Growth, Yield, and Economic Performance of Mungbean (Vigna radiata L.) Under Different Nutrient Management Practices in Chitwan, Nepal

In the fertile river valleys of Nepal, farmers face a constant balancing act: how to grow enough food to feed their families while keeping the soil healthy for the next season. Among the crops they rely on is the mungbean, a small, nutritious legume that acts as a natural powerhouse. Unlike many other plants that must pull all their nitrogen—a vital nutrient for growth—from the soil, mungbeans have a unique partnership with microscopic bacteria living in their roots. These bacteria act like tiny factories, pulling nitrogen directly from the air and storing it in the soil, essentially fertilizing the ground for future crops. However, this natural process is not always enough. When farmers do not manage nutrients correctly, or when the soil lacks specific minerals like zinc, the plants struggle to reach their full potential, leading to lower harvests and less income.

In the Chitwan district of Nepal, where the climate is warm and the land is rich but often depleted of certain nutrients, researchers set out to find the best way to help these crops thrive. They wanted to know if mixing different types of food for the plants—such as chemical fertilizers, organic compost, and special bacterial starters—could produce better results than what farmers were currently doing. The goal was simple: to discover a method that not only boosts the amount of grain harvested but also makes financial sense for the people growing it.

The study took place on a research farm in Rampur, Chitwan, during the spring of 2025. Scientists planted the same variety of mungbean, known as Kalyan, across twenty-four separate plots of land. They divided these plots into six different groups, each receiving a unique treatment. Some plots received the standard recommended amount of chemical fertilizer along with organic manure, which is decomposed animal waste. Others got the standard fertilizer mixed with zinc sulfate, a mineral supplement, or with Rhizobium, the beneficial bacteria that helps the plant fix nitrogen. One group followed the traditional methods used by local farmers, while another received a spray of micronutrients over the leaves. A final group received nothing at all, serving as a control to see how the plants would perform without any extra help.

As the season progressed, the researchers watched the plants closely, measuring their height, counting their leaves, and checking the health of their root systems. Surprisingly, the different treatments did not make the plants grow much taller or change the number of branches they produced. The plants seemed to grow at a similar pace regardless of what they were fed. However, the real differences appeared when the researchers looked at the harvest. The plants that received the standard fertilizer combined with organic manure, or the standard fertilizer combined with the bacterial starter, produced significantly more seeds per pod and heavier seeds than the others. The plots that received no treatment at all struggled the most, producing the fewest seeds and the lightest grains.

The most telling results came from the economic analysis. The researchers calculated the cost of every input, from the seeds and fertilizers to the labor required, and compared it to the money earned from selling the harvested grain. The plots that received no treatment actually resulted in a financial loss for the farmer. In contrast, the plots treated with the combination of standard fertilizer and organic manure, or the standard fertilizer and bacterial starter, turned a solid profit. For every unit of currency invested in these two methods, the farmers earned back more than one and a half units. This made them the most financially sound choices, offering a clear path to higher income compared to the traditional methods or the use of chemical fertilizers alone.

The study concludes that while the plants may look similar in size, the way they are fed dramatically changes how much food they produce and how much money they generate. The research suggests that farmers in the Chitwan region should consider mixing standard chemical fertilizers with either organic manure or bacterial starters to get the best results. These methods not only maximize the yield of the mungbean crop but also ensure that the investment pays off, offering a sustainable and profitable solution for local agriculture. By adopting these specific nutrient strategies, farmers can bridge the gap between what their crops are capable of and what they are actually producing, securing a better future for their fields and their families.