AVAILABLE OPTIONS FOR SOIL FERTILITY MANAGEMENT FOR
RESETTLED A1 FARMERS IN ZIMBABWE
F. Mtambanengwe*, H. Nezomba, G. Manzeke, J. Rurinda, C.Chagumaira, T.Gwandu, T. Mtangadura, G. Kanonge, N. Kurwakumire and T. Mashavave
Soil Fertility Consortium for Southern Africa (SOFECSA), Department of Soil Science &
Agricultural Engineering, P.O. Box MP 167, Mount Pleasant, HARARE
The agrarian reforms of the 1980’s through to 2000s by the Government of Zimbabwe brought with it the opening up of ‘new’ land for arable agriculture, bringing along with it hopes for increased farm-level productivity among many. However, with close to 70% of the country being covered by granitic sandy soils, much of the anticipated productivity associated with new agricultural lands may be not realized without employing science-based technologies. The soils are known for their inherently low nutrient supply capacity, high acidity and associated low organic matter contents, and require different management strategies to bring them into productivity. Recent findings by the Soil Fertility Consortium for Southern Africa (SOFECSA) working with smallholder farming communities of Hwedza (old communal area) and Makoni (resettlement), under similar environments may be extrapolated to benefit newly resettled A1 farmers improve crop yields and maintain environmental integrity. Under its research for development initiatives, SOFECSA promotes use of integrated soil fertility management (ISFM) technologies among smallholder farmers to enhance crop productivity under challenging soils. The ISFM options, which included combinations of organic and inorganic (mineral) fertilizer inputs, crop rotations and intercrops with beneficial crops such as legumes, green-manuring and/or indigenous legume fallows (indifallows) were tailored as best-fit options for different farmer resource groups. Examples of resource-constrained farmers with no access to cattle manure, but used woodland litter or composted crop residues in combinations with some mineral fertilizer inputs managed to raise their maize yield by between 40 to >100%, from the normal <500 kg ha-1 to >1.5 t ha-1, on sandy soils with <10% clay content. Similarly, use of legume green manures significantly increased maize grain yields and lowered the demands of mineral fertilizer use by half over two seasons. One emerging conclusion was that the granite-derived sandy soils, regardless of whether there were virgin soils or had previously been under extensive management, require some level of external nutrient resource inputs to maintain productivity, and ISFM offers one such entry point.
Link to this article:http://www.uzpublications.ac.zw