Intercropping of Tropical Grassland and Pigeon Pea: Impact on Microclimate, Soil Water, and Forage Production

Abstract

Although several strategies can be used for pasture recovery, pasture degradation remains an issue in Brazilian cattle raising. The use of shrub legumes can change the environment (microclimate and water consumption) and productive potential of the pasture. Therefore, the objective of this study was to evaluate the effect of two pasture recovery strategies on the microclimate, soil water dynamics, and forage accumulation of tropical pastures. The research was conducted between 2020 and 2022 in signalgrass (Urochloa [syn. Brachiaria] decumbens Stapf cv. Basilisk) pastures managed under continuous and variable stocking rate throughout the experimental period in São Carlos, SP, Brazil. Three production systems were assessed: 1) degraded pasture without N fertilization (DEG); 2) recovered pasture with application of 200 kg N-urea ha⁻¹ yr⁻¹ (REC); and 3) recovered pasture by intercropping with pigeon pea (Cajanus cajan L. Millsp. cv. BRS Mandarim) (MIX). Soil moisture in the 0–60 cm layer and microclimate, which included photosynthetically active radiation and the animal thermal comfort index, were assessed. The vegetative and productive characteristics of pastures, as well as the total mass production of the production systems, were also evaluated. Overall, intercropping pigeon pea plants with tropical pasture did not significantly affect the soil water content or the animal thermal comfort index. However, it did alter the transmission of photosynthetically active solar radiation to the pasture (0%‒65%) and decreased wind speed (0%‒60%). During the 2 yr, the pigeon pea exhibited a great forage accumulation potential (12 615 kg·ha⁻¹·yr⁻¹). Additionally, pigeon pea provided high-quality forage available during the dry season. Forage accumulation increased in both pasture recovery strategies (REC and MIX), with a significantly greater amount of crude protein (CP) content in the MIX. Intercropping tropical pastures with pigeon pea can be used as a strategy for pasture recovery and dry season forage supplementation.