Malta-based agroforestry system: an emerging option for improving productivity, profitability and land use efficiency

The fruit tree-based agroforestry system (FAFS) is an important component of Bangladesh's highland cropping systems that provides multiple benefits, including offering solutions to declining agricultural land and countering the effects of climate change. The present research involved the transformation of an early stage of malta (Citrus sinensis) orchard into AFS, where the performance of winter vegetables (broccoli and pea) and year-round spices (ginger and turmeric) were investigated in a distant-dependent manner, and afterward compared with the corresponding crops grown in open-field condition (control). The results demonstrate that the growth and yield-related attributes of vegetables and spices were less impeded in AFS as contrasted with the performances of corresponding open-field crops. These findings strongly suggest that the photosynthetically active radiation (PAR), which is indispensable for crop growth, was less interfered in FAFS by the less dense canopy of young malta trees. Nonetheless, spices and crops that were grown closer to the base of the malta tree and either from ginger or turmeric raised bed, respectively, often produce less yield, which could be attributable to the competition of below-ground resources between trees and crops. Among different combinations of agroforestry systems, the highest benefit–cost ratio (2.92) was noted in the malta-broccoli-turmeric combination, while the highest land equivalent ratio was reported in the malta-broccoli-ginger amalgamation (2.01), which coincided with judicious use of supplied inputs (fertilizers, irrigation) as well as augmented soil fertility. Concisely, the current study concluded that AFS focused on malta, spices and vegetables, could be an excellent alternative to the highland cropping system in Bangladesh to ensure higher economic returns, optimize land use and soil fertility, and promote food and nutrition security.