Tropentag, September 16 - 18, 2026, Göttingen "Towards multi-functional agro-ecosystems promoting climate-resilient futures"

Pineapple-legume rotation drives first-cycle pineapple growth, yield, and quality improvements while reducing mineral fertiliser needs

¹University of Abomey-Calavi, Research Unit Sustainable Management of Soil Fertility, Laboratory of Soil Sciences, Benin
²University of Abomey-Calavi, Lab. of Biomathematics and Forest Estimations, Benin
³COLEAD, Research & Innovation Brokerage Department, Belgium

Abstract

Pineapple production in southern Benin is constrained by declining yields and heterogeneous fruit quality, largely driven by continuous monoculture and inefficient fertilisation practices. Leguminous cover crops are widely recognised for restoring soil fertility in tropical systems, yet their benefits are generally assumed to manifest only after multiple cropping cycles. This study evaluated whether pineapple–legume rotations can generate immediate agronomic benefits within a single production cycle and reduce dependence on mineral fertilisers.

An unbalanced factorial design in randomised blocks including 13 treatment combinations and four replications was implemented across four farmer fields on Ferralsols of the Allada plateau. Treatments combined three cropping systems - pineapple monoculture (control), pineapple–Mucuna pruriens–pineapple, and pineapple–Crotalaria juncea–pineapple — with varying levels of recommended mineral fertiliser (0%, 50%, 100%) and compost (0%, 50%, 100%) amendments. Cover crops were grown for four months, incorporated into the soil, and followed by pineapple cultivation (cv. Sugarloaf). Growth, biomass, yield, and fruit quality were analysed using linear mixed-effects models.

Both Mucuna and Crotalaria produced comparable biomass (~10 t ha^-1), indicating similar organic matter inputs. Rotation treatments significantly improved pineapple growth, biomass accumulation, fruit weight, juice weight, and total soluble solids from the first production cycle. Notably, rotations combined with 50% of the recommended mineral fertiliser consistently matched or outperformed conventional monoculture under equivalent fertiliser levels. In contrast, compost-only treatments improved performance relative to monoculture but remained inferior to mineral fertiliser amendments, highlighting the critical role of mineral nutrients, particularly potassium.

These findings demonstrate that pineapple–legume rotations can deliver immediate productivity and quality gains while enhancing fertiliser use efficiency. The absence of major differences between Mucuna and Crotalaria suggests that the rotation effect itself is more important than species choice. This study provides strong evidence for integrating leguminous cover crops into pineapple systems as a cost-effective, sustainable intensification strategy with direct relevance for smallholder adoption in West Africa.

Keywords: Cover crops, Crotalaria, fertiliser use efficiency, Mucuna, pineapple, rotation

Contact Address: Pieterjan De Bauw, COLEAD, Research & Innovation Brokerage Department, Rue de Berger 17, 1050 Brussels, Belgium, e-mail: pieterjan.debauwcolead.link