The effects of soil moisture content on soil respiration and root development in upland rice

To investigate the effects of different soil moisture contents on soil respiration rate and root development in upland rice and to optimize water management strategies in arid regions, this study established five moisture gradients: 65%, 75%, 85%, 95%, and 100% of soil water-holding capacity (WHC). Using a pot-cultivation method to simulate the upland rice growth environment, the study systematically analyzed soil respiration rates and root development characteristics under each treatment. The results showed that soil respiration rates gradually decreased with increasing soil moisture content, and the number of roots was significantly reduced. Changes in soil respiration rates during the tillering and heading stages revealed a gradual decline under 100% WHC, while other treatments exhibited an initial increase followed by stabilization. Daily variation analysis indicated that soil respiration rates under 65%-85% WHC increased initially and then stabilized, whereas those under 95%-100% WHC peaked before significantly declining. Soil temperature also varied significantly with the moisture gradient, peaking at 75% WHC and being lower under 95% and 100% WHC. Moreover, appropriate soil moisture levels positively impacted both root development and soil respiration in upland rice, while excessive or insufficient moisture hindered healthy growth. Comprehensive analysis suggested that 75% WHC is the optimal soil moisture condition for upland rice growth, significantly improving water use efficiency and crop yield. This study provides scientific evidence for upland rice water management and supports the sustainable development of agriculture in arid regions.