Resumen de Thermal stability of organic carbon in soil aggregates of maize-wheat system in semi arid India
Understanding the stability and carbon retention ability of aggregates under common cropping sequences is essential to ascertain terrestrial carbon storage. Surface soil samples (0-15 cm) were collected and dry sieved to separate the macro (>250µm) and micro sized aggregates (<250µm). The separated aggregates were subjected to 60 days incubation at four different temperatures (25, 30, 35 and 40 °C). Nutrient management was more prominent than tillage in determining water stable aggregates. 100% organic treated plots in bed planting and mineral fertilizers + crop residues in conventional tillage gave maximum mean weight diameter values of 1.01 and 0.95 respectively. Irrespective of the treatments, microaggregates were found to be poorer in carbon content, but richer in their capacity to retain it by way of larger activation energies. The Q10 values were found to be higher in microaggregates than macroaggregates for all treatments, confirming the thermal sensitivity hypothesis of stable carbon fractions.
