Source: UNIVERSITY OF ARKANSAS submitted to NRP
DEVELOPMENT OF CROP NUTRIENT MANAGEMENT DECISION AIDS BASED ON PLANT AND SOIL ANALYSES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1013560
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2017
Project End Date
Sep 30, 2022
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF ARKANSAS
(N/A)
FAYETTEVILLE,AR 72703
Performing Department
Crop, Soil & Environmental Sciences
Non Technical Summary
Nutrient management is an important aspect of food production but has also become an important social issue that influences the quality of life of all people.The use of sound science is needed to guide agronomic management of land, fertilizer, manure, and other crop inputs used for crop production.Farms are getting larger and the land-grant system is no longer the primary provider of information to farmers and consultants.A large amount of information about various products and practices is available to growers and consultants that has little or no unbiased research supporting the short- and long-term effectiveness for increasing food production, soil productivity, or farm economics. Applied research that defines and demonstrates effective nutrient management and develops tools that can aid farmers in making science-based decisions is needed more than ever.This project will develop information to aid farmers and consultants in all aspects of the 4R Nutrient Management Program (Right Source, Right Rate, Right Time and Right Place) with emphasis on improving our understanding of nitrogen, phosphorus, potassium, and zinc nutrition of soybean and rice.We expect to develop recommendations on rapid methods of assessing the potassium nutritional status of soybean, develop a field-based rating system for accurately identifying chloride tolerant soybean cultivars, evaluating several new methods of zinc fertilization, and improving the accuracy of plant and tissue analysis of crops grown in Arkansas that include old and new practices that are used or being adopted by farmers.
Animal Health Component
50%
Research Effort Categories
Basic
20%
Applied
50%
Developmental
30%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020110200034%
1021530200033%
1021899200033%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
0110 - Soil; 1530 - Rice; 1899 - Oilseed and oil crops, general/other;

Field Of Science
2000 - Chemistry;
Goals / Objectives
The overall goal of this project is to improve recommendations involving chemical soil tests and tissue analysis for plant nutrient concentrations by increseing ourability to interpret the analytical information for making sound agronomic nutrient management decisions.Evaluate soybean [Glycine max (L.) Merr.] response to potassium (K) application time and validate the accuracy of critical plant-tissue K concentrations during reproductive growth.Develop and validate a new field-based rating method for characterizing the chloride (Cl) includer/excluder trait for soybean cultivars.Assess the efficacy of low-use-rate, zinc-fertilization (Zn) methods for rice (Oryza sativa L.).Assess how cover crops influence soil chemical properties including Mehlich-3 extractable nutrients and subsequent soil-test-based fertilizer recommendations.Develop databases regarding crop response to soil-test, nutrient-availability indices and nutrient fertilization that can be used to correlate and calibrate crop nutrient management recommendations.Train graduate students in soil fertility and nutrient management.
Project Methods
Objective 1: Characterizing soybean response to K application timing and use of tissue analysis to identify potential K deficiency.This objective involves three components including the assessment of i) traditional tissue analysis and rapid (in-field) sap-K concentrations, ii) irrigated soybean yield and uptake response to K application timing, and iii) development and validation of critical tissue K concentrations during reproductive growth. All three objectives will be assessed in long-term K fertilization trials established at the Pine Tree Research Station (PTRS) and Rice Research Extension Center (RREC) and short-term trials at these and other sites as needed. Soybean yield and K uptake responses to K application times ranging from preplant to the R6 stage will be assessed in short-term trials on K-deficient soils. Soybean actual and/or relative yield expressions to a standard K rate will be regressed across time (e.g., days after emergence or planting). The K timing trials will assess multiple rates applied at selected times but will focus on responses to 120 lb K2O/acre, which is usually sufficient to produce near maximal yields on most soils. Trifoliolate leaf, petiole and petiole sap-K concentrations will be measured from samples (10 trifoliate leafs per plot/tissue) collected 2 weeks after K applications made in reproductive growth (R1 to R6 stages) to determine K uptake and the effect of K timing on tissue K. Leaf- and petiole-K concentrations will be determined using traditional lab methods involving digestion and analysis via inductively coupled atomic emission spectrophotometry. Sap-K concentrations will be measured using the Horiba B-731 LAQUAtwin Compact K Ion Meter. Yield and tissue-K concentrations from short- and long-term trials will be used to validate and, if needed, refine, the proposed critical leaf-K concentrations proposed by Parvej et al. (2016b). Critical tissue-K concentrations will be identified by regressing soybean yield against K concentration for each growth stage. The critical tissue-K concentrations for each growth stage will then be regressed against time expressed as days after R1 growth stage as estimated by the SoyMap program (Popp et al., 2016) to develop a continuous critical tissue-K concentration across time.Objective 2 (Develop a new rating method for characterizing the chloride (Cl) includer/excluder trait for soybean cultivars) - This research will focus on developing a new rating method and system to determine the Cl rating for new cultivars using field-grown plants. The rating system will be based on composite leaf-Cl concentrations of field-grown soybean planted in the Arkansas Soybean Variety Performance Trials (SVPT). The new rating system will recognize that many cultivars are comprised of a population of plants that are heterozygous in regards to