Practical Guidelines for Farm Waste Utilization in Sustainable Kale Production

Natural amendments from agricultural waste to improve soil physicochemical properties continuously attract research interest in promoting eco-friendly plant production. The present study evaluated the proper use of sawdust, biochar, and compost made from farm waste for kale production from seedling propagation to field conditions. From the seedling propagation process, the results demonstrate that the most suitable growing medium for kale seedings was 0.5:1:1 v/v of sawdust + biochar + compost, which gave the fastest mean germination times (2.71 days) and the highest seed germination percentage (78.33%). In addition to investigating the selected growing media as the soil amendments at five different rates (0, 6.25, 12.50, 18.75, 25.00, and 31.25 t ha−1), the result reveals that the fresh weight of marketable leaves was significantly highest under the 31.25 t ha−1 treatment. The application rate that yielded the highest gross profit margins was eight times higher than the control. Moreover, in some harvesting periods, the kale leaf yields under the treatment of 31.25 t ha−1 showed higher total chlorophyll and carotenoid contents.