THE SILENT DECLINE IN SOIL POTASSIUM LEVELS AND ITS EFFECT ON ALFALFA PRODUCTIVITY IN THE CENTRAL AND WESTERN US

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: OTHER GRANTS
• Reporting Frequency: Annual
• Accession No.: 1010209
• Grant No.: 2016-70005-25649
• Cumulative Award Amt.: $250,000.00
• Proposal No.: 2016-06099
• Project Start Date: Sep 1, 2016
• Project End Date: Aug 31, 2020
• Grant Year: 2016
• Program Code: [AFRP]- Alfalfa and Forage Program

Recipient Organization
UNIVERSITY OF WYOMING
1000 E UNIVERSITY AVE DEPARTMENT 3434
LARAMIE,WY 82071-2000

Performing Department
Plant Sciences

Non Technical Summary
The goal of the projectis to develop a potassium (K) fertility management program that will improve alfalfa production and quality within the central and western U.S. We will generate much needed information for alfalfa producers, crop consultants, and other central and western alfalfa stakeholders through a planned regional alfalfa workshop while communicating state specific results through local extension programs. This goal will be accomplished by two research (Obj. 1-2) and two extension (Obj. 3-4) objectives. Field studies will be conducted in three central and western states focusing on alfalfa growth, yield, and quality by application of different levels of K under two cutting intervals (Obj. 1). We will determine K uptake and forage quality of selected alfalfa cultivars at different growth stages (Obj. 2). Finally, we will develop K fertility recommendations and update alfalfa soil fertility guides for the central and western U.S. (Obj. 3) and develop supporting documents for the initiation of an Alfalfa Community of Practice (CoP) within eXtension (Obj. 4).

Animal Health Component

40%

Research Effort Categories

Basic

40%

Applied

40%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
205	2499	1060	50%
205	1649	1060	50%

Knowledge Area
205 - Plant Management Systems;

Subject Of Investigation
1649 - Forage legumes, general/other; 2499 - Plant research, general;

Field Of Science
1060 - Biology (whole systems);

Keywords

alfalfa

forage quality

forage yield

potassium levels

soil mining

Goals / Objectives
The goal of this multi-state, multi-institutional project is to develop a potassium (K) fertility management program that will improve alfalfa production and quality across the central and western U.S. The project will generate much needed information for alfalfa producers and stakeholders of the entire region and communicate the results through extension programs. This goal will be accomplished by the following research and extension objectives.Determine irrigated alfalfa growth, yield, and quality with selected cultivars across three central and western states with different levels of K. The study will be initiated in the fall of 2016 and completed in the fall of 2019.Determine K uptake and forage quality of selected alfalfa cultivars at different growth stages. Soil samples will be collected in the fall (2016) and annually (2017, 2018, and 2019) during the study for nutrient analysis. Forage quality and K content will be measured using wet-chemistry and near infrared reflectance spectroscopy (NIRS) from individual plot samples collected at each harvest. This objective will be completed in the fall of 2019.Develop K fertility recommendations and update alfalfa soil fertility guides for the central and western U.S. This objective will be initiated in the late fall of 2016 and completed in the fall of 2019.Develop supporting documents for the initiation of a Community of Practice (CoP) within eXtension. An initiative will be taken to develop an Alfalfa CoP with supporting materials from the central and western regions to be completed by fall of 2019.

