Impact of short-term pasture development on soil aggregation, temperature sensitivity of soil organic carbon, and functional diversity in semi-arid ecosystem

Abstract

Pasture development could be a viable option to restore degraded land in semi-arid region. New knowledge on soil functional diversity, aggregation, and temperature sensitivity (Q10) of soil organic carbon (SOC) after pasture development would assist to accomplish the scope of global pastureland management for climate change mitigation and land restoration. To understand the impact of pasture development on soil aggregation, SOC stock, and its Q10, research was undertaken at three development sites (RS1, RS2, RS3) in India with seeding of Cenchrus ciliaris, Megathyrus maximus, and Stylosanthes seabrana (at a line-ratio of 2:2:1). After three years, biomass productivity and for SOC, aggregation, enzyme activities, etc. at 0–20 and 21–40 cm depths were estimated. Pasture development improved biomass productivity from 0.68 mg ha−1 in undeveloped site to 3.62–4.64 mg ha−1. Pasture development enhanced SOC stock from 5.85 to 7.31 mg C ha−1 at the surface layer with an annual accumulation rate of 28–112 kg SOC ha−1year−1. Greater activities of extracellular enzymes were observed at the surface soil layer in pasture development sites over undeveloped control. The mean weight diameter was ∼23–38% higher at pasture development sites over undeveloped sites. The Q10 being controlled by the labile carbon was significantly higher (13–29%) at the pasture development sites over undeveloped site. Hence, short-term pasture development could improve the SOC stocks at the surface layer only, but the stocks were vulnerable to C loss at higher temperature. However, long-term pasture development could have a great potential to accrue C to mitigate climate change.