Competing uses, dynamics, and production and utilization constraints of crop residues in East Africa: Implications for conservation agriculture 1 Kindu Mekonnen, 2 Gedion Rachier, 3 Dagnachew Lule, 4 Mesfin Bahta, 1 Diego Valbuena, 1 Alan Duncan and 1 Bruno Gerard International Congress on Water 2011: Integrated Water Resources Management in Tropical and Subtropical Drylands , Mekelle, Ethiopia, 19-26 September 2011 1 International Livestock Research Institute (ILRI), P.O. Box 5689, Addis Ababa, Ethiopia . 2 Kenya Agricultural Research Institute (KARI), P.O. Box 169, Kakamega, Kenya 3 Bako Agricultural Research Center (BARC), P.O. Box 03, Bako, Ethiopia 4 Sirinka Agricultural Research Center (SARC), P.O. Box 74, Woldia, Ethiopia

3. Research findings and discussion 3.1. Crops and crop residues Sorghum- Kobo Teff- Nekemte Beans- Kakamega Crop types Kobo Nekemte Kakamega cereals teff, sorghum, maize maize, teff, sorghum, finger millet, wheat, barley, oat maize, finger millet, sorghum legumes chickpeas faba beans, field peas, soya beans common beans, climbing beans and soya beans oil crops nd noug bambara nuts, ground nuts hort. crops vegetables (onion) vegetables (beet root, potato, anchote) vegetables (sweet potato), cassava, banana, tea, sugarcane

Sorghum stover Teff straw Maize stover Crop residues Kobo Nekemte Kakamega cereals teff straw, sorghum stover, maize stover teff straw, maize stover, barley straw, wheat straw, finger millet straw maize stover, maize cobs, finger millet straw legumes chickpea haulms and husks faba bean haulms and husks common and climbing beans oil crops nd nd groundnut haulms, hort. crops nd nd sugarcane tops, sweet potato vines, banana stems and leaves, vegetable stalks

Area coverage of crops and hh growing them in the main rainy season at the three east African sites. Note: nd-there is no data, and np- there is no practice Cropping systems Land allocated (ha) Area coverage (%) HHs growing (%) Kobo cereals 963 97 75 legumes 19 2 37 oil crops nd nd nd hort. crops 5 1 8 fallow np np np Nekemte cereals 581 74 78 legumes 13 2 46 oil crops 54 7 59 hort. crops 24 3 85 fallow 107 14 71 Kakamega cereals 1238 31 53 legumes 859 22 89 oil crops nd nd nd hort. crops 1776 44 75 fallow 133 3 nd

3.2. Cropping technologies Area (%) Kobo Nekemte Kakamega tillage by tractor 6.43 (11.4) np 14.4 (17.7) tillage by animal 99.5 (1.4) 100.0 (0.0) 63.8 (28.9) new seed 2009 25.2 (36.5) 28.3 (32.0) 89.4 (4.2) chemical fertilizer 1.8 (2.9) 72.8 (19.4) 78.8 (13.8) manure application 9.3 (14.1) 22.3 (26.0) 54.4 (28.2) hand weeding 100.0 (0.0) 97.9 (6.0) 97.8 (3.5) herbicide application 34.1 (26.8) 51.1 (29.4) 2.8 (4.0) pesticide application 25.3 (38.4) 39.5 (33.0) 4.1 (3.2) thresher use np 4.0 (0.0) 1.0 (0.0) chopper use for feed np np 2.3 (2.3) Data represent means with standard deviations in parentheses. The number of villages (n) is 8 for each of the three east African sites.

3.3. Competing uses of crop residues 0 20 40 60 80 100 120 Kobo Nekemte Kakamega other uses households fuel stall feeding sell from home and field grazing by animals left as mulch

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