Effects of improved pigeonpea fallows on biological and physical soil properties and their relationship with maize yield

Misheck Musokwa,Paramu L. Mafongoya

doi:10.1007/s10457-021-00598-7

Misheck Musokwa, Paramu L. Mafongoya

Open Access

https://doi.org/10.1007/s10457-021-00598-7

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Abstract

Declining soil properties have triggered lower maize yields among smallholder famers in South Africa. Legume trees such as pigeonpea can be used as improved fallows to replenish degraded soils. The objectives of the study were to: (1) examine the effects of improved pigeonpea fallows on enhancing biological, physical soil properties and maize yield responses and (2), analyze the relationship of maize grain yield to biological and physical soil properties after improved pigeonpea fallows at Wartburg, South Africa. Pigeonpea fallows were established in 2015/16 season and terminated in 2017 and subsequently maize was planted. A randomized complete block design replicated three times was used with five treatments: continuous sole maize without fertilizer (T1), natural fallow then maize (T2), pigeonpea + grass—pigeonpea then maize (T3), maize + pigeonpea—pigeonpea then maize (T4), two-year pigeonpea fallow then maize (T5). Improved pigeonpea fallows increased maize yields through improvement in soil macrofauna species abundance, richness and diversity, aggregate stability, infiltration rate. Pigeonpea fallows increased maize yield by 3.2 times than continuous maize without fertilizer. The maize grain yield (3787 kg ha−1), was the highest on two-year pigeonpea fallows while continuous maize without fertilizer had the least (993 kg ha−1). There was a significant positive correlation between soil macrofauna indices and physical soil properties to maize yields. Smallholders who have limited access to fertilizers can sustainably use improved fallows to restore degraded soils to achieve higher maize yields in South Africa.

Highlights

Soil degradation in high density areas of the African continent is exacerbated by unsustainable management agricultural practices that have led to biological, chemical and physical soil degradation (Drechsel et al 2001; Tittonell and Giller 2013; Zingore et al 2015)
Meloidae, Pheidole, Technomyrmex, Camponotus and Oligochaeta were the most five dominant orders of macrofauna observed in almost all treatments, with two-year pigeonpea fallow plots harboring more individuals than other treatments
Continuous maize without fertilizer recorded the least soil macrofauna species diversity and richness while no significant difference was observed on natural fallow (T2) versus continuous maize without fertilizer and (Table 4)

Summary

Introduction

Soil degradation in high density areas of the African continent is exacerbated by unsustainable management agricultural practices that have led to biological, chemical and physical soil degradation (Drechsel et al 2001; Tittonell and Giller 2013; Zingore et al 2015). The advent of short fallow periods using fast nitrogen fixing legume trees on degraded agricultural fields have shown to replenish degraded soils and increase crop productivity under smallholder farming systems (Sanchez 1999; Mafongoya et al 2006; Munthali et al 2014). Sequential agroforestry practices involve the use fast growing legume trees as fallows. They are an alternative or complement to the use of chemical fertilizers, mainly in SSA where they are not regularly accessible and when available their prices are prohibitive beyond reach by many smallholder farmers (Bationo and Waswa 2011; Sileshi et al 2014).

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