9. Optimizing Fertilizer Use within the Context of Integrated Soil Fertility Management in Malawi Patson C Nalivata 1 patienalivata@yahoo.com, Moses W Munthali 2 , Wilson I Makumba 3 , Emmanuel Mbewe 1 and Hastings Manase 1 1 Lilongwe University of Agriculture and Natural Resources, Bunda Campus, P.O. Box 219, Lilongwe, Malawi 2 Bvumbwe Agricultural Research Station, Box 5748, Limbe, Malawi 3 Department of Agricultural Research Services, P.O. Box 30, Lilongwe, Malawi 9.1 Agricultural systems of Malawi 9.1.1 Agro-ecological zones (AEZ) There are four AEZ in Malawi based on altitude: the highlands; the mid-elevation and upland plateau; lakeshore, middle and upper Shire Valley; and the lower Shire Valley (Figure 9.1). The sub-humid tropical agro-ecosystems of Malawi are characterised by a long dry season, with a unimodal rainfall pattern between November and April (Table 9.1) (MoAFS 2012). The highlands AEZ, lying between 1320 and 3000 m above sea level (masl), consist of isolated mountains with extensive highland plateaus found in Nyika, Viphya and Mulanje, while Dedza and Zomba are more isolated. The climate is sub-humid with 84% of the rainfall occurring during December to March. The minimum and maximum mean temperatures range is 9 to 16 and 19 to 25 o C, respectively (Table 9.1). The predominant soils are the leached Latosols, Alfsols and Utilsols. The major crops include maize, pigeonpea, tea, cofee, bananas, pineapples, cassava, potatoes and many more. The mid-elevation and upland plateau AEZ lies between 760 and 1300 masl. This zone consists of escarpments and plateaus running from Karonga in the north to Nsanje in the south. The plateaus have a fat to rolling topography with scattered rock inselbergs. The climate is semi-arid with monthly rainfall range of 1 to 221 mm; and minimum and maximum mean temperatures range of 8 to 17 and 24 to 30 o C, respectively (Table 9.1). The escarpment soils are predominantly shallow latosols. Soils higher in the plateau catenas are deep well drained latosols while poorly drained sand and clay soils dominate in the valleys, locally called dambos. Other important soil groups include Ferrasols, Luvisols, Lixisols, Lithic and Leptosols. The major crops include maize, tobacco, cassava, rice and pulses. The lakeshore, middle and upper Shire Valley AEZ lies between 200 and 760 masl. It is fat to gently undulating, with deep calcimorphic soils in the valleys and the shorelands of Lake Malawi. The Upper Shire River fows through a broad fat valley from the south of Lake Malawi. Mopanosols are found in some areas of the Shire River Valley. The climate is semi- arid. Monthly rainfall ranges from 0 to 339 mm and mean monthly minimum and maximum Fertilizer Use Optimization in Sub-Saharan Africa (2017) Charles S. Wortmann and Keith Sones (eds). Published by CABI. Karonga ADD Mzuzu ADD Kasungu ADD Lilongwe ADD Machinga ADD Blantyre ADD Shire Valley ADD Mzuzu Lilongwe Blantyre Zomba Kasungu Karonga Mchinji Chitipa Salima Lower Shire Valley: < 200 m elevation Lakeshore, Middle & Upper Shire: 200 - 760 m Highlands: > 1300 m Mid-elevation Upland Plateau: 760 - 1300 m T. B ens on; 10 /9 8 MALAWI Nsanje Salima ADD Mzimba Mangochi Figure 9.1: Agro-ecological zones of Malawi. 113