Location: Crop Production Systems Research2012 Annual Report
1a. Objectives (from AD-416):
Develop cropping systems, conservation management practices and crop rotations with improved water management and enhanced economic and environmental sustainability.
1b. Approach (from AD-416):
Improved irrigation scheduling and application technologies and water management tools will be developed and delivered to producers to improve water use and crop yield and quality. The research will develop production systems and identify management practices that improve soil quality and increase profitability by incorporating conservation production practices, alternative crops and crop rotations. Profitability of management practices and production systems will be tested with economic analysis. Fundamental principles of successful production systems will be delineated, and examined for impacts on risks, competitiveness and environmental impacts.
3. Progress Report:
Significant progress was made in the implementation and testing of water management tools. The new Mississippi Irrigation Scheduling Tool (MIST) was tested and validated for common corn and soybean production practices and soil types in Mississippi in research and production fields. Watermark soil water sensors were installed at six inch (15 cm) increments to a depth of three feet (0.91 m), and soil water measurements downloaded weekly. Plant growth measurements were taken weekly, and used to develop single crop coefficients as outlined in established procedures. Dual crop coefficients are being explored as a possible method of accounting for variability of alluvial soils. Soil water measurements and plant growth measurements were compared to evapotranspiration calculations made with the Modified Penman-Monteith in the MIST program to adjust crop coefficients to better reflect actual crop water use in the soils and environment of the Delta. Water release curves for typical Mississippi soils were developed and soil moisture sensors calibrated to known water contents. Soils textural analysis is used to adjust recommended irrigation levels based on soil water holding capacity. Note that most soils are silt and loam; no soils that were analyzed were true clay soils. Analyzed soils will have approximately 1.2 – 2.5 inches of plant available water per foot of soil. Soil cores were taken from production and research fields, and bulk density, soil nutrient and soil hydraulic properties determined. Weather data was downloaded from all weather stations reported by the Delta Research and Extension Center Weather Center and Natural Resources Conservation Service (NRCS) Soil Climate Analysis Network (SCAN) weather systems was analyzed for completeness and accuracy. The impact of planting date and irrigation on soybean yield was determined. Early planted soybeans yielded higher, but were more susceptible to lack of adequate water. Two primary crop parameters can be used for tracking crop growth: plant height and interception of sunlight. Results show that light interception is more appropriate for tracking crop growth as a single curve can be used for most planting dates. Plant height differs with planting date. The overall magnitude of crop height is most likely cultivar dependent. However, later planting increases the rate of crop growth, altering the initial stage of the crop height growth curve. The uniform resource locator for the web site server is now open. We have begun writing summaries and educational materials for the water management website. The information can be viewed at: http://www.agwater.msucare.com. The irrigation scheduler has been implemented into the user interface, and the interface is being tested.
1. Principle-based development of sustainable agricultural production systems. Agriculture in the U.S. is facing profound challenges from increasing urbanization, turbulence in input costs and commodity prices, and shifts in consumer demands and global competition. Future advances will need to address an increasing population with a shrinking land base for agricultural production, food safety and security concerns, and resource preservation and environmental issues. The Integrated Agricultural Systems workgroup is a consortium of ARS scientists from several locations throughout the U.S. who are examining agricultural systems to determine fundamental principles that underlie successful production systems. The results demonstrate that the internal social driver that values the farming lifestyle is the principal factor that leads people to farming, while economic drivers and marketing options are the primary drivers that determine the production systems and management choices implemented. Knowledge of these fundamental principles of agricultural systems is critical to design new production systems and markets that are flexible enough to respond to changing societal demands and adequately address emerging issues of economic feasibility and environmental sustainability. The key drivers and principles identified in this research will impact how producers, scientists and policy makers direct agricultural production and agricultural research towards sustainability.
2. Development of accurate weather data for calculation of crop water use. Producers, increasingly reliant on irrigation to enhance yields and improve return on investment, could clearly benefit from a tool that would indicate when they need to irrigate and how much. However, no easy to use irrigation scheduling tools have been developed and calibrated for the humid, high-rainfall environment and highly variable alluvial soils of Mississippi. Researchers at USDA Agricultural Research Service at Stoneville, MS, and El Reno, OK, and Mississippi State University are developing a daily irrigation scheduling tool that calculates reference evapotranspiration (ET) from weather data to establish a crop water balance which will indicate when irrigation is needed. The research team identified common sources of error in the data available from weather stations, and developed quality assessment and control procedures to identify and correct erroneous measurements. The protocols will establish consistent, accurate, and reliable data needed for calculation of reference crop ET for irrigation scheduling and crop management. Developing technologies to manage agricultural water resources of the humid southern United States will provide means for agricultural producers to increase water use efficiency and mitigate ground water depletion.
3. Improving nutrient use efficiency at the farm and country scale. Efficient nutrient use is critical to ensure economical crop production while minimizing impacts of excessive nutrient applications on the environment. Nitrogen (N) is a key component of agricultural production, both as an input to support crop production and as a waste product of livestock production. ARS scientists at Stoneville, MS, and El Reno, OK, in collaboration with university colleagues in Poland, used case studies to explore crop and animal production systems, drivers impacting management choices, and the outcome of those choices to assess the utility of gross annual N balances in tracking the progress of management decisions in minimizing environmental impacts of agricultural production systems. Changes in cropping systems in response to economic drivers that improved the N balance could, in some cases, be masked by detrimental growing conditions that were outside of the producers’ control, and use of large area-scale indices such as country or state-wide balances may mask the severity of localized nutrient imbalances that result from regionalized production systems. Development of policies to address environmental impacts and establish sustainable production systems must consider the year-to-year variability of drivers impacting agricultural production and the spatial heterogeneity of nutrient imbalances. Improvements to agricultural production that address nutrient use efficiency will enhance the overall nutrient balance of the agricultural ecosystem, while improved knowledge of crop responses to balanced plant nutrition at the country level will impact agricultural and environmental policies and enhance the sustainability of agricultural production systems.
Sassenrath, G.F., Schneider, J.M., Schmidt, A.M., Silva, A.M. 2012. Quality assurance of weather parameters for determining daily evapotranspiration in the humid growing environment of the Mid-South. Journal of the Mississippi Academy of Sciences. 57:178-192.