No abstract

Pastures may act as carbon sources and sinks depending on grazing pressure and management practices. Soil organic carbon (SOC) stock and its fractions were quantified under 3 different grazing intensities using 5, 10 and 15 sheep/ha under sown, improved and natural pastures in the semi-arid tropics of India. Results revealed that after 3 years, improved pasture had significantly higher particulate organic carbon (POC ~4.5 g/kg), SOC (~0.53 %), total organic carbon (TOC~7 g/kg) and SOC stock (~15 mg/ha) as compared with sown and natural pastures. Labile carbon (LC ~185 mg/kg) and soil microbial biomass carbon (SMBC ~378 µg/g soil) were higher under natural pasture. A moderate grazing intensity of 10 sheep/ha resulted in significantly greater carbon fractions, TOC and SOC stock. SOC stock and its fractions were significantly higher in the topsoil layers as compared with the subsoil layers. These results indicate that improved pasture management practices with moderate grazing intensity can be recommended for improving SOC stock and its fractions in semi-arid tropical pastures.

No abstract

Livestock rearing is an integral part of rural livelihood in the Himalayan region. In spite of abundance of pasture resources, total biomass is insufficient to meet the forage demand. Indiscriminate grazing has caused an alarming decline in the carrying capacity of grazing lands and has caused severe land degradation. This study was carried out with the objective of increasing biomass potential, improving livestock productivity and to arrest environmental degradation. The study was conducted at Ghanetta and Dagoh (Kangra) and Jogindernagar (Mandi) districts in Himachal Pradesh through silvipastoral intervention in conjunction with soil and water conservation measures. Grasslands of the study area were of alluvial–loamy soil with shallow depths. Soil organic matter was 0.72 (Ghanetta), 0.76 (Dagoh) and 0.80% (Jogindernagar). Organic carbon content in the subsurface (15–45 cm) layer was only 30 to 39% of the surface layer (0–15 cm). Chrysopogon (20%) was found the most dominant species, followed by Heteropogon (13%). Average herbage production was 5.613 DM tonne/ha (Ghanetta), 5.458 DM tonne/ha (Dagoh) and 5.233 DM tonne/ha (Jogindernagar). Leaf biomass of different fodder trees ranged from 0.23–0.60 DM tonne/ha (Ghanetta), 0.16–0.51 DM tonne/ha (Dagoh) and 0.21–0.59 DM tonne/ha (Jogindernagar). Maximum biomass of 9.17 DM tonne/ha was obtained at Ghanetta followed by 8.26 DM tonne/ha and 8.23 DM tonne/ha at Dagoh and Jogindernagar, respectively, showing substantial improvement in total biomass potential with silvipastoral intervention in conjunction with soil and water conservation measures.

No abstract