The study looked at how different levels of soil moisture affected the growth of maize plants in a field in Heilongjiang province. They found that the soil moisture in the top 30 cm of soil decreased in 2011. The researchers discovered that soil moisture had a significant impact on the size of the maize plants' leaves and their overall weight. Within a certain range of soil moisture, increasing the moisture by 1% led to an increase in leaf area by 28.34 cm2. Having the right amount of moisture in the soil was found to be beneficial for increasing the leaf area and dry weight of the maize plants.