Browsing by Author "Senthilkumar, Kalimuthu"

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    Potential of Cultivating Dry Season Maize along a Hydrological Gradient of an Inland Valley in Uganda
    (Agronomy, 2019) Alibu, Simon; Neuhoff, Daniel; Senthilkumar, Kalimuthu; Becker, Mathias; Köpke, Ulrich
    Inland valley wetlands with higher soil moisture than surrounding uplands o er a yet unexplored opportunity for increasing maize production in East Africa. For three consecutive years, we conducted field experiments to assess the potential of an inland valley in Central Uganda for producing dry season maize. A randomized complete block design was used with six treatments including farmer’s practice, unfertilized control, organic and inorganic fertilizer applications at high and low rates. These were repeated four times at each of the three hydrological positions of the inland valley (fringe, middle, and center). The maize grain yield of 3.4 t ha􀀀1 (mean across treatments and years) exceeded the national yield average by 42%. High and sustained soil moisture in the center position of the inland valley was associated with the highest grain yields irrespective of the year. Due to soil moisture deficit in the fringe and middle hydrological positions, grain yields were not only lower but also highly variable. Intensive manuring with a combination of green and poultry manure produced high yields that were comparable to those with mineral fertilizers (both at 120 kg N ha􀀀1). Lower amounts of either mineral or organic fertilizer (60 kg N ha􀀀1) provided no yield gain over the unfertilized control. Inland valley wetlands, thus, o er promise for farmers to harvest an additional maize crop during the dry season, thus contributing to farm income and regional food security.
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    Quantifying rice yield gaps and their causes in Eastern and Southern Africa
    (Journal of Agronomy and Crop Science, 2020) Senthilkumar, Kalimuthu; Rodenburg, Jonne; Dieng, Ibnou; Vandamme, Elke; Silas Sillo, Fitta; Johnson, Jean-Martial; Rajaona, Arisoa; Amielle Ramarolahy, Jemima; Gasore, Rene; Abera, Bayuh Belay; Kajiru, Geophrey J.; Mghase, Jerome; Lamo, Jimmy; Rabeson, Raymond; Saito, Kazuki
    The demand for rice in Eastern and Southern Africa is rapidly increasing because of changes in consumer preferences and urbanization. However, local rice production lags behind consumption, mainly due to low yield levels. In order to set priorities for research and development aimed at improving rice productivity, there is a need to characterize the rice production environments, to quantify rice yield gaps—that is, the difference between average on-farm yield and the best farmers’ yield—and to identify causes of yield gaps. Such information will help identifying and targeting technologies to alleviate the main constraints, and consequently to reduce existing yield gaps. Yield gap surveys were conducted on 357 rice farms at eight sites (19–50 farmers per site) across five rice-producing countries in Eastern and Southern Africa—that is Ethiopia, Madagascar, Rwanda, Tanzania and Uganda—for one or two years (2012–13) to collect both quantitative and qualitative data at field and farm level. Average farm yields measured at the eight sites ranged from 1.8 to 4.3 t/ha and the average yield gap ranged from 0.8 to 3.4 t/ha. Across rice-growing environments, major causes for yield variability were straw management, weeding frequency, growth duration of the variety, weed cover, fertilizer (mineral and organic) application frequency, levelling and iron toxicity. Land levelling increased the yield by 0.74 t/ha, bird control increased the yield by 1.44 t/ha, and sub-optimal management of weeds reduced the yield by 3.6 to 4.4 t/ha. There is great potential to reduce the current rice yield gap in ESA, by focusing on improvements of those crop management practices that address the main site-specific causes for sub-optimal yields.