It is widely known that a close relationship exists between crop production and water stress. In this study, field‐measured data were used to test the performance of AquaCrop and its ability to capture this relationship for rainfed maize (Zea mays L.) in Pennsylvania. The objectives were to evaluate AquaCrop’s ability to simulate the progression of cumulative biomass and grain yield with time, final biomass and harvestable yield, and volumetric water content at six depths. Two years of data from a study conducted in Rock Springs, PA, were used to validate AquaCrop’s ability to accurately simulate the progression of cumulative biomass and grain yield with time, as well as final biomass and harvestable yield. Data collected from January 2004 to March 2006 from a study conducted near Landisville, PA, were used to assess AquaCrop’s ability to effectively simulate soil moisture content at six depths. In addition, the 2004 and 2005 seasonal final biomass measurements obtained from the Landisville location were compared with the model’s simulated values. The results indicated that AquaCrop was able to accurately simulate the progression of cumulative biomass and grain yield with time, with index of agreement values ranging from 0.96 to 0.99. Comparisons between simulated and measured final biomass and final harvestable yield produced biomass deviations ranging from 2.4 to 20.7% and yield deviations of 2.9 and 15.3%. The water balance evaluation indicated that, averaged across all depths, the results were consistent with other validation studies of soil water balance models, with RMSE ranging from 1.5 to 9.8% (v/v).

Incorporating stakeholder engagement into environmental management may help in the pursuit of novel approaches for addressing complex water resource problems. However, evidence about how and under what circumstances stakeholder engagement enables desirable changes remains elusive. In this paper, we develop a conceptual framework for studying social and environmental changes possible through stakeholder engagement in water resource management, from inception to outcomes. We synthesize concepts from multiple literatures to provide a framework for tracing linkages from contextual conditions, through engagement process design features, to social learning, community capacity building, and behavioral change at individual, group, and group network levels, and ultimately to environmental change. We discuss opportunities to enhance the framework including through empirical applications to delineate scalar and temporal dimensions of social, behavioral, and environmental changes resulting from stakeholder engagement, and the potential for negative outcomes thus far glossed over in research on change through engagement.

Hairy vetch (Vicia villosa Roth) is a promising winter cover crop for northern climates, but germination can be limited by low soil moisture conditions. Farmers may be reluctant to use hairy vetch, concerned that hard seed will emerge as weeds in succeeding crops. This work examines germination, dormancy, and viability of hairy vetch seeds from nine commercial seed sources, and evaluates the effects of mechanical scarification and ambient temperature hydropriming on the degree of hard‐seededness, germination, seed viability and seedling vigor in a range of simulated soil moisture conditions. Hydropriming increased germination by 5% across seed sources and water potentials, but reduced seedling growth by 16%. Mechanical scarification eliminated all hard‐seededness, but increased physiologically dormant seed by ∼5% and nonviable seed by ∼2% and reduced seedling growth by 39%. This work indicates that pretreatments may increase germination and reduce hard‐seededness, but reduce seed viability and seedling vigor in some seed sources.

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A field experiment was conducted for the purpose of determining the worst‐case potential for solute leaching under furrow‐irrigated conditions, and to assess the spatial variability associated with solute movement. The experiment was carried out on a Mohall sandy loam soil (fine‐loamy, mixed, hyperthermic Typic Haplargid) within a field of upland cotton (Gossypium hirsutum L.), with uniformity of all management factors including fertilizer N and irrigation water. Six mainplot areas were identified throughout the study area to provide characterization of spatial variability. Within each main plot, five subplots (1 m2 each) were further identified. To each subplot area, 20 g KBr was applied in 500 mL of solution using the Br‐ as a biologically conserved tracer. Soil from each subplot was sampled to a depth of 180 cm and separated into 30‐cm depth increments. Soil samples were then subjected to a 1:1 (soil/water) extraction and analyzed for Br‐ and NO‐3‐N. Appreciable amounts of solute movement were measured, with a very high degree of spatial variability. The highest degree of leaching potentials was measured early in the season, when soil water depletions were the lowest and crop root development would not be extended past very shallow regions of the soil profile. The results reinforce the need to split fertilizer‐N applications throughout the course of a growing season, and to base fertilization rates and frequency on properly calibrated plant‐tissue tests.