Water Use Efficiency of Maize (<i>Zea mays</i> L.) Crop under Selected Soil and Water Conservation Practices along the Slope Gradient in Ruzizi Watershed, Eastern D.R. Congo
Espoir Mukengere Bagula,
Jackson-Gilbert Mwanjalolo Majaliwa,
Twaha Ali Basamba,
Jean-Gomez Mubalama Mondo,
Bernard Vanlauwe,
Geofrey Gabiri,
John-Baptist Tumuhairwe,
Gustave Nachigera Mushagalusa,
Patrick Musinguzi,
Sarah Akello,
Anthony Egeru,
Moses Makooma Tenywa
Affiliations
Espoir Mukengere Bagula
Faculty of Agriculture and Environmental Sciences, Université Evangélique en Afrique, Bukavu P.O. Box 3323, Democratic Republic of the Congo
Jackson-Gilbert Mwanjalolo Majaliwa
College of Agriculture and Environmental Sciences, Makerere University, Kampala P.O. Box 16811, Uganda
Twaha Ali Basamba
College of Agriculture and Environmental Sciences, Makerere University, Kampala P.O. Box 16811, Uganda
Jean-Gomez Mubalama Mondo
Faculty of Agriculture and Environmental Sciences, Université Evangélique en Afrique, Bukavu P.O. Box 3323, Democratic Republic of the Congo
Bernard Vanlauwe
International Institute of Tropical Agriculture, Nairobi 30772-00100, Kenya
Geofrey Gabiri
Department of Geography, Faculty of Arts and Humanities, Kyambogo University, Kyambogo P.O. Box 1, Uganda
John-Baptist Tumuhairwe
College of Agriculture and Environmental Sciences, Makerere University, Kampala P.O. Box 16811, Uganda
Gustave Nachigera Mushagalusa
Faculty of Agriculture and Environmental Sciences, Université Evangélique en Afrique, Bukavu P.O. Box 3323, Democratic Republic of the Congo
Patrick Musinguzi
College of Agriculture and Environmental Sciences, Makerere University, Kampala P.O. Box 16811, Uganda
Sarah Akello
College of Agriculture and Environmental Sciences, Makerere University, Kampala P.O. Box 16811, Uganda
Anthony Egeru
College of Agriculture and Environmental Sciences, Makerere University, Kampala P.O. Box 16811, Uganda
Moses Makooma Tenywa
College of Agriculture and Environmental Sciences, Makerere University, Kampala P.O. Box 16811, Uganda
Maize (Zea mays L.) productivity is constrained by water shortages in the predominantly rainfed agriculture of the tropical semi-arid Ruzizi Plain, in the eastern Democratic Republic of Congo (DRC). The region is characterized by a high seasonal and inter-annual rainfall variability and a frequent occurrence of consecutive dry days within growing seasons. Consequently, planning water utilization in rainfed agriculture has become complex, as appropriate soil water conservation (SWC) practices are lacking among most smallholder farmers. Identifying practices that increase water use efficiency (WUE) along the slope gradient is crucial for supporting maize production in the region. In this study, we assessed, for three growing seasons, the effectiveness of two SWC practices (tied ridges and Zai pits) in improving the WUE of two maize varieties along three slope gradients (0–2, 2–8, and 8–15%) in the tropical semi-arid Ruzizi Plain. In this area, rainfall amounts (142–289 mm) were consistently below the evapotranspiration demands (356–533 mm) across the three growing seasons. Tied ridges recorded the highest grain yield (2.16 t ha−1) and WUE (15.23 kg mm−1), especially at low slopes, when compared to Zai pits and conventional tillage. For all SWC practices, WUE decreased with the slope gradient (p 2 = 58.5%). In conclusion, tied ridges showed potential for improving maize WUE and yield in the water-deficient conditions that characterize the Ruzizi Plain, and could be promoted to improve the maize productivity among smallholder farmers.
