Influences of Soil Physical Properties on Water-Supplying Capacity

The water-supplying capacity of two agricultural soils, red soil in Jiangxi Province and meadow soil in Henan Province, was assessed mainly using physical investigations. The reticulated mottting horizon in the red soil was a horizon limiting roots distribution due to its high density and hardness in structure and low pH (pH 5.05). The resistance of the red soil to drought hazard was poor because of its low water-supply capacity and poor hydraulic conductivity. The meadow soil had superior profile infiltration to that of the red soil and great available water-storage capacity) which resulted in low run-off loss, especially in the wheat-growth season. It was difficult for water stored in the deep layers of the meadow soil to reach the surface due to the low unsaturated hydraulic conductivity of its clay-rich horizon in subsoil. However, water stored in deep layers was still available because the roots could extend to the deep layers due to the relatively low density in soil structure.

Lowland pasture in Himalayan highland: edaphic properties and species composition

This study was carried out to investigate if on-farm cut vs. grazed pastures differed in soil fertility and species density in the temperate Himalayan highlands. Soil fertility and species relative density were measured from 30 cut and 30 grazed dairy pastures. In both types of pasture, soil pH, available phosphorus(P) and exchangeable potassium(K) were negatively correlated with pasture age and slope. In cut pasture, cocksfoot(Dactylis glomerata) and pasture age were positively correlated,whereas in grazed pasture, they were negatively correlated. In grazed pasture, unsown species and pasture age were positively correlated. Soil available P was significantly greater in cut pastures whereas soil exchangeable K was significantly greater in grazed pastures. In terms of species density, cut pasture had greater densities of cocksfoot and Italian ryegrass(Lolium multiflorum), whereas grazed pasture showed greater densities of white clover, sedge and local grass. Our study suggests that, if there are no improvements in the current method of pasture management, the cut pastures in the future are likely to have a simple pasture mixture constituting only cocksfoot and white clover(Trifolium repens).Whereas in grazed pasture, the pasture mixture is likely to be comprised of white clover and unsown species such as sedge, local grass and broadleaf weeds.

Total Carbon Storage in Himalaya Rangeland of Milke-Jaljale Area, Eastern Nepal

Rangelands occupy 51% of the terrestrial land surface, 23% total land of Nepal. It contains about 36% of the world＇s total carbon in above and belowground biomass. Rangelands can aid in the mitigation of rising atmospheric carbon dioxide concentrations via carbon storage in biomass and soil organic matter. A study on carbon stock on soil and vegetation at various altitudinal gradients in Milke-Jaljale rangeland area of Eastern Nepal was made. The study was carried out at three altitudinal gradients （above sea levels） Milke （3,000 m）, Gorujure （3,500 m） and Jaljale （4,000 m）. This method required establishing a transect line. Sample points were located by pacing the appropriate distances from the point of origin at a transect line. To determine distribution and quantity of plant carbon and soil organic carbon （SOC）, 45 sample points were established and 15 points were sampled from each study site. Total soil carbon was estimated as follows： 17.65 t/ha at Milke, 17.27 t/ha at Gorujure and 28.33 t/ha at Jaljale. Similarly, total vegetation carbon was estimated 22.68 t/ha at Milke, 29.79 t/ha at Gorujure and 42.54 t/ha at Jaljale. Highest elevation study site with least external disturbance （Jaljale area） had high storage of carbon in both cases vegetation and soil.