2011 Annual Report
1a.Objectives (from AD-416)
The goal of this research will be to obtain knowledge and develop tools that will enable planners, decision makers, and producers to more effectively manage, conserve, and protect water resources. Specific objectives are as follows: 1)Develop cotton and peanut production systems for humid areas that are based on site-specific water and nutrient applications, 1a)Develop water management strategies in humid areas that optimize spatial and temporal water applications, 1b)Develop and explore spatial nutrient management for irrigated and non-irrigated crops in humid areas; 2)Develop practices that increase crop water use efficiency in rainfed/irrigated cropping systems in relation to tillage, irrigation, and crop management practices; and.
3)Develop practices and technologies that enhance denitrification and expand the knowledge of microbial communities including their genetics and implication on geospecific disease in riparian buffers, wetlands, and streams for improving water quality.
1b.Approach (from AD-416)
This 5-year project utilizes a systems approach to identify and develop strategies for improved spatial management of water and nutrients. The project explores the spatial components of irrigation, tillage, and nutrient management. In spatial irrigation, the project will focus on identifying strategies for managing a site-specific irrigation system to conserve water and nutrients while maintaining cost effective production. In tillage management, the project will focus on efficiency of water use using tillage practices that will improve infiltration and soil water-holding capacities under site-specific irrigation to determine the spatial uptake and water use efficiency to improve spatial water management. In nutrient management, the project will focus on both in-field and off-site management. In-field nutrient management will focus on spatial nitrogen applications on cotton and Coastal bermudagrass to improve crop production and reduce the impact of off-site nitrogen movement. Off-site nitrogen and water management will focus on understanding the geospatial variability of microbial communities along with nitrous oxide emissions from riparian buffers, wetlands, and streams. In Objective 3, the Experimental Approach is altered to expand the sites under the Denitrification Enzyme Activity section and delete the Treatment Wetland Microcosms section.
A peanut irrigation experiment designed to assess the potential of the irrigation scheduling model ‘Irrigator Pro’ as a tool for site-specific irrigation was completed in October 2010. Three spatial irrigation methods were used a) individual soil types within plots watered based on soil water tension readings, b) individual soil types based on an Irrigator Pro scheduling, and c) whole plot watering based on the Irrigator Pro scheduling. Soils from the various irrigation treatments were collected to evaluate the residual nitrogen contents. Initial data analyses are underway and a journal manuscript will be submitted in fall 2011.
An experiment to evaluate spatial nutrient management for irrigated crops in humid regions was completed in fall 2010. The study included 4 irrigation amounts, 3 nitrogen rates, 2 cutting frequencies, and 3 replications (72 plots). Experimental design was a split-plot with cutting frequency as main plots and the irrigation by nitrogen levels as subplots. Vegetative indices were measured during the growing season and biomass samples collected for forage nitrogen concentration and forage ruminant nutritive quality. In the current year, we are evaluating the use of the vegetative indices to spatially apply nitrogen to the bermudagrass crop. Initial data analyses are underway and a journal manuscript will be submitted in September 2011.
Irrigation effect on flax: Commercial interests are building facilities in South Carolina to process flax straw for cotton-linen blended apparel. Much of the fiber they plan to use in the facilities is to be grown in the region. Currently, there is no commercial production of flax in the region and the region does not have production recommendations available on irrigating flax. In collaboration with USDA-ARS Clemson, Naturally Advanced Technologies, Inc., and Hanesbrand, Inc., we initiated studies to investigate the effect of irrigation on the yield and quality of flax grown for linen fibers. Four western European flax fiber cultivars and one oilseed cultivar were evaluated under irrigated and rainfed conditions. The flax fiber cultivars had higher straw yields than the oilseed cultivar under both irrigated and rainfed conditions. Irrigating flax increased straw yields by approximately 40% due to unseasonable (but not uncommon) dry weather in May and early June. Fiber percentage and fiber properties are to be determined.
Riparian buffer sites were selected in the Mid-Atlantic and southeastern Coastal Plain areas. Microbial DNA was extracted from soil samples and assayed to determine the abundance of genes involved in nitrification and denitrification. Statistical analysis correlating these gene abundance to denitrification enzyme activity is currently underway.
Fuzzy logic for assessment of soil water movement. As rain infiltrates into soil, it splits into water percolating deep into the profile and water retained for plant growth. Estimating how water splits help producers determine plant water needs. Using measured soil water contents in a cotton field, both a traditional mass-balance method and a fuzzy logic method were used to estimate percolation and evapotranspiration. Fuzzy logic is a semi-quantitative approach that uses simple calculations combined with expert opinion. In our computations, evapotranspiration was calculated to come mainly from the top foot of soil, even though the soil was tilled to open it up for deep root growth. The fuzzy logic results compared closely with the mass-balance method. These methods offer a new opportunity to easily assess the fate of water as it moves through the soil to groundwater or to the plant.
Krueger, E., Kurtener, D., Busscher, W.J., Bauer, P.J. 2010. Development and application of fuzzy indicator for assessment of soil water flows. In: Kurtener, D.A., Yakushev, V.P., Torbert, H.A., Prior, S.A. and Krueger, E.D., editors. Applications of Soft Computing in Agricultural Field Experimentations. Saint Petersburg, Russia:Agrophysical Research Institute. p. 131-142.