Project Methods
A field experiment will be conducted at three locations across the central and western U.S. under irrigated conditions. In Wyoming, it will be at the University of Wyoming James C. Hageman Sustainable Agriculture Research and Extension Center near Lingle. In Colorado, it will be at the Colorado State University Agricultural Research, Development and Education Center near Fort Collins while in Kansas, it will be at the Kansas State University North Agronomy Farm in Manhattan. The selection of experimental sites will be based on soil test results. A site with a marginally adequate soil K level (e.g., 100 to 150 ppm) will be chosen at each location to minimize variation among locations.Treatments will include four K rates (0.0 [control], 50, 100, and 150 pounds K2O per acre) from a single K source (muriate of potash, KCl) applied annually in the fall. All other nutrients will be managed for adequacy. Two recently released commercial cultivars (including one reduced lignin; cultivars to be decided) will be used at all three locations. A recommended seeding rate of 20 pounds pure live seed (PLS) per acre will be used. Seeds will be inoculated with alfalfa specific Rhizobium bacteria to insure N fixation. The study will be planted in early fall of 2016 using commercial grade planters available at each site that have recommended row spacings of 7 to 9 inches. Individual plot size will be 10' × 40'. There will be two cutting interval treatments - one at the optimum growth stage (late bud to early [10%] bloom) and another about 7-10 days after the first cut. This treatment will help estimate the effects of cutting interval on growth, yield, and quality of alfalfa. All alfalfa plots will be harvested 2-4 times (depending on weather conditions in each state) using a research grade harvester. Subsamples from each harvested plot will be collected and oven dried for at least 48 h at 140°F (60°C) to estimate moisture content which will be used to adjust bulk yield samples to a dry matter (DM) basis. In addition to DM yield, data collection will include establishment success (plant density) and visual growth, K deficiency (if any), and weed infestation monitoring. This will be repeated every year for the entire study period.Alfalfa samples from each harvest will be oven dried at 140°F (60°C), ground through a 2 mm Wiley mill, and then a 1 mm cyclone mill for NIRS scanning and prediction. Using the NIRS Consortium (NIRSC, 2013) alfalfa hay equations, we will predict N, P, K, calcium (Ca), and magnesium (Mg) along with fiber concentration and digestibility. Because of the anticipated variability in alfalfa quality and nutrient concentrations based on soil nutrient and fertilizer application treatments over harvests and years, dried samples will be packed twice and scanned once per packing for each harvested plot. These twice packed samples will be averaged to provide a better prediction of quality and nutrient content for each plot. Also, a subset of samples (10% of total samples) will be run through wet chemistry via a commercial lab to cross-check and validate the NIRS results. Soil samples will be collected from all plots after final harvest each year and analyzed for K to determine levels at the end of the growing season.Information and data will be compiled and a recommendation guide, especially on soil K levels and their effects on alfalfa production, will be developed based on this multi-state regional study. In depth information on soil analyses, tissue analyses, and nutrient effects on alfalfa cultivars will be summarized and tabulated.Bulletins and informational guides for an eXtension CoP will be written. Extension CoP publications for alfalfa hay producers will include tables of new results and recommendations for K rates.

