Long‐term non‐flooded mulching cultivation influences rice productivity and soil organic carbon

A field experiment was conducted for 10 years to examine the long‐term effects of non‐flooded mulching cultivation on rice yield and soil organic carbon on Chengdu Plain, south‐west China. Compared with traditional flooded cultivation (TF), non‐flooded plastic film mulching (PM) resulted in a 14% higher average rice (Oryza sativa L.) yield. However, non‐flooded straw mulching (SM) decreased the average rice yield by 11% compared with TF. After 10 years, PM led to similar or higher (SM) soil organic carbon (SOC) and total soil N (TN) in the top 5 cm of the soil profile compared with TF. No differences were found among the three cultivation systems in SOC or total N at 5–12 and 12–24 cm soil depths. Small macroaggregates (0.25–2 mm) were predominant in the top 5 cm of the soil (58–63% of whole soil) across the three cultivation systems. However, the proportion of large macroaggregates (>2 mm) from SM and PM was significantly larger than from TF in the top 5 cm of the soil. Non‐flooded mulching cultivation led to increased C and N contents in large macroaggregates and mean weight diameter of aggregates in the 0–5 cm soil depth. This suggests that non‐flooded mulching cultivation increased soil aggregation concomitant with soil C stabilization within the improved soil structure.