Transformation of jackfruit (Artocarpus heterophyllus Lam.) orchard into multistory agroforestry increases system productivity

摘要

A number of traditional and modern agroforestry systems are common in the agricultural landscape of Bangladesh. Jackfruit (Artocarpus heterophyllus Lam.) based agroforestry is one of them and predominantly found in terrace ecosystems. There is an enormous opportunity to improve the system through utilizing available space by growing compatible associated crops. For this, a jackfruit orchard was transformed into a multistoried agroforestry system during the period from 2012 to 2013, where jackfruit trees were kept as overstory, and associated crops, such as papaya and eggplant were grown as middle and lower story crops, respectively. In the improved system, jackfruit yield increased by 32.7% due to fertilizers and irrigation applied for the middle and lower-storied crops. Yields of papaya and eggplant were reduced by 22.8 and 17.4%, respectively, because of competition for both belowground and aboveground resources. For example, light interception by the middle and lower story crops were 55.5 and 30.8%, respectively. However, the total production per unit area (by combining the yields of jackfruit, papaya, and eggplant) in the multistoried agroforestry system was remarkably higher than the monoculture system for the same area due to intensive land use. The benefit-cost ratio and land equivalent ratio for the studied multistoried agroforestry systems were 5.47 and 2.59, respectively. These results suggest that the traditional jackfruit orchard could be transformed to multistoried agroforestry systems for its higher system productivity including higher yield, and increased income that ultimately will improve the livelihood of the farming community.