Progress 09/01/16 to 08/31/20

Outputs
Target Audience:Producers, stakeholders, scientists, and students. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has provided professional development and mentoring opportunities to young scientists and graduate students through research, training, and field days. Outreach and demonstrations were conducted for producers during the field days. Forage field days and workshops were organized and data and plots were demonstrated to the participants. Additionally, plots and findings were presented to participants including undergraduate and graduate students at Western Society of Crop Science meetings and tri-societies (ASA-CSSA-SSSA) meetings. How have the results been disseminated to communities of interest?Results and information obtained from the study has been delivered to relevant communities such as ranchers, producers, and students who participated in the field days and producer 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? 1. The study was successfully established and a good stand was achieved at the James C. Hageman Sustainable Agriculture Research and Extension Center near Lingle, WY and Western Colorado Research Center near Fruita, CO in 2016; and at the Kansas State University North Farm in Manhattan, KS in 2017. Treatments included four K rates (0, 56, 112, and 168 kg K2O ha-1), two alfalfa cultivars (conventional "AFX 457"; highly digestible "Hi-Gest 360"), and two harvest times (early harvest, late bud to early [10%] bloom; late harvest, 7-10 days after early harvest). Due to unfavorable weather conditions (hot and dry), stand establishment was not successful in 2016 in KS. In 2016, there were no harvests, however, data was taken on seedling emergence and seedling count, and plots were managed for weed control mainly through mowing. At Lingle, WY in 2017, 2018, and 2019, four harvests were made each year under each harvest time treatment and data on plant growth, dry matter yield, and forage nutritive value was collected. At Fruita, CO in 2017, 2018, and 2019, four harvests were made each year under each harvest time. Similar protocols as in WY were followed for data collection and data analysis. At Manhattan, KS in 2017, no harvesting was conducted due to establishment year. However, four harvests under each harvest time were done in 2018 and 2019. Similar procedures as in WY were followed for data collection and data analysis. In WY, results showed that, on average, plots receiving 168 kg K2O ha-1 at early harvest produced the highest forage yield 7.9 Mg ha-1. Similar forage yield was also observed from plots receiving 112 kg K2O ha-1 at late harvest. Harvest time had significant effect (P <0.05) on alfalfa yields, however cultivar (conventional vs. highly digestible) and K had no effect on alfalfa yields. Potassium uptake by alfalfa followed a similar trend as in forage yields indicating that K uptake was directly related to forage yield. Nutritive value was not affected (P > 0.05) by K throughout the study period probably due to the high residual soil test K levels. Cultivar affected nutritive value with higher nutritive values in highly digestible alfalfa compared to conventional alfalfa. Study results suggest that applying high rate of K at early harvest and moderate rate of K at late harvest have potential for sustainable and profitable alfalfa production. In CO, the yield response of alfalfa to added K was not consistent even though levels of K in the soil were below concentrations. One possible explanation is that application rates of K were not high enough to meet plant needs and illicit a yield response. There was a small yield increase measured at the highest rate (168 kg K2O ha-1). This suggests that the needs of the alfalfa were just beginning to be met at the 168 kg K2O ha-1 rate and additional studies need to be conducted to investigate higher rates of application. The harvest regime significantly affected total forage yields. Potassium levels in the forage were well within normal ranges for alfalfa. In KS, similar results were also observed as in CO. Harvesting time had significant effect on forage yields and nutritive value. However, cultivar and K application rate did not affect forage yields, nutritive value, and soil K levels. Overall, results of the project showed that K fertilization based on harvest schedules along with soil test K levels have potential to sustain high alfalfa production in the region. The highly digestible cultivar performed well in that it had a lower lignin content, higher digestibility, and higher crude protein content compared to the conventional cultivar that was tested in this study. Due to its higher quality, producers should expect to see greater gains or milk production by feeding this cultivar to their beef or dairy cows. It should also garner a higher price in the market based on its higher forage quality. 2. Soil samples were collected at all three locations and analyzed for baseline nutrient status. Plant samples were collected in each year and analyzed for forage quality. Soil samples from individual plots were collected after the final harvest for K uptake determination in each year. Uptake of K did not differ (P > 0.05) among the cultivars. However, K x harvest time x number of harvests interaction affected (P < 0.05) K uptake by alfalfa. On average, K uptake was high at 168 kg K ha-1 at early harvest (275 kg ha-1) compared to that of 112 kg ha-1 at late harvest (267 kg ha-1). Nutritive value was not affected by the application of K, however cultivar and harvest time had significant effect on nutritive value. 3. Treatments did not differ for residual soil K and other soil properties at the end of the growing season (P > 0.05). In general, residual soil K was high especially in WY and KS. Residual K decreased with increasing depth. As far as K levels in the forage, they were well within normal ranges for alfalfa and there was no indication of luxury consumption by the alfalfa plants, even at the highest rate of application. This provides support to the idea that rates of K fertility were not high enough in this study to meet plant needs and warrants further studies with higher rates of K. 4. Data is being analyzed and compiled over all years and all locations. After analysis and compilation of three years of data, supporting documents will be prepared for the initiation of a Community of Practice (CoP) within eXtension. Consultation with eXtension is being made and ongoing.

