The study looked at how different levels of nitrogen and zinc affected the growth and yield of black gram plants. They tested nine different treatments in the field and found that using 25 kg/ha of nitrogen and 0.5% zinc resulted in the highest plant height, number of nodules, branches, dry weight, pods, seeds per pod, test weight, grain yield, stover yield, net return, and benefit-cost ratio. This means that applying 25 kg/ha of nitrogen and 0.5% zinc led to the best overall growth and yield of black gram plants.