Charles J. Barden

Mid-Season High-Resolution Satellite Imagery for Forecasting Site-Specific Corn Yield

A timely and accurate crop yield forecast is crucial to make better decisions on crop management, marketing, and storage by assessing ahead and implementing based on expected crop performance. The objective of this study was to investigate the potential of high-resolution satellite imagery data collected at mid-growing season for identification of within-field variability and to forecast corn yield at different sites within a field. A test was conducted on yield monitor data and RapidEye satellite imagery obtained for 22 cornfields located in five different counties (Clay, Dickinson, Rice, Saline, and Washington) of Kansas (total of 457 ha). Three basic tests were conducted on the data: (1) spatial dependence on each of the yield and vegetation indices (VIs) using Moran’s I test; (2) model selection for the relationship between imagery data and actual yield using ordinary least square regression (OLS) and spatial econometric (SPL) models; and (3) model validation for yield forecasting purposes. Spatial autocorrelation analysis (Moran’s I test) for both yield and VIs (red edge NDVI = NDVIre, normalized difference vegetation index = NDVIr, SRre = red-edge simple ratio, near infrared = NIR and green-NDVI = NDVIG) was tested positive and statistically significant for most of the fields (p < 0.05), except for one. Inclusion of spatial adjustment to model improved the model fit on most fields as compared to OLS models, with the spatial adjustment coefficient significant for half of the fields studied. When selected models were used for prediction to validate dataset, a striking similarity (RMSE = 0.02) was obtained between predicted and observed yield within a field. Yield maps could assist implementing more effective site-specific management tools and could be utilized as a proxy of yield monitor data. In summary, high-resolution satellite imagery data can be reasonably used to forecast yield via utilization of models that include spatial adjustment to inform precision agricultural management decisions.

Assessing the effectiveness of various riparian buffer vegetation types

Agricultural riparian buffer research has focused on examining water flow through native forest stands or grass filter strips (Sheridan et al. 1999), and has been conducted primarily in the Mid-Atlantic and southeastern United States (Jordan et al. 1993; Lowrance et al. 1984). Recently established riparian buffer strips, usually adjacent to crop fields, have become increasingly common in the Midwest. The climate, soils, and hydrology differ considerably between the Midwest and the eastern seaboard, thus the effectiveness of newly planted riparian buffers for filtering agricultural field runoff needs to be documented.

Cross-Cultural Collaboration for Riparian Restoration on Tribal Lands in Kansas

Collaborative partnerships for environmental education and implementation between Land Grant University programs, tribal colleges and the tribes themselves which manage land and waters within their borders have proven difficult to establish and maintain. Lack of trust among the parties results, in part, from lack of knowledge about tribal culture, authority and decision-making mechanisms. Cooperation between Kansas State University, Haskell Indian Nations University and the Prairie Band Potawatomi Nation in a successful riparian restoration project which has become the basis for ongoing collaboration to improve natural resource management demonstrates that trust can be built.

Management Implications for a Poplar Phytoremediation Plantation

Phytoremediation with poplar trees has recently shown promise for remediating many types of contaminants. However, the management of phytoremediation plantations has not been optimized for maximum remediation performance. It was hypothesized that increased management of a poplar plantation can improve poplar root development and reduce the time to gain hydraulic control of a landfill leachate plume. In order to sufficiently understand the potential of increased management to increase hydraulic control of a ground water plume, a field study site was used. This site, located in Manhattan, Kansas, focused on the impacts of tree management by exploring the differences in nutrient applications. A plantation composed of two varieties of poplar trees (Populus L.) was planted in the spring of 2006. Half of the trees received only fresh water and the other half received a treatment of 50% fresh water and 50% lagoon effluent. Measurements taken included tree height, trunk diameter, tree crown area and soil moisture (tensiometers and neutron probe). After receiving treatments over the course of the summer, the data indicated that there were no significant differences in the trees receiving lagoon treatments and the trees receiving only fresh water. The expected irrigation treatment effect was most likely masked by the inherent high fertility of the site. However, all trees were effective at reducing soil moisture. It is thought that after several years of growth the trees receiving nutrient applications will be more effective at drying out the soil as the existing soil nutrients are utilized. In addition to phytoremediation applications, this management strategy can be used to reduce the ecological impacts of animal feeding operations.

Assessing the Use of Poplars for Hydraulically Controlling a Groundwater Plume

Worldwide reliance on groundwater and global municipal waste production intersect as a significant public health threat. Landfill leachate plumes often contain hazardous chemicals that are harmful to human, animal, and environmental health. Recent advances in phytoremediation suggest that deep-rooted vegetation may be more effective at remediating these sites than the traditional pump-and-treat method. Because phytoremediation is a relatively new technology, optimized management practices have not yet been developed. It is hypothesized that hydraulic control of a leachate plume can be obtained using poplar trees and increased management can improve root development and reduce the time to gain hydraulic control. In the spring of 2005, seven rows of cottonwood trees (Populus deltoids, Marsh.) were planted down gradient from a buried chemical waste landfill to impede plume migration and enhance the uptake of the contaminant, 1,4 dioxane. By assessing the groundwater, precipitation, evapotranspiration, surface runoff, and vadose zone soil moisture in the system, it was possible to estimate the required evapotranspiration for plume control. In addition to the water balance calculation to determine the effectiveness of hydraulic control, the effects of increased plant management were studied. Recent studies at Kansas State University indicated that bare root cottonwood (Populus deltoids) plantings treated with animal lagoon effluent produced significantly more biomass and used up to three times the amount of water during their first two years of growth compared with seedlings receiving only tap water. It was hypothesized that trees irrigated with nutrient-rich lagoon water grow faster, requiring more water and enhancing the potential for gaining hydraulic control at the site. Irrigation regimes with and without lagoon water from the Kansas State University Animal Science Farm will be studied at site beginning spring 2006. The use of lagoon water not only served as a nutrient source to enhance the growth of the trees and reduce the time to gain hydraulic control, but also provided a beneficial use for animal waste. Based on the preliminary water balance, it was concluded that hydraulic control will eventually be obtained as the poplars continue to grow.