowledge they have gained from their observations and discern long-term trends in the probabilistic distribution of seasonal conditions is more subjective, mainly due to the compounding interactions between climate and other factors such as soil fertility, soil water and land use change that determine the climate's overall influence on crop productivity. There is a general tendency among the farmers to give greater weight to negative impacts leading to higher risk perception. In relation to long-term changes in the climate, farmer observations in our study that rainfall patterns are changing corroborated well with reported perceptions from other places across the African continent but were not supported by the observed trends in rainfall data from the five study locations. The main implication of our findings is the need to be aware of and account for the risk during the development and promotion of technologies involving significant investments by smallholder farmers and exercise caution in interpreting farmers’ perceptions about long-term climate variability and change.

scholarly journals Global vegetation variability and its response to elevated CO<sub>2</sub>, global warming, and climate variability – a study using the offline SSiB4/TRIFFID model and satellite data

2019 ◽  
Vol 10 (1) ◽  
pp. 9-29 ◽  
Author(s):  
Ye Liu ◽  
Yongkang Xue ◽  
Glen MacDonald ◽  
Peter Cox ◽  
Zhengqiu Zhang
Keyword(s):  
Global Warming ◽  
Climate Variability ◽  
Environmental Drivers ◽  
Arid Areas ◽  
Area Index ◽  
Substantial Impact ◽  
Positive Effects ◽  
Vegetation Fraction ◽  
Before And After ◽  
Semi Arid

Abstract. The climate regime shift during the 1980s had a substantial impact on the terrestrial ecosystems and vegetation at different scales. However, the mechanisms driving vegetation changes, before and after the shift, remain unclear. In this study, we used a biophysical dynamic vegetation model to estimate large-scale trends in terms of carbon fixation, vegetation growth, and expansion during the period 1958–2007, and to attribute these changes to environmental drivers including elevated atmospheric CO2 concentration (hereafter eCO2), global warming, and climate variability (hereafter CV). Simulated leaf area index (LAI) and gross primary production (GPP) were evaluated against observation-based data. Significant spatial correlations are found (correlations > 0.87), along with regionally varying temporal correlations of 0.34–0.80 for LAI and 0.45–0.83 for GPP. More than 40 % of the global land area shows significant positive (increase) or negative (decrease) trends in LAI and GPP during 1958–2007. Regions over the globe show different characteristics in terms of ecosystem trends before and after the 1980s. While 11.7 % and 19.3 % of land have had consistently positive LAI and GPP trends, respectively, since 1958, 17.1 % and 20.1 % of land saw LAI and GPP trends, respectively, reverse during the 1980s. Vegetation fraction cover (FRAC) trends, representing vegetation expansion and/or shrinking, are found at the edges of semi-arid areas and polar areas. Environmental drivers affect the change in ecosystem trend over different regions. Overall, eCO2 consistently contributes to positive LAI and GPP trends in the tropics. Global warming mostly affects LAI, with positive effects in high latitudes and negative effects in subtropical semi-arid areas. CV is found to dominate the variability of FRAC, LAI, and GPP in the semi-humid and semi-arid areas. The eCO2 and global warming effects increased after the 1980s, while the CV effect reversed during the 1980s. In addition, plant competition is shown to have played an important role in determining which driver dominated the regional trends. This paper presents new insight into ecosystem variability and changes in the varying climate since the 1950s.

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