Carbon sequestration and selected hydraulic characteristics under conservation agriculture and traditional tillage practices in Malawi

Simwaka, P L and Tesfamariam, E H and Ngwira, A R and Chirwa, P W (2020) Carbon sequestration and selected hydraulic characteristics under conservation agriculture and traditional tillage practices in Malawi. Soil Research (TSI). ISSN 1838-675X

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Abstract

Conservation agriculture (CA) is increasingly promoted among smallholder farmers of sub-Saharan Africa in a quest to improve food security while sustaining the natural resource base of the agro-ecosystems where agriculture is based. The aim of this study was to investigate the effects of CA and traditional tillage on soil organic carbon (SOC) and selected hydraulic properties in two contrasting agro-ecological zones of Malawi. Six farmers hosted on-farm trials in each location, with each farmer having the following treatments: CA with continuous sole maize (CA-SM), CA with maize–legume intercrops (CA-ML), and traditional tillage with continuous sole maize (CT-SM). Soil samples were randomly collected in October 2015, from farmers’ fields located in Chipeni, Chinguluwe, Lemu, and Zidyana where CA had been implemented for 10 years (2005–2015) at six depth intervals: 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm. Bulk density, soil water characteristics, and pore size distribution were determined using undisturbed core samples. At all sites, CA improved total SOC, carbon stocks, and the stable fraction of particulate organic carbon. Maize–legume intercropping under CA had 35%, 33%, and 73% more total SOC than CT-SM in Chipeni, Lemu, and Zidyana respectively. In Chinguluwe and Lemu, CA-ML had 0.54 and 0.50 g kg–1 respectively more stable fraction of particulate organic carbon (POMP) than CT-SM; whereas in Chipeni, CA-SM had 0.73 g kg–1 higher POMP compared with CT-SM. CA also improved soil porosity, pore size distribution, and water retention capacity by increasing the proportion of mesopores and micropores compared with CT-SM. Thus, changing management practices from CT-SM to CA has the potential to improve the soil organic matter and soil hydraulic properties across agro-ecological zones in Malawi, which is important for sustainable agriculture. Farmers should be encouraged to minimise tillage, retain residues as mulch on the soil surface, and practice crop rotation.

Item Type:	Article
Divisions:	Research Program : Innovation Systems for the Drylands (ISD)
CRP:	CGIAR Research Program on Grain Legumes and Dryland Cereals (GLDC)
Uncontrolled Keywords:	Agro-ecological zones, Carbon sequestration, Conservation agriculture, Hydraulic characteristics, Smallholder farmers, Traditional tillage
Subjects:	Others > Agriculture Others > Smallholder Farmers Others > Agriculture-Farming, Production, Technology, Economics
Depositing User:	Mr Arun S
Date Deposited:	05 Oct 2020 07:08
Last Modified:	05 Oct 2020 07:53
URI:	http://oar.icrisat.org/id/eprint/11625
Official URL:	https://doi.org/10.1071/SR20007
Projects:	UNSPECIFIED
Funders:	USAID, CGIAR Fund
Acknowledgement:	This material is based upon work supported by the United States Agency for International Development, as part of the Feed the Future initiative, under the CGIAR Fund, award number BFS-G-11–00002, and the predecessor fund the Food Security and Crisis Mitigation II grant, award number EEM-G-00–04–00013. PLS would also like to thank Total Land Care Malawi (TLCM) and CIMMYT for allowing research to be conducted in their trial sites in Malawi.
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