the allelle that controls Cl uptake rather than a population of plants that all contain a homozygous dominant trait that excludes Cl. Trifoliolate leaf samples will be collected from at least one or two of the SVPT sites each year when plants are in an early to middle reproductive growth stage, processed and analyzed for Cl concentration. The resulting leaf-Cl concentrations will be ranked from low to high and assigned a rating of 1 to 5 (or, alternatively, 1 to 10) with 1 being a variety comprised of ≥80% excluder plants and ≤20% includer plants. Standard varieties will be used to calibrate the rating system. We will examine the data for consistency of variety ratings between sites within a year and between years to ensure the system is viable. Modifications to the planned rating system may be required during its development. Tissue from numerous individual plants may also be analyzed to establish and/or verify the makeup of a cultivars' plant population.Objective 3 (Assess the efficacy of low-use-rate, zinc-fertilization (Zn) methods for rice) -Experiments will be established to examine how low-Zn-rate fertilization methods used alone or in combination with other Zn fertilization strategies influence seedling Zn concentration and rice grain yield. The methods evaluated will include, but not be limited to, no Zn, 10 lb Zn/acre as a granular, water-soluble ZnSO4 fertilizer (standard method), Zn seed treatment, foliar application of Zn-EDTA, use of MESZ fertilizer (10-40-0-10S-1Zn, the Mosaic Company), and selected manufacturer recommended rates of WolfTrax Zn-DDP (Compass Minerals, Overaland Park, KS). The trial will be set up as a factorial using two seed Zn rates (0 & 0.50 lb Zn/cwt seed) applied in combination with the other methods. Rice dry matter and Zn concentration of seedlings will be evaluated shortly after flooding during early tillering and grain yield will be measured at maturity. The Canopeo iPhone/iPad application will be used as a non-destructive method to assess early-season growth differences or canopy cover. The data will be analyzed using ANOVA and significant differences interpreted when P≤ 0.10. Each trial will be a randomized complete block arranged in a factorial treatment structure with at least five blocks.Objective 4 (Assess how cover crops influence soil chemical properties including Mehlich-3 extractable nutrients and subsequent soil-test based fertilizer recommendations)Experiments will be established in adjacent areas to study the effect of annual applications of four rates of P and four rates of K. The trials will be on silt loam soils at the Rohwer Research Station and the Lon Mann Cotton Research Station (Marianna) and include conventional (no fall/winter cover crop) and cover crop production systems with cover crops serving as the main plot in each block of a randomized complete block design (12.67 wide x 200 ft long plot dimensions). The plots will be cropped to a corn, cotton and soybean rotation and yield will be measured annually. Treatments will be assigned to random plots for the first year but the assigned fertilizer treatments will not be applied so that we can examine whether any inherent differences in productivity exist when only fertilizer N. In the fall (2017), treatments will be reassigned to remove inherent field variability (if needed), cover crops will be established, and P and K treatments implemented with the initial soil samples collected in the fall/winter months. Soil samples will be collected annually to monitor the long-term effects of cover crop and fertilizer rate and multiple times during the fall and winter months to examine short-term trends of these same variables. Soil samples (0-6 inches) will also be submitted to the Cornell Soil Health Lab to assess initial soil health and the effect of treatments on short- and long-term soil health.Objective 5 (Develop databases regarding crop response to soil-test, nutrient-availability indices and nutrient fertilization that can be used to verify and/or correlate and, if appropriate, calibrate crop fertilizer recommendations)Existing databases will be maintained and built upon from various trials including previously established long-term trials (involving rice) at the Pine Tree Research Station and Rice Research Extension Center. In addition, the long-term trials established from efforts in Objective 4 and short-term, multiple-rate fertilization trials established at multiple locations will be added to the databases. Agronomic and economic interpretations of data will be assessed using methods reported by Slaton et al. (2010).Objective 6 (Train graduate students) - qualified and motivated graduate students will be recruited and into my research program.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The primary target audiences for the described research and outreach activities were open to all individuals, which includes interested farmers, consultants, landowners, Extension agents, farm service personnel, peer scientists, and interested general public. Efforts to disseminate information were made via popular press articles and interviews, publication of reports in refereed and non-refereed journals, and oral and poster presentations. Oral presentations were made on soil testing and crop fertilization to regional, state (Arkansas), and local audiences at several meetings. Research results were used/presented at the following professional meetings: Tri-Society International meeting in San Antonio, TX), Arkansas Crop Management Meeting (January 2020, North Little Rock), and the Cotton and Rice Conservation Tillage Conference (January 2020, Memphis, TN). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?All of the research involved training and educating graduate students in the use of laboratory and field research techniques, scientific writing, scientific ethics and the statistical analysis of data. How have the results been disseminated to communities of interest?Results have been disseminated via written materials including abstracts, reports, and journal publications. Oral presentations were also given at educational meetings. What do you plan to do during the next reporting period to accomplish the goals?Research data will continue to be collected, statistically analyzed, and summarized for publication. Research projects and funding will be continued.

