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Late planted maize: a source of low productivity for farmers in subhumid areas of Zimbabwe

S.R. Waddington1 and E.M. Shumba2

1 CIMMYT Maize Programme, P.O. Box MP154, Mount Pleasant
Agronomy Institute, DR&SS, PO Box 8100, Causeway, Harare, Zimbabwe

Early planting of maize, Zea mays, has long been known to increase grain yield in Zimbabwe. Previous research has examined dry-planting and reduced tillage to allow earlier planting (1,2). However, most smallholder (communal area) farmers in subhumid parts of Zimbabwe continue to plant some of their maize late. Among other factors, this is due to poor access to animal draught power for timely seedbed preparation and the need to manage risk associated with erratic rainfall.


Diagnostic surveys and an on-farm experiment were undertaken between 1983 and 1990 to determine the area of maize planted late by smallholder farmers in those areas, the grain yield losses encountered and the crop management or climatic reasons for low yield. The experiment consisted of three planting dates (approximately 18 days apart), three levels of nitrogen (N) fertiliser and two maize hybrids under constant high management at four on-farm sites over three years (1983/84-1985/86) in Mangwende, a representative communal area.

Results and discussion

A survey of 10 communal areas in 1989/90 estimated that 175 000 ha of maize is planted late (24 or more days after the start of maize plantings) each year by smallholders in subhumid parts of Zimbabwe, 32.9% of the total subhumid maize area in Zimbabwe.

The on-farm experiment showed that a planting delay of 20 days reduced grain yield from 6.6 t/ha to 4.6 t/ha, and after a delay of 36 days to 3.4 t/ha (P<0.01), under constant inputs. Surveys of farmers' fields during 1987/88 and 1988/89 in Mangwende showed delayed planting reduced grain yield from an average of 4.9 t/ha for the first 25% of plantings to as little as 1.1 t/ha (last 25% of plantings). This was equivalent to 300 000 t of maize grain foregone each year in subhumid parts of Zimbabwe because of late planting.

The late planted maize crop developed more quickly prior to tasselling than early plantings and this represented a lower grain yield potential for late planted crops. Input and management differences likely to be major contributors to the low grain yield of late-planted maize were: (i) relayed application of basal NPK fertiliser (by three leaves) and topdressed N fertiliser (two leaves later); (ii) reduced rates of the basal and topdressed fertiliser (applied at just 60% of the rate given to early plantings), and (iii) more weed competition in late plantings because of late first weeding.

These results led to the following proposed technologies to improve the productivity of late-planted maize in Zimbabwe: (i) earlier maturity maizes with better response to intermediate levels of N and P fertiliser and tolerance to weeds; (ii) appropriate amounts and timings of N and P fertilisers, and (iii) alley crop systems with perennial legumes.


Metelerkamp, H.H.R. 1989. In: Cropping in the Semiarid Areas of Zimbabwe. (AGRITEX, DR&SS and GTZ: Harare). pp. 190-315.

Shumba, E. 1989. Farming Systems Bulletin, Eastern and Southern Africa 1, 1-13.

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