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Summary Sediment size distribution greatly affects sediment transport and deposition. A better understanding of sediment sorting will improve understanding of erosion and sedimentation processes, which in turn will improve erosion modeling. To address this issue, a total of 12 rainfall simulation experiments were conducted in a 1 m by 5 m box with varying steep slopes (10°, 15°, 20° and 25°), and the simulated rainfall lasted for 1 h at a rate of 90 mm h−1. For each simulated event, runoff and sediment were sampled at 3-min intervals, which were performed to study in detail the temporal change in size distribution of the eroded materials. These data were used to interpret the real-time sequence of transport mechanisms acting in response to the simulated rainfall. Total soil loss is the sum of suspended, saltating and contact loads. The proportion of sediment

Controlling soil hydrological processes and combating soil erosion on agricultural fields are high priorities for crop production and ecological environments. In this research, the effect of land application of rock fragments on surface runoff, subsurface runoff, infiltration and soil loss on Regosols had been investigated under field conditions using a portable rainfall simulator. Experimental twin-plot (two subplot with 1-m wide by 2-m long, 32% slope) with different rock fragment covers ranging from 0–40% were exposed to three rainfall intensities, low (57 ± 2 mm h-1), medium (91 ± 3 mm h-1), and high (122 ± 5 mm h-1). Fifteen treatments were conducted in the experiments in duplicates. Surface runoff, subsurface runoff, soil moisture and sediment were measured. Results show that surface rock fragment cover retarded surface runoff, increased infiltration and subsurface runoff, and diminished sediment concentration and soil loss. The final infiltration rates, which increased with increasing rock fragment covers, were 16.5–42.7 mm h-1 at low intensity, 19.7–50.8 mm h-1 at medium intensity and 23.8–56.4 mm h-1 at high intensity. Compared with bare soils, surface runoff rates were reduced to 24%, 51% and 64% in soils with 40% rock fragment cover at low, medium and high intensity rainfall, respectively. Subsurface runoff volume was significantly higher and time to start subsurface runoff was shorter as surface rock fragment cover increased. Compared with bare soils, subsurface runoff coefficients increased to 3.5, 3.3 and 2.9 times in soils with 40% rock fragment cover at low, medium and high intensity, respectively. Sediment concentrations increased from 9.8 g L-1 for 40% rock fragment cover under high intensity rainfall to 51.5 g L-1 for bare soils with rain falling at high intensity. The erosion rate was 15 g m-2 min-1 for bare soils under low intensity. The relationship between rock fragment cover and soil loss ratio can be expressed by an exponential function with a high degree of reliability, regardless of rainfall intensities. Overall, results indicate the surface rock fragments can be influential in shaping hydrological processes and soil loss from sloping farmland.

Summary Soil erosion poses a serious problem for sustainable agriculture and the environment. Owing to long-term anthropic pressure including overuse and inappropriate development, soil erosion has become a serious issue in the Three Gorges Area (TGA), China. Recently, integrated small watershed management (ISWM) for soil conservation in the TGA was rapidly developed. This study was conducted to investigate the impact of ISWM on soil erosion and sediment delivery in the Wangjiaqiao watershed in the TGA. The WATEM/SEDEM distributed erosion and sediment transport model was used to evaluate the effectiveness of the ISWM project. The model was calibrated against long-term measured suspended sediments at the watershed outlet. Land use and conservation measures were mapped and analyzed for 1995 and 2005, paying particular attention to quantification of changes in soil erosion and sediment delivery due to ISWM. The results showed that a combination of decreased soil loss (from 18.5 t ha −1 y −1 in 1995 to 13.2 t ha −1 y −1 in 2005) and increased sediment deposition (from 7.7 to 12.4 t ha −1 y −1 ) has led to a strong decrease in sediment yield (from 8.4 to 3.9 t ha −1 y −1 ) and the sediment delivery ratio (from 0.454 to 0.295). The results of scenario analysis showed that soil conservation measures taken in fields effectively reduce on-site soil loss and sediment yield. However, off-site sediment control measures appear to be much less effective at reducing sediment yield. This diachronic comparison of soil erosion and sediment delivery revealed that ISWM is quite effective and efficient; therefore, it is the appropriate method to combat soil erosion in the TGA and similar areas.

The emerging interdisciplinary field of hydropedology promotes synergistic integration of pedology and hydrology to enhance the holistic study of soil–water interactions across space and time. Our study illustrated this integration, exemplifying from plot-scale hydrological processes investigations on the sloping lands with different soil thickness in the Three Gorges Area of China. Our aims were to deal with (i) the watershed scale soil thickness survey, soil profiles description and hydrological processes inferential analysis for the plots with typical soil thickness from the pedological perspective, and (ii) the identification of dominant hydrological processes of these plots based on hydrological monitoring under simulated rainfall (designed as 60 mm h−1) from the hydrological perspective. The main results can be summarised as follows: (i) soil thickness of the sloping lands exhibited a wide range of variability along hillslopes. Thin soils reflected weaker pedogenesis degrees and less intense human intervention as compared with thick soils. (ii) Deep percolation and subsurface flow were the dominant processes in thin soils, whereas in thick soils, surface flow, deep percolation and storage were the dominant processes. (iii) Regarding to the surface flow, the 23-cm plot was mainly in the form of saturated overland flow, whereas the other plots were Horton overland flow. As to the subsurface flow, both 23- and 31-cm plots mainly took the form of preferential flow, the 59- and 76-cm plots mainly in the form of matrix flow regardless of soil horizon and the 45-cm plot displayed mainly the matrix flow in the A horizon and mainly the preferential flow in the AC horizon. Our study suggested that, relative to its parent disciplines of both pedology and hydrology, hydropedology improved synergies between pedology and hydrology in the plot-scale hydrological processes investigations. Copyright © 2011 John Wiley & Sons, Ltd.