Impacts
What was accomplished under these goals? Research from this project has made substantial contributions advancing our knowledge of soybean and rice potassium (K) deficiency and how to interpret K concentrations in multiple tissues at different growth stages, understanding whether flood-irrigated rice responds to starter-N on clayey soils, and developing databases that contribute to understanding the frequency and magnitude of rice and soybean yield response to phosphorus (P) and K fertilization that will be meaningful to millions of acres across the world. The research and summation efforts associated with the FRST project will influence nutrient management decisions on millions of acres in the USA and establish guidelines on research protocols for decades into the future. Data from multiple years of field research were statistically analyzed to develop a dynamic continuous critical potassium concentration in rice flag leaves in research performed by Chandler Gruener.Critical Y-leave potassium concentrations from the R1 stage to R3-R4 stages were developed for pure-line rice cultivars grown in a direct-seeded, flood-irrigated system.The relationship was strong until flag leave emergence at which time the ability to predict plant potassium sufficiency from the Y-leaf declined as potassium was rapidly remobilized from leaves to the developing panicle. The research also showed that sap extracted from Y-leaves as performed in these field trials was not consistent and could not be used to predict plant potassium sufficiency. The research also showed that hybrid rice responds to soil and fertilizer potassium differently than pure-line cultivars. Databases developed from 5-20 years of soil-test potassium correlation and calibration research with rice and soybean were provided to an agricultural economist who developed models and Excel-based- programs to determine the fertilizer-potassium rates that maximize profits using the price of fertilizer-potassium sources and the price of the commodity. These programs show that in most instances the profit-maximizing fertilizer-potassium rate is lower than the agronomic-based fertilizer-potassium rate needed to produce maximum yield.Journal articles describing profit-maximizing potassium rate research for both commodities were published and the development of decision-aid tools is planned. We also completed research aimed at identifying how late in the growing season (e.g., plant growth stage) fertilizer potassium could be applied before permanent yield loss occurred. Fertilizer potassium had to be applied earlier in reproductive growth to recover lost yield potential as the severity of potassium deficiency increased. Publication of this research sets the stage for us to summarize our research to developdynamic critical potassium concentrations for soybean leaflets and petioles. These data were reviewed, summarized, and statistically analyzed for publication. Research was also initiated to examine the effect of soil-moisture content at the time of soil sample collection on soil-core uniformity and soil-test results as well as the effect of soil-core collection place in fields with beds from the previous crop (e.g., furrow, shoulder, or top of ridge).Preliminary results show that very dry or wet field conditions cause variation in the soil depth that is effectively sampled and the effect is greater for some soil probes and sample depths than others.The loss of soil from cores or the inability to insert soil probes to the proper depth influences the extracted nutrient concentrations. The availability of some soil nutrients was also influenced by the moisture content due presumably to their mobility in soil. The long-term trials investigating the effect of cover crop and fertilizer-phosphorus and potassium rates continued in 2019-2020. The growth of the cover crop has shown to influence the soil-test results for some nutrients between the late fall to late