Recipient Organization
UNIVERSITY OF GEORGIA
200 D.W. BROOKS DR
ATHENS,GA 30602-5016
Performing Department
Crop & Soil Sciences
Non Technical Summary
Fertilizer applications must be optimized in order to increase productivity, limit costs, and reduce environmental impacts. Achieving all three nutrient management goals can be particularly challenging in Georgia because of the unique climatic and soil conditions. The overall goal of this project is to enhance row crop production in Georgia through effective nutrient management. Different studies will be undertaken to (a) track the levels of primary, secondary, and micro-nutrients under different nutrient stress conditions; (b) evaluate the interactive effects of primary, secondary, and micro-nutrient application and the subsequent impact on row crop productivity, and (c) quantify nutrient uptake and fertilizer use efficiency under different nutrient management systems. In addition, demonstration trials are proposed to ascertain the productivity and benefit-cost implications of implementing an adaptive nutrient management program on-farm. Producers, extension agents, and other relevant stakeholders will be engaged throughout the project lifespan via workshop training, webinars, conference and field day presentations, as well as extension and peer-reviewed publications.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
0%
Goals / Objectives
The overall goal of this project is to enhance row crop production in Georgia through effective nutrient management. Specific objectives include:Track the levels of primary, secondary, and micro-nutrients in plant tissues under different nutrient stress conditions.Evaluate the interactive effects of primary, secondary, and micro-nutrient application and the subsequent impact on corn productivity.Quantify nutrient uptake, fertilizer use efficiency, and environmental implications under different nutrient management systems.Educate row crop producers to adopt a proactive nutrient management program.
Project Methods
Nutrient Stress StudyThis study will evaluate four nutrient management systems to induce different nutrient stress levels using cotton as the test crop. The study will be established at the C.M. Stripling Irrigation Research Park in Camilla, GA. The nutrient management treatments will include:Early-season nutrient stress: No application of any essential plant nutrient will be made from planting until the formation of squares where it will receive 50% of all the recommended nutrient rates. The remaining 50% of all the nutrient rates will be applied between the second and third week of bloom.Late-season nutrient stress: Only 40% of the recommended nutrient rates will be applied at the early stage of planting. There will be no in-season nutrient application.Reduced nutrient stress: 30% of the recommended nutrient rates will be applied at the early stage of planting, 30% at the formation of squares, 30% between the second and third week of bloom, and 10% at peak boll formation stage.Standard nutrient management: The nutrient application will be made according to the current University of Georgia Agricultural and Environmental Services Laboratory (UGA-AESL) fertilizer recommendation rate and timing to achieve 1681 kg ha-1 cotton lint yield.The nutrients to be assessed in the study are N, P, K, Ca, Mg, S, Fe, Mn, Zn, B, and Cu. The recommended nutrient application rates for the nutrient elements for treatments (a), (b), and (c) will be determined by considering initial soil tests and the nutrient recommendations by UGA-AESL and the Waters Agricultural Laboratory Inc. Applicable treatment plots will receive fertilizer application via broadcasting at preplant and via side-dressing at and after planting. The fertilizers will be mechanically and manually applied depending on the growth stage of the crop. The application rate of the various nutrients will depend on initial soil analyses and nutrient recommendations following the University of Georgia Agricultural and Environmental Services Laboratory. In-season tissue analyses will be made by sampling the most recently mature leaf blades every two weeks. Total N in the leaves will be analyzed by dry combustion on a PerkinElmer® 2400 Series II CHNS/O Elemental Analyzer and the other nutrients analyzed on a PerkinElmer® Avio 200 Cross-Flow ICP-OES after acid digestion. Crop management practices for planting, irrigation, as well as weeds, insects, and disease control will follow the University of Georgia production guide for cotton. The crops will be harvested at maturity to determine yield and quality.Nutrient Interaction StudyThis study will evaluate the interactive effects of primary (N, P, and K), secondary (Ca, Mg, and S), and micro-nutrient (Fe, Mn, Zn, Cu, and B) application on the productivity of corn. The study will be established at the research farm of Coastal Plains Experiment Station in Tifton, GA. The treatments will consist of two primary nutrient application rates and three secondary and micro-nutrient application rates. The primary nutrient application rate will include applying the University of Georgia recommended N, P, and K rates to achieve 12.6 t ha-1 yield, and an adaptive rate where the N, P, and K levels will be maintained within the high-end of the reference sufficiency ranges for corn by the UGA-AESL. The secondary and micronutrient rates will include:Adaptive application of only secondary nutrients, where they are maintained within the high-end of the reference sufficiency ranges for corn by the UGA-AESL and the Southern Cooperative Series Bulletin (SCSB) (Campbell, 2000).Adaptive application of only micro-nutrients, where they are maintained within the high-end of the reference sufficiency ranges for corn by the UGA-AESL and SCSB.Adaptive application of secondary and micro-nutrients, where they are maintained within the high-end of the reference sufficiency ranges for corn by the UGA-AESL and SCSB.The study will be laid in a split-plot design, with four replications, where the primary nutrient rates will be assigned to the main plots, and the secondary and micro-nutrient rates assigned to the subplots. A control treatment where the plots will receive no fertilizer application will be included. Soil samples at 15 cm depth will be collected before planting and Mehlich-1 extractable nutrients analyzed on a PerkinElmer® Avio 200 Cross-Flow ICP-OES. The results will be used to determine the nutrient application rates. For all adaptive nutrient application treatment plots, we will ensure that at least 60, 40, 50, 6, 6, 6, 2, 2, 1, 0.5, 0.5, and 0.5 kg ha-1 of N, P, K, Ca, Mg, S, Fe, Mn, Zn, B, Cu, and Mo, respectively, are available in the soil before planting. If the noted nutrient levels are not available, an appropriate amount will be supplied to reach those levels. Also, we will use the designated levels as the application rate whenever a nutrient level falls below the designated threshold. In-season tissue analyses will be made every two weeks by sampling either the whole plant (plants that are < 30 cm in height), most recently mature leaf (plants that are > 30 cm in height, but prior to tasselling), or ear leaf (after tasselling). The tissue samples will be analyzed for total nutrients. Total N will be analyzed by dry combustion on a PerkinElmer® 2400 Series II CHNS/O Elemental Analyzer and the other nutrients analyzed on a PerkinElmer® Avio 200 Cross-Flow ICP-OES after acid digestion.Crop management practices for planting, irrigation, as well as weeds, insects, and disease control will follow the University of Georgia production guide for corn. At maturity, six plants will be sampled from each plot and partitioned into four components: (a) leaf blades, (b) stalks and leaf sheaths, (c) tassel, cob, husk, and (d) seeds. The samples will be oven-dried at 65oC until constant weight and analyzed for total nutrients. Also, soil samples to a depth of 15 cm will be collected at maturity and analyzed for Mehlich-1 extractable nutrients. The measurements will be used to quantify the nutrient uptake and fertilizer use efficiencies according to Moll et al. (1982). The entire middle two rows of each plot will be harvested with a plot combine equipped to measure seed weight, test weight, and moisture content, which will further be used to calculate grain yield adjusted to 15.5% moisture content.Demonstration TrialsThe best nutrient management systems that will be identified based on the findings of the above two studies will be evaluated in an on-farm demonstration trial at the final project year. The trials will be non-replicated within a farm, where a one-acre area will be maintained following a producer's routine nutrient management plan and another acre area maintained based on recommendations from this study. The productivity and benefit-cost ratio of implementing the recommended nutrient management plan of this project will be assessed. Extension agents will be brought on board to coordinate the demonstration trials.