Browsing by Author "Home, P. G."

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    Adoption, constraints and economic returns of paddy rice under the system of rice intensification in Mwea, Kenya
    (Elsevier, 2013-11-01) Ndiiri, J. A.; Mati, B. M.; Home, P. G.; Odongo, B.; Uphoff, N.
    A detailed farm survey was conducted in Mwea Irrigation Scheme, Kenya during the 2010/2011 and 2011/2012 main growing seasons to assess the adoption and to quantify the net income advantages of using system of rice intensification (SRI) management over farmer practices (FP) for rice cultivation. Data were collected through questionnaires and structured interviews with farmers who were practicing both SRI and FP methods of rice production on their farms. Under FP, three seedlings aged 28 days are transplanted in respective hills at random spacing. The fields are then flooded with water throughout the growing period. For SRI practice, factors considered as essential were transplanting only one seedling per hill aged 8–15 days with spacing of at least 20cm by 20cm; weeding the crop at least three times at intervals of ten days; and intermittently irrigating the fields. The contributions of using organic manure for fertilization and soil-aeration weed control methods were not considerations in this study since the availability of organic materials and mechanical push-weeders were challenges at the time of study. A total of 40 farmers in 10 units out of the 50 SRI farmers from 18 units of the irrigation scheme were sampled. Benefit–cost relationships were estimated using tabular analysis of all the variable costs and income from production using the survey data. On average, yield under SRI management increased by 1.6t/ha (33%), with seed requirements reduced by 87% and, water savings of 28%. SRI required 9% more labor than FP on average, but this factor of production showed great variability; in three Mwea units, labor costs were reduced by an average of 13%. SRI required 30% more labor for weeding than FP in the first season, but this was reduced to 15% in the second season when push-weeders became available. The results showed SRI giving a higher benefit–cost ratio of 1.76 and 1.88 in the first and second seasons, respectively, compared to 1.3 and 1.35 for FP. The results indicated that SRI practices of planting younger seedlings, with wider spacing and intermittent irrigation, lead to increased paddy rice yields with concomitant rise in the income accruing to farmers. Possibly further increases in net benefit could come with enhanced availability of mechanical weeders and using organic material for fertilization. Up-scaling of SRI in Mwea can be expected to help achieve greater national and household food security
  • Publication
    Publication
    Use of downscaled tropical rainfall measuring mission data for meteorological drought monitoring: case study of Narumoru catchment
    (International Journal of Advances in Engineering & Technology, 2014) Mutuga, K. J.; Nyadawa, Maurice O.; Home, P. G.
    Remotely sensed satellite rainfall data has gained popularity in the recent past, been especially attractive to ungauged catchments or poorly gauged catchments. Tropical Rainfall Measuring Mission (TRMM) data is considered to be most accurate of the satellite derived rainfall data and with the best spatial resolution at 250 x 250 grid. For purposes of hydrological modelling in small catchments, this data is usually downscaled to 1km x 1km grid to bring it closer to point measurement rain gauge data. This study evaluates whether downscaling of TRMM improves its meteorological drought monitoring capacity. TRMM was downscaled from the original 250 x 250 resolution (Approximately 28km x28km) to 1km x 1km resolution based on the relationship between Normalised Difference Vegetation Index (NDVI) and precipitation. Standardized Precipitation Index (SPI) was computed at 3, 6, 9, 12, and 24-month aggregation periods using the downscaled TRMM data (TRMM1km), TRMM at original resolution (TRMM28km) and observed rain gauge data. Analysis of Variance (ANOVA), t-test and data visualization methods were used to determine the similarity of the SPIs from the three datasets. Similarly, correlation analysis was done to determine dependency and modelling capability of the datasets. TRMM1km derived SPI was found to have lower correlation with the (correlation coefficients ranging from 0.34 to 0.42 for the different aggregation periods) rain gauge derived SPI as compared to TRMM28km derived SPI which had correlation coefficients ranging from 0.57 to 0.66. From analysis of variance, there was no significant difference between the SPI computed from TRMM and from that computed from rain gauge data. Additionally, SPI visualization indicated similar drought patterns were identified by both TRMM and rain gauge computed SPIs. Therefore, it was concluded that TRMM data, whether downscaled or at original resolution are useful for meteorological drought monitoring in Narumoro catchment