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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Research Project #432460

Research Project: Managing Water Availability and Quality for Sustainable Agricultural Production and Conservation of Natural Resources in Humid Regions

Location: Coastal Plain Soil, Water and Plant Conservation Research

2018 Annual Report

1. Develop effective irrigation and crop management techniques that increase profitability, conserve water, and protect water quality in surrounding ecosystems. 1a. Evaluate the potential use of the ARS Irrigation Scheduling and Supervisory Control and Data Acquisition System (ISSCADA) for variable rate irrigation management of corn in the humid Southeastern U.S. 1b. Evaluate variable rate irrigation using crop feedback for site-specific irrigation management in the Southeastern U.S. Coastal Plain. 1c. Quantify how cover crops and tillage affect soil water availability, soil pore water nitrogen, and crop productivity. 1d. Evaluate how water availability and microbial population dynamics are influenced by soil improvement practices on a spatial basis. 2. Assess the effects of innovative management and production practices on nutrient losses via hydrologic pathways from farms and watersheds. 2a. Quantify nitrogen balance, water-use efficiency and crop yield of irrigated and rain-fed corn as affected by fertilizer management strategy in the Southeastern U.S. Coastal Plain. 2b. Determine the runoff potential of recovered P sources when surface applied as fertilizer in no-tillage systems.

The overall goal of this project is to improve water and nutrient management in humid regions. The research focuses on two main objectives. The first objective is to develop effective irrigation and crop management techniques that increase profitability, conserve water, and protect water quality in surrounding ecosystems. In this objective, we will evaluate the potential of using within season crop feedback for managing variable-rate irrigation (VRI) systems and also evaluate the use of an automated VRI system for managing irrigations. For rain-fed production, we will investigate how soil conservation practices affect nitrogen cycling, soil microbial populations that influence soil carbon cycling, and soil water availability. The second objective is to assess the effects of innovative management and production practices on nutrient losses via hydrologic pathways from farms and watersheds. In this objective, we will investigate N fertilizer management under irrigated and rain-fed conditions for nutrient use efficiency and potential loss of N to the surrounding ecosystem. We will also evaluate the potential of reducing dissolved P in runoff from fields managed with conservation tillage by applying recovered P fertilizer products that have low water solubility. Research methods include field and laboratory experiments, demonstrations, and leading-edge analytical techniques. The research outlined in this project addresses components of two of the four problem areas identified in the ARS - Water Availability & Watershed Management National Program Action Plan. Research products will consist of water and nutrient management practices that conserve water, sustain production, and enhance environmental quality. These products will also provide information vital to national water management and water quality policies. The expected benefits of the research program are the long-term conservation and protection of the nation’s water resources. Conservation and protection of the nation’s water resources will ensure production of food and fiber for current and future populations in an economically viable and environmentally sustainable manner.