Publications

• Type: Book Chapters Status: Accepted Year Published: 2020 Citation: Islam, M.A. and Baidoo, M.M. 2020. Potassium Effect on Growth and Physiology of Alfalfa. In: Handbook of Plant and Crop Physiology, 4th Edition (M. Pessarakli, Ed.). CRC Press, Taylor & Francis Publishing Company, Florida. (In press).
• Type: Other Status: Published Year Published: 2020 Citation: Baidoo, M. and Islam, M.A. 2020. Potassium, Cultivar, and Harvest Management for Improved Alfalfa Production. 2020 Field Days Bulletin, University of Wyoming Agricultural Experiment Station.
• Type: Other Status: Published Year Published: 2020 Citation: Baidoo, M. and Islam, M.A. 2020. Response of Alfalfa to Phosphorus and Potassium in Association with Calcium, Magnesium, and Harvest Management. 2020 Field Days Bulletin, University of Wyoming Agricultural Experiment Station.
• Type: Other Status: Published Year Published: 2019 Citation: Islam, M.A., and Baidoo, M. 2019. Improving alfalfa productivity. Progressive Forage, Issue 10, November 1, 2019, pp. 29-31. Available at https://www.progressiveforage.com/forage-types/alfalfa/improving-alfalfa-productivity.
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Baidoo, M. and Islam, M.A. 2020. Potassium, Cultivar, and Harvest Management Effects on Alfalfa Productivity. Proceedings of the ASA-CSSA-SSSA International Annual Meetings (Virtual) November 9-13, 2020. (American Society of Agronomy, Crop Science Society of America, Soil Science Society of America).
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Baidoo, M. and Islam, M.A. 2020. Forage Yield Response of Alfalfa to Potassium, Cultivar, and Harvest Time. Proceedings of the Western Society of Crop Science Annual Meetings (Virtual) July 7-8, 2020. (Western Society of Crop Science).
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Baidoo, M. and Islam, M.A. 2020. Potassium Rate, Cultivar, and Harvest Management Affect Potassium Uptake in Alfalfa. Proceedings of the Western Society of Crop Science Annual Meetings (Virtual) July 7-8, 2020. (Western Society of Crop Science).
• Type: Theses/Dissertations Status: Published Year Published: 2019 Citation: Baidoo, M. Potassium and harvest management effect on productivity of alfalfa. MS Thesis, Department of Plant Sciences, University of Wyoming, May 2019.

Progress 09/01/18 to 08/31/19

Outputs
Target Audience:Producers, stakeholders, scientists, and students. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has provided professional development and mentoring opportunities to young scientists and graduate students through research, training, and field days. Outreach and demonstrations were conducted for producers during the field days. Forage field days and workshops were organized and data and plots were demonstrated to the participants. Additionally, plots and findings were presented to participants including undergraduate and graduate students at Western Society of Crop Science meetings. How have the results been disseminated to communities of interest?Results and information obtained from the study have been delivered to relevant communities such as ranchers, producers, and students who participated in the field days and producer meetings. What do you plan to do during the next reporting period to accomplish the goals?To accomplish the goals of the project, the study will be continued, data will be collected and analyzed, and finally findings will be disseminated to relevant communities. A final report will be submitted summarizing the results.