Recently there have been reports of forest regrowth occurring in different regions across the world. There is also a growing recognition of the potential beneficial impact that secondary forests may have on the global environment: providing crucial ecosystem services such as soil conservation, stabilization of hydrological cycles, carbon sequestration, and support for forest dependent communities. Consequently, there is a growing awareness of the need to recognize that landscapes are complex shifting mosaics wherein forest clearing and reforestation take place. In this study, the rates of reforestation, deforestation, forest regrowth and degradation were measured using multi-temporal Landsat images of Danjiangkou, China. Landsat data from 1990, 1999 and 2007 were (1) classified as dense forest, open forest and non-forest areas and (2) compared between years to identify forest cutting, regeneration and degradation. The results showed that there was a net gain of 29,315 ha of forest area (including dense and open forest) from 1990 to 2007, showing a clear trend of reforestation in the study area. Forest modification (degradation and regrowth) and change categories (deforestation and reforestation) occurred simultaneously during the observation time period. Socioeconomic data from public statistics and environmental attributes allowed the assessment of the socioeconomic factors and the environmental conditions that caused these changes using non-metric multidimensional scaling (NMDS). The research showed that the socioeconomic factors due to different policies were major driving forces of forest transition, whereas environmental attributes of the underlying landscape constrained forest cover changes. These findings have led to a better understanding of forest transition at a local scale in our study region. Comprehensive knowledge of these relationships may be useful to reconstruct past forest transitions and predict future changes, and may help to enhance sustainable management practices aimed at preserving essential ecological functions.

Regeneration of degraded grassland ecosystems is a significant issue in restoration ecology globally. To understand the effects of artificial management measures on alpine meadows, we surveyed topsoil properties including moisture, organic carbon (SOC), nitrogen (N), and phosphorus (P) contents five years after fencing and fencing + reseeding management practices in a sandy meadow in the eastern Qinghai-Tibetan Plateau, northwestern China. Both the fencing and fencing + reseeding management practices significantly increased soil moisture storage, SOC, total N, available N, total P, and available P, as compared to the unmanaged control. Fencing plus reseeding was more effective than fencing alone for improving soil C, N, and P contents. These suggested that rehabilitation by reseeding and fencing generally had favorable effects on the soil properties in degraded sandy alpine meadows, and was an effective approach for restoration of degraded meadow ecosystems of the Qinghai-Tibetan Plateau.

It has been suggested that above and belowground interactions produce important feedbacks in natural ecosystems. It is necessary to study the relationships between aboveground plant functional group traits and belowground biomass and soil chemical properties in natural grasslands. In a field study, four natural alpine meadows dominated by different plant functional groups were selected. We assigned the plant species to one of two functional groups: the grasses functional group (GFG) or the forbs functional group (FFG). The aboveground GFG and FFG biomass and total belowground biomass were measured. At the same time, for each sampling quadrat, soil pH, soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP), and available phosphorus (AP) were determined. GFG-dominated meadows had significantly higher total belowground biomass, SOM, TN, TP, AN, and AP than FFG-dominated meadows. Correlation analyses showed that total belowground biomass (to a depth of 30 cm) and soil nutrient contents were significantly and positively correlated with the GFG biomass proportion, but negatively correlated with the FFG biomass proportion. There were significant positive correlations among above and belowground biomass and the soil chemical properties studied. The GFG proportion may thus be an indicator of soil chemical properties in the studied meadow types. This implies that natural increases in, or introduction of more, GFG species in FFG-dominated meadows may improve soil nutrient conditions. This study provides the basis of understanding for future studies on plant-soil interactions and feedbacks in grassland ecosystems.

To understand the effects of grazing on grassland plants sexual and clonal recruitment, we conducted a demographic field investigation of species recruitment along a grazing gradient in the Tibetan alpine grassland. Grazing intensity had significant effects on quantity and diversity of sexual and clonal recruitment. Sexual recruitment increased significantly, but clonal offspring production decreased significantly with increased grazing intensity. Grazing intensity had different, significant effects on offspring recruitment of the various functional groups in the community, grasses (GG), sedges (SG), legumes (LG) and forbs (FG). Higher grazing intensity reduced offspring recruitment of GG and SG; it increased offspring recruitment of LG and FG. Seedlings were significantly more abundant in lightly grazed, moderately grazed and heavily grazed meadows than in non-grazed grasslands. Offspring diversity from sexual recruitment was significantly higher than that from clonal recruitment in grazed than in non-grazed grasslands. Our studies indicate that moderate grazing had positive effects on seedling recruitment and offspring diversity, but heavy gazing may alter community succession by affecting recruitment patterns among the four plant functional groups. (C) 2010 Elsevier GmbH. All rights reserved.

Mountain region citrus production systems occupy large parts of the landscape prone to soil erosion in the Three-Gorges Area of China. Several soil conservation measures, such as terracing hedgerows, are widely implemented in citrus orchards to control soil erosion. However, little is known about the effect of those measures on soil properties. The objective of this work was to analyse the changes of soil properties in citrus orchards subjected to different conservation measures. Experiments were conducted in four plots: control plot (SC, sloping orchard without conservation measures), sloping orchard with contour hedgerows (SCH), terraced orchard (TC) and terraced orchard with grass cover (TCG). Samples of soil surface from 0 to 15 cm were collected to analyse texture, bulk density (BD), aggregate stability, saturated hydraulic conductivity, soil organic matter (SOM) and soil nutrients. The spatial variability of those properties was also evaluated at slope and field scales. The results showed that the three conservation measures significantly increased saturated hydraulic conductivity, aggregate stability, SOM and available N, P, K, but decreased BD. The terracing with grass cover measures were the most effective in improving soil fertility among the three measures. The average SOM, available P, N, K in TCG were 0·27, 0·50, 1·74 and 1·72 and these rates are larger than for the in SC. Compared to SC, silt content was increased the SCH, while clay content was increased with TC and TCG. There was a downslope increase in clay content and total N but a decrease in gravels in the SC plot. However, that trend did not exist in the other plots. At the field scale, the soil aggregate stability and total nitrogen were significantly higher near the hedgerow under SCH, and the available N was significantly higher in the middle position under TC; the other soil properties had no significant trends based on the distance to hedgerow or stone bunds. Results of this study will contribute to a further understanding of the environmental influence of soil conservation measures. Copyright © 2010 John Wiley & Sons, Ltd.

