Herbage Productivity and Botanical Composition of Hill Pasture as a Function of Clipping and Site Features
Complex topography and varied soil of hill-land pastures create microsite conditions that support an array of floristic associations and herbage production patterns. This complicates management for forage and livestock production because the seasonal distribution and quantity of forage vary. Our objective was to determine herbage production and floristic composition of a hill pasture as a function of site characteristics and canopy management. An existing 3-ha hill pasture watershed was oversown with white clover (Trifolium repens L.) and orchard-grass (Dactylis glomerata L.) and fertilized with reactive phosphate (PO 4 ) rock (PR). Replicated plots on each of four sites were clipped once (stockpiled), twice (hay harvest), or three times (long rotation) annually. Site had a significant impact on cumulative herbage production, whereas the influence of clipping was mixed. The least (1.9 Mg ha -1 ) amount of herbage production in a given season occurred on a northeast (NE)-facing site and the greatest (4.6 Mg ha -1 ) in a natural drainage area (ND) traversing the pasture. Herbage production increased by about 80% with overseeding and PR, but the relative ranking of production among sites stayed the same. Botanical composition was also strongly influenced by site, with velvetgrass (Holcus lanatus L.) predominating in ND and red fescue (Festuca rubra L.) occurring primarily on the NE site. The stockpiled treatments became dominated by grasses and weeds 4 yr after treatments were imposed, regardless of site, and were similar to the least productive site (NE-facing) in the pasture. Our results suggest that application of amendments to the more productive portions of a site are likely to have greater return.
Soil spatial variability relationships in a steeply sloping acid soil environment
Management of pastures in steep terrain can be expensive in terms of time, chemical inputs, and equipment requirements. Management of those portions of pasture that will yield the most for minimum inputs requires a knowledge of the spatial patterns of the soil and atmospheric environments. A steep 2.4-ha unimproved pasture in southern West Virginia was studied to determine the spatial dependency of aboveground biomass production on soil characteristics. The predominant soil of the study site was Gilpin silt loam (fine-loamy, mixed, mesic, Typic Hapludults) with an average A-horizon pH (1:1 H 2 O) of 4.5 (range 3.8 to 6.1). The study site was broadcast seeded with red fescue (Festuca rubra L.) in 1982, making it the major plant species. However, several other plant species, including orchardgrass (Dactylis glomerata L.), red clover (Trifolium pratense L.), white clover (Trifolium repens L.), broomsedge (Adropogon virginicus L.), velvet grass (Holcus lanatus L.), yarrow (Achillea millefolium L.), and wild strawberry (Fragaria virginiana L.), and others were common. Transects were laid out up and down the north-facing, south-facing, and west-facing slopes and one transect was established on the contour for measurement of soil characteristics at a 1-m spacing. Plant aboveground biomass was measured at a 2-m spacing on three of the slope transects and on the contour transect. Although correlation analysis failed to find many statistically significant relationships between biomass production and soil characteristics, cross-semivariogram analyses of biomass production and surface soil pH and extractable Al, Mn, and P indicated that a strong spatial dependency exists. Those relationships were used for identifying homogeneous areas of biomass production and associated soil characteristics by ordinary kriging.
Basic Legal Issues of the Management of Natural Resources of the Caspian Sea
Taking into account different interpretations of legal status of the Caspian Sea, the paper focuses on the current and future legal regime of its natural resources. The relevant international instruments are considered and in this context national approaches of the Caspian states to resource management are legally assessed. In conclusion, some basic prerequisites for the developing scope of the legal regime of the Caspian natural resources are suggested.