Impacts
What was accomplished under these goals? 1. The study was successfully established and a good stand was achieved at the James C. Hageman Sustainable Agriculture Research and Extension Center near Lingle, WY and Western Colorado Research Center near Fruita, CO in 2016; and at the Kansas State University North Farm in Manhattan, KS in 2017. Due to unfavorable weather conditions (hot and dry), stand establishment was not successful in 2016 in KS. In 2016, there were no harvests, however, data was taken on seedling emergence and seedling count, and plots were managed for weed control mainly through mowing. At Lingle, WY in 2017 and 2018, four harvests were made each year under each harvest time treatment and data on plant growth, dry matter (DM) yield, and forage nutritive value was collected. At Fruita, CO in 2017 and 2018, four harvests were made each year under each harvest time. Similar protocols as in WY were followed for data collection and data analysis. At Manhattan, KS in 2017, no harvesting was conducted due to establishment year. However, four harvests under each harvest time were done in 2018. Similar procedures as in WY were followed for data collection and data analysis. In 2019, two harvests were made in all three locations. Overall, results of the project showed that potassium fertilization based on harvest schedules have potential to sustain high alfalfa production in the region. Data collection will be continued in 2019 and 2020. Additional measures include taking soil samples from the control plots in the spring of 2019 and subsequent year as a measure of mineralization over the winter. Furthermore, a set of deeper soil samples will be collected to find out if there is an accumulation of available potassium lower in the soil profile. 2. Soil samples were collected at all three locations and analyzed for baseline nutrient status. Plant samples in 2017 and 2018 were collected and analyzed for forage quality. Also, plant samples collected in 2018 and 2019 are currently being ground in preparation for forage quality analysis. Soil samples from individual plots are being collected after the final harvest for potassium uptake determination in each year. 3. Data collected in 2017 and 2018 is being analyzed to develop fertility recommendations. 4. Data is being analyzed and compiled. After analysis and compilation of four years of data, supporting documents will be prepared for the initiation of a Community of Practice (CoP) within eXtension.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Islam, M.A. and Baidoo, M. 2019. Soil Potassium Levels and Its Effect on Alfalfa Productivity. Proceedings of the SSSA International Soils Meeting January 6-9, 2019. San Diego, CA (American Society of Agronomy, Crop Science Society of America, Soil Science Society of America).
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Islam, M.A. and Baidoo, M. 2019. Soil Potassium Levels and Its Effect on Alfalfa Productivity. Proceedings of the SSSA International Soils Meeting January 8, 2019. San Diego, CA.
• Type: Other Status: Published Year Published: 2019 Citation: Baidoo, M. and Islam, M.A. 2019. Yield Response of Reduced Lignin and Conventional Alfalfa Cultivars to Potassium. 2019 Field Days Bulletin, University of Wyoming Agricultural Experiment Station.
• Type: Other Status: Published Year Published: 2019 Citation: Baidoo, M. and Islam, M.A. 2019. Potassium and Harvest Management Effect on Alfalfa Production Under Controlled Conditions. 2019 Field Days Bulletin, University of Wyoming Agricultural Experiment Station.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Islam, M.A. and Baidoo, M. 2019. Potassium and Harvest Time Affect Forage Production, Nutritive Value, and Potassium Uptake of Alfalfa. Proceedings of the ASA-CSSA-SSSA International Annual Meetings November 10-13, 2019. San Antonio, TX (American Society of Agronomy, Crop Science Society of America, Soil Science Society of America).

Progress 09/01/17 to 08/31/18

Outputs
Target Audience:Producers, stakeholders, scientists, and students. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided professional development and mentoring opportunities to young scientists and graduate students through research, training, and field days. Outreach and demonstrations were conducted for producers during the field days. A forage field day and workshop was organized and data and plots were demonstrated to the participants. Additionally, plots and findings were presented to participants including undergraduate and graduate students at Western Society of Crop Science meetings. How have the results been disseminated to communities of interest?Results and information obtained from the study have been delivered to relevant communities such as ranchers, producers, and students who participated in the field days. What do you plan to do during the next reporting period to accomplish the goals?To accomplish the goals of the project, the study will be continued, data will be collected and analyzed, and finally findings will be disseminated to relevant communities.

