Integrated spatial decision support system for precision agriculture

Excessive application of plant nutrients and pesticides on agricultural land has resulted in both environmental degradation and economic loss to the farming community. Agricultural non-point source pollution was cited as the primary source of the water quality problems in many areas of the United States. Environmental concerns resulting from agricultural non-point source pollution has placed demands on farmers and ranchers to implement the best management practices (BMPs) to reduce the delivery of pollutants to streams and aquifers. Precision agriculture, a relatively recent crop production and agricultural management strategy holds great promise to minimize environmental pollution while to maximize economic productivity and profitability. It has benefited from rapidly evolving geospatial information technologies, such as global positing systems (GPS), geographic information systems (GIS), remote sensing (RS), and electronic sensors and intelligent controllers. However, the complexity of making routine, coherent, and cost-effective farm management decisions presents a formidable challenge to farmers. What is lacking in precision agriculture is an analytical tool that integrates these component technologies with biophysical and economic models for tactical, strategic, and policy-level decision make. In this dissertation, a decision support system called IDSSPA is developed to include modules for evaluating crop yield and chemical losses in response to site-specific management of agricultural inputs. Using this system, not only can users store, visualize, manipulate, and analyze spatial/non-spatial field experiment data, but they also can do various simulations through the easy-operated biophysical models, which take field spatial variability into account. In the system, the functionalities of the traditional models and analysis methods have been enhanced by coupling them with each other and with ArcView GIS. Uniquely designed GIS-based interfaces enable the lumped biophysical models to incorporate and represent field spatial variability. Statistical and data mining tools are also included in the system to improve analysis of field measured data and to further enhance interpretation of model simulation results. Other components incorporated into the system are as follows: The CERES-Maize plant growth model seamlessly integrated with RZWQM to provide an alternative phonologically based model for predicting growth and yield of maize (corn), and several tools for evaluating economic and ecologic risks of precision agriculture implementation. The application examples indicated that IDSSPA is a useful research and decision make tool for precision agriculture at field and watershed scales

Evaluation of prairie grasses for reducing the environmental impact of herbicide contamination

The primary goal of this dissertation was to evaluate the use of prairie grasses for reducing the environmental impact of herbicides. Studies included: use of prairie grasses as a phytoremediation tool for contaminated soil; comparison of grass species for use in vegetative buffer strips; fate of 14C-pendimethalin in vegetated and unvegetated soil; and environmental hazards of pendimethalin contaminated soil.;Throughout this dissertation, evidence was presented that prairie grasses can increase the dissipation rate of herbicides. In one study, 78% less metolachlor and 39% less pendimethalin remaining in vegetated treatments as compared to unvegetated treatments. In a separate study, the presence of nearly all grasses tested, but specifically the prairie grasses, resulted in greater degradation of atrazine and metolachlor in rhizosphere soil as compared to unvegetated soil. Phytoremediation mechanisms likely involve plant uptake and increased soil degradation.;Prairie grasses were also shown to decrease movement of pesticides both through the soil column and into biota, thus serving as a phytostabilization agent. Nearly 20% of the metolachlor in unvegetated columns leached out of the bottom of the column after application of an artificial rain event , while only 5% leached out of vegetated columns. It was also shown that even though vegetated columns allowed infiltration of artificial surface runoff at a much faster rate, the total amount of herbicide moving through the column was held constant, and the amount leaching through after initial applications of herbicide was reduced. Additionally, the presence of vegetation decreased the bioavailability of pendimethalin as measured by earthworm uptake and toxicity to lettuce seedlings.;Pendimethalin residues are very persistent and are likely to be present at some level following bioremediation. Therefore, a hazard evaluation was performed to determine tolerable soil concentrations of pendimethalin that could remain without risk to the biota in the environment. Even low levels of pendimethalin, 10mg/kg or less, were shown to have toxic effects on plants and earthworms, and concentrations as low as 30 mg/kg were shown to have potentially toxic effects through trophic transfer. Thus remediation would need to continue until pendimethalin is reduced to field application levels (10 mg/kg) or less

