4 minute read
Chris Teutsch: Things That Make You Go Hmm…Late Fall Fertilization
Things That Make You Go Hmm…Late Fall Fertilization
Chris Teutsch Univerity of Kentucky Grain and Forage Center of Excellence, Princeton, Kentucky
I wanted to start with a brief update on the progress we are making at the research station. The cleanup is well underway, and we are making good progress. This winter I headed up debris removal from more than 1,000 acres of crop, hay, and pasture fields at the station. The process was slow and tedious and involved 5-gallon buckets, walking six miles a day, and bending over more than 1,200 times a day. I am not going to lie, after the first week of pickup, there was no spot on my body that didn’t hurt. The second week was better and by the third week I felt OK. I want to thank all the folks that came and helped us with this 2 ½ month process. We had groups and individuals come from as far away as Oklahoma and Wisconsin. The design process for the rebuild is well under way and we hope to finalize plans in the very near future. While we are not able to conduct research and extension programs at 100%, I have been amazed at what our faculty and staff are getting done with such limited resources! We are open for business and can be reached by cell phone or email. Please don’t hesitate to contact us! As always, your best local resource is your county agent, and we encourage you to work closely with them. So, onto the topic at hand… One the things that makes me go hmm is late fall fertilization of cool-season grass stands. This is something that has been recommended and implemented in the turfgrass industry for decades. A late fall application of nitrogen, around Thanksgiving, has been shown to strengthen grass, increase tiller numbers, and enhance early green up in the spring. I am not really sure why we have never explored this practice in forages. So, in the fall of 2020, I had a graduate student, Josh Duckworth, put a small study out that evaluated the impact of late fall nitrogen applications on the growth of a cool-season hayfield the following spring. Below is a summary of the results from this study that was presented at the 2022 annual meeting of the American Forage and Grassland Council. Late season nitrogen fertilization is a practice that has long been implemented in turfgrass production. This practice involves applying nitrogen from September through December and results in an extended green period in the fall without stimulating excessive shoot growth. The longer green period results in higher levels of carbohydrate reserves and enhanced root growth compared with a spring-summer fertilization program. In addition to these benefits, sods fertilized in late fall have been shown to green up two to six weeks earlier in the spring. Limited research has considered the impact of late fall nitrogen applications on grass growth in hayfields and pastures. The objective of this study was to evaluate the impact of late fall nitrogen fertilization on dry matter production of an established tall fescue stand. The study was conducted at the UK Research and Extension Center located in Princeton, KY. The experimental design was a random complete block with four replications. On December 1, 2020, 0, 30, 60, and 90 lb N/A was applied as ammonium nitrate, ammonium sulfate, and SYMTRX 20S. An additional 80 lb N/A was applied as urea to all plots the following spring. Plots were harvested on 13-May-2021 using self-propelled sickle bar type forage harvester equipped with load cells. Fall applied nitrogen resulted in a linear increase in dry matter yield of 25.1, 25.7, and 16.1 lb DM/lb fall applied nitrogen for ammonium nitrate, ammonium sulfate, and SYMTRX 20S, respectively. Plots receiving fall applied nitrogen also initiated growth earlier in the spring. The results of the current study need to be confirmed with additional research. So, what is the take home? The initial results of this study look promising as a way of getting hayfields and maybe pastures ready to grow in the spring, but we need to confirm these results before making widespread recommendations. I have a second graduate student, Brittany Hendrix, repeating this experiment and she has just harvested her plots in May and we are currently analyzing the data. So, stay tuned for more results!
Fall Nitrogen Increased First Harvest Tall Fescue Yield
C.Teutsch1 , J. Duckworth2, and B.L Hendrix3
Fig. 1 Plots receiving fall nitrogen applications greened up earlier and yield increased linearly to fall nitrogen applications, even though all plots received 80 lb N/A in the spring
Fig. 2 Impact of nitrogen rate averaged over nitrogen source on compressed sward height (estimate of early spring growth). Bars within a sampling date with the same letter are not different according to Fisher’s protected least significant difference (P < 0.05).
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