Initiated in 1984, the Committee Earth Observing Satellites' Working Group on Calibration and Validation (CEOS WGCV) pursues activities to coordinate, standardize and advance calibration and validation of civilian satellites and their data. One subgroup of CEOS WGCV, Land Product Validation (LPV), was established in 2000 to define standard validation guidelines and protocols and to foster data and information exchange relevant to the validation of land products. Since then, a number of leaf area index (LAI) products have become available to the science com-

Soils maps of China have been generated at different scales from ground surveys and laboratory analyses. A comprehensive effort coordinated by the Office for the Second National Soil Survey of China resulted in a series of soil maps covering the extent of the country at a scale of 1:1,000,000. The map series is now being converted from its current paper form to a digital format. The 1:1,000,000 digital soil map of China will consist of three parts: soil mapping unit boundaries, soil attributes, and the “reference system for Chinese soils.”The spatial data is based on the soil genetic classification of China, consisting of 12 orders, 61 great groups, 235 subgroups, and 909 families. The 1:1,000,000 soil maps are delineated based on the soil family definitions. The sampled soil attributes included physical, chemical, and fertility properties measured for 2473 soil species (series) (known as TuZhong in Chinese). The reference system for Chinese soils will use the attribute data for each soil species (series) to cross reference soil names in three classification systems, namely, Soil Genetic Classification of China, U.S. soil taxonomy, and the FAO World Reference Base for Soil Resources (WRB). The cross‐reference system will be constructed in a relational database so that any Chinese or international scientists can access equivalent names for a soil in any of the three systems.

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Soil classification systems are not consistent among countries or organizations thereby hindering the communication and organizational functions they are intended to promote. The development of translations between systems will be critical for overcoming the gap in understanding that has resulted from the lack of a single internationally accepted classification system. This paper describes the application of a process that resulted in the translation of the Genetic Soil Classification of China (GSCC) to Soil Taxonomy (ST). A brief history of soil classification in China is also provided to familiarize readers with GSCC and its origins. Genetic Soil Classification of China is the attribute base for the recently assembled digital form of the 1:1 000 000 soil map of The People's Republic of China. The translation between GSCC and ST was based on profile, chemical, and physical descriptions of 2540 soil series. First, the 2540 soil series were classified to their equivalent soil order, suborder, great group, and subgroup according to ST and GSCC subgroup descriptors. Order names for both classification systems were then linked to corresponding map units in the 1:1 000 000 digital soil map of China using a geographic information system (GIS). Differences in classification criteria and in the number of orders of the two systems (there are more GSCC orders than ST orders) meant that each GSCC order could possibly be assigned to more than one ST order. To resolve the differences, the percent correspondence in area between orders was determined and used as the criterion for assigning GSCC orders to ST orders. Some percentages of correspondence were low so additional processing was used to improve the assignment process. The GSCC suborders were then matched with ST orders. When the area for each order was summarized, the percentage of correspondence increased except for two subgroups in the Ferrasols order.

A method is described for the routine fractionation of inorganic soil phosphates. Use of constant suction pipettes, two molybdophosphoric reductants with different sensitivities, and an isobutyl alcohol extraction for the determination of reductant soluble phosphates greatly increased the speed of the phosphorus determinations. Results from 100 deplicated soil samples had average coefficients of variation and correlation between duplicates within samples for the four phosphate fractions of 3.7% and 0.998, respectively.

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areas contract and expand within and between events. Variable source areas are a function of topography, The targeting of critical surface runoff-producing zones should soils, geology, climate, and management. Within VSA account for the influence of subsurface soil characteristics. In this study we assessed the runoff response of contrasting colluvial and hydrology, surface runoff generation is classified as eiresidual soils. The study was conducted along two hillslopes within a ther infiltration excess or saturation excess (Sklash, 39.5-ha mixed land use watershed in Pennsylvania. Six sites (four 1990). Infiltration excess, or Hortonian overland flow, colluvial, two residual) were monitored for runoff, hydraulic head, occurs when rainfall intensities exceed the infiltration water table depth, and soil water content. A total of 111 rainfall events capacity of a soil. Variable infiltration capacities in the were monitored during the periods of July to December 2000, April landscape cause partial areas of infiltration-excess surto December 2001, and April to December 2002. Two high-intensity face runoff (Betson, 1964). Saturation excess occurs (5-min peak Ͼ 8 cm h Ϫ1) events had return periods of 2.5 and 4 yr. when the water table rises to saturate the soil profile, The colluvial soils are somewhat poorly and moderately well drained filling storage zones and minimizing infiltration capacwith fragipans and high clay content (37-44%) argillic horizons (fine, ity. Ideally, P management strategies should differ demixed, semiactive, mesic Aquic Fragiudalfs); the residual soils are well drained with moderate clay content (24%) argillic horizons (fine-pending on the dominant surface runoff generation loamy, mixed, semiactive, mesic Typic Hapludults). Across all events, mechanism in a watershed. An infiltration-excess-based overall runoff yields averaged 2.4% from the four colluvial sites and approach should target soils with a low infiltration ca-0.01% from the two residual sites. The two colluvial sites with the pacity, while a saturation-excess-based strategy should greatest runoff production were located at the base of a primarily target near-stream and other zones that are subject to colluvial hillslope. The largest events at these sites occurred during surface saturation (Gburek et al., 1996) regardless of periods of surface saturation (soil surface to a depth of at least 30 cm). infiltration capacity at these sites. These results suggest that nonwinter P management for these residual The saturation-excess mechanism has been studied soils should focus on rare, large events. Nutrient management planning primarily under forest and grassland vegetation (Bonell, could be improved if runoff estimation methods were to better inte-1993). In most temperate forested landscapes, infiltragrate information on subsurface and upslope soil hydrologic properties.

A multidisciplinary approach combining field surveys, aerial photographic techniques, digital terrain modelling, and GIS technology was used to analyze spatial interrelationships at a study site in the northern foothills of the Brooks Range, The sensitivity of snow drifting to topography at the site is pronounced. The drift patterns indicate winter winds are predominantly from the south with a major secondary component from the southwest. These southwest winds are likely in conjunction with storm events. The deepest snow beds are found on the steeper, north‐facing slopes. Snow also has an effect on vegetation that is evident at the scale of mapping (1:6000). Communities dominated by Cassiope tetragona are associated with deeper snow regimes, and may be useful indicators of deeper snow regimes even at much smaller scales because of their unique spectral signatures. The analyses conducted to date demonstrate the power of the GIS for analyzing terrain‐geobotanical interrelationships, which will increase as we add new layers for other variables, and are able to correlate these with satellite data.