Progress Report
A corn irrigation experiment is in its second year of evaluating the use of an automated irrigation management system to control a variable rate irrigation system developed by ARS. The automated irrigation management system was developed by scientists and engineers at Bushland, Texas, under a CRADA. The systems are being evaluated in different climatic regions including Florence, South Carolina, Portageville, Missouri, and Stoneville, Mississippi. In Florence, wireless infrared thermometers were installed on the center pivot lateral to measure crop canopy temperatures. Volumetric soil water content sensors along with soil water potential sensors were installed to monitor soil moisture levels. These sensors were integrated with weather data to estimate crop water requirements and levels of crop stress using the ARSmart Pivot software. Several scans of the corn field have been performed and irrigation prescriptions have been developed and utilized. The experiment will evaluate the use of the integrated crop water stress index based management system and investigate how it may need to be modified for humid regions. New this year, we have installed brackets to mount Normalized Difference Vegetative Index (NDVI) sensors for spatially calculating crop coefficients to manage spatial irrigations. The first year of an irrigated cotton experiment was conducted to evaluate the potential for using crop reflectance to manage spatial or variable rate irrigations. NDVI measurements were collected through the season from plots planted to high and low plant populations. The NDVI data were converted into crop coefficients and used for creating prescription maps for variable rate irrigation applications. Using variable rate irrigation reduced total water applied during these applications, but applying irrigation did not impact yield above rainfed levels. The experiment is being repeated this summer. A study is continuing to evaluate the impact of winter cover crops on the productivity of summer crops at the on-going long-term tillage (since 1978) plots. Winter cover crops were established into the rotations with corn and soybean. This spring, both corn and soybean have been planted and soil moisture sensors have been installed. Soil and corn plant samples were collected at V6 and V16 growth stages. Cotton plots monitoring and sampling are continuing at the Clemson Pee Dee Extension and Research Center. Pre-plant and three-week post-emergence samples have been collected and analysis has begun to look at microbial activity and population dynamics. Soil carbon and nitrogen cycling exoenzyme results indicate that microbial activity in high soil electrical conductivity (EC) areas are significantly reduced. An experiment for improving yield and nitrogen (N)-use efficiency of corn production with smart fertilizer and supplemental irrigation management is continuing for a second year. This experiment is to evaluate the effect of different rates (0, 120, and 240 kg N/ha) and sources of N (urea vs. controlled-release urea) with and without irrigation on yield, biomass and N-use efficiency of corn in the Coastal Plain region. Our early results indicated significant interaction effects amongst sources, rates of N fertilizers and irrigation management on corn biomass. We observed greater biomass of corn when applied with controlled-release urea and 100% irrigation. Corn was planted on April 12, 2018 for our second year of the field study. Data from a greenhouse experiment evaluating the agronomic value of turkey litter ash amended to the soil with either calcitic limestone or gypsum were analyzed. Two trials of the experiment have been completed and plant biomass data, plant nutrient analysis, and soil chemical analysis data have been collected. At the request of our customer, we have conducted preliminary trials on pelletizing turkey litter ash for more economical transport. Results from these trials are promising. Also with our customer, we have initiated field studies comparing turkey litter ash to commercial fertilizer in corn, cotton, and wheat production.

1. Improved sorghum productivity in Coastal Plains soils. The U.S. eastern Coastal Plain produces a large amount of poultry and livestock and much of the grain used to feed these animals is imported. To reduce the amount of imported grains in the eastern Coastal Plains, there was an emphasis by the livestock and grain producers to increase regional grain production with grain sorghum. Sorghum production in the U.S. Central and semi-arid Southern High Plains has greatly increased with the widespread use of irrigation, greater fertilizer usage, and adapted hybrids. However, little is known about the grain sorghum response to the combined effects of irrigation and nitrogen fertilization in humid U.S. Coastal Plains region. ARS researchers at Florence, South Carolina, studied the use of supplemental irrigation and nitrogen fertilization in grain sorghum production. Although, they found no overall increase in harvested grain from supplemental irrigation, they found increased nitrogen applications and supplemental irrigation increased grain sorghum biomass accumulation, nitrogen uptake, and nitrogen use efficiency. These results will assist the Coastal Plains region’s grain producers in managing irrigation and nutrients in grain sorghum production.

Review Publications
Sigua, G.C., Stone, K.C., Bauer, P.J., Szogi, A.A. 2018. Biomass and nitrogen-use efficiency of grain sorghum (Sorghum bicolor L.) with nitrogen and supplemental irrigation in Coastal Plain Region, USA. Agronomy.
Stone, K.C., Sigua, G.C., Bauer, P.J. 2018. Supplemental irrigation for grain sorghum production in the US Eastern Coastal Plain. Applied Engineering in Agriculture. 34(2):395-402.
Edralin, D.L., Sigua, G.C., Reyes, M.R., Mulvaney, M.J., Andrews, S.S. 2017. Conservation agriculture improves yield and reduces weeding activity in sandy soils of Cambodia. Agronomy for Sustainable Development. 37:52.
Sigua, G.C., Stone, K.C., Bauer, P.J., Szogi, A.A. 2017. Phosphorus dynamics and phosphatase acitivity of soils under corn production with supplemental irrigation in humid coastal plain region, USA. Nutrient Cycling in Agroecosystems. 109(3):249-267.
Hugie, K.L., Bauer, P.J., Stone, K.C., Barnes, E.M., Jones, D.C., Campbell, B.T. 2018. Improving the precision of NDVI estimates in upland cotton field trials. The Plant Phenome Journal. 1(1):1-9.