winter or early spring. To date, the results have been inconsistent due to wet fall weather inhibiting the establishment and substantial growth of the cereal rye cover crop. The effects of cover crop and annual fertilizer potassium or phosphorus rates on the summer crop have been minimal to date but provide valuable data to the overall efforts of correlating and calibrating soil-test-based fertilizer crops for the three cash crops grown in this project. Research on starter-N fertilizer source on the growth and yield of rice grown on clayey soils in southeast Arkansas and in Mississippi was statistically analyzed for summation and publication in 2021. A nominal rate of starter-N appears to be beneficial to early-season canopy closure and yield of hybrid rice that is planted using very low seeding rates, but not pure-line cultivars that are planted with higher seeding rates.The database we have accumulated from soil-test phosphorus and potassium research with corn and cotton in Arkansas performed by other scientists was summarized and analyzed to examine the accuracy of current soil-test level definitions and fertilizer rate recommendations. We expect to publish this information and adjust soil-test recommendations in 2021.We also provided a database of soil-test P data and soybean yield response to phosphorus fertilization to project leaders coordinating the FRST national soil-test database to examine the effect of different relative yield calculation methods on soil-test correlation, lead a committee of scientists to develop a minimum database for soil-test correlation and calibration research, and contributed to a survey of land grant institution scientists to that was initiated and completed in 2020. The first paper describing the FRST effort was published in 2020 and outlined the projects objectives.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Lyons, S.E., D.L. Osmond, N.A. Slaton, J.T. Spargo, P.J.A. Kleinman, and D.K. Arthur. 2020. FRST: A national soil testing database to improve fertility recommendations. Agric. Environ. Letters 2020;5:20008. doi: 10.1002/ael2.20008
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Popp, M., Slaton, N.A., & Dixon, B. (2020). Rice yield response to potassium: An economic analysis. Agronomy Journal, DOI: 10.1002/agj2.20471
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Popp, M., Slaton, N.A., & Roberts, T.L. (2020) Profit-maximizing potassium fertilizer Recommendations for Soybean. Agronomy Journal, 112, 5081 5095. 10.1002/agj2.20424
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Slaton, N. A., Roberts, T. L., Ross, W. J., & Richmond, T. L. (2020). Irrigated soybean response to granular fertilizer potassium application timing. Agronomy Journal, 112: 4344 4357. DOI: 10.1002/agj2.20342
  • Type: Other Status: Published Year Published: 2020 Citation: Smartt, A.D., N.A. Slaton, T.L. Roberts, L. Martin, S. Hayes, C. Treat, and C.E. Gruener. 2020. Cover Crop and Phosphorus and Potassium. In: N.A. Slaton, editor, Wayne E. Sabbe Arkansas Soil Fertility Studies 2018. Ark. Agric. Exp. Stn. Res. Ser. 666. Fayetteville, AR. p. 68-73.
  • Type: Other Status: Published Year Published: 2020 Citation: Gruener, C.E., N.A. Slaton, J.T. Hardke, T.L. Roberts, and A.D. Smartt. 2019. Yield Responses of Pure-Line and Hybrid Rice to Potassium Fertilization for Long- and Short-Term Trials. In: K.A.K. Moldenhauer, B. Scott, and J. Hardke, editors, B.R. Wells Arkansas Rice Research Series 2019. Ark. Agric. Exp. Stn. Res. Ser. 667. Fayetteville, AR. p.211-213.
  • Type: Other Status: Published Year Published: 2020 Citation: Martin, L.R., N.A. Slaton, B.R. Golden, R.J. Norman, J. Hardke, and T.L. Roberts. 2020. Starter nitrogen source and preflood nitrogen rate effects on rice grown on clayey soils. In: K.A.K. Moldenhauer, B. Scott, and J. Hardke, editors, B.R. Wells Arkansas Rice Research Series 2019. Ark. Agric. Exp. Stn. Res. Ser. 667. Fayetteville, AR. p.231-234.


