Can an increase in plant population benefit or impede soybean crop productivity in Petric Plinthosols?

The rising global demand for soybeans has resulted in using land with soils that are poorly suited for agriculture, such as Petric Plinthosols. However, most annual crops cultivated in these soils lack an adequate and sustainable technological framework to maintain stable productivity under the challenges posed by climate change. One of the primary challenges of soybean cultivation in these environments is achieving optimal crop establishment to ensure considerable productivity gains. In this context, examining whether soybean plants respond proportionally or more intensively to stand changes in Petric Plinthosols than to those in Ferralsols is pertinent. The influence of the plant growth environment on intraspecific competition among soybean plants in Plinthosols, characterized by limited environmental resources (particularly water availability), warrants examination. If one soil exhibits lower water availability than another, such as a Petric Plinthosol, can larger populations adversely impact productivity by extracting water from the soil at a faster rate? Therefore, this study aimed to compare different populations of two legume varieties exhibiting distinct drought tolerances in Petric Plinthosols and Ferralsols, to identify optimal management practices for cultivation in gravelly soils. The results indicated differences in the responses of the two varieties to the two soil types. Higher population densities led to increased productivity in Ferralsols. Although productivity did not correlate directly with the plant population increase in the Petric Plinthosols, this increase resulted in a greater leaf area and plant height, thereby increasing the risk of soybean lodging.