Water availability is one of the most serious natural resource issues facing California, especially given projections for future climate change. The 3 million ha of oak (Quercus spp.) woodlands play a critical role in California's water supply system, providing runoff primarily from winter rainfall events and hosting two‐thirds of the state's drinking water reservoirs. Thus, understanding water storage and streamflow regulation by soils in these watersheds is essential for water resource planning under future climate change scenarios. The primary objectives of this research were to identify the drivers of soil moisture dynamics and the hydrologic budget at the catchment scale and their relationships with streamflow generation. A 33‐ha headwater catchment in the Sierra Nevada foothills of northern California was instrumented to monitor climate, subsurface lateral flow, streamflow, and soil moisture within 100 pedons distributed throughout the catchment. A catchment‐scale water balance was used to examine factors regulating spatial and temporal soil water distribution within the catchment. Relationships between soil, topographic, and vegetation characteristics and soil water content at each pedon were analyzed using a linear mixed‐effects model with four fixed effects: vegetation type or cover, presence or absence of a claypan, compound topographic index, and solar radiation. Streamflow was limited to periods when lower soil horizons were at or near saturation. Following saturation, each rainfall event generated subsurface lateral flow above the clay‐rich argillic horizon, resulting in sharp hydrograph responses with little base flow between rainfall events. For the two water years examined, 9.6 and 11.5% of rainfall left the catchment as streamflow. Vegetation (tree vs. grassland), presence or absence of a claypan, aspect, and compound topographic index (index of wetness) were all significantly correlated to soil moisture status and thus streamflow generation at various times throughout the year. Findings indicated that watershed‐scale hydrologic models based solely on surface topography will not fully explain dynamic temporal and spatial variability in hydrologic flow paths and streamflow generation in these oak woodland catchments. In particular, watershed‐scale knowledge of soil stratigraphy (e.g., claypan distribution) was important for understanding catchment hydrology, especially the occurrence of subsurface lateral flow dynamics.

Streamflow generation in semiarid Mediterranean environments is governed by the timing and amount of precipitation. Although topography is widely considered a dominant factor controlling the delivery of water to streams, we hypothesized that antecedent soil moisture and soil stratigraphy regulates the vertical dimension of hydrologie flowpaths and streamflow generation in a headwater catchment of the Sierra Foothill Region in California. We monitored soil moisture, subsurface lateral flow, streamflow, and meteorological conditions in a 33-ha catchment to study the linkage between hydrologie flowpaths in soil and streamflow characteristics. A total of 100 soil profiles were instrumented with soil moisture sensors at four depths in A, AB, Btl, and 2Btss horizons. A hillslope perched-water collection system was used to measure subsurface lateral flow from these same horizons using tipping buckets. Streamflow was monitored using a V-notch weir for low flows and Parshall flume for high flows. Integrated hydrologie measurements show a close synchrony between streamflow and subsurface lateral flow in AB and Bt horizons overlying a hydraulically restrictive claypan (2Btss horizon). The thickness of the perched water table controlled the magnitude of subsurface lateral flow, which was greatest when AB horizons became saturated. Stream recession characteristics were controlled by lateral flow in less permeable horizons (Bt) directly overlying the claypan. Through the course of the water year, subsurface lateral flow from near surface horizons (A and AB) increased as antecedent soil moisture and thickness of the perched water table increased catchment-wide. The dynamic nature of hydrologie flowpaths in this system has implications for water quality as water is short-circuited to tbe stream through upper soil horizons. This study highlights the need for a detailed understanding of soil stratigraphie relationships to fully understand and model streamflow and water quality dynamies in semiarid soils with strongly contrasting physieal properties.

The leaf area determination are extremely important in agronomic and physiological studies, as they provide valuable information in vegetable metabolism RESUMO A determinação da área foliar é importante, em estudos agronômicos e fisiológicos, para a obtenção de informações sobre o metabolismo vegetal e as técnicas utilizadas devem ser simples. O objetivo deste estudo foi desenvolver modelos polinomiais para estimar a área foliar (AF). Foram utilizados os métodos de discos foliares e software ImageJ, com as medidas do comprimento (C) e da largura (L), e a relação entre o comprimento vezes a largura (CL) em folhas da cultura do pimentão, em dois ensaios com dois híbridos, Arcade e Impacto, e correlacionar os valores encontrados pelos dois métodos. Através

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R ESU M OAs atividades de mineração e de viticultura do Rio Grande do Sul têm contribuído para a contaminação do solo por cobre. Este trabalho objetivou avaliar o efeito de doses de cobre no crescimento e na qualidade de mudas de timbó (Ateleia glazioviana) e dedaleiro (Lafoensia pacari). O delineamento foi inteiramente casualizado em arranjo fatorial (2 x 4), formado de duas espécies florestais e quatro doses de cobre (0, 64, 128 e 192 mg kg -1 de solo) com cinco repetições. Avaliaram-se altura da planta, diâmetro do colo, peso da matéria seca radicular e da parte aérea, comprimento e área superficial específica radicular e os seguintes índices de qualidade de mudas: relação entre altura da parte aérea e diâmetro do coleto; altura da parte aérea e peso da matéria seca da parte aérea e o índice de qualidade de Dickson, em que os resultados revelaram que as doses de cobre testada reduziram a qualidade de mudas do timbó enquanto o dedaleiro apresentou melhor qualidade com 128 mg kg -1 de Cu. O cobre influenciou os parâmetros de crescimento das mudas de timbó porém aumentou significativamente o comprimento e a área superficial específica do dedaleiro até 128 mg kg -1 de Cu. Mudas de dedaleiro são mais tolerantes à contaminação do solo que as de timbó e apresentam melhor qualidade em doses mais elevadas de cobre. Palavras-chave: espécies florestais, metal pesado, tolerânciaGrowth and quality of Ateleia glazioviana and Lafoensia pacari seedlings cultivated in copper contaminated soil A B ST R A C T The mining and viticulture activities in the State of Rio Grande do Sul, Brazil have contributed to soil contamination by copper. The aim of this study was to evaluate the effect of copper doses on growth and quality of Ateleia glazioviana and Lafoensia pacari seedlings. The experimental design was completely randomized in a factorial scheme (2 x 4) with five replications. The experiment involved two forest species and three copper doses (64, 128 and 192 mg kg -1 ). The plant height, stem diameter, root and shoot dry-mass, length and specific superficial area of roots, as well as seedlings quality index: relationship between shoot height and stem diameter, shoot height and dry-mass of shoots were evaluated. In addition, Dickson's quality index was estimated. The results showed that the tested copper doses reduce the quality of seedlings of Ateleia glazioviana; however, the Lafoensia pacari quality was better with Cu dose of 128 mg kg -1 . Dose of copper influenced the growth of Ateleia glazioviana seedlings, but increased significantly the length and specific surface area of the Lafoensia pacari up to Cu dose of 128 mg kg -1 . Lafoensia pacari seedlings are more tolerant to soil contamination than Ateleia glazioviana and display better quality of seedlings at high copper doses.