Progress 10/01/18 to 09/30/19

Outputs
Target Audience:The primary target audiences for the described research and outreach activities includes interested farmers, consultants, landowners, Extension agents, farm service personnel, peer scientists, and interested general public. Efforts to disseminate information were made via popular press articles and interviews, publication of reports in refereed and non-refereed journals, and oral and poster presentations. Oral presentations were made on soil testing and crop fertilization to regional, state (Arkansas), and local audiences at several meetings. Research results were used/presented at the following professional meetings: Soil Science Society of America Meeting International meeting (January 2019, San Diego, CA), Arkansas Crop Management Meeting (January 2019, North Little Rock), and the Arkansas Crop Protection Association Research Meeting (November 2018 Fayetteville, AR). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?All of the research involved training and educating graduate students in the use of laboratory and field research techniques, scientific writing, scientific ethics and the statistical analysis of data. How have the results been disseminated to communities of interest?Results have been disseminated via written materials including abstracts, reports, and journal publications. Oral presentations were also given at educational meetings. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Research from this project has made substantial contributions advancing our knowledge of soybean and rice potassium (K) deficiency and how to interpret K concentrations in multiple tissues at different growth stages, understanding whether flood-irrigated rice responds to starter-N on clayey soils, and developing databases that contribute to understanding the frequency and magnitude of rice and soybean yield response to phosphorus (P) and K fertilization. Nine long-term or multiyear projects were continued in 2019 at four different research stations with the long-term fertilizer-K rate trials serving as important components of research developing continuous critical leaf K concentrations for rice and soybean.. The correlation and calibration databases for rice was shared with economist who developed response curves that couple the average agronomic yield response curves with profitability metrics that will, when published allow growers and consultants to observe and compare the agronomic soil-test-based fertilizer recommendations to dynamic recommendations that use the anticipated price of fertilizer-K and the price of rice. Data for soybean will be shared in the coming year to develop similar response curves and grower decision aids. Data collected from annual trials will continue to be added to the correlation and calibration databases for rice and soybean. Databases that include corn and cotton P and K correlation and calibration results have also been developed to validate and update soil-test-based fertilizer-P and -K recommendations for these crops. Eight fertilizer-K rate trials with rice were established in 2019 with two being from long-term trial sites and six being single-year trials located at three sites having low soil-K availability. The three sites each included a trial seeded with a pure line cultivar and a hybrid cultivar. Each trial was sampled to characterize how rice Y-leaf K concentration changes across time as affected by cultivar and fertilizer-K rate. The 2018 and 2019 trial results both suggest that hybrid rice is less responsive to K fertilization than pure line cultivars and may require lower critical soil-test K thresholds to trigger fertilization, lower fertilizer-K rates to maximize yield or both. Soybean leaf samples were collected from a variety performance trial conducted at the Rohwer Research Station. Analysis of trifoliolate-leaflet samples collected during reproductive growth for chloride concentration is not yet complete but will be used to rate current and new cultivars across herbicide technologies for their chloride trait. Results from analysis completed from the 2018 variety trial were used to rate varieties in the Arkansas Soybean Variety Publication. For the long-term cover P and K crop trials, the wet fall of 2018 prevented timely establishment of a cover crop at Rohwer (wheat seeded in early 2019) and Marianna (cereal rye) with very little biomass production at either location before crop establishment. As expected, soil-test P and K values increased as the rates of P and K applied to the 2018 crop increased. Soybean was planted following the 2018 cotton crop and mean yields were excellent at the Rohwer site (+80 bu/acre) and average (50 bu/acre) at the Marianna site due to later planting. At Rohwer, soybean yield was not affected by cover crop, fertilizer-P or K rates, or their interactions where soil-test P and K were near optimal when the trial began. At Marianna, only cover crop had a significant effect on soybean yield in P rate trial (51 bu/acre with cover crop vs 49 bu/acre without cover crop). In the K trial the main effects of cover crop and K rate both influenced soybean yield. Yield was greater with a cover crop (47 bu/acre) than without (45 bu/acre) and yields were increased by fertilizer-K application regardless of the rate (45 bu/acre without K vs 47 bu/acre with K). In the long-term P, K and micronutrient trial at the Pine Tree Research Station, soybean yield was affected only by the main effect of nutrient source, but not by P rate or the P rate by nutrient source interaction. Yields were equal and greatest when annual applications of monoammonium phosphate plus muriate of potash (57 bu/acre) or MicroEssentials (12-40-0-10S-1Zn) plus Aspire (0-0-60-0.5B) (57 bu/acre) were applied compared to P alone (49 bu/acre), K alone (49 bu/acre), or no fertilizer (47 bu/acre). The K only treatment was added to the treatments in 2019 by converting one of two no fertilizer control treatments into a K only treatment. Annual soil-test results continued to show that soil-test P increased as P rate increased, regardless of P fertilizer source, and that annual application of S, Zn and B in the MicroEssentials plus Aspire treatment caused soil-test values of these nutrients to gradually increase across time. Starter-N trials with rice grown on clayey soils in southeast Arkansas and in Mississippi continued to show that preflood N rate had a significant influence on rice grain yield and early season canopy coverage. The effect of starter-N source on yield and early-season canopy coverage was less consistent but tended to show more frequent and significant benefits when applied to hybrid rice seeded at a low rate compared to pure line cultivars. Although inconsistent across site-years, the starter N applied as urea or ammonium sulfate tended to produce greater yields at lower preflood-N rates than no starter or diammonium phosphate starter. The effect of starter N was significant for at least three weeks after application at the 2-leaf stage persisting at least 1 or 2 weeks following preflood N application.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Fryer, M., N.A Slaton, T.L. Roberts, and W.J. Ross. 2019. Validation of soil-test-based phosphorus and potassium fertilizer recommendations for irrigated soybean. Soil Sci. Soc. Am. J. 83:825837. doi:10.2136/sssaj2019.02.0032
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Fryer, M., N.A Slaton, T.L. Roberts, J.T. Hardke, R.J. Norman. 2019. Validation of soil-test-based phosphorus and potassium fertilizer recommendations for flood-irrigated rice. Agron. J. 111:1-13. doi:10.2134/agronj2019.03.0159
  • Type: Theses/Dissertations Status: Published Year Published: 2019 Citation: Coffin, M.D. 2019. The Evaluation of Low-Use-Rate Zinc Fertilization Strategies on Seedling Canopy Coverage, Zn Concentration, Biomass, and Grain Yield. M.S. Thesis. University of Arkansas.
