Browsing by Author "Ngetich, Felix K."

Now showing 1 - 3 of 3
  • Publication
    Publication
    Homogeneous land-use sequences in heterogeneous small-scale systems of Central Kenya: Land-use categorization for enhanced greenhouse gas emission estimation
    (Elsevier, 2022) Mairura, Franklin S.; Musafiri, Collins M.; Kiboi, Milka N.; Macharia, Joseph M.; Ng'etich, Onesmus K.; Shisanya, Chris A.; Okeyo, Jeremiah M.; Okwuosa, Elizabeth A.; Ngetich, Felix K.
    The current understanding of the link between land management practices and GHG (greenhouse gas) emissions is limited in the small-scale farm sector of sub-Sahara regions due to insufficient or fragmented land-use data. Land-use categories recognized in the national GHG inventories in Kenya are coarse. Therefore, they do not adequately account for the diversity in small-scale land uses. Characterization of land-use and knowledge of key drivers of land-use change is necessary to improve national GHG inventories in the SSA (Sub-Sahara Africa) region. We implemented a cross-sectional survey to characterize land-use and determine factors which influenced changes in land use within small-scale farms of Tharaka-Nithi County, Kenya. We sampled 300 farmers using multistage sampling and collected crop sequence recall data at plot level for three years (seven seasons). We grouped crop sequences into clusters using the ‘TraMineR’ R package. We derived four clusters including banana, tea, and declining fallows (cluster 1, 19.2% of plots), cereal-legume systems (cluster 2, 55.1%), fodder (cluster 3, 11.7%) and coffee (cluster 4, 14.0%). We observed higher N application rates in perennial cropping systems, than in annual crops, including cereal-legume systems. We observed that farmers in higher potential agro-ecological zones, male-managed farms, with higher per capita land area, higher remittances and higher total house-hold incomes, were associated with a higher propensity to adjust crop enterprises, leading to more unstable land-use sequences. Contrariwise, farmers with higher education, credit access, secure land tenure, increasing slope, good soil fertility, and longer farming experiences recorded a lower propensity to adjust their land uses, resulting in more stable crop sequences. Farmer socio-demographic characteristics influenced land-use change, which is directly linked with soil GHG emissions. Our findings propose the adoption of Tier II GHG quantification approaches which disaggregate between annual and perennial crop enterprises. GHG emissions are likely to be more generalizable in stable perennial crop systems than annual systems. Thus, better disaggregation of GHG sampling in annual crop systems is needed due to high diversity in crop and soil fertility management, and the dynamic nature of C and N cycling in these systems.
  • Publication
    Publication
    Homogeneous land-use sequences in heterogeneous small-scale systems of Central Kenya: Land-use categorization for enhanced greenhouse gas emission estimation
    (Elsevier, 2022-02-09) Mairura, Franklin S.; Musafiri, Collins M.; Kiboi, Milka N.; Macharia, Joseph M.; Ng'etich, Onesmus K.; Shisanya, Chris A.; Okeyo, Jeremiah M.; Okwuosa, Elizabeth A.; Ngetich, Felix K.
    The current understanding of the link between land management practices and GHG (greenhouse gas) emissions is limited in the small-scale farm sector of sub-Sahara regions due to insufficient or fragmented land-use data. Land-use categories recognized in the national GHG inventories in Kenya are coarse. Therefore, they do not adequately account for the diversity in small-scale land uses. Characterization of land-use and knowledge of key drivers of land-use change is necessary to improve national GHG inventories in the SSA (Sub-Sahara Africa) region. We implemented a cross-sectional survey to characterize land-use and determine factors which influenced changes in land use within small-scale farms of Tharaka-Nithi County, Kenya. We sampled 300 farmers using multistage sampling and collected crop sequence recall data at plot level for three years (seven seasons). We grouped crop sequences into clusters using the ‘TraMineR’ R package. We derived four clusters including banana, tea, and declining fallows (cluster 1, 19.2% of plots), cereal-legume systems (cluster 2, 55.1%), fodder (cluster 3, 11.7%) and coffee (cluster 4, 14.0%). We observed higher N application rates in perennial cropping systems, than in annual crops, including cereal-legume systems. We observed that farmers in higher potential agro-ecological zones, male-managed farms, with higher per capita land area, higher remittances and higher total house-hold incomes, were associated with a higher propensity to adjust crop enterprises, leading to more unstable land-use sequences. Contrariwise, farmers with higher education, credit access, secure land tenure, increasing slope, good soil fertility, and longer farming experiences recorded a lower propensity to adjust their land uses, resulting in more stable crop sequences. Farmer socio-demographic characteristics influenced land-use change, which is directly linked with soil GHG emissions. Our findings propose the adoption of Tier II GHG quantification approaches which disaggregate between annual and perennial crop enterprises. GHG emissions are likely to be more generalizable in stable perennial crop systems than annual systems. Thus, better disaggregation of GHG sampling in annual crop systems is needed due to high diversity in crop and soil fertility management, and the dynamic nature of C and N cycling in these systems.
  • Publication
    Publication
    Quantifying Effects of Selected Soil Fertility Management Techniques on Water Use Efficiency in the Central Highlands of Kenya
    (International Journal of Plant & Soil Science, 2019-10-04) Etemesi, Beryl; Ngetich, Felix K.; Kiboi, Milka N.; Zeila, Abdi; Adamtey, Noah; Mugendi, Daniel N.
    Declining rainfall distribution and variability lead to low soil moisture amounts and high evapotranspiration rates reducing water use efficiency that negatively affects crop productivity. Various soil fertility management techniques have been put in place to improve soil fertility status, but there is little attempt to asses their effects on water use efficiency and grain yields. The overall objective of the study was to quantify the effects of soil fertility management techniques on water use efficiency in the Central Highlands of Kenya. The experiment was laid out in a randomised complete block design with fourteen treatments replicated four times. Treatments were sole mineral fertilizer (Rf), crop residues + mineral fertilizer (RMf), crop residues + mineral fertilizer + animal manure (RMfM), crop residue + Tithonia diversifolia + animal manure (RTiM), crop residue + Tithonia diversifolia + rock phosphate (RTiP). Data on yield and water use efficiency was analysed using statistical analysis systems software version 9.2 at P=0.05. We observed significant (P<.0001) effect of the treatment on biomass water use efficiency during the short rains 2017, however, there was no significant effect of the treatments on grain water use efficiency because of the frequent dry spells that occurred during the study period. Soil fertility management techniques had a significant effect on grain yield at P<.0001 during the study period. Yields increased significantly (P<0001) under Rf, RMf, RMfM RTiM and RTiP by 90, 110, 120, and 176%, respectively. Water use efficiency also increased significantly under Rf, RMf, RMfM RTiM and RTiP by 200, 140, 180, 129, and 176%, respectively compared to the control. From the study, the combination of organic inputs and mineral fertilisers enhanced water use efficiency and yield hence provides a preferred practise for improved water use efficiency and yield increase.