Location: Coastal Plain Soil, Water and Plant Conservation Research
2017 Annual Report
Objectives
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.
Approach
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
This report documents progress for Project Number 6082-13000-010-00D, which started on December 29, 2016 and continues research from Project Number 6082-13000-009-00D, entitled “Managing Water Availability and Quality to Maintain or Increase Agricultural Production, Conserve Natural Resources, and Enhance Environmental Quality in Humid Regions.”
In sub-objective 1a, a corn irrigation experiment was initiated to evaluate 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 with Valmont Industries. The system is being evaluated in different climatic regions including Florence, South Carolina, Portageville, Missouri, and Stoneville, Mississippi. In Florence, we installed wireless infrared thermometers on the center pivot lateral to measure crop canopy temperatures. We also installed soil sensors to measure volumetric water contents and soil water potentials to monitor soil moisture levels. These sensors are 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 preformed 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.
In sub-objective 1b, a cotton experiment was initiated to evaluate the potential for using crop reflectance to manage spatial or variable rate irrigations. Cotton was planted and Normalized Difference Vegetative Index (NDVI) and soil water measurements are being collected. NDVI measurements will be converted into crop coefficients and used for creating prescription maps for variable rate irrigation applications.
In sub-objective 1c, a study was initiated 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.
In sub-objective 1d, Cotton plots have been established 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.
In Sub-objective 2a, the experimental set-up and layout of this field study were completed. The suction lysimeters were installed and fully functional. Irrigation and all fertilizer treatments were initiated. Soil samples and plant samples were collected at V6 and V16 growth stages of corn. Lysimeter samples from each plot with or without irrigation and fertilizer treatments were collected and preserved for analyses. Soil carbon fluxes are being monitored using a Licor Carbon Flux while fluxes of ammonia and nitrous oxide are being measured using a static flux chamber with a photoacoustic multi-gas analyzer.
In sub-objective 2b, data are currently being collected from a greenhouse experiment evaluating the agronomic value of turkey litter ash amended to the soil with either calcitic limestone or gypsum. Two trials of the experiment have been completed and plant biomass data and soil chemical analysis data have been collected. Analysis of the plant biomass for nutrient concentration is in progress. 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 collected field data on the uniformity of application of turkey litter ash, turkey litter ash mixed with gypsum, and turkey litter ash mixed with calcitic limestone using a commercial spreader. These preliminary results suggest that application of turkey litter ash without amendments may be possible.
Accomplishments
1. Irrigation management to protect water quality. Although agriculture is one of the largest sources of nutrient losses into the environment, mainly nitrogen fertilization of crops, proper irrigation management can reduce nutrient leaching while maintaining crop yield. A three-year corn field study was conducted by ARS scientists in Florence, South Carolina, to evaluate the effects of three irrigation scheduling methods and two nitrogen rates on pore water nitrate and phosphate in four soil types with corn production in U.S. Coastal Plain Region. Although, soil pore water nitrate varied significantly, irrigation scheduling with an expert system had the lowest mean soil water pore nitrate compared to traditional irrigation scheduling methods. Soil water pore phosphate was not affected by irrigation scheduling method. Using an expert system for irrigation management resulted in lower soil water pore nitrate and phosphate concentrations. These results indicate the irrigation scheduling method may be a way of achieving optimum yields while potentially minimizing potential nutrient losses.
Review Publications
Sigua, G.C., Stone, K.C., Bauer, P.J., Szogi, A.A., Shumaker, P.D. 2017. Impact of irrigation scheduling on pore water nitrate and phosphate in coastal plains soils with corn production. Agricultural Water Management. 186:75-85.
Sigua, G.C., Stone, K.C., Bauer, P.J., Szogi, A.A. 2016. Nitrate leaching, water-use efficiency and yield of corn with different irrigation and nitrogen management systems in coastal plains, USA. WIT Transactions on Ecology and the Environment. 203:159-170. https://doi.org/10.2495/EID160151.
Reay-Jones, F., Greene, J.K., Bauer, P.J. 2016. Stability of spatial distributions of stink bugs, boll injury, and NDVI in cotton. Environmental Entomology. 45(5):1243-1254.
Edralin, D.I., Sigua, G.C., Reyes, M.R. 2016. Dynamics of soil carbon, nitrogen and soil respiration in farmer’s field with conservation agriculture Siem Reap, Cambodia. International Journal of Plant and Soil Science. 11(1):1-13.
Berihu, T., Girmay, G., Sebhatleab, M., Berhane, E., Zenebe, A., Sigua, G.C. 2016. Soil carbon and nitrogen losses following deforestation in Ethiopia. Agronomy for Sustainable Development. doi:10.1007/s13593-016-0408-4.
Mehmood, K., Chavez Garcia, E., Schirrmann, M., Ladd, B., Kammann, C., Wrage-Monnig, N., Siebe, C., Estavillo, J.M., Fuertes-Mendizabal, T., Cayuela, M., Sigua, G.C., Spokas, K.A., Cowie, A.L., Novak, J.M., Ippolito, J.A., Borchard, N. 2017. Biochar research activities and their relation to development and environmental quality: A meta-analysis. Agronomy for Sustainable Development. doi:10.1007/s13593-017-0430-1.