The assessment of soil erodibility to water erosion in the field is often expensive and time-consuming. This study was designed to reveal the effects of aggregate breakdown mechanisms on interrill erosion dynamics and develop an improved model for assessing interrill soil loss, which incorporated the soil aggregate stability tests as a substitute for the interrill erodibility parameter, from both disturbed and undisturbed samples for red soils in subtropical China. Six cultivated areas of sloping land with red soils were selected, and topsoil aggregate stability was analyzed using the Le Bissonnais method to determine the different disaggregation forces. Laboratory rainfall simulations were designed to distinguish the effects of slaking (at different wetting rates) and mechanical breakdown (with and without screening) on soil erosion characteristics. Field rainstorm simulations with medium and high rainfall intensities were conducted on runoff plots (2 m 1 m) with slope gradients varying from 10% to 20% for each soil type. A new instability index, Ka , which considers aggregate breakdown mechanisms in interrill erosion processes, was proposed based on the disturbed sample results. Ka showed a close relationship with erosion rates in both disturbed and undisturbed samples. Following from the results of undisturbed sample experiments, Ka was used as a substitute for the erodibility factor, and introduced into the WEPP model, establishing a new erosion predication formula for red soils which had a good correlation coefficient ( R 2 = 0.89**). This research made a good attempt at estimating the interrill erosion rate on the basis of aggregate stability from simple laboratory determinations. These results extend the validity of soil aggregation characterization as an appropriate indicator of soil susceptibility to interrill erosion in red soils from subtropical China. The formula based on the instability index, Ka , has the potential to improve the methodology used for assessing interrill erosion rates.

An aggregate stability test and a simulated rainfall test were conducted on four representative Ultisols from southeastern China. The soils selected, with clay contents ranging between 117 and 580 g kg−1, were derived from shale and Quaternary red clay. The stability of aggregates (2–5 mm in diameter) obtained from the soil samples were determined by the Le Bissonnais method. For determination of infiltration, runoff, and erosion, the soil samples were packed in 30 cm × 60 cm trays, wetted at rates of 2, 10, and 60 mm h−1, and then exposed to simulated rainfall at 60 mm h−1 for 1 h. The results indicated that both aggregate stability and slaking caused by fast wetting increased with increasing clay content. The effect of wetting rate (WR) on infiltration and seal formation varied with clay contents. In the soil with low clay content (sandy loam), the infiltration rate was affected slightly by WR due to low aggregate stability and slaking. In the soils with medium clay content (silt clay loam and clay), WR affected infiltration significantly due to the high aggregate slaking force. In the soil with high clay content, the effect of WR on infiltration was significant, but not as evident as in the soils with medium clay content, which may be related to high aggregate stability by wetting partially compensating for slaking force. The effect of WR on soil loss was similar to that of runoff, but more pronounced. The findings from this study indicated that the relationship between wetting rate and clay content should be considered when predicting interrill erosion in Ultisols.

The Danjiangkou reservoir lies in the upper Hanjiang basin and is the source of water for the Middle Route Project (MRP) under the South-to-North Water Transfer Scheme (SNWT) in China. The eco-environment of water resource areas plays an important role in water conservation and purification and would have significant implications for the economic prosperity in Hanjiang basin as well as for the SNWT. Focusing on the Danjiangkou Reservoir Area (DRA), this study established an environmental information system database. Based on the database, an eco-environmental vulnerability assessment method using integrated fuzzy AHP (FAHP) and GIS was developed for the DRA. According to eco-environmental conditions and anthropic effects, vulnerability was classified into five levels: potential, light, medium, heavy and very heavy. The eco-environmental vulnerability distribution and major problems of the eco-environment were analysed and discussed. The results indicated that eco-environmental vulnerability in the DRA was moderate overall. Regions with lower eco-environmental vulnerability were located in Qinling Mountain area in the northwest, Daba Mountain area in the south and the area immediately surrounding Danjiangkou Reservoir in the east. Two regions with very high eco-environmental vulnerability were located in the north of Danjiangkou Reservoir in Henan province and in the western part of Shanxi province. On the basis of analysis of distribution of the different factors of eco-environmental vulnerability, different environmental protection measures were proposed for different areas. This study demonstrated that the proposed method was an effective approach for the assessment of environmental vulnerability. The results gained closely reflected the reality of the eco-environmental vulnerability of the DRA.

Reliable and cost-effective soil erosion assessment is an important precondition for soil conservation measures, which remains a major challenge at large scale. Considering that the neuro-fuzzy model has the special advantage in multi-index comprehensive assessment and GIS technology is adept at geo-spatial information processing, through the combination of them, it is possible to provide an effective approach for this difficult problem. Taking Hubei Province as a case study area, five evaluating indicators were selected for the large-scale assessment, in which the GIS technology was used to construct the classification maps of evaluating indicators and to divide basic assessment units, and the neuro-fuzzy model was adopted to extract fuzzy rules for individual units assessment from available ground truth data. According to the optimized assessment criteria generated by the neuro-fuzzy model, the soil erosion state of the entire study area was then assessed. To represent the spatial distribution of soil erosion, a detailed map was produced by statistical mapping, which was represented with six erosion levels (from slight to severe) at a map scale of 1:250 000. The resulting map showed that about 30.1% of the total land area in Hubei was affected by different levels of soil erosion problem. Western high mountains and eastern low mountains suffered from the most serious erosion damage, a strong level of soil erosion was widely observed in these mountains. Large areas of moderate level erosion occurred in the northern hills. In contrast, most of the central plains were characterized as slight level erosion effect. The validation indicated that an overall accuracy of 88% and a κ of 0.89 were achieved, proving that the resulting map was in conformity with actual conditions, which indicates this assessment approach was reasonable and applicable. Copyright © 2009 John Wiley & Sons, Ltd.

Soil erosion hazard maps can be an essential tool in erosion prone areas as they explain and display the distribution of hazards and areas likely to be affected to different magnitudes. Therefore, it is very useful to planners and policy makers initiating remedial measures and for prioritizing areas. In this study, a numerical model was developed for soil erosion hazard assessment, in which Z-score analysis was combined with a geographical information system (GIS) to compute a synthetic soil erosion hazard index (SEHI). For this model, nine factors which have notable impact on soil erosion were selected. To generate the selected factors remote sensing, analytical hierarchy process (AHP) and GIS techniques along with spatial models were applied. To standardize all of the factors and establish the factor weights, the AHP method was adopted. For Z-score analysis with selected standardized factors, the Integrated Land and Water Information System (ILWIS) software was used and nine individual layers with Z-scores were prepared. Afterwards, the layers were integrated with their factor weights by means of a weighted linear combination to derive a SEHI value for each pixel. To classify the discrete SEHI map to represent a meaningful regionalization of soil erosion hazard, the equal distance cluster principle was used and graded into four levels of hazard; very high, high, moderate and low. The results depicted that in general, a moderate hazardous condition of soil erosion was found in the study area and the proposed approach was also able to identify the areas under high and very high hazards that require urgent intervention on a priority basis. Based on this study, comprehensive erosion hazard management strategies were anticipated for the efficient management of present and future erosion disaster in the area.

