Achieving sustainable agricultural production under farmer conditions in maize-gliricidia intercropping in Salima District, central Malawi

Harrington Nyirenda

doi:10.1016/j.heliyon.2019.e02632

Abstract

Smallholder farmers in Malawi are faced with limited options for climate smart agriculture that would restore soil fertility and increase maize yield. Ten plots of maize intercropped with Gliricidia sepium (MIG) and 10 traditional sole-maize (TSM) plots (0.2 ha each) were studied under farmer conditions from 2013/14 to 2017/18 in Salima District, central Malawi. The aim was to assess performance of MIG on soil fertility restoration and maize yield in degraded agricultural land. G. sepium trimmings were incorporated in MIG in October, January and September of every season. A total of 92 kg N ha-1 was applied in both treatments. Soil and maize yield measurements were done from 10 m x 10 ridges centre of each plot and a paired t-test in R Statistical Software was used for data analysis. Organic matter (p < 0.001) and nitrogen (p < 0.011) were significantly higher in MIG than in TSM while bulk density was significantly lower (p < 0.006) in MIG than in TSM. Higher maize yield was achieved in MIG (5.52 t/ha) than in TSM (1.48 t ha-1) (p < 0.001). Nonsignificant differences between MIG and TSM fields for potassium (p > 0.678) and phosphorus (p > 0.149) suggests that the nutrients were not affected by presence or absence of G. sepium and may not have contributed to differences in yields. Effective gestation period for maize-gliricidia intercropping was at least two years where significant maize yields were first achieved. The findings in MIG provide farmers with sustainable agricultural option for soil health renewal and maize yield increase in central Malawi.

Highlights

Developing countries including those in Africa will be the most affected by the impacts of climate change, increase in population, reduced land cover and the associated unsustainable land use (Kertesz, 2009)
The forest woodlands in the area are dominated by tree species like Pterocarpus rotundifolius, Combretum sp, Bauhinia petersiana, Lannea discolor while the agricultural land is dominated by Faidherbia albida, Philenoptera violacea Stereospermum kunthianum (Nyirenda et al, 2019)
In this study where it was hypothesised that there is no difference in soil nutrient levels in maize intercropped with Gliricida sepium and traditional sole-maize fields; and that there is no difference in maize yield in maize intercropped with Gliricida sepium and traditional sole-maize fields

Summary

Introduction

Developing countries including those in Africa will be the most affected by the impacts of climate change, increase in population, reduced land cover and the associated unsustainable land use (Kertesz, 2009). In Malawi, the main CSA practises are agroforestry, conservation agriculture (CA), afforestation, System of Rice Intensification (SRI) and manure utilisation (Kaczan et al, 2013). These practices improve ecological systems, increase agricultural yields, reduce soil erosion and loss of nutrients. They improve agricultural sustainability by restoring degraded soils (Powlson et al, 2016). The consistent practice of CSA measures contributes to general soil health with pronounced effect on increase on soil organic carbon (Food and Agriculture Organisation of the United Nations, 2013; Powlson et al, 2016; Khatri-Chhetri et al, 2017)

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