Student Short Biography:
Eng. Dr. Jedidah Wandia Maina, holds a PhD in Climate Change and Adaptation from the University of Nairobi, 2020. She also holds a Master’s degree (Msc.) in Environmental and Biosystems Engineering from the University of Nairobi and a Bachelor of Science (Bsc. Hons.) degree in Agricultural Engineering from the same University. Her Master’s degree was to establish the emissions and performance characteristics of a compression ignition engine operated on biodiesel from Cape Chestnut. She holds a Certificate in Energy Planning and Sustainable Development from the University of Oslo, Norway.
Eng. Dr. Jedidah Maina is a registered Professional Engineer (PE) in the field Agricultural Engineering with the Engineers Board of Kenya (EBK), Corporate Member of The Institution of Engineers of Kenya (IEK) and a member of the Kenya Society of Environmental, Biological and Agricultural Engineers (KeSEBAE). Eng. Dr. Jedidah Maina has over 20 years’ experience in Engineering Consultancy in the design and supervision of plumbing and drainage works, water reticulation, ventilation and air conditioning works, firefighting works, solar heating works and other related mechanical works in the Building Services industry. Since January 2015, Eng. Dr. Jedidah Maina has been a member of the academic staff at the Technical University of Kenya (TUK) in the Department of Biosystems and Environmental Engineering. In TUK she is involved in teaching, research and administrative duties where at one time she was the acting chair of the department. Eng. Dr. Jedidah Maina’s main area of research is in Engineering and Environment. The thematic areas of interest include Renewable Energy (Biofuels), Climate Change (Rainwater Harvesting, Supplemental Irrigation, Land Use and Land Cover Changes (LULCC), and Analysis of Rainfall and Temperature Trends). She also has research interest in the thematic areas of Engineering Hydrology and Water Resources Engineering.
Project Summary
Thesis Title: RAINFALL AND TEMPERATURE TRENDS, FARMING PATTERNS AND RAINWATER HARVESTING TECHNOLOGIES IN KIENI SUB-COUNTY.
Thesis Abstract
The study area was in Tigithi Sub-location of Kieni constituency in Nyeri County which is an Arid and Semi-Arid zone with unreliable rainfall and high temperatures. The area experiences a bimodal rainfall pattern. The study analyzed seasonal average rainfall (1984-2013) and seasonal average maximum temperature (1983-2012) trends to detect the presence of climate change. To investigate changing farming patterns from 1987 to 2017, a sectional survey was conducted in 2017 in which 400 households participated. The percentage change detection in land use and land cover in the area was accomplished with the use of remote sensing and GIS. The study engaged the community in harvesting rain water which was used to grow Kale as supplemental irrigation whose results were compared to the same crop grown depending fully on the rains. Kale was grown in three seasons whereby each season produced a rain-fed and supplemental irrigated Kale. The growing of Kale involved farmer 1 and farmer 2
Analysis of seasonal average rainfall and average maximum temperature trends was calculated by the Mann-Kendall test together with Sen’s slope Estimator application using the MAKESENS template in Excel from the Finish Meteorological Institute. The March April May (MAM) rainfall season had positive average Mann-Kendall test value of 0.33 and positive Sen’s slope average value of 0.32 which was upward rainfall trend. The OND rainfall season had an average Mann-Kendall test value of -0.06 and an average Sen’s slope value of 0.02. The OND average rainfall results showed a decreasing rainfall trend. The highest mean rainfall for both seasons was experienced in April with over 115mm.
The MAM and OND seasonal maximum temperature returned positive Man-Kendall test and Sen’s slope values. The average Mann-Kendal test for MAM season was 1.09 while the average Sen’s slope for the season was 0.016. The same tests for OND returned the values of 1.55 and 0.025 as the results for Mann-Kendall and Sen’s slope respectively. The MAM and OND average maximum temperature trend analysis showed an upward trend. The highest mean temperature recorded for both MAM and OND season was in March with maximum temperature of 26.50C.
The investigation of the changing farming practices in the study area as a result of declining average seasonal rainfall and increasing seasonal temperature, a sectional survey was conducted through administration of questionnaires and the collected data analyzed with SPSS Statistics Version 23 program. The survey established that more than 70% of the farmers settled in the area from the 1990s and about 70% of them own farms of size of between 1 and 5 acres. Maize, potatoes and beans were the crops grown in the 1980s at 100%, 93% and 67.7% of the respondents respectively but reported to have declined in 2017 by 10.2%, 4.5% and 26.2% respectively. There was a significant rise in the growing of horticultural crops at about 30% from a low of 2% in the 1980s. The farming of Napier grass increased by almost 22% from low of 4%.
Land use land cover changes in the study area for the 1987-2017 period involved downloading and processing Landsat images of 1987, 1995, 2002, 2010 and 2017. Land use and land cover in the area was categorized into the following six classes: bare areas, bushlands, farmlands, forest, grasslands and water bodies. The percentage cover of farmlands classification increased significantly by over 160% in 2017 from 1987. The forest percentage cover declined by almost 50% over the same period. Farming practices have been changing due to climate change from growing wholly rain-fed crops like maize and beans to growing horticultural crops and Napier grass.
Brassica oleracea (1000 headed kale) was grown both as rain-fed and under supplemental irrigation for three seasons each comprising of 14 weeks. The rain-fed and supplemental irrigated total Kale yields were analyzed using Analysis of Variance (ANOVA) with a set significant level
of 5%. The famer 1’s rain-fed Kale had a total yield of 18.5t /ha and the Kale grown under supplemental irrigation had total yields of 25t/ha an increase of 35%. Famer 2’s both rain-fed and supplemental irrigated Kale had total yields of 16.4t/ha and 26.4t/ha a 62% increase in yields.
The increasing seasonal temperature and decreasing rainfall in Kieni as a result of climate change and climate variability occasioned changes on how farming was conducted. Horticultural crops farming was being practiced by more farmers. More farmers were getting involved with zero grazing as evidenced by the increase in growing of Napier grass.
Local farmers can increase resilience in the face of climate change by adapting rainwater harvesting for supplemental irrigation which will increase crop yields by as much as 60% as in this study. The crops grown with supplemental irrigation will also provide soil cover reducing soil erosion and the dead foliage providing humus to the soil.
Key words: Climate Change, GIS, MAKESENS, Land Use Land Cover, Water Harvesting