The use of contour hedgerows is widely advocated to sustain crop production and reduce soil loss on steeplands in the Three Gorges Area of China. However, little is known about the effects of soil management on soil fertility within these systems, or about the spatial gradients in soil nutrients that may develop in terraces formed behind the vegetative barriers. Therefore, we carried out a study on the effects of various long-term soil management practices on soil fertility and spatial variation of fertility between hedgerows. At a site in the Three Gorges Area, China, we applied five treatments to a contour hedgerow system: control (no fertilizer and manure); chemical fertilizer (CF); chemical fertilizer and mulch (CF + MU); pig manure (PM); and mulch, pig manure, and chemical fertilizer (CF + PM + MU). Soil samples were collected from the topsoil horizon (0–20 cm) of the selected five treatments in 2006 after 11 crop cycles, and physical and chemical properties were analyzed. The results showed that chemical fertilizer clearly improves nutrient status of the topsoil, while pig manure also increased the amount of soil organic matter. This increase in organic matter was associated with an increase in soil aggregate stability, a reduction in bulk density, and reduced penetration resistance of the soil. Mulch with pig manure and chemical fertilizer was the best management practice for improving soil quality and crop yields in the Three Gorges Area. Further, mulch and pig manure addition also decreased the magnitude of the spatial variation, but did not offset the soil fertility gradients because tillage resulted in significant movement of soil. More favorable soil properties were found at the lower positions within each alley, regardless of the management practice applied.

During raindrop impact soil, aggregates breakdown and produce finer, more transportable particles and micro-aggregates. These particles and micro-aggregates appreciably affect the processes of infiltration, seal and crust development, runoff, and soil erosion. Aggregate stability is, therefore, an important property that may explain, quantify, and predict these processes. This study was designed to develop improved formulae for assessing interrill erosion rate by incorporating the aggregate stability index ( A s ) in the prediction evaluations for soil erodibilites of Ultisols in subtropical China. Field experiments of simulated rainfall involving rainstorm simulations with medium and high rainfall intensity were conducted on six cultivated soils for which the soil aggregate stability was determined by the LB-method. This study yielded two prediction equations D i = 0.23 A s I 2 (1.05 − 0.85 exp −4sin θ ) and D i = 0.34 A s qI (1.05 − 0.85 exp −4sin θ ) that allowed a comparison of their efficiency in assessing the interrill erosion rate. A s is an aggregate stability index, which reflected the main mechanisms of aggregate breakdown in interrill erosion process, θ is the slope angle, I is the rainfall intensity, and q is the runoff rate. Relatively good agreement was obtained between predicted and measured values of erosion rates for each of the prediction models ( R 2 = 0.86 ** , and R 2 = 0.90 ** ). It was concluded that these formulae based on the stability index, A s , have the potential to improve methodology for assessing interrill erosion rates for the subtropical Chinese Ultisols. Considering the time-consuming and costly experimentation of runoff rate measurements, the equation without runoff rate ( q ) was the more convenient and effective one to predict interrill erosion rates on Ultisols of subtropical China.

It is crucial for effective water resource management in a watershed that the relationship between land use changes and baseflow. This study quantifies the influence of land use changes on the baseflow dynamics using a hydrological model and partial least-squares (PLS) regression in the Upper Du Watershed (8961 km2), China. Our study suggests that forest can be a major factor with a negative impact on the baseflow. Additionally, farmland and urban land have second-order negative effects on the baseflow dynamics. Baseflow increases when forest is replaced by farmland because the evapotranspiration (ET), associated with baseflow recession, is weaker and shorter in duration in the farmland than in the forest. The conversion of forest to urban land increases baseflow owing to the presence of non-contributing impervious surfaces in urban areas, which prevents the urban land from intercepting the baseflow discharge. These results indicate that the baseflow dynamics are closely associated with varying land use types within a watershed. Thus, this study is intended to provide a deeper understanding of the baseflow processes and useful quantitative information on land use factors in watersheds, enabling more informed decision-making in forest and watershed management.

Traditional fingerprinting methods are limited in their ability to identify soil erosion sources where geologic variations are small or where different land uses span geological boundaries. In this study, a new biomarker for fingerprinting, specifically, n-alkanes, was used in a small catchment to identify sediment sources. The n-alkanes were based on land uses, could provide vegetation information, and were relatively resistant to diagenetic modifications and decomposition. This study used a composite fingerprinting method that was based on two types of fingerprint factors (27 biomarker properties and 45 geochemical properties) with 60 source samples (i.e., gully, grassland, forest, and cropland) and nine soil profiles. Genetic algorithm (GA) optimization has been deployed to find the optimal source contribution to sediments. The biomarker results demonstrated that young forest is the main sediment source in this catchment, contributing 50.5%, whereas cropland, grassland and gully contributed 25.6%, 14.4% and 9.5%, respectively; the geochemistry results were similar to the biomarkers. The forest and grassland contributions gradually increased from upstream to downstream, and the sediment contributions of cropland gradually decreased in the direction of the runoff pathway at the check dam. In a comparison of biomarker and geochemical fingerprinting data, the latter may have overestimated the forest inputs to the catchment sediment yields because of a mixed land use history (i.e., forest and grassland). The geochemical fingerprint approach limits its ability to fully discriminate sources based on land management regimes, but the biomarker (individual n-alkanes) displayed the potential to discriminate between a greater number and different types of sediment sources and to provide greater detail regarding sediment sources.

Adenocarcinoma of the oesophagogastric junction (AEG) potentially metastasizes to lymph nodes (LNs) in the abdomen and thorax. The aim of this study was to analyse the impact of metastatic LN location on prognosis in patients with AEG.From May 2000 to March 2002, 645 patients with AEG underwent resection in our hospital. There were 525 males and 120 females, aged from 31 to 78 years (median = 60 years). Follow-up was carried out by correspondence every 6 months. N-classification according to the number (0, 1-2, 3-6,6; N0-3), station (0, 1, 2, 3; S0-3) or field (0, 1 (abdominal or mediastinal), 2 (abdominal and mediastinal); F0-2) of LN metastasis and other prognostic factors were evaluated by univariate and multivariate survival analyses.Of the 645 patients, 307 (47.6%) had LN metastasis. The 5-year survival rate for patients with LN metastases was 16.0% compared to 36.8% for those without LN metastases (P = 0.000). The length of tumour, and the number, station and field of the LN metastasis were independent prognostic factors by multivariate analysis. However, when patients without LN metastasis were excluded from the survival analysis by log-rank test, there were significant differences only in patients with F1 versus F2 LN metastasis, with 5-year survival rates of 14.4% and 8.0%, respectively (P = 0.022).The presence of LN metastases concurrently in both the abdomen and mediastinum is a significant adverse prognostic factor for patients with AEG, and should be included in the future TNM staging system.

