Microclimate Modification in Lowland Beetroot Cultivation Using Arachis pintoi as a Living Biomulchs

Abstract

Beetroot (Beta vulgaris L.) has potential as a functional horticultural crop for lowland production; however, its productivity is constrained by high root-zone temperature, intense radiation, and soil-moisture fluctuations. A field experiment using a split-plot design with three replications was conducted from September to November 2022 at Agrotechno Park Jatikerto, Universitas Brawijaya, Malang, Indonesia. The main-plot factor was the planting time of Arachis pintoi, consisting of three levels: 4 weeks before beetroot transplanting, 2 weeks before beetroot transplanting, and simultaneous planting with beetroot. The subplot factor was A. pintoi spacing, consisting of 5 × 20, 5 × 15, and 5 × 10 cm. Planting time significantly affected vegetative growth and yield components, whereas spacing mainly influenced total soluble solids and soil microclimate. Significant interactions were observed for storage-root fresh weight, soil temperature, and soil moisture. The highest storage-root fresh weight was obtained from simultaneous planting at 5 × 20 cm, reaching 285.09 g plant⁻¹. Conversely, 5 × 10 cm spacing reduced soil temperature to 24.79 °C and maintained soil moisture up to 75.83%, but did not produce the highest yield. These findings indicate a trade-off between microclimate improvement and crop yield performance, consistent with potential competition from the living biomulch.