  • Type: Other Status: Published Year Published: 2019 Citation: Slaton, N.A., T.L. Roberts, L. Martin, S. Hayes, C. Treat, and A. Smartt. 2019. Cover crop and phosphorus and potassium effects on soil-test values and cotton yield. In: N.A. Slaton, editor, Wayne E. Sabbe Arkansas Soil Fertility Studies 2018. Ark. Agric. Exp. Stn. Res. Ser. 657. Fayetteville, AR. p. 52-56.
  • Type: Other Status: Published Year Published: 2019 Citation: Slaton, N.A., T.L. Roberts, J. Hedge, and A. Smartt. 2019. Corn yield and soil-test responses to annual fertilization with different phosphorus and potassium-containing fertilizers. In: N.A. Slaton, editor, Wayne E. Sabbe Arkansas Soil Fertility Studies 2018. Ark. Agric. Exp. Stn. Res. Ser. 657. Fayetteville, AR. p. 57-60.
  • Type: Other Status: Published Year Published: 2019 Citation: Martin, L.R., N.A. Slaton, B.R. Golden, R.J. Norman, J. Hardke, and T.L. Roberts. 2019. Starter nitrogen source and preflood nitrogen rate effects on rice grown on clayey soils. In: R.J. Norman and K.A.K. Moldenhauer, editors, B.R. Wells Arkansas Rice Research Series 2018. Ark. Agric. Exp. Stn. Res. Ser. 659. Fayetteville, AR. p.316-320.
  • Type: Other Status: Published Year Published: 2019 Citation: Coffin, M.D., N.A. Slaton, E.E. Gbur, A.D. Smartt, C.E. Gruener, and L.R. Martin. 2019. Low-use-rate zinc fertilization strategies for rice. In: R.J. Norman and K.A.K. Moldenhauer, editors, B.R. Wells Arkansas Rice Research Series 2018. Ark. Agric. Exp. Stn. Res. Ser. 659. Fayetteville, AR. p.253-259.
  • Type: Other Status: Published Year Published: 2019 Citation: Gruener, C.E., N.A. Slaton, J.T. Hardke, T.L. Roberts, A.D. Smartt, and M.D. Coffin. 2019. Delineation of continuous, critical leaf potassium concentrations during reproductive growth for monitoring rice potassium status. In: R.J. Norman and K.A.K. Moldenhauer, editors, B.R. Wells Arkansas Rice Research Series 2018. Ark. Agric. Exp. Stn. Res. Ser. 659. Fayetteville, AR. p.283-289.


