Abstract
Sub-Saharan Africa (SSA) faces climate change and food insecurity challenges, which require action to create resilient farming systems. Conservation agriculture (CA) is widely promoted across SSA but the impacts on key soil physical properties and functions such as soil structure and hydraulic properties that govern water storage and transmission are not well understood. The aim of this study was to assess the impacts of long term (10–12 years) maize-based CA on soil hydraulic conductivity, water retention and pore size distribution. Root zone (0–30 cm depth) soil total porosity, pore size distribution, saturated hydraulic conductivity (Ksat) and plant available water capacity (PAWC) of conventional maize monocrop farming systems (CP) are compared with those of adjacent CA trials with either sole maize or maize intercrop/rotation with cowpea (Vigna unguiculata L.), pigeon pea (Cajanus cajan L.) or velvet bean (Mucuna pruriens L) in trial locations across central and southern Malawi. Results show that maize-based CA systems result in significant changes to soil hydraulic properties that correlate with improved soil structure. Results demonstrate increases of 5–15 % in total porosity, 0.06−0.22 cm/min in Ksat, 3–7 % in fine pores for water storage and 3–6 % in PAWC. Maize monocrop CA had similar effect on the hydraulic properties as the maize-legume associations. The values of Ksat for CA systems were within optimum levels (0.03–0.3 cm/min) whereas PAWC was below optimum (<20 %). There was no significant build-up in soil organic matter (OM) in the CA systems. The results lead to a recommendation that crop residue management should be more pro-actively pursued in CA guidance from agricultural extension staff to increase soil OM levels, increase yields and enhance climate resilience of sub-Saharan African farming systems.
| Original language | English |
|---|---|
| Article number | 104639 |
| Number of pages | 8 |
| Journal | Soil and Tillage Research |
| Volume | 201 |
| Early online date | 16 Apr 2020 |
| DOIs | |
| Publication status | Published - Jul 2020 |
Bibliographical note
Funding Information:This work was supported by the Biotechnology and Biological Sciences Research Council through UK Research and Innovation as part of the Global Challenges Research Fund, AFRICAP programme, grant number BB/P027784/1. We would like to thank the International Maize and Wheat Improvement Centre (CIMMYT), Total LandCare and Machinga ADD for giving us access to their on-farm field trials. We thank CISANET staff especially Alfred Kambwiri and Pamela Kuwali for their support in Malawi. We are very grateful to the farmers and Extension Officers at Mwansambo and Lemu, Total LandCare staff and the Soil Laboratory staff of Chitedze Research Station for their immense support during soil sample collection and analysis. Special thanks to Dr Moses Munthali for providing the necessary facilities needed in the laboratory.
Funding Information:
This work was supported by the Biotechnology and Biological Sciences Research Council through UK Research and Innovation as part of the Global Challenges Research Fund, AFRICAP programme , grant number BB/P027784/1 . We would like to thank the International Maize and Wheat Improvement Centre (CIMMYT), Total LandCare and Machinga ADD for giving us access to their on-farm field trials. We thank CISANET staff especially Alfred Kambwiri and Pamela Kuwali for their support in Malawi. We are very grateful to the farmers and Extension Officers at Mwansambo and Lemu, Total LandCare staff and the Soil Laboratory staff of Chitedze Research Station for their immense support during soil sample collection and analysis. Special thanks to Dr Moses Munthali for providing the necessary facilities needed in the laboratory.
Publisher Copyright:
© 2020 The Authors
Keywords
- Climate resilience
- Conservation agriculture
- Dry spells
- Porosity
- Soil structure
- Soil water retention