2025-07-20 COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2025 56(卷), 13(期), (2026-2035页)
Soil carbon (C) dynamics are increasingly studied because of their role in the global C cycle and potential influence on atmospheric carbon dioxide concentrations and climatic changes. The substitution of native forests by crop fields usually decreases soil C stocks. However, C stocks may increase in irrigated fields of semiarid areas because high biomass production and litter incorporation may compensate for the fast turnover of organic matter. Using 13C isotopic techniques, we determined soil C dynamics in the 1 m superficial layer, in irrigated sugarcane fields established 10 and 30 years before. From 57% to 78% of the original C stock were lost after 10 years of cultivation and from 85% to 95% after 30 years. However, these high losses were more than compensated by sugarcane biomass inputs, and the total soil C stock increased from 94 to 169 Mg ha-1 between 10 and 30 years of cultivation. This last C stock is higher than any reported for soils in the Brazilian semiarid region. Therefore, substituting native dry deciduous forests by irrigated permanent sugarcane in semiarid areas may increase soil C stocks, contrary to most rain-fed and irrigated cropping systems with crops that accumulate less biomass than sugarcane.