Impacts
What was accomplished under these goals? 1. The study was successfully established and a good stand was achieved at the James C. Hageman Sustainable Agriculture Research and Extension Center near Lingle, WY and Western Colorado Research Center near Fruita, CO in 2016; and at the Kansas State University North Farm in Manhattan, KS in 2017. In 2016, there were no harvests, however, data was taken on seedling emergence and seedling count, and plots were managed for weed control mainly through mowing. At Lingle, WY in 2017, four harvests were made under each harvest time treatment and data on plant growth, dry matter (DM) yield, and forage nutritive value was collected. Initial soil samples were collected and analyzed to determine the nutrient status. After the final harvest in 2017, soil samples were collected from all plots and analyzed for determining soil potassium levels at the end of the growing season and to estimate potassium uptake by plants. There was an interaction effect of potassium × cultivar × number of harvest on forage DM yield (P < 0.05). Hi-Gest 360 (low lignin) produced the highest total DM yield (8372 kg ha-1) when treated with 150 pounds potassium (K2O acre-1) while AFX 457 (conventional) had the highest total DM yield (8283 kg ha-1) when treated with 100 pounds K2O acre-1. Overall, total DM yield was higher in AFX 457 (7694 kg ha-1) than Hi-Gest 360 (7549 kg ha-1). In general, late harvest produced higher DM yield (2260 kg ha-1) compared to early harvest (2058 kg ha-1). For forage nutritive value, no differences were observed (P > 0.05) among the treatments. Potassium uptake followed similar trend to DM production with the highest total uptakes in Hi-Gest 360 (366 g kg-1) at 150 pounds K2O acre-1 and in AFX 457 (360 g kg-1) at 100 pounds K2O acre-1. Potassium uptake was higher in late harvest (87 g kg-1) compared to early harvest (81 g kg-1). At Fruita, CO in 2017, averaged across potassium rates, total seasonal DM yields for the conventional alfalfa cultivar were slightly higher than the low lignin cultivar by 6.4 and 5.4% for the early and late harvests, respectively. Averaged across all treatments, DM yields were about 4% higher for the early compared to late harvest cutting regime. The reason for this result was due to lower yields for the fourth harvest for the late harvest regime. When averaged across cultivars and harvest regimes for total seasonal DM yield, there was only a slight increase (3.7%) at the 150 pounds K2O acre-1 rate with no differences among the control and other two rates. A trend of increasing potassium concentrations in the forage was evident for the early harvest alfalfa for both cultivars as potassium rate increased. At Manhattan, KS in 2017, no harvesting was conducted due to establishment year. However, two harvests were done so far in 2018. There was no difference in DM yield between alfalfa cultivars (low lignin vs. conventional). By delaying one more week of harvesting alfalfa did not increase alfalfa DM yield and this showed a decreasing trend in both first and second harvests. This might be due to severe drought in Manhattan in the summer of 2018. Different application rates of potassium did not affect the alfalfa DM yield. This was primarily because of high residual potassium in the soils. 2. Initial soil samples were collected at all three locations and analyzed for baseline nutrient status. Plant samples in 2017 were collected and analyzed for forage quality. Also, plant samples collected in 2018 are currently being ground and in preparation for forage quality analysis. Soil samples from individual plots are being collected after the final harvest for potassium uptake determination in each year. 3. Data collected in 2017 is being analyzed and in the process towards developing fertility recommendations. 4. Data is being analyzed and compiled. After analysis and compiling of 3 years data, supporting documents will be prepared for the initiation of a Community of Practice (CoP) within eXtension.

