Maize and sesbania production in relay cropping at three landscape positions in Malawi

A D K Phiri,G Y Kanyama-Phiri,S Snapp

doi:10.1023/a:1006263312685

A D K Phiri, G Y Kanyama-Phiri + Show 1 more

Open Access

https://doi.org/10.1023/a:1006263312685

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Abstract

The relay cropping of sesbania (Sesbania sesban) — a N2-fixing legume — with maize (Zea mays) has been proposed as a strategy to increase soil fertility and food production in densely populated areas in southern Africa. We determined the production of relay-cropped maize and sesbania at three landscape positions under researcher-designed and farmer-managed conditions in southern Malawi. Three landscape positions (dambo valley or bottomland, dambo margin with 12% slope) were examined in factorial combination with N sources for maize (no added N, relay-cropped sesbania, and calcium ammonium nitrate fertilizer). Relay cropping of sesbania with maize increased maize grain yield, as compared to unfertilized sole maize in two of three years. Split application of 96 kg N ha−1 as N fertilizer, however, was more effective than sesbania in increasing maize yields. Survival of sesbania seedlings and biomass production of sesbania were greater in the dambo valley and dambo margin than on steep slopes. Maize yields tended to be lower on steep slopes than in the dambo valley and dambo margin areas. Biomass production of sesbania and hence the potential benefits of intercropping sesbania with maize appear greater in the dambo valleys and dambo margins than on steep slopes.

Highlights

Per capita food production has declined in sub-Saharan Africa as a result of rapid population growth and declining soil fertility (Sanchez et al, 1997)
While the capacity of soil to build organic matter may be related to soil texture for the moderate slope landscape positions (Giller et al, 1997), this relationship might not hold for steep slopes such as those in this watershed
The results show that both opportunities and challenges exist for maize and sesbania production under relay cropping at the three landscape positions

Summary

Introduction

Per capita food production has declined in sub-Saharan Africa as a result of rapid population growth and declining soil fertility (Sanchez et al, 1997). Land limitation in Malawi has caused farmers to cultivate dambos, which are bottomlands with poor drainage and seasonally waterlogged (Jiah, 1993; Kanyama-Phiri, 1993). In Malawi, dambos account for 259,000 ha or 12% of the total land area The increase in human population has forced farmers to open fields on steep slopes with shallow, eroded soils that are marginal for arable cultivation (Banda et al, 1994). In Malawi, 45% of the total land area has > 12% slope, which under the Malawi Government land husbandry policy is classified as non-arable (Shaxon et al, 1977)

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