Progress 10/01/17 to 09/30/18

Outputs
Target Audience:The primary target audiences for the described research and outreach activities were open to all individuals, which includes interested farmers, consultants, landowners, Extension agents, farm service personnel, peer scientists, and interested general public. Efforts to disseminate information were made via popular press articles and interviews, podcasts, publication of reports in refereed and non-refereed journals, and oral and poster presentations. Oral presentations were made on soil testing and crop fertilization to regional, state (Arkansas), and local audiences at several meetings row crop producing counties and several agent and consultant specific trainings. Research results were used/presented at the following professional meetings: American Society of Agronomy International meeting (November 2017, Tampa, FL), Arkansas Crop Management Meeting (January 2018, North Little Rock), SERA-IEG 6 Annual meeting (June 2018 in Athens, GA), and the Arkansas Crop Protection Association Research Meeting (late Nov. 2017, Fayetteville, AR). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?All of the research involved training and educating graduate students in the use of laboratory and field research techniques, scientific writing, scientific ethics and the statistical analysis of data. How have the results been disseminated to communities of interest?Results have been disseminated via written materials including abstracts, reports, and journal publications. Oral presentations were also given at county, state, and national/international educational meetings. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Our research has made substantial contributions advancing our knowledge of soybean and rice potassium (K) deficiency and how to interpret K concentrations in multiple tissues at different times, understanding whether flood-irrigated rice responds to starter-N on clayey soils, and developing databases that contribute to understanding the frequency and magnitude of rice and soybean yield response to phosphorus (P) and K fertilization. For objective 1, we have advanced our with understanding soybean K nutrition continued to research critical K concentrations for leaf and petiole tissues and petiole sap during reproductive growth to refine and validate continuous leaflet and petiole K concentrations during reproductive growth. Two research trials were initiated to determine how late fertilizer-K can be applied to K deficient soybean with significant yield increases and improve the time scale used to interpret soybean tissue K concentrations using soybean planted on 30-inch wide beds. Bothtrials showed soybean yield response to fertilizer-K gradually declines aroundthe R3-R4 stage. The 'SoyMap' program accurately predicted the R1 growth stage and is suitable for use in diagnostic programs to monitor soybean K sufficiency. Petiole sap K concentrations were measured via a portable K ion meter (Horiba K meter) and compared to traditional leaflet and petiole analysis. The second year of a data were added to the petiole sap K database which was started in 2017 and appears promising yet less accurate than traditional tissue analysis, but has the advantage of beinga rapid in-field method of monitoring plant K status.Additional research is needed develop this information into recommendations and correlate the information to yield which can be started once all of the data is analyzed in the lab. This project was expanded to include rice in 2018. The rice leaf sap was not a good indicator of Plant K status as its concentration was highly variable and fluctuated too much when sap was extracted by two different methods. Soybean sap was more stable in this regard and much easier to extract from petioles than leaf blades. Rice Y-leaf tissue concentration via traditional lab analysis appears to be a good method for assessing plant K status. The ability to accurately interpret plant tissue concentrations during the season provides farmers with the ability to monitor the soybean plants' K nutritional status as a supplement to soil testing to ensure that soil-test based fertilization recommendations are accurate. The database now contains15+ site-years of field research relating tissue K to yieldand an Excel program is available for preliminary usewith lab analysis results that contain maturity group, geographic locationand planting date.Five site-years of data were collected for rice in 2018. For objective 2, leaf samples were collected and analyzed from oneArkansas Variety Performance Trial site located at theRowher Research Station with more than 100 varieties sampled. A rating of 1 (low Cl concentration indicating CL excluder variety trait) to 5 (ultra-high leaf C concentration indicating a population of Cl including soybean plants) was developed and compared to the traditional greenhouse rating system (Includer, Mixed, Excluder rating system). Thirty individual plants of 12 varieties were sampled to examine population diversity for the includer/excluder trait. One more year of field testing is needed to validate the new method. Some populations were uniform in leaf Cl while others were quite variable indicating the potential for multiple genes controlling Cl uptake by soybean. Five trials evaluating low-use-rate Zn fertilization methods on rice were established in a graduate student problem to