Treesearch

Irrigation research in the mid-south United States has not kept pace with a steady increase in irrigated area in recent years. This study used rainfall records from 1895 to 2016 to determine rainwater deficit and irrigation demand for soybean [Glycine max (L.) Merr.], corn (Zea mays L.), and cotton (Gossypium hirsutum L.) in the Blackland Prairie region of Mississippi with a soil water balance model developed in Structural Thinking and Experiential Learning Laboratory with Animation (STELLA) software. The longterm analysis showed annual rainfall exceeded 1125 mm in 3 out of 4 yr. Median...

Loads of naturally occurring total organic carbons (TOC), refractory organic carbon (ROC), and labile organic carbon (LOC) instreams control the availability of nutrients and the solubility and toxicity of contaminants and affect biological activities throughabsorption of light and complex metals with production of carcinogenic compounds. Although computer models have become increasingly popular in understanding and management of TOC, ROC, and LOC loads in streams, the usefulness of these models hinges on the availability of daily data for model calibration and validation. Unfortunately,...

Agricultural ponds are an important alternative source of water for crop irrigation to conserve surface and ground water resources. In recent years more such ponds have been constructed in Mississippi and around the world. There is currently, however, a lack of a tool to simultaneously estimate crop irrigation demand and pond water availability. In this study, a Pond-Irrigation Model (PIM) was developed to meet this need using STELLA (Structural Thinking, Experiential Learning Laboratory with Animation) software. PIM simulated crop land and agricultural pond hydrological processes such as...

Storage of belowground carbon (C) is an important component of total forest C. However, belowground C changes temporally due to forest growth and tree mortality (natural and via harvesting) and these fluctuations are critical for modeling C in forests under varying management regimes. To date, little progress has been made in quantifying the rate of decay of southern pines in general, and specifically in longleaf pine (Pinus palustris Mill.) coarse root systems. Decomposition rates of lateral roots and tap roots of longleaf pine were quantified in situ under field conditions across the...

A novel and emerging eastern white pine (Pinus strobus L.) dieback phenomenon is occurring in the Southern Appalachian Mountains in the eastern United States. Symptomatic eastern white pine trees exhibit canopy thinning, branch dieback, and cankers on the branches and bole. These symptoms are often associated with the presence of a scale insect, Matsucoccus macrocicatrices Richards (Hemiptera: Matsucoccidae), and a fungal pathogen, Caliciopsis pinea Peck (Coryneliales: Coryneliaceae). We determined the extent, range, and severity of dieback of 2,061 eastern white pine trees from 40 sites...

The primary goal of invasive species management is to eliminate or reduce populations of invasive species. Although management efforts are often motivated by broader goals such as to reduce the negative impacts of invasive species on ecosystems and society, there has been little assessment of the consistency between population-based (e.g., removing invaders) and broader goals (e.g., recovery of ecological systems) for invasive species management. To address this, we conducted a comprehensive review of studies (N = 151) that removed invasive species and assessed ecological recovery over...

Identifying an effective protocol for sampling crayfish in streams that vary in habitat and physical/chemical characteristics has proven problematic. We evaluated an active, combined-gear (backpack electrofishing and dipnetting) sampling protocol in 20 Coastal Plain streams in Louisiana. Using generalized linear models and rarefaction curves, we evaluated environmental and gear (separate and combined) effects on crayfish catch-per-uniteffort (CPUE), orbital carapace lengths, sex ratios, frequencies of rare species, and sample richness.

Conversion of agricultural lands to urban uses affects regional and global climate not only through the release of greenhouse gases but also through altering land surface physical processes such as energy and water balances. Most existing studies on the meteorological impacts of urbanization focus on urban heat island effects with little attention on its impacts of atmospheric humidity, a key variable in hydrometeorology and climate science. We define the influences of urbanization on reducing atmospheric humidity and elevating vapor pressure deficit as urban dry island (UDI) effects. We...

Shallow groundwater responses to rainfall in forested headwaters can be highly variable, but their relative strengths of influences remain poorly understood. We investigated the roles of storms and landscape characteristics on short-term, shallow groundwater responses to rainfall in forested headwater catchments. We used field observations of shallow groundwater combined with random forest modeling to identify the factors that affect shallow groundwater responses and the relative influences of key response drivers. We found that the rainfall thresholds required for groundwater responses...

Many factors influence yard care in urban and suburban areas, but the explicit difference between front versus back yards is one factor that has not been fully examined. This paper introduces the Landscape Mullet concept. The two key components of this concept are: (1) social norms are an important driver of yard management; and (2) the influence of those norms varies spatially between front (public) to back (private). Thirty-six semi-structured interviews were conducted in six neighborhoods of Baltimore, MD, USA in the summer of 2016. We found that social pressures for yard care practices...