Your search found 4 records
(Location: IWMI-HQ Call no: P 7344 Record No: H037052)
2 Jama, B.; Kwesiga, F.; Niang, A. 2006. Agroforestry innovations for soil fertility management in Sub-Saharan Africa: Prospects and challenges ahead. In Garrity, D.; Okono, A.; Grayson, M.; Parrott, S. (Eds.). World agroforestry into the Future. Nairobi, Kenya: World Agroforestry Centre. pp.53-60.
(Location: IWMI-HQ Call no: 634.99 G000 GAR Record No: H039074)
(Location: IWMI HQ Call no: e-copy only Record No: H044818)
(0.16 MB)
Soil quality deterioration and consequent reduced productivity characterize the Vertisols in the highlands of Ethiopia. The problem is exacerbated by lack of appropriate land preparation alternatives for the major crops in the area. A field experiment was carried out for 6 years (1998–2003) at Caffee Doonsa in the central highlands of Ethiopia to evaluate alternative land preparation methods on the performance of wheat (Triticum durum Desf.), lentil (Lens culinaries Medik L) and tef (Eragrostis tef L) grown in rotation. Four methods of land preparation (broad bed and furrow, green manure, ridge and furrow and reduced tillage) were arranged in a randomized complete block design with three replications on permanent plots of 22 m by 6 m. Broad bed and furrow significantly increased the grain yield of lentils by 59% (from 1029 to 1632 kg ha1) as compared to the control. On the other hand, reduced tillage resulted in the highest grain yield of wheat (1862 kg ha1) and tef (1378 kg ha1) as compared to 1698 kg ha1 of wheat and 1274 kg ha1 of tef for the control although the increase was not statistically significant. A gross margin analysis showed that BBF is the most profitable option for lentil with 65% increase in total gross margin. On the other hand, RT resulted in 11 and 8% increase in gross margin of wheat and tef, respectively as compared to the control. Based on the agronomic and economic performances best combinations of crop and land preparation method were: lentil sown on broad bed and furrow, and wheat and tef sown after reduced tillage.
(Location: IWMI HQ Call no: e-copy only Record No: H049124)
(3.06 MB)
Increasing water scarcity and Asia’s rapid economic and social development, specifically the growing demand for animal products and biofuels, is forcing farmers to transform their traditional lowland double-rice cropping systems [R-R] to mixed lowland-upland systems where upland crops such as aerobic rice [R-A] or maize [R-M] are grown instead of paddy rice during the dry period. Such changes have implications on the C and N cycling in the soil-plant system, including major shifts in soil greenhouse gas (GHG) emissions from CH4 to N2O once paddies are used for upland cropping. Moreover, soil organic carbon stocks are decreasing, thereby jeopardizing soil fertility. In this study, we investigated if straw residue incorporation and/or catch crop cultivation impairs the greenhouse gas footprint of diversifying rice cropping systems and thus, presents an alternative to open-field straw burning and intensive mineral N fertilization. For this, we calculate annual global warming potentials (GWP) and yield-scaled GWPs of three different rice systems (R-R: rice-rice, R-A: rice- aerobic rice, R-M: rice maize) without (control) or with additions of straw (+6 Mg ha-1 [S]) or + straw + mungbean as catch crop ([M + S]) on the basis of high-temporal-resolution GHG emissions (CH4 and N2O), and measurements of yield parameters. The field trial was carried out at the International Rice Research Institute (IRRI), Philippines, covering two full years. Although dry season N2O emissions increased twice- to threefold in the diversified systems (R-A, R-M), the strong reduction of CH4 emissions during this period resulted in significantly lower annual yield-scaled GWP as compared to the traditional R-R system. The same pattern was observed after application and incorporation of organic material (straw and mungbean), but led to higher substrate availability for methanogens during the following season. Therefore, the GWP was 9–39% higher in treatments including straw incorporation as compared to a control treatment without organic substrate amendments. Additional incorporation of mungbeans further increased GWPs, whereby the increment was highest in R-R rotation (88%) and lowest in R-M rotation (55%), with annual GHG emissions of 11.8 and 5.6 Mg CO2-eq ha-1, respectively. Our study shows that the yield-scaled GWP, as well as irrigation water demand, is lowest for rice-maize (R-M) cropping systems, followed by R-A and R-R systems. This ranking persists even with the incorporation of crop residues, a requirement for farmers as the ban of open-field burning is increasingly enforced. Our work also calls for a refinement of IPCC emission factors for lowland-upland rotations and the inclusion of the land-preparation period within the GHG balance of rice cropping systems.
Powered by DB/Text
WebPublisher, from