Publications

• Type: Other Status: Published Year Published: 2018 Citation: Baidoo, M. and Islam, M.A. 2018. Effect of Potassium on Yield of Newly Released Alfalfa Cultivars. 2018 Field Days Bulletin, University of Wyoming Agricultural Experiment Station, pp. 100-101. Available at http://www.uwyo.edu/uwexpstn/publications/field-days-bulletin/2018-field-days-bulletin.pdf.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2018 Citation: Baidoo, M. and Islam, M.A. 2018. Response of Alfalfa Cultivars to Potassium Application and Harvest Time. Proceedings of the ASA-CSSA International Annual Meetings November 4-7, 2018. Baltimore, MD (American Society of Agronomy, Crop Science Society of America, Soil Science Society of America).
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2018 Citation: Baidoo, M. and Islam, M.A. 2018. Effect of Potassium and Harvest Time on Potassium Uptake and Nutritive Value of Alfalfa. Proceedings of the ASA-CSSA International Annual Meetings November 4-7, 2018. Baltimore, MD (American Society of Agronomy, Crop Science Society of America, Soil Science Society of America).
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Baidoo, M. and Islam, M.A. 2018. Effect of Potassium and Harvest Time on Forage Accumulation and Potassium Uptake of Alfalfa. Proceedings of the Western Society of Crop Science Annual Meetings June 19-20, 2018. Laramie, WY (Western Society of Crop Science).
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Baidoo, M. and Islam, M.A. 2018. Potassium and Harvest Time Affect Production and Nutritive Value of Alfalfa. Proceedings of the Western Society of Crop Science Annual Meetings June 19-20, 2018. Laramie, WY (Western Society of Crop Science).
• Type: Other Status: Published Year Published: 2018 Citation: Islam, M.A. 2018. Potassium and Harvest Management in Alfalfa. The 6th Annual Wyoming Forage Field Day, June 12, 2018. James C. Hageman Sustainable Agriculture Research and Extension Center, Lingle, WY.
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Islam, M.A. 2018. Response of Alfalfa to Soil Potassium, Cultivars, and Harvesting Intervals. The International Congress and Exo on Agriculture and Horticulture August 14, 2018. Amsterdam, Netherlands.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2018 Citation: Islam, M.A., Baidoo, M., Brummer, J., and Min, D. 2018. Effects of potassium, cultivar, and harvest time on sustainable alfalfa production. Proceedings of the 2nd World Alfalfa Congress, November 11-14, 2018, Cordoba, Argentina.

Progress 09/01/16 to 08/31/17

Outputs
Target Audience:Producers, stakeholders, scientists, and students. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided professional development and mentoring opportunities to young scientists and graduate students through research, training, and field days. Additionally, outreach and demonstrations were conducted for producers during the field day. How have the results been disseminated to communities of interest?Preliminary results and information have been delivered to relevant communities such as ranchers, producers, and students who participated in the field day. What do you plan to do during the next reporting period to accomplish the goals?To accomplish the goals of the project, the study will be continued, data will be collected and analyzed, and finally findings will be disseminated to relevant communities.

Impacts
What was accomplished under these goals? 1.The study was laid out, potassium fertilizer treatments were applied, and alfalfa wasseeded in early September (8 September, 2016) at the James C. Hageman Sustainable Agriculture Research and Extension Center near Lingle, WY;Western Colorado Research Center near Fruita, CO; and at the farmer's field in KS. A good stand of alfalfa was achieved by the time the plants went dormant at Lingleand Fruita but poor stand was achievedin KS. A new seeding was done on May 12, 2017 at the Kansas State University North Farm in Manhattan, KS and a good stand was achieved. Plant growth and forage yield have been determined three times between May 30, 2017 and August 26, 2017Lingle.Early harvest was conducted at 10-15% bloom followed by late harvest 7-10 days later. Althoughno differences were observed in dry matter yield at this early stage, harvest date had significant influence (p<0.0001) on plant height. Plants harvested late were on average taller (44 cm) than those cut a week earlier (37 cm) regardless of cultivars and potassium rates. At Fruita,there does not appear to be a response to the added potassium at this point. No harvesting was done yet inManhattan. 2. Initial soil samples were collected at all three locations and analyzed for baseline nutrient status. Plant samples are currently being ground and in preparation for forage quality analysis. Soil samples from individual plots will be collected after the final harvest for potassium uptake determination. 3. Data is being analyzed and in the process towards fertility recommendations. 4. After compiling of 2-3 years data, supporting documents will be prepared forthe initiation of aCommunity of Practice(CoP) within eXtension.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Islam, M.A. 2017. Silent Decline in Soil Potassium May Influence Sustainable Production of Alfalfa. Proceedings of the International - Conference Frontiers of Potassium January 25-27, 2017 Rome, Italy (International Plant Nutrient Institute).