Vol.:(0123456789) 1 3 Environmental Sustainability https://doi.org/10.1007/s42398-020-00139-5 ORIGINAL ARTICLE Malta‑based agroforestry system: an emerging option for improving productivity, proftability and land use efciency Ashim Kumar Das 1  · Md. Abiar Rahman 1,2  · Sanjida Sultana Keya 1  · Satya Ranjan Saha 1  · Md. Mezanur Rahman 1 Received: 20 May 2020 / Revised: 2 October 2020 / Accepted: 15 October 2020 © Society for Environmental Sustainability 2020 Abstract The fruit tree-based agroforestry system (FAFS) is an important component of Bangladesh’s highland cropping systems that provides multiple benefts, including ofering solutions to declining agricultural land and countering the efects 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-feld 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-feld crops. These fndings strongly suggest that the photosyntheti- cally 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 diferent combinations of agroforestry systems, the highest beneft–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. Keywords Beneft–cost ratio (BCR) · Fruit tree-based agroforestry · Land equivalent ratio (LER) · Spices · Winter vegetables Introduction Bangladesh is trapped between the melting ice caps of the Himalayas, the increasingly vicious rainstorms from the north, and the rising tides of the Bay of Bengal to the south, making the country highly vulnerable to cataclysmic occa- sions caused by climate change (Abdullah and Rahman 2015; BBS 2018; Naser et al. 2019; Rahman et al. 2019). In addition, Bangladesh harbors nearly 163 million people (BBS 2018), expected to rise by 2050 to 192.6 million (UN 2019). The sustainable livelihoods of these millions of peo- ple rely exclusively on agriculture, which serves as a corner- stone of the economy, but is severely disturbed by climatic changes and anthropogenic hazards (Miah et al. 2016; Rah- man et al. 2018, 2020). Despite these hazards, Bangladesh has an impressive record of improvement in agriculture over the past decades, yet nearly 24.2 million people sufer from food insecurity (Hassan et al. 2019; Molla 2019). On the other hand, rapid industrialization, impromptu urbanization and an increase in settlements are collectively responsible for the reduction of 69,000 hectares of agricultural land per year, and if this continues at the current annual rate, there will be no cultivable land left in Bangladesh in the next 50 years (Rahman et al. 2016; Muhsin et al. 2018; Khan * Md. Abiar Rahman abiar@bsmrau.edu.bd 1 Department of Agroforestry and Environment, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh 2 South Asia Program, World Agroforestry Centre (ICRAF), Nairobi, Kenya