Understanding how sediment concentrations vary with land use/cover is critical for evaluating the current and future impacts of human activities on river systems. This paper presents suspended sediment concentration (SSC) dynamics and the relationship between SSC and discharge (Q) in the 8973 km2 Du catchment and its sub-catchment (4635 km2). In the Du catchment and its sub-catchment, 4235 and 3980 paired SSC–Q samples, respectively, were collected over 30 years. Under the influence of the Household Contract Responsibility System and Grain-for-Green projects in China, three periods were designated, the original period (1980s), cultivation period (1990s) and reforestation period (2000s). The results of a Mann–Kendall test showed that rainfall slightly increased during the study years; however, the annual discharge and sediment load significantly decreased. The annual suspended sediment yield of the Du catchment varied between 1.3 × 108 and 1.0 × 1010 kg, and that of the sub-catchment varied between 6.3 × 107 and 4.3 × 109 kg. The SSCs in the catchment and sub-catchment fluctuated between 1 and 22400 g m−3 and between 1 and 31800 g m−3, respectively. The mean SSC of the Du catchment was relatively stable during the three periods (±83 g m−3). ANOVA (analysis of variance) indicated that the SSC did not significantly change under cultivation for low and moderate flows, but was significantly different under high flow during reforestation of the Du catchment. The SSC in the sub-catchment was more variable, and the mean SSC in the sub-catchment varied from 1058 ± 2217 g m−3 in the 1980s to 1256 ± 2496 g m−3 in the 1990s and 891 ± 1558 g m−3 in the 2000s. Reforestation significantly decreased the SSCs during low and moderate flows, whereas cultivation increased the SSCs during high flow. The sediment rating curves showed a stable relationship between the SSC and Q in the Du catchment during the three periods. However, the SSC–Q of the sub-catchment exhibited scattered relationships during the original and cultivation periods and a more linear relationship during the reforestation period.

A computerized parametric methodology was applied to monitor, map, and estimate vegetation change in combination with “3S” (RS—remote sensing, GIS—geographic information systems, and GPS—global positioning system) technology and change detection techniques at a 1:50000 mapping scale in the Letianxi Watershed of western Hubei Province, China. Satellite images (Landsat TM 1997 and Landsat ETM 2002) and thematic maps were used to provide comprehensive views of surface conditions such as vegetation cover and land use change. With ER Mapper and ERDAS software, the normalized difference vegetation index (NDVI) was computed and then classified into six vegetation density classes. ARC/INFO and ArcView software were used along with field observation data by GPS for analysis. Results obtained using spatial analysis methods showed that NDVI was a valuable first cut indicator for vegetation and land use systems. A regression analysis revealed that NDVI explained 94.5% of the variations for vegetation cover in the largest vegetation area, indicating that the relationship between vegetation and NDVI was not a simple linear process. Vegetation cover increased in four of areas. This meant 60.9% of land area had very slight to slight vegetation change, while 39.1% had moderate to severe vegetation change. Thus, the study area, in general, was exposed to a high risk of vegetation cover change.

The Three Gorge Project (TGP) of China necessitates the resettlement of over 1 million population (mostly farmers) to more rugged and isolated areas than their original settlements. Soil erosion is a serious environmental and production problem in this area. To decrease the risk on environmental impacts, there is an increasing demand for sound, and readily applicable techniques for soil conservation planning in the Three Gorge Areas (TGA). The objectives of the study were to develop and validate a soil erosion-predicting model based on the revised Universal Soil Loss Equation (RUSLE) in a geographic information systems (GIS) environment. The use of GIS to develop conservation-oriented watershed management strategies in the Wangjiaqiao watershed is presented. Data used for the RUSLE were either determined or taken from published literature pertaining to the Wangjiaqiao watershed. In combination with IDRISI, GIS software (Eastman, R.J., 1997. IDRISI for Windows: User's guide (Version 2.0). Clark University, Graduate School of Geography, Worcester, MA, Chapters 4–17) was used to evaluate different agricultural management strategies in terms of predicted soil loss in the watershed. This model allowed for easy assessment of soil erosion hazards under different crop and land management options over the entire watershed. The study revealed that the annual average soil loss rate from relatively flat agricultural land was approximately 26 t/ha, whereas 52 t/ha was found on the cultivated sloping lands, which constitutes a large proportion of soil loss in the watershed. In the watershed, approximately 38 ha of agricultural land had slopes >47% (25°) and should be reforested or returned to pasture. Contour tillage (CT) and contour farming with a seasonal no-till ridge (CTN) were most effective in reducing soil loss rates. If CT and CTN were implemented, approximately 31% and 70%, respectively, of the areas with soil loss > T EP would be reduced to T EP . T EP is soil loss tolerance for economic planning and was set at ≤10 t/ha year. In addition to soil loss reduction, the CTN has the potential to increase crop yield. Soil erosion hazards may be alleviated in over 91% of the agricultural lands if combined conservation measures including terraces, CTN, CT, and crop rotations were implemented in the watershed. The results of the study indicate that the RUSLE-GIS model is a useful tool for resource management and soil conservation planning. This technology is readily transferable and accessible to other land managers and agronomists in the TGA.

To investigate the effect of erythromycin on electrical activity and emptying of the intrathoracic stomach after esophagectomy for esophageal cancer.Thirty patients undergoing esophagectomy for cancer and esophagogastrostomy above the aortic arch were divided into the study group (n=15) and the control group (n=15). Electrogastrography and radionuclide gastric emptying were examined for these patients before and 1, 3, 6, 12 months after surgery. Patients in the study group received erythromycin (0.25 g tid po) for 1 week before examination.The wave amplitude (Uv), dominant frequency (CPM) and percentage of normal slow wave (%) of electrogastrogram decreased after surgery and returned to normal at the first postoperative month in the study group and the 12th postoperative month in the control group (P0.05). Gastric emptying was significantly delayed after esophagectomy, and returned to normal one year after operation in the study group (P0.05). However, gastric emptying remained abnormal in the control group (P0.01).Erythromycin improves electrical activity and emptying of the stomach after esophagectomy for cancer. Gastric emptying recovery later than the recovery of electrical activity, which may be related to gastric ischemia and edema.

