Soil nutrient dynamics under poplar-based agroforestry: A comparative study in north-western India

Agroforestry system integrates woody perennials with agricultural crop and/or livestock. The system is being increasingly acknowledged for its potential to improve soil quality and productivity as compared to monoculture. The present study investigated the impact of poplar-based agroforestry system on soil quality to adjacent monoculture cropping of cucurbits and baby corn at the Punjab Agricultural University, Ludhiana, over the period of 2020 and 2023. In 2020, the study assessed the soil beneath a five-year-old poplar plantation intercropped with cucurbits, whereas in 2023, the focus was on baby corn grown under a two-and-a-half-year poplar plantation. Soil samples were taken at three different depths (0-15 cm, 15-30 cm, and 30-45 cm) in both the agroforestry and monoculture systems. The physical and chemical properties of soil were analysed. The study revealed that the soil pH was higher in open conditions (8.3 in sole cucurbits and 8.0 in sole baby corn) compared to poplar-based system (8.2 in intercropped cucurbits and 7.6 in intercropped baby corn). Additionally, the agroforestry system exhibited higher levels of electrical conductivity (dS/m), organic carbon (%), and availability of nitrogen (kg/ha), phosphorus (kg/ha), and potassium (kg/ha) at all sampled depths. The improvement in soil characteristics is attributed to the increased biomass input from both tree and crop components, enhanced nutrient cycling, and reduced soil disturbance. The findings underscore the potential of poplar-based agroforestry system to significantly enhance soil quality and fertility in the region.