Reversing Agro-Based Land Degradation through Conservation Agriculture: Emerging Experiences from Zambia’s Smallholder Farming Sector

Abstract

This study reports on the land degradation minimizing effects of Conservation Agriculture (CA) as promoted among smallholder Zambian farmers. It found no evidence of CA associated improvements in soil fertility after five years of CA practice, most probably because crop residues were removed from the fields. The study reports high phosphorus (15.53 mg kg -1 ) and potassium (0.75 cmol kg -1 ) levels, low nitrogen (0.12 %) and organic carbon (1.19 %) levels, and no plough/hoe pans in soils from both CA and conventionally (CV) managed fields. This is in part contrary to the dominant land degradation narratives which have been the basis for promoting CA in the study areas. Faidherbia albida, a leguminous tree promoted as part of the CA package in Zambia, is associated with significantly higher levels of nitrogen, organic carbon and potassium under its canopy. Its planting by CA farmers is linked to the incentives provided by CA promoters. Average maize yields of 3.8 t ha -1 and 2.8 t ha -1 were reported under CA and CV systems respectively. Government subsidies for mineral fertilizer and hybrid seed promote maize mono-cropping and remain unsupportive of CA. It is concluded that the dominant land degradation narrative, which posits population induced land degradation, may not hold in this case. Instead, the removal of crop residues and low levels of mineral fertilizer and manure amendments may better explain the soil fertility status of the study areas. More nutrient replacement strategies are required if the benefits of CA on soil fertility are to be actualized in the immediate future.

Hardpan and maize root distribution under conservation and conventional tillage in agro-ecological zone IIa, Zambia

“…The lenses and bands reflected differences in soil parent material and differences in clay migration during soil formation. These results support observations of no hardpans by Umar (2012) in the same regions of Zambia.…”

A critical review and re-assessment of theories of smallholder decision-making: a case of conservation agriculture households, Zambia

“…The superiority of yields from CA fields compared with conventionally farmed fields was reported by all the 129 households that participated in the semi-structured interviews and from the 2-year field assessments during this study; and other studies on CA in Zambia (Table 2) [59][60][61][62] . The superiority of yields from CA fields compared with conventionally farmed fields was reported by all the 129 households that participated in the semi-structured interviews and from the 2-year field assessments during this study; and other studies on CA in Zambia (Table 2) [59][60][61][62] .…”

Old Wine in New Skins? Community Markets for Conservation and its Performance in Northern Zambia

“…The use of herbicides among COMACO members remains contentious. The higher weeding requirements under CA has been acknowledged by many scholars writing on CA practice among smallholders in southern Africa (Arslan et al, 2014; Baudron et al, 2007; Bellotti & Rockocouste, 2014; Haggblade & Tembo, 2003; Sims et al, 2012; Umar, 2012). COMACO farmers requesting to use herbicides indicates that their practice of COMACO’s organic version of CA was superficial, as we have argued earlier.…”