2007 Annual Report
1a.Objectives (from AD-416)
Develop measurement tools and decision support tools for quantifying soil factors and processes influencing soil productivity.
1b.Approach (from AD-416)
Surrogate indicators of soil hydrologic properties and landscape position will be assessed using analysis of yield data and remote sensing imagery. A new approach to pedotransfer functions will be pursued. Remote sensing of crop residue cover and nutrient stats will be investigated using image spectral reflectance signature analysis. Nutrient status and other indicators of crop response to soil productivity will be investigated via investigation of remote sensing image spatial/texture analysis of the patterns and spacing of groups of pixels. An unmanned aerial vehicle system based on model aircraft technology will be assessed for agricultural applications.
1. Soil Hydraulic Property Software Developed:
Amount of water stored and released from soils influences both crop production and the transport of chemicals through soil to underlying groundwater. Soil property and horizon information collected from survey data bases and a knowledge of landscape position, surface slope, and climate was shown to be a good predictor of soil water hydrology. Parametric and non-parametric algorithms developed from the Natural Resources Conservation Resources Service (NRCS), UNsaturated SOil DAta (UNSODA), and the HYdraulic PRoperties of European Soils (HYPRES) soil data bases were ranked according to amount and type of data input and spatial applicability. This information was incorporated into a web based software package and a users manual is being prepared in cooperation with NRCS. This research supports the Soil Resource Management National program, Problem Area 4,Nutrient Management for Crop Production and Environmental Protection.
2. Effective Procedure for Monitoring and Modeling Chemical Transport in the Field Developed:
Due to the interaction of soil heterogeneities, agricultural chemical interaction with soil properties, and complex soil water dynamics methods for accurately monitoring chemical transport and subsequently modeling its field behavior was severely deficient. In a nationwide effort, scientists were able to develop a procedure for recovering over 90% of the chemical tracers applied to either a tile-drained system or agricultural land with a shallow water table (i.e. within 3m). In addition to the high recoveries these team of scientist found that these chemical transport studies were reproducible, a first for field transport investigations. With chemical transport times accurately monitored a model that captures all major subsurface flow pathways was developed and successfully tested in Wisconsin, Iowa, Indiana, and New York. This research supports the Soil Resource Management National Program, Problem Area 4, Nutrient Management for Crop Production and Environmental Protection.
3. Hydrologic Zones Found to Influence Pesticide Volatilization:
To fully achieve the goals of the Conservation and Effects Assessment Project (CEAP) major chemical loss pathways for agricultural chemicals must be understood and modeled. However, one of the largest and least understood loss pathways is pesticide volatilization to the atmosphere. Recently, ground-penetrating radar was used to quantify locations of various hydrologic activity (hydrologic zones) by identifying surface and subsurface soil features that could impact surface-subsurface water interactions. The hydrologic zones algorithm was able to successfully identify areas of a field where subsurface soil water influenced surface soil contents and corn grain yield, and now were found to influence pesticide volatilization. Elaborate direct measurements of pesticide volatilization revealed that the more hydrologically active areas (wetter surface soils) lost as much as 50% more pesticide through the vapor phase than the corresponding drier portions of the field. The strong influence of surface soil moisture on pesticide volatilization suggests that remote sensing and hydrologic zone designations may be useful tools for quantifying field and watershed scale pesticide losses to the atmosphere. This research supports the Soil Resource Management National Program, Problem Area 4, Nutrient Management for Crop Production and Environmental Protection.
4. Remote Sensing of Crop Residue:
Although management of crop residues is an integral part of many conservation tillage systems, current methods of measuring residue cover are inadequate for characterizing the spatial variability of residue cover over large fields or watersheds. Although remote sensing approaches for estimating crop residue cover have promise they are adversely affected by variations in surface soil moisture conditions. In controlled experiments, moisture in crop residues and soils reduced reflectance across all wavelengths and significantly affected all spectral indices used for estimating crop residue cover. New spectral indices for mitigating the effects of soil and residue moisture content on remotely sensed estimates of crop residue cover were proposed and evaluated using ground-based reflectance data. Regional surveys of the adoption of conservation practices that affect crop residue cover may now be feasible using aircraft- and satellite-based imaging systems. This research supports the Soil Resource National Program 202, Problem Area 5, Adoption and Implementation of Soil and Water Conservation Practices and Systems.
5. Precision Farming Reduces N input without Reducing Yields:
Farmers must balance competing goals of supplying adequate N for their crops while minimizing N losses to the environment. Effective N management depends on identifying crop needs and applying the right amount of N at the right time. Side-dress N applications were applied either at uniform rates based on yield goals or at variable rates based on yield history, soil nitrate tests, and surface and subsurface water flow patterns. Although corn grain yields were nearly identical for the two fields, at least 30% less N was applied in the variable rate field. Additionally, remotely sensed maps of the spatial variability of crop growth and leaf chlorophyll concentration may provide surrogate indicators of subsurface water flow patterns for applying appropriate amounts of N fertilizer to optimize grain yields and minimize environmental impacts. This research supports the Soil Resource Management National Program, Problem Area 4, Nutrient Management for Crop Production and Environmental Protection.
6. Unmanned Airborne Vehicles for Determining Nitrogen Status of Crops:
Detailed information about growth, health and nutrient status of crops are necessary for site-specific agriculture and precision farming. Remote sensing can meet these needs; however, current platforms are have too coarse of a spatial resolution, require considerable time for delivery of information, and are relatively expensive. ARS scientists from Beltsville, MD working with private industry designed and flew a small unmanned airborne vehicle (UAV) that overcomes current obstacles of remote sensing. In collaboration with farmers on the Eastern Shore of Maryland, the UAV performed well in flying over nitrogen trials of winter cover crops. This new technology is now available to farmers and natural resource managers as a tool for nutrient management. This research supports the Soil Resource and Management National Program, Problem Area 4: Nutrient Management for Crop Production and Environmental Protection.
5.Significant Activities that Support Special Target Populations
|Number of active CRADAs and MTAs||1|
|Number of non-peer reviewed presentations and proceedings||8|
Gish, T.J., Kung, K-J., S. 2006. A protocol for quantifying shallow groundwater leachate fluxes in a non-tile drained system. Geoderma. 138:57-64.
Daughtry, C.S.T., Doraiswamy, P.C., Hunt, E.R., Stern, A.J., McMurtrey, J.E., Prueger, J.H. 2006. Remote sensing crop residue cover and soil tillage intensity. International Journal of Soil and Tillage Research. 91:101-108.
De Lanney, G.J.M., Verhost, N.E.C., Houser, P.R., Gish, T.J. Van Meirvenne, M. 2006. Spatial and temporal characteristics of soil moisture in an intensively monitored agricultural field (OPE3). Journal of Hydrology. 331:719-730.