EFFECT OF THE OPTIMIZED GUIERA SENEGALENSIS SYSTEM ON CROP PERFORMANCE (MILLET, PEANUT) IN THE NORTHERN PEANUT BASIN (SENEGAL)

Subsistence farmers of the Sahel, exacerbated by climate change, are facing increasing challenges of drought, degraded soils, and encroaching desertification. Research has shown that an agroforestry system where crops are interplanted with indigenous shrubs can restore degraded soils and significantly increase crop productivity. However, there is limited information on the performance of this system when managed by farmers. Therefore, the objective was to compare farmer-managed Optimized Shrub-intercropping System (OSS) (increased density of 1200-1500 Guiera senegalensis shrubs ha^-1 by planting seedlings and annual incorporation of coppiced biomass) with the Traditional Management System (TMS) (low density <100-350 shrubs ha^-1 and annual burning of coppiced biomass). The study was done in the Meckhe zone of Senegal from 2019 to 2022 with a peanut (Arachis hypogaea L.) and millet (Pennisetum glaucum L.) rotation. The experiment had a randomized block design with fifteen replications and paired treatments of OSS and TMS where each farm was a block. Plant height, LAI, NDVI, yield components, and rainwater use efficiency were measured. Rainfall was a limiting factor in three out of the four years with 2020 being the only year of adequate and well-distributed seasonal rainfall. That year OSS significantly out-yielded TMS for grain by 32% (P<0.01). Further benefits of OSS were shown in the low rainfall years by improved growth properties other than crop yield. This included low rainfall in 2021, where OSS significantly improved peanut rainwater efficiency by >12% (P<0.05) and NDVI (during the gynophorization phase) (P<0.01), and in 2022 for millet where biomass increased by 17% (P<0.05) and grain-1000 wt. by 32% (P<0.01) over TMS. Based on previous long-term research, these crop production benefits would be expected to increase as production of shrub biomass will increase over time for the transplanted seedlings. The results are important because OSS utilizes a local resource that was successfully managed by subsistence farmers and does not require external input or new infrastructure. Furthermore, the outcomes justify scaling of OSS to the broader farming community of Senegals Peanut Basin.