Taking the water level fluctuating zone of the Danjiangkou Reservoir as a case, and by the method of hierarchical cluster analysis, the soil seed banks at 37 sampling plots within the areas of 140-145 m elevation were divided into 6 groups, and the species composition, density, and diversity of the soil seed banks among the groups were compared. The differences between the soil seed banks and the aboveground vegetations were analyzed by S0rensen similarity coefficient, and the correlations among the soil seed banks, aboveground vegetations, and environmental factors were explored by principal component analysis (PCA) and multivariable regression analysis. At the same altitudes of the water level fluctuating zone, the species composition of the soil seed banks had obvious heterogeneity, and the density and diversity indices of the soil seed banks among different groups were great. The similarity coefficient between the soil seed banks and aboveground vegetations was low, and the species number in the soil seed banks was obviously lesser than that in the aboveground vegetations. The density of the soil seed banks was highly positively correlated with the aboveground vegetations coverage and species number and the soil texture, but highly negatively correlated with the soil water-holding capacity and soil porosity.

A large amount of soil loss is caused by a small number of extreme events that are mainly responsible for the time compression of geomorphic processes. The aim of this study was to analyze suspended sediment transport during extreme erosion events in a mountainous watershed. Field measurements were conducted in Wangjiaqiao, a small agricultural watershed (16.7 km(2)) in the Three Gorges Area (TGA) of China. Continuous records were used to analyze suspended sediment transport regimes and assess the sediment loads of 205 rainfall-runoff events during a period of 16 hydrological years (1989-2004). Extreme events were defined as the largest events, ranked in order of their absolute magnitude (representing the 95(th) percentile). Ten extreme erosion events from 205 erosion events, representing 83.8% of the total suspended sediment load, were selected for study. The results of canonical discriminant analysis indicated that extreme erosion events are characterized by high maximum flood-suspended sediment concentrations, high runoff coefficients, and high flood peak discharge, which could possibly be explained by the transport of deposited sediment within the stream bed during previous events or bank collapses.

Erosion and sediment characteristics were measured using simulated rainfall on two cultivated soils from the Loess Plateau, China. The size distribution of eroded sediment (non-dispersed) was compared with equivalent measurements of the same samples after chemical and mechanical dispersion(dispersed) to investigate the aggregation ratio (AR) and enrichment ratio (ER). Results show that clay content is increasing with the length and rainfall intensity. The loessial soil increased by 8.77% and 2.43%, but the Lou soil increased by only 2.76% and 0.4%. With the increase of slope, the clay content of the two loess reduced by 4.91% and 3.93%, respectively. AR values were less than 1 and ER values were greater than 1. These indicated that relatively slight clay dispersion occurred and that most of the clay in the sediments was in the form of aggregates. The results will improve understanding of erosion and sedimentation processes, which in turn will improve erosion modeling. Knowledge of temporal variations of clay in sediment can also provide the basis for understanding and modeling the transfer of nutrients on hillslope.

Taking the Wulongchi catchment of Danjiangkou in central China as a case, the soil moisture regime in the observation period from April to October, 2008 was divided into different dry-wet time periods by two way indicator species analysis (TWINSPAN), and the environmental factors that had significant effects on the spatial pattern of soil moisture in different dry-wet time periods were selected by forward selection and Monte Carlo tests. The redundancy analysis (RDA) was adopted to identify the relationships between the distribution pattern of soil moisture and the environmental factors in different time periods, and the partial RDA was applied to quantitatively analyze the effects of environmental factors, spatial variables, and their interactions on the variation pattern of the soil moisture. The soil moisture regime in the observation period was divided into 7 types, and grouped into 4 time periods, i. e. , dry, semi-arid, semi-humid, and humid. In dry period, land use type was the dominant factor affecting the spatial pattern of soil moisture, and the soil thickness, relative elevation, profile curvature, soil bulk density, and soil organic matter content also had significant effects. In semi-arid period, soil thickness played dominant role, and land use type, topographic wetness index, soil bulk density, and profile curvature had significant effects. In semi-humid period, topographic wetness index was the most important affecting factor, and the land use type and the sine value of aspect played significant roles. In humid period, the topographic compound index and the sine value of aspect were the dominant factors, whereas the relative elevation and catchment area were the important factors. In the four time periods, there was a better consistency between the spatial distribution pattern of soil moisture and the environmental ecological gradient. From dry period to humid period, the independent effects of environmental factors on soil moisture pattern decreased but were still in dominant, the independent effects of spatial location had less change and maintained at lower level, while the interactions between environmental factors and spatial location contributed more and more.

Based on RS and GIS, this paper analyzed the dynamic characteristics, spatial differences, distributive characteristics of different slope and elevation of land use change in Danjiangkou reservoir from 1990 to 2007. And it also analyzed the driving factors of land use change. Results show that all types of land use increased to different degrees except dry land and paddy field. With maximum annual rate of change of residential land, rural and urban areas were 12.85%, 7.47% repectively. The land use change among different types was mainly reflected by the arable land transferring into woodland, shrub, grassland and residential land. In addition, there were also obvious mutual transformation among the woodland, shrub and grassland. Social and economic development, population growth and government policy guidance were the main driving factors of land use change in Danjiangkou reservoir.

Surface markers were studied at first relapse in 66 cases of acute myeloid leukaemia (AML), using a panel of five monoclonal antibodies directed to CD13, CD14, CD15, CD33 and CD34 antigens. At time of relapse, there was increased expression of CD33 (P = 0.002) and CD34 (P = 0.0001), and decreased expression of CD13 (P = 0.004) and CD15 (P = 0.0001) antigens by comparison to initial diagnosis. There was no strict correlation with the FAB classification. However, CD13 and CD33 expression changes preferentially affected granulocytic leukaemias. At relapse, CD14 and CD34 were significantly more expressed in monocytic than in granulocytic AML (P = 0.01 and 0.003 respectively). In a multivariate analysis, CD34 expression was associated with a low CR rate (P = 0.001) and short survival (P = 0.05), whereas CD15 expression was associated with long survival (P = 0.0004). These results suggest that AML tends to relapse with a less differentiated phenotype than observed at diagnosis and that AML with less differentiated phenotype is of poor prognosis after first relapse, as also observed at diagnosis.