Models for Analyzing Agricultural Nonpoint-Source Pollution

Mathematical models are useful means of analyzing agricultural nonpoint-source pollution. This review summarizes and classifies many of the available chemical transport and planning and management models. Chemical transport models provide estimates of chemical losses from cropland to water bodies; they include continuous simulation, discrete simulation, and functional models. A limited number of transport models have been validated in field studies, but none has been tested extensively. Planning and management models, including regional impact, watershed planning and farm management models, are used to evaluate tradeoffs between environmental and agricultural production objectives. Although these models are in principle the most useful for policy making, their economic components are much better developed than components for predicting water pollution

SWAP Version 3.2. Theory description and user manual

SWAP 3.2 simulates transport of water, solutes and heat in the vadose zone. It describes a domain from the top of canopy into the groundwater which may be in interaction with a surface water system. The program has been developed by Alterra and Wageningen University, and is designed to simulate transport processes at field scale and during whole growing seasons. This is a new release with special emphasis on numerical stability, macro pore flow, and options for detailed meteorological input and linkage to other models. This manual describes the theoretical background, model use, input requirements and output tables

Subsurface Upflow Wetland System for Nutrient and Pathogen Removal in Wastewater Treatment Systems

Methods and systems for a subsurface upflow wetland for wastewater treatment that includes a series of parallel treatment cells, each cell including from bottom to top, a layer of gravel, a layer of sand over the gravel to remove pathogens from a septic effluent, a pollution control medium above the sand later to remove nurtients, total suspended solid, and biochemical oxygen demand and a growth media mixture layered on top of the pollution control pmedia to grow plants, and a gravity distrubition system to distribute effluent to the series of parallel treatment cells. The pollution control medium inlcudes at least one recycled material and at least one naturally occuring material. In an embodiment in includes recycled tire crumb, sand, and limestone or recycled tire crumb, compost, sand and limestone

Use of biochar geostructures for urban stormwater water cleanup

Introduction Stormwater runoff from urban catchment areas is a leading contributor to water quality pollution which can result in limitations on urban development. Engineering systems used for the treatment of stormwater runoff, use in most cases, non-renewable resources. Biochar or charcoal is a renewable resource and is being investigated as a filtration media for stormwater cleanup. Background Currently engineering systems are available to control the volume of runoff after a storm event from urban catchments and influence the runoff water quality. In these engineered systems the water is not only slowed down, but also, physical, chemical and microbial processes are utilized for the removal of unwanted contaminants. An organic medium being researched for the use of stormwater cleanup is Biochar. Biochar is a form of charcoal produced through the thermochemical conversion of organic materials or biomass. The biomass remaining after pyrolysis is a fine-grained, highly porous material which gives the material large amounts of surface area resulting in a highly adsorbent material. Methodology The use of Biochar for improving stormwater water quality has been growing worldwide with product developers and researchers working to prove, advance science and markets of this emerging material. This thesis has been compiled using research material collated from various sources which provides insight into the use of Biochar geostructures for urban stormwater cleanup. Collectively, the material contained within this thesis represents research already undertaken by other parties; however it will provide information on emerging technologies using biochar. Key Outcomes Initial trials using biochar as a medium for improving stormwater quality for urban runoff has provided positive results. Additional research is required to determine cost effective, easy maintainable and to monitor performance versus economic considerations for the use of biochar geostructures. Research using enzyme additives to improve biochar performance is emerging. Further Work The next stage is the use of biochar as a medium for different geostructures for urban stormwater water cleanup and record the results of the reduction of heavy metals, herbicides and organics in stormwater. Conclusions The use of Biochar for improving stormwater water quality in urban catchments is in its infancy for practical testing. The different biomass used to create Biohar has an effect on its performance for improving stormwater runoff quality. Research is continuing to evolve to determine whether enzymes can be used to improve the performance of Biochar