The researchers conducted a field experiment to study how adding zinc and iron to soil affects the growth and yield of different types of pearlmillet plants. They found that using genotypes high in zinc and iron led to higher levels of important nutrients like nitrogen, phosphorus, and potassium in the soil. These plants also absorbed more zinc and iron, resulting in higher grain and stover yields compared to plants without these nutrients. Applying zinc and iron to the soil and leaves further increased the uptake of these micronutrients, leading to even higher yields. Overall, adding zinc and iron to the soil can improve the growth and yield of pearlmillet plants.