Based on the fixed-spot observation, this paper analyzed the effects of soil thicknesses on the spatiotemporal pattern of soil moisture in the Wulongchi catchment of Danjiangkou, China. The soil moisture content increased soon after precipitation events, followed by a decline as the soil dried down, whilst its spatial heterogeneity exhibited an opposite pattern. The profile-averaged soil moisture content differed significantly with soil thickness. The soil with a thickness of 20 cm had lower profile-averaged moisture content whose variation trend was similar to that of precipitation and varied obviously among seasons; medium thickness (20-40 cm) soil had medium level of profile-averaged moisture content whose seasonal variation was moderately and affected by the characteristics of precipitation; while the soil with a thicknesses of40 cm had higher profile-averaged moisture content whose seasonal variation was relatively small. The profile distribution pattern of soil moisture was determined by the integrated effects of precipitation, evapotranspiration, and leakage, exhibiting increasing-type at semi-humid stage, waving-type at humid stage, and both of the two types at arid stage. There was a significant positive correlation between profile-averaged soil moisture content and soil thickness, and the correlation coefficient was 0.630-0.855. The moisture content in 0-15 cm soil layer had less correlation with soil thickness, but the moisture content in 20-55 cm soil layer was significantly correlated with soil thickness.

Land use and land cover change is gaining recognition as a key driver of environmental change. Rapid change of land use has occurred in the red soil hilly region of southeast China in the past three decades due to rural land reform, population pressure and rapid economic growth. In this paper, land use change and its impacts on environmental quality of Xianning County were investigated using technologies of remote sensing (RS), geographic information systems (GIS), and spatial principal components analysis (SPCA). It was indicated that the area of paddy field and upland decline rapidly while the area of woodland, horticulture farm and residential land increased sharply between 1978 and 2002. The driving forces probably were land use policy of the State government, structural adjustment of agricultural sectors and implementation of environmental conservation measures. Based on the assessment of environmental implications of land use practices, the environmental quality of some land use types (i.e. Woodland, sparse woodland, and paddy field) tended to improve, while horticulture farms, water body, and residential land showed a deterioration trend of environmental quality during 1978-2002. Perhaps the most significant finding of this study is that environment appears a negative tendency in the study area from 1991 to 2002, because little attention has been paid to the status and management of agricultural lands, which account for a substantial proportion of total land area. Therefore, for further improving environment in red soil hilly region in China, urgent action is required to improve the advisory services support to farmers on new tillage practices, soil and water conservation practices, raising the efficiency of fertilizer and manure use.

Based on the multi-temporal and multi-source sensor images of 1987-2005, the dynamic changes of forest vegetation coverage in Letianxi basin of Three Gorges Reservoir Area were investigated by the methods of color balancing, image fusion, and radiometric normalization. The results showed that in 1987-2005, the forest area in the basin increased from 265.82 km2 to 346.45 km2. Vegetation coverage also had an increasing trend, but the increment was not uniform in the whole basin. The change process of the forest vegetation could be divided into three stages, i.e., slight destroying, starting restoration, and complete restoration. The gravity center of the forests in different coverage classes changed significantly, e.g., the gravity center of the forests with vegetation coverage less than 45% transferred to the north before 1987, but moved back to the south thereafter, while that of the forests with vegetation coverage greater than 45% moved constantly from northwest to southeast. The changes of forest vegetation coverage in the study area were deeply affected by the human disturbance, regional economic development, and national comprehensive management measures. Through 10 years ecological restoration, human disturbance was decreasing, and the forest area with vegetation coverage above 60% reached 217.88 km2, occupying about 62.9% of the total forest area, which implied that the ecological environment was improved gradually.

To evaluate the therapeutic effects of anterior stromal punctures (ASP) in patients with bullous keratopathy (BK).Twenty-seven patients awaiting penetrating keratoplasty with a diagnosis of BK were examined. They were seen before treatment with ASP and 1, 4, and 12 weeks after treatment. The examination included slit-lamp examination, photography of the cornea, ultrasonic pachymetry, central esthesiometry, and pneumotonometry. Subjective evaluations of pain, discomfort, and photophobia were also done using a visual scale model. Photographs were analyzed by computer-assisted planimetry and used to measure the corneal surface covered by bullae and microcysts. Pretreatment and posttreatment values (mean +/- SEM) were compared using the Student paired t test.At 3 months, a significant reduction in pain was noted. A decrease in the mean corneal surface covered by bullae (BKPreASP = 2733 +/- 553 microns2; BK3mo = 1006 +/- 356 microns2, P = .004) was observed. A decrease in the esthesiometry (E) measurement (EPreASP = 3.5 +/- 0.4 cm; E3mo = 1.3 +/- 0.3 cm, P.001), an increase in corneal thickness ([CT] CTPreASP = 869 +/- 24 microns; CT3mo = 902 +/- 21 microns, P.001), and a decrease in the number of quadrants through which iris (I) details could be seen (IPreASP = 1.7 +/- 0.3; I3mo = 1.2 +/- 0.3, P = .015) were also noted. These findings corroborate the clinical observation of increased subepithelial fibrosis following ASP.Anterior stromal punctures reduce bullae formation and alleviate pain in patients with BK, and they constitute a valuable alternative to penetrating keratoplasty should surgery be delayed or contraindicated.

Offspring recruitment is an important part of population dynamics, as well as for plant-community structure and succession. One generality regarding grasses and fire is that clonal grasses tolerate fire extremely well and in most cases reach their maximum production in the immediate post-fire years. One qualification to this statement is that post-fire offspring, recruitment mode is very important. However, respective data are scare in the semiarid perennial steppe. We studied the relative importance of asexual v. sexual recruitment in the post-fire recovery in semiarid steppe on the Loess Plateau of north-western China. We observed differences in regeneration strategy after different times post-fire (burnt in 2008, burnt in 1999, and no fire history for at least 30 years). Results showed that fire significantly increased offspring recruitment numbers, but not species richness. The increase of asexual recruitment after a fire made a major contribution to the increase of total offspring number. Meanwhile, there was no significant difference for the ratio of asexual to sexual recruitment among sites with different times since fire. The asexual to sexual recruitment ratio was significantly different for different species, with some species not recruiting offspring via sexual recruitment. Our results indicated that seedling recruitment contributed little to post-fire recovery of the perennial-steppe community. Lack of sexual recruitment is not related to fire management but to inherent traits of the occurring plants.

