DEVELOPMENT OF BIOPORES IN THE SUBSURFACE BY BURROWING ORGANISMS AND THEIR IMPACTS ON INFILTRATION, RUNOFF, AND CONTAMINANT TRANSPORT CHARACTERISTICS.
A major agent that can develop an extensive network of macropores in the subsurface is burrowing organisms that may include both vertebrates and invertebrates. Biopores created by burrowing animals and invertebrates could have a significant influence on hydrological processes. Understanding the burrowing process evokes interest among other disciplines such as soil morphology and entomology. Among the burrowing invertebrates, a species that has garnered significant attention in the U.S is the mole cricket. The project would be the first multi-disciplinary project to study biopore development by mole crickets and their effects on storage, transport, infiltration and runoff processes. The project will synergistically study biopore development from both hydrologic and entomological perspectives. The influence of biopores on infiltration, contaminant transport and runoff processes will be studied as a function of their age, as the pores are developed by mole crickets. We will also study the effects of biological coatings of the biopores on soil hydraulics using micro-morphological techniques. The project includes laboratory/ field-scale experiments as well as modeling work, which will shed new light on the evolution of biopores due to burrowing mole crickets at different scales. The biopores created by mole crickets will also be compared with similar-sized artificial macropores for their effects on infiltration and contaminant transport. The results from the project will be characterized using appropriate mathematical models to simulate effects of biopores on hydrologic processes. Specifically, we will develop modeling methods to describe how and why the biopores are different from artificial macropores, in terms of anisotropy in their flow characteristics.
The project will have broader impacts on our knowledge of macropores from both hydrologic as well as entomological perspectives. The project will improve our basic understanding of the biopore development and their effects on infiltration and runoff processes. New information will be available on the differences between biopores encountered in soils and the artificial macropores typically used in laboratory studies. From an entomological perspective, the study will shed light on the burrowing behavior of mole crickets, the most important pest of recreational and pasture turfgrass in the southeastern U.S. This project will provide new insights into the behavior of this pest and for developing more efficient pesticide delivery strategies for controlling mole crickets.
Macropores are ubiquitously found in subsurface systems and can have significant impact on hydrological processes. For example, presence of macropores can lead to preferential water flow through both unsaturated and saturated soils, which can directly impact groundwater flow and contaminant transport patterns. One of the major agents that develop macropores in subsurface systems is burrowing organisms. A number of burrowing animals create macropores in soils for different depths and these include frogs, amphibians, reptiles, birds as well as numerous invertebrates such as insects, spiders, earthworms and nematodes. Biopores created by burrowing animals can have significant influence on large-scale hydrological processes. The behavior of burrowing animals is also of interest to other fields including entomology. In this study, we investigated the impacts of macropores on several bulk characteristics of surface soil. We used a common burrowing organism, mole cricket, to study the effects biological macropores on storage, transport, infiltration processes. The project attempted to synergistically study macropore development processes from both hydrologic and entomological perspectives. In terms of basic sciences, the proposed project helped improve our basic understanding of macropore development processes and their effects on subsurface systems. The study has shed considerable light on the three-dimensional burrowing patterns of mole cricket, a widely found pest in agricultural lands and recreational turfgrasses. This information is useful for pest-controls managers to develop sustainable approaches for controlling mole crickets in recreational facilities such as golf courses. Our laboratory experiments that used synthetic macropores helped us define a relationship between soil conductivity and macropore distributions. The theoretical models developed in this study helped to describe a macroscopic parameter which can be used for defining the time scale of groundwater flow transport processes. The project helped train 2 masters students, 1 Phd student, and 1 post-doctoral fellow at two EPSCOR-State institutions, Auburn University, Alabama, and Dessert Research Institute, Nevada. The project has produced 2 master theses, 2 published/accepted journal articles, 1 submitted journal article and several conference presentations. The project activities also fostered interdisciplinary research interactions between three diverse programs (Agronomy and Soils, Entomology and Plant Pathology and Civil and Environmental Engineering) at Auburn University.
