Interactive Effects of Sowing Date and Planting Density on Productivity in Maize–groundnut Intercropping Systems

Abstract

Groundnut (Arachis hypogaea L.) and maize (Zea mays L.) are staple crops of major nutritional and economic importance in regions reliant on sustainable agriculture. This study aimed to evaluate the effects of sowing date and planting density on the productivity of a maize–groundnut intercropping system in Mankono, central-western Côte d’Ivoire. The experiment was conducted from April to July 2022 using a randomized complete block design with three replicates. Treatments combined crop type, sowing date (J0, J5, J10, and J15), and planting density. Groundnut was established at 250,000 plants/ha (20 × 20 cm) and 111,111 plants/ha (30 × 30 cm), while maize density was maintained at 10,000 plants ha⁻¹ (1 × 1 m). Agronomic and yield data were collected from 30 plants per plot for each species. Groundnut yield ranged from 0.28 to 1 t/ha and was primarily associated with pod number (4–14), biomass (78–122), and pod mass. In maize, agronomic traits were strongly related to yield (r > 60%), which varied from 0 to 1.26 t/ha. Planting density significantly influenced groundnut performance, with the 30 × 30 cm spacing producing the highest values for most parameters. Sowing date also significantly affected both crops, as simultaneous sowing (J0) resulted in the highest yields, whereas delayed sowing (up to J15) reduced productivity. The interaction between planting density and sowing date further influenced system performance, with the combination of 30 × 30 cm spacing and simultaneous sowing producing the best yields for both crops, while high-density planting combined with delayed sowing resulted in the lowest yields (≈0.4 t/ha). Overall, the results demonstrate that optimized spacing and simultaneous sowing enhance maize–groundnut intercropping productivity through improved resource-use complementarity, including more efficient use of light, water, nutrients, and growing space, while reducing interspecific competition.