Seed germination is a central component of plant life history. To investigate the proposed role of seed size on germination strategy in plant communities, a semifield experiment was conducted in alpine meadow of the Qinghai–Tibetan Plateau, China. Interspecies relationships of seed mass and seed germination characteristics were studied under semifield conditions with different light availability. Light availability and seed mass had significant effects on final germination percentage and time to germination for studied species. There was a significant negative correlation between the strength of light required for germination and seed mass. Fifteen study species (e.g. Ligularia przewalskii, Artemisia sieversiana Willd, Tripolium vulgare Ness. and Saussurea morifolia Chen) exhibited a synchronous germination strategy. Seeds from large-seeded species, such as Dracocephalum ruyschiana, Laniophlomis rotate (Benth.) and Salvia przewalskii Maxim., were less likely to require light for germination than those of small-seeded species, such as A. sieversiana Willd, Senecio diversipinnus Ling and Saussurea mongolica (Franch.). We propose that germination strategies of small-seeded species are well suited to unpredictable environmental variation in this alpine grassland community.

The effects of four recombinant hemopoietic growth factors (HGF) and of the impure factor HTB9 on proliferation and maturation of marrow myeloid (CFU-GM) and erythroid (BFU-E) progenitor cells were studied in 22 cases of myelodysplastic syndromes (MDS). In most cases, IL-3, GM-CSF and G-CSF increased significantly the number of myeloid colonies, the best combination being IL-3 + GM-CSF. A significant increase in the myeloid colony/cluster ratio was also noted, but cytological examination of colony cells showed little maturation. The analysis of myeloid colony surface markers with four monoclonal antibodies (to CD13, CD15, CD33 and CD34) showed minor modifications with an increase of CD13 and CD15 in about one third of cases when compared to control without HGF. Erythroid colonies were obtained in one case with erythropoietin alone, and in 19 cases with the addition of GM-CSF and/or IL-3. In short-term liquid cultures, IL-3, GM-CSF and G-CSF increased 3H-thymidine incorporation. We conclude that progenitor cells of most MDS are able to proliferate in the presence of HGF, with wide case-to-case variations. However, the pattern of growth remains abnormal when compared to normal marrow. Although the combination of IL-3 and GM-CSF is the most efficient, there is a large overlap in the stimulating effects of all factors studied.

A study of surface markers and in vitro growth in semi-solid and liquid medium was performed in 35 patients with newly diagnosed myelodysplastic syndrome (MDS). Surface markers were studied by CD34, CD13, CD14, CD15, and CD33 monoclonal antibodies. There was no strict correlation with the FAB typing, but CD34 was expressed only in refractory anemia with excess of blasts (RAEB) or RAEB in transformation (RAEB-t). CD14 was markedly positive in the 4 cases of chronic myelomonocytic leukemia. Colony-forming cells were assessed by culture in semi-solid medium in the presence of HTB9 as growth factor. Four growth patterns were identified: a) normal growth (6 cases); b) no growth or low plating efficiency (10 cases); c) low colony and high cluster number (15 cases); and d) normal or high colony number with high number of clusters (4 cases). Expression of CD34 was associated with low colony and high cluster number. Finally we studied the proliferation and differentiation capacities in liquid culture without stimulating factor. Fifteen patients had a spontaneous proliferation. This was not correlated with any surface marker. Differentiation assessed by the loss of CD34 and/or the increase of CD15 by more than 20% at day 7 was observed in 21 cases. None of the surface markers or growth patterns was associated with a specific chromosomal abnormality, except the lack of growth in liquid culture observed in all 5q deletion cases. In univariate analysis, RAEB and RAEB-t FAB subtypes, percentage of blasts higher than 5%, staining by CD33 and CD34, and lack of differentiation in liquid culture were significantly associated with progression to leukemia and shorter survival. In multivariate analysis, only CD34 expression (P = .002) and percentage of blasts (P = .05) remained independent significant variables. CD34 was the only significant variable for prediction of survival (P = .05). It is concluded that surface marker analysis at diagnosis and after liquid culture may be a useful tool for the initial evaluation of MDS.

The myelodysplastic syndromes (MDS) correspond to morphological entities characterized by the presence of one or several cytopenias and marrow maturation abnormalities in association with stem-cell disorders. MDS occur particularly in the elderly population, and in up to 40% of patients evolution will be characterized by overt acute myelogenous leukemia transformation. Clonal abnormalities exist within the bone marrow of patients with MDS and have been defined by characteristics in vitro marrow myeloid growth patterns and cytogenetics [1–3]. The colony-forming capacities of hematopoietic precursor cells are quite low or absent in the majority of patients with MDS [4–7]. Cellular growth is dependent on hematopoietic growth factors (HGFs) [8]. Purified and recombinant HGFs are available, and several have been shown to possess in vivo activity particularly with MDS patients [9–13]. This report presents a study of the in vitro response of MDS progenitors to several HGFs (IL-3, GM-CSF, G-CSF, M-CSF) and to various comparisons with cultures with HTB9, in the attempt to define the major effect on proliferation and differentiation.

Objective: To study the effect of patching on the speed of reepithelialization, slit-lamp signs of epithelial wound healing, and patient discomfort following a corneal abrasion. Methods: Forty-eight eyes of 46 patients with corneal erosion sparing Bowman membrane were randomized into 2 groups: with or without patching. Slit-lamp examination and photographs of the fluorescein-stained cornea were performed on a daily basis until reepithelialization was complete. Photographs were analyzed using computer-assisted planimetry. Results: No statistically significant difference was found between patched (n=25) and nonpatched (n=22) eyes for the mean size of the initial erosion (patched eyes, 23.7 mm2; nonpatched eyes, 18.9 mm2;P=.42), linear speed of reepithelialization (reduction over time of the radius of the largest circle included in the erosion: patched eyes, 0.0375 mm/h; nonpatched eyes, 0.0353 mm/h;P=.78), and surface speed of reepithelialization (reduction over time of the erosion area: patched eyes, 0.6510 mm2/h; nonpatched eyes, 0.5657 mm2/h;P=.60). The power to detect a 12-hour delay of epithelial closure was 95%. There were no significant differences between the 2 groups for pain, analgesia, insomnia, aspect of the epithelial border, intensity and duration of stromal edema, Descemet folds, anterior uveitis, and filaments. Conclusions: Patching a corneal erosion does not significantly accelerate reepithelialization and does not alter the epithelial wound healing pattern. It does not reduce the incidence and severity of inflammation nor relieve pain when compared with treatment without patching.