The Kapingazi River Basin in Kenya is home to a range of ecosystem services. Agricultural and industrial activities have negatively impacted water quality and flows. This study assesses the willingness to pay for improving water service provision. Two-thirds of the respondents are willing to pay for improved water quality and quantity. The respondents were willing to pay an average of US$9.10 per annum for improved water services, not counting water connection fees. Logistic regression analysis revealed that age, education and household size were factors influencing respondents’ willingness to pay.
Tag: water management
Woody species alongside earth contour bunds enhance the soil water-infiltration capacity in the Sahel, West Africa
Land degradation, including the loss of tree, forest and vegetation cover, and its related loss of water availability are the main constraints affecting the rainfed agricultural systems in West African Sahel and dry savanna. Therefore, farmers are implementing various soil and water conservation techniques such as zaï pits, half-moons, contour stone and earth bunds to improve crop production through reduced erosion and enhanced water retention. This study explores the effect of woody and herbaceous vegetation established along earth contour bunds on soil infiltration capacity in southern Mali. The soil infiltration measurements were carried out from September to December 2019 using single ring infiltrometers up-slope and down-slope of the bunds built on contour lines in 2015 and 2016 with four types of vegetation: (1) natural annual herbaceous vegetation; (2) planted Andropogon gayanus (perennial grass); (3) planted Gliricidia sepium (woody species) and (4) planted Acacia colei (woody species). The field-saturated hydraulic conductivity (Kfs) was estimated from the infiltration data and subjected to statistical analysis to compare the effect of the four types of vegetation on soil infiltration capacity. The results revealed significant differences in infiltration rate and Kfs between the four vegetation types. The highest infiltration rate and Kfs were observed for earth contour bunds reinforced with woody species G. sepium (299.5 ± 0.6; 45.3 ± 1.4 mm h−1), followed by A. colei (232.2 ± 2; 38.2 ± 1.6 mm h−1). These were followed by the grass A. gayanus (189.4 ± 2.5; 33.0 ± 1.7 mm h−1) and natural annual herbaceous vegetation (132 ± 2.3; 20.7 ± 1.9 mm h−1). In addition, soil water-infiltration rate and Kfs were higher for down-slope compared to up-slope areas for the two woody species. In practice, it is appropriate for farmers to reinforce contour bunds with woody species and perennial herbs given the beneficial effect on soil water infiltration and retention capacity and the expected socio-economic benefit they can get from them.
Negative effects of water deficit on cocoa tree yield are partially mitigated by irrigation and potassium application
Yields of most tropical crops are strongly reduced by drought, but this may be partially mitigated by irrigation and potassium application. Understanding the mechanisms regulating these relationships is essential to select crop varieties reaching high yield under environmental stress. We conducted a 2-year field experiment (2020–2022) to investigate the effects of seasonal irrigation, potassium application and their interaction on cocoa reproduction and yield, using six genotypes in Côte d’Ivoire. Potassium application increased pod number and size, contributing significantly to annual yield, but this effect was conditional to soil water availability. Similarly, irrigation when combined with potassium application almost doubled yield from 1.5 to 3.0 kg/tree (2000 kg ha−1 yr−1 to 4000 kg ha−1 yr−1, respectively). This yield effect was mostly the result of positive effects of irrigation on pod number per tree and, to a lesser extent, due to its positive effects on bean number per pod and bean mass. Irrigation effects on pod number were associated with an increased number of cherelles whereas the larger pod number during the major harvest compared to the minor harvest was associated with lower cherelle wilt. We also found a more than two-fold genotypic difference in yield, with the genotypes CI02 and CI03 and to a lesser extent hybrid M having lower yields having lower yields than the genotype CI01. These genotypic yield differences were associated with differences in both cherelle wilt and initial cherelle production rates. The effects of withholding irrigation on yield were significantly dependent on the genotype, reflecting a potential genotypic difference in drought tolerance. The development of climate adaptive strategies for cocoa production requires integrating effects of irrigation, potassium application and cocoa genotype on yields. Future research should focus on unraveling the underlying genotypic and ecophysiological mechanisms of the results presented here, and identifying other potential approaches to enhance the resilience of cocoa to increasing water deficit under climate change.
Explore before you restore: Incorporating complex systems thinking in ecosystem restoration
The global movement for ecosystem restoration has gained momentum in response to the Bonn Challenge (2010) and the UN Decade on Ecosystem Restoration (UNDER, 2021–2030). While several science-based guidelines exist to aid in achieving successful restoration outcomes, significant variation remains in the outcomes of restoration projects. Some of this disparity can be attributed to unexpected responses of ecosystem components to planned interventions. Given the complex nature of ecosystems, we propose that concepts from Complex Systems Science (CSS) that are linked to non-linearity, such as regime shifts, ecological resilience and ecological feedbacks, should be employed to help explain this variation in restoration outcomes from an ecological perspective. Our framework, Explore Before You Restore, illustrates how these concepts impact restoration outcomes by influencing degradation and recovery trajectories. Additionally, we propose incorporating CSS concepts into the typical restoration project cycle through a CSS assessment phase and suggest that the need for such assessment is explicitly included in the guidelines to improve restoration outcomes. To facilitate this inclusion and make it workable by practitioners, we describe indicators and methods available for restoration teams to answer key questions that should make up such CSS assessment. In doing so, we identify key outstanding science and policy tasks that are needed to further operationalize CSS assessment in restoration. Synthesis and applications. By illustrating how key Complex Systems Science (CSS) concepts linked to non-linear threshold behaviour can impact restoration outcomes through influencing recovery trajectories, our framework Explore Before You Restore demonstrates the need to incorporate Complex Systems thinking in ecosystem restoration. We argue that inclusion of CSS assessment into restoration project cycles, and more broadly, into international restoration guidelines, may significantly improve restoration outcomes.
Exploring biochar and Moringa oleifera seed proteins for greywater remediation on small farms
This study investigated the potential of using biochar and Moringa oleifera seed proteins for sustainable greywater treatment in rural Kenya. Greywater samples from washing clothes were collected from households in the Kenyan counties of Kwale and Siaya. Two treatment methods, batch stirring and filtration, were used to assess the effectiveness of using biochar and Moringa oleifera seed protein extract together to treat greywater at a household level. Both methods achieved a significant reduction in contaminants: colour was reduced by up to 43% in Kwale and 67% in Siaya, turbidity decreased by 91–98%, and surfactant levels were lowered by 89–93%. There were increases in total organic carbon and total dissolved solids post-treatment, but both methods effectively reduced levels of phosphates, nitrates and iron. This research highlights the potential of using locally available materials for greywater treatment and provides insights into sustainable water management nature-based solutions in the Global South.