Global climate change has increased the uncertainties and risks that have always been inherent in agriculture, especially in regards to the availability of water resources for crops. In response to this heightened jeopardy, some experts have advised the promotion of soil and water conservation (SWC) technologies for farmers. SWC technologies include bunds (structures to control runoff and reduce erosion), grass strips, tree planting, irrigation, and water harvesting structures such as dams and ponds. Farmers must weigh the risks of adopting a new technology with the potential gains in crop yield in order to decide if implementing a particular SWC technology will be beneficial. This study creates a mathematical model to assess the impact of SWC techniques in 5 ecologically different regions of the Nile Basin in Ethiopia. After running statistical analysis, the model suggests that all of the SWC options studied have large positive impacts on crop output in low-rainfall areas, while only waterways and tree planting have an impact in high-rainfall areas. In addition, irrigation alone has no effect or results in lower yields in both high- and low-rainfall areas of the country, but when it is combined with other SWC technologies, large positive impacts can be seen in all regions. This finding should lead us to consider that the answer to water management in the face of climate change will not be a “silver bullet” solution, but rather the result of interactions between many different technologies. The results from this statistical model may be used to give advice to farmers in Ethiopia, improve targeting of SWC techniques to certain areas, and provide insight for policymakers, NGOs, and other development agencies in order to help farmers adapt to changing water resources in the face of global climate change.–Nora Studholme
Kato, E., Ringler, C., Yesui, M., Bryan, E., 2011. Soil and water conservation technologies: a buffer against production risk in the face of climate change? Insights from the Nile basin in Ethiopia. Agricultural Economics 42, 593–604.
In order to build an accurate statistical model, researchers used diverse data from 50 households across 5 regions of Ethiopia, resulting in a total sample size of 6,000 plots. Researchers then separated the regions based on historical rainfall patterns, so that the impact of different technologies could be observed in disparate ecological environments.
The model assumes that farmers are risk-averse and want to maximize their profits. The equation is set up to show how farmers might maximize utility using different levels of SWC inputs. In order to account for the fact that different crops might be produced in larger or smaller quantities, the success of the inputs is based on the value of the crops produced per hectare of land on a plot. In addition, the statistical model controls for soil type, plot size, human capital, and fertilizer. After running the numbers, a positive coefficient from the equation means that the inputs have risk-increasing effects, while a negative coefficient implies risk-decreasing effects.
Each region was affected differently by SWC technologies, and the degree to which the innovations helped them was also variable. Grass strips and soil bunds have more risk-reducing results in low-rainfall areas, while some techniques, such as rainwater harvesting and irrigation, require a certain amount of rainfall to be viable. Even within the same rainfall area, some SWC technologies produced different results. This could be because of differing chemical properties of the soil, availability of nutrients, the needs of a specific crop, or other physical characteristics. What is clear is that it is important to investigate effects of SWC technologies with a specific region in mind in order to determine the best way to reduce risk in the face of climate change.
This statistical model and the results it has already produced will be valuable resources for farmers and policymakers as water resources become more jeopardized and droughts, floods, and other climate-driven events continue to plague the world. SWC technologies have great potential to mitigate the effects of climate change on water resources, and thus improve agricultural yields and food production worldwide even in these unstable ecological times.