Browsing by Author "Mahoo, Henry F"

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Crop water productivity of an irrigated maize crop in Mkoji sub-catchment of the Great Ruaha River Basin, Tanzania
(Elsevier, 2006-09-16) Igbadun, Henry E; Mahoo, Henry F; Salim, Baanda A; Tarimo, Andrew K. P. R.
Crop water productivity (CWP) is a quantitative term used to define the relationship between crop produced and the amount of water involved in crop production. It is a useful indicator for quantifying the impact of irrigation scheduling decisions with regard to water management. This paper presents CWP quantified from field experimental data. Three fields were cultivated to maize under irrigation during the 2004 dry season in a traditional irrigation scheme in Tanzania. The maize crop was irrigated at eight different seasonal water application depths: 400, 490, 500, 510, 590, 600, 610 and 700 mm, in two of the three fields, and at five water application depths: 400, 590, 600, 610 and 700 mm in the third field. The variation in seasonal water application depth was achieved by skipping the weekly irrigation once after every other irrigation at some pre-defined stages of the crop growth. CWP were computed in terms of …
Optimizing water and nitrogen application for neglected horticultural species in tropical sub-humid climate areas: a case of African eggplant (Solanum aethiopicum L.)
(Elsevier, 2021) Mwinuka, Paul Reuben; Mbilinyi, Boniface P; Mbungu, Winfred B; Mourice, Sixbert K; Mahoo, Henry F; Schmitter, Petra
African eggplant, a traditional and important nutrient-dense crop to Tanzania’s nutrition and food security. However, yields remain low as a result of sub-optimal irrigation and fertilizer practices. To reduce the yield gap, a randomized split-plot design set up with irrigation as a main and nitrogen (N) treatments as a sub-factor. The irrigation regimes were 100 % (I100), 80 % (I80) and 60 % (I60) of crop water requirements whilst nitrogen levels were 250 kg N/ha (F100), 187 kg N/ha (F75), 125 kg N/ha (F50) and 0 kgN/ha (F0). The study evaluated the effect of irrigation water and N on crop growth variables and yield, fruit quality, WUE and NUE. The study showed the importance of combining different irrigation performance indicators which responds to different levels of water and nitrogen to evaluate and assess suitable irrigation and fertilizer strategies for African eggplant. The crop growth variables (plant height and LAI) had a good correlation with fruit yield (R2 = 0.6 and 0.8). The fruit quality was best performed by 100 % water in combination with 75 % N treatment. The best WUE and NUE was attained at 80 % and 100 % levels of water in combination with 75 % N. However, minimizing trade-offs between the various indicators, the optimal application for African eggplant would likely be around 80 % of the total irrigation requirement and 75 % of the N requirement in sandy clay loam soils under tropical sub humid conditions.
Pathways for increasing agricultural water productivity
(2007-01-03) Molden, David; Oweis, Theib Y; Pasquale, Steduto; Kijne, Jacob W; Hanjra, Munir A; Bindraban, Prem S; Bouman, Bas AM; Mahoo, Henry F; Silva, Paula; Upadhyaya, Ashutosh
Water productivity is defined as the ratio of the net benefits from crop, forestry, fishery, livestock, and mixed agricultural systems to the amount of water required to produce those benefits. In its broadest sense it reflects the objectives of producing more food, income, livelihoods, and ecological benefits at less social and environmental cost per unit of water used, where water use means either water delivered to a use or depleted by a use. Put simply, it means growing more food or gaining more benefits with less water. Physical water productivity is defined as the ratio of the mass of agricultural output to the amount of water used, and economic productivity is defined as the value derived per unit of water used. Water productivity is also sometimes measured specifically for crops (crop water productivity) and livestock (livestock water productivity). To feed a growing and wealthier population with more diversified diets will require more water for agriculture on an average annual basis [well established]. Evapotranspiration from agricultural land is estimated at 7,130 cubic kilometers and without increases in water productivity could increase by 60%–90% by 2050 (see chapter 3 on scenarios). Agricultural water withdrawals from natural systems are estimated at 2,664 cubic kilometers, or about 70% of water withdrawn for human purposes. Additional water for agriculture will strain terrestrial and aquatic ecosystems and intensify competition for water resources. Improving physical water productivity in agriculture reduces the need for additional water and land in irrigated and rainfed systems and is thus a critical response to increasing water scarcity, including …