Browsing by Author "Tian, G."
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- Integrated soil management for the savanna zone of W. Africa: legume rotation and fertilizer NCarsky, R. J.; Oyewole, B.; Tian, G. (Springer Science+Business Media B.V., Formerly Kluwer Academic Publishers B.V., 1999)Integrated soil management with leguminous cover crops was studied at two sites in the northern Guinea savanna zone of northern Nigeria, Kaduna (190 day growing season) and Bauchi (150 days). One-year planted fallows of mucuna, lablab, and crotalaria were compared with natural grass fallow and cowpea controls. All treatments were followed by a maize test crop in the second year with 0, 30, or 60 kg N/ha as urea. Above ground legume residues were not incorporated into the soil and most residues were burned early in the dry season at the Kaduna site. Legume rotation increased soil total N, maize growth in greenhouse pots, and dry matter and N accumulation of maize. Response of maize grain yield to 30 kg N ha1 as urea was highly significant at both sites and much greater than the response to legume rotation. The mean N fertilizer replacement value from legume rotation was 14 kg N/ha at Kaduna and 6 kg N/ha at Bauchi. W ith no N applied to the maize test crop, maize grain yield following legume fallow was 365 kg/ha higher than natural fallow at Bauchi and 235 kg/ha higher at Kaduna. The benefit of specific legume fallows to subsequent maize was mostly related to above ground N of the previous legume at Bauchi, where residues were protected from fire and grazing. At Kaduna, where fallow vegetation was burned, maize yield was related to estimated below ground N. The results show that legume rotation alone results in small maize yield increases in the dry savanna zone.
- Long-term effects of fallow systems and lengths on crop production and soil fertility maintenance in West AfricaTian, G.; Kang, B. T.; Kolawole, G. O.; Idinoba, P.; Salako, F. K. (2005)This article analyzes the results of a twelve year farm trial in West Africa examining the transition from shifting cultivation using a natural vegetation fallow, a leguminous cover crop fallow, and an woody alley crop fallow. The research determines that the cover crop and the alley crop fallows offer superior performance after one year. The cover crop is effective in increasing maize yield while the alley crop makes a more substantive contribution to soil organic carbon. If allowing a two year fallow, the natural vegetation also restores productivity and soil carbon. Thus, the paper provides evidence for farmers to pursue a cover cropping or alley cropping as an a more immediately productive return for a fallowed system in West Africa.
- Nitrogen fertilizer replacement indexes of legume cover crops in the derived savanna of West AfricaTian, G.; Kolawole, G. O.; Kang, B. T.; Kirchhof, G. (Netherlands: Kluwer Academic Publishers, 2000)Using a three year trial in Nigeria, this article examines the effectiveness of leguminous cover crops on maize yield in West Africa. Testing multiple types of cover crops, the study universally demonstrates the cover crops conserve nitrogen and result in improvements for maize yield in both drier and wetter years. While the cover crop was more effective in improving nitrogen in wetter conditions, yields still improved during the drier year with the cover crop.