bring the total research sites over the last two years 7. Results show that Zn seed treatments increase whole seedling Zn concentration by about 2 ppmand results in about 3 bu/acre yield increase. Methods that include early-season N lead to increased dry matter and seedling size (canpoy coverage) but do not contribute to yield. None of the low-use-rate methods increase tissue Zn concentration like the addition of 10 lb elemental Zn/acre. Objective 4, the cereal rye cover crop growthresulted in slightly lower soil-test K values in spring at termination than where the soil was winter fallowed. At one site, the cereal rye cover crop limited seedcotton yield by presumably immobilizing some of the applied fertilizer N. Cotton responded positively to K fertilization at one site, but the response was not affected by cover crop.These are long-term plots and 2018 marked the first year of annualP and K fertilization. Cotton did not respond to P fertilization at either site. For objective 5, development of crop response databases, multiple field trials examined rice and soybean responses to P and K fertilization with standard and new fertilizer sources. Rice, soybean, corn and cotton databases were updated with results from 2017 and 2018 field trials conducted in Arkansas.We continue to examine the utility of P and K extraction from field-moist soil rather than oven-dry soilfor both rice and soybean. The rice data-base shows the amount of K extracted differs between moist and dry soil, but both are equally effective in predicting rice yield response to K fertilization. For soybean, moist-soil K explains more of the variability in relative soybean yield than oven-dry soil analysis, but both are likely suitable for making fertilizer recommendations.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Cox, D.D., N.A. Slaton, W.J. Ross and T.L. Roberts. 2018. Trifoliolate leaflet chloride concentrations for characterizing soybean yield loss from chloride toxicity. Agron. J. 10:1589-1599. doi:10.2134/agronj2017.12.0725
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Richmond, T,L., N.A. Slaton, J.T. Hardke, T.L. Roberts, and R.J. Norman. 2018. Rice aboveground nitrogen content, development, and yield as affected by nitrogen fertilization and flood timing. Agron. J. 110: doi:10.2134/agronj2018.05.0308
  • Type: Book Chapters Status: Awaiting Publication Year Published: 2019 Citation: Korres, N.E., V.K. Varanasi, N.A. Slaton, A.J. Price and T. Bararpour. 2019. Effects of salinity on rice and rice weeds: short- and long-term adaptation strategies and weed management. In: M. Hasanuzzaman, M. Fujita, K. Nahar, and J.K. Biswas, editors, Advances in Rice Research for Abiotic Stress Tolerance. Woodhead Publishing, Duxford, United Kingdom. p.159-176. ISBN: 978-0-12-814333-9
  • Type: Other Status: Published Year Published: 2018 Citation: Slaton, N.A., L. Martin, S. Hayes, C. Treat, R. DeLong, and T. Jones. 2018. Initial Soil Chemical Property and Health Ratings for Long-Term Fertilization Trials. In: N.A. Slaton, editor, Wayne E. Sabbe Arkansas Soil Fertility Studies 2017. Ark. Agric. Exp. Stn. Res. Ser. 649. Fayetteville, AR. p.43-47.
  • Type: Other Status: Published Year Published: 2018 Citation: Slaton, N.A., R. DeLong, J. Hedge, Y. Liyew, and T. Jones. 2018. Crop and Soil Test Responses to Annual Fertilization with Different Fertilizers. In: N.A. Slaton, editor, Wayne E. Sabbe Arkansas Soil Fertility Studies 2017. Ark. Agric. Exp. Stn. Res. Ser. 649. Fayetteville, AR. p.48-51.
  • Type: Other Status: Published Year Published: 2018 Citation: Coffin, M.D., N.A. Slaton, T.L. Roberts, R.J. Norman, and J.T. Hardke. 2018. Low-Use-Rate Zinc Fertilization Strategies for Rice. In: R.J. Norman and K.A.K. Moldenhauer, editors, B.R. Wells Arkansas Rice Research Series 2017. Ark. Agric. Exp. Stn. Res. Ser. 651. Fayetteville, AR. p.238-243.
  • Type: Other Status: Published Year Published: 2018 Citation: Slaton, N.A., R.J. Norman, J. Hardke, T.L. Roberts, R.E. DeLong, Travis Jones, and D. Frizzell. 2018. Summary of Crop Yield and Soil-Test Phosphorus and Potassium Responses to Long-Term Fertilization Rate. In: R.J. Norman and K.A.K. Moldenhauer, editors, B.R. Wells Arkansas Rice Research Series 2016. Ark. Agric. Exp. Stn. Res. Ser. 651. Fayetteville, AR. p.341-348.
  • Type: Other Status: Published Year Published: 2018 Citation: Cox, D.D., N.A. Slaton, T.L. Roberts, T.L. Richmond, D.A. Sites, R.E. DeLong, and J. Hedge. 2018. Why Does Variability Exist among Variety Soybean Chloride Ratings? In: J. Ross, editor, Arkansas Soybean Studies 2016. Ark. Agric. Exp. Stn. Res. Ser. 648. Fayetteville, AR. p.119-121.
  • Type: Other Status: Published Year Published: 2018 Citation: Martin, L.R., N.A. Slaton, B.R. Golden, R.J. Norman, J. Hardke, and T.L. Roberts. 2018. Starter Nitrogen Source and Preflood Nitrogen Rate Effects on Rice Grown on Clayey Soils. In: R.J. Norman and K.A.K. Moldenhauer, editors, B.R. Wells Arkansas Rice Research Series 2017. Ark. Agric. Exp. Stn. Res. Ser. 651. Fayetteville, AR. p.297-301.
  • Type: Other Status: Published Year Published: 2018 Citation: Slaton, N.A., D.A. Sites, D.D. Cox, T. Richmond, J. Hardke, T.L. Roberts, and J. Hedge. 2018. Evaluation of a Rapid, In-Field Method for Assessing Soybean Potassium Nutritional Status. In: J. Ross, editor, Arkansas Soybean Studies 2016. Ark. Agric. Exp. Stn. Res. Ser. 648. Fayetteville, AR. p.115-118.