Optimizing Planting Density to Enhance Soil Heat Utilization and Its Effect on Cotton ( <scp> <i>Gossypium hirsutum</i> </scp> L.) Biomass and Yield Formation Under Varied Climate Conditions

ABSTRACT The relationship between planting density and resource utilization, including water and light, has been extensively studied concerning cotton ( Gossypium hirsutum L .) biomass and yield. However, understanding the effect of planting density on soil heat resource utilization remains limited. This study investigates the impact of planting density on soil heat utilization across different soil layers and growth stages, focusing on cotton biomass, yields and soil heat conversion efficiency (PE soil ). Conducted over 3 years (2022–2024), the experiment utilized various planting densities (D1:15,000, D2:33,000, D3:51,000, D4:69,000, D5:87,000 and D6: 105,000 plants ha −1 ) in a randomized complete block design. Our findings indicated that biomass accumulation showed a significant positive correlation with the effective accumulated temperature (EAT) in 2022, but this relationship turned negative in 2023 and 2024. PE soil correlated positively with yield across treatments. Under warmer temperature conditions, D5 achieved the highest yield, exceeding D3 and D4 by 5% and 7%, respectively. In contrast, under moderate temperature conditions with well‐distributed rainfall, D3 and D4 outperformed D5 by 4% and 3%, respectively. These findings suggest that excessively high planting densities did not further improve yield or PE soil . Instead, optimizing planting density according to climatic conditions is critical for maximizing cotton productivity and soil heat conversion efficiency. Moderate planting densities (D3–D4) are recommended under normal climatic conditions, whereas slightly higher density (D5) may improve yield under warmer conditions. This climate‐adaptive density management strategy provides a practical pathway for improving sustainable cotton production in the North China Plain.