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Timothy Seed Residue Management Strategies

2012 Final Report
Kevin Gulay B. Sc. (Agric)
MFSA Research Manager

Introduction
After harvest, timothy seed crops produce significant amounts of residue which often have value as livestock feed, or straw. Traditionally, many of these grass seed growers had their own livestock, and it was economical to bail the residue. However, now that many operations focus solely on cropping, in many situations it is no longer economical, or practical to have this residue bailed. Further, previous studies have shown that different management techniques can affect the grass seed yield in subsequent years. A study in Oregon by Chastain et al. (1999), found that open field burning resulted in a greater yield than bailing, but bailing still had a greater yield than crop flailing in Kentucky bluegrass seed production. This study looks at three different management techniques: 1) Bail the straw post harvest 2) Combine chops and spreads the residue over the field 3) Straw left to sit for one week post harvest, and then passed through the combine the second time to be chopped and spread. The different cover of trash on the field potentially affects the following year’s seed crop. The decomposition of the residue can influence nutrient availability.
A healthy soil could influence how rapidly this residue is decomposed. Characteristics of a healthy soil include good fertility, good drainage, and extensive microbial activity. Producers may try products such as Bio–Desolve to improve the health of their soils. “Bio-desolve, is distributed by MTS Environmental, and is a combination of the products Tough Stuff, Agri Grow, humic carbon and water. Tough Stuff is a pure microbial innoculant which contains a diverse selection of bacteria. Each microbial family performs a specific function which is vital to soil disease decontamination, residue breakdown, plant health and plant growth. The second component, Agri Grow, is a natural bio-stimulant in liquid concentrate form. It contains a variety of enzymes, amino acids, plant growth hormones, complex carbohydrates and micronutrients. The final addition to the biological treatment mixture is humic carbon. Humic carbon is a natural element in liquid concentrate form. It is said to provide macro and micro nutrients, greatly increase root system organisms, improve trace element nutrition through chelation, speed rate of crop residue breakdown by an increase in microorganisms, promote soil drainage and improve the soil’s capacity for water retention.” (Martins, 2011) This study also examines how a fall application of Bio–Desolve affects subsequent timothy seed crop yields.

Materials and Methods
This project took place at three different sites over a three year period. Fields were selected that appeared to have good stands, which had more than one year of production remaining. That way any cumulative effects, from the treatments being used on the same sites for consecutive years, would be observed. One of the fields used was located in the Arborg area on the NE 28-22-3E. Data was collected from this field in the 2011 and 2012 crop season. Another field in Riverton was used on the W 12-23-3E. Data was collected from this field in the 2010 and 2011 crops seasons. The other site was located in Oakbank on the SW 8-11-5E. Data was collected in the 2011 2012 crop season.
The projected was designed as a strip trial which had the three residue management strategies. Strip sizes were determined based on the size of the equipment used. Strip one was combined and the straw was bailed. Treatment two was harvested with a rotary combine and spread over the field on the first pass. Treatment three was harvested with a rotary combine and left in a swath for one week. Then it was run through the combine a second time and spread over the field. A strip of Bio-Desolve was then sprayed across the treatments creating six treatments in total. See fig. 1 below for plot setup.
Figure 1. Design of residue management trials resulting in 6 different treatments

Tiller analysis took place each spring on all treatments. This was determined by counting how many leaves were left to emerge on each tiller before head emergence. Approximately 70 tillers were analyzed from each treatment to provide an accurate representation of the plot. Samples were taken late May to early June.
Once the crop was ready to swath, MFSA sub sampled 1x3m plots from each treatment. These samples were bagged and dried in a heat room. Once the samples were dry enough they were run through a Wintersteiger plot combine. Samples were then weighed and cleaned to obtain the yield results.
Soil samples were taken in fall following harvest within each plot. In fall samples were analyzed for nutrients and microorganisms. Fall 2010 all treatments were analyzed for nutrients and microorganisms. Fall 2011 treatments were analyzed for micro-organisms presents.
Once all of the data was tabulated, a statistical analysis was done to examine the data. Averages, coefficient of variation (CV), and least significant differences (LSD) values were calculated.


Results
Each spring a tiller analysis was done. The results from all sites can be seen in table 1 below. The tiller analysis does not show any treatments that have consistent measurements from year to year, or from site to site.
Table 1. Tiller analysis showing the leaves that remain to emerge per tiller.

Yield measurements were taken, and they are displayed in table 2 below. Again, the yield measurements don’t show any treatments that have consistent measurements from year to year, or from site to site.
Table 2. Yield in lbs/A of timothy from each treatment

Table 3, below, summarizes the average leaves to emerge counts and yields from each treatment. The CV shows high variability within the data, and the LSD value suggests that no treatments are different from one another.

Table 3. Statistical analysis showing averages of tiller analysis and yield from each treatment along with CV and LSD.
Results from the 2011 fall soil test DNA multi-scan are available in table 4 below. The micro-organisms present are very similar amongst all treatments, and are primarily harmful to the crop.
Table 4. Micro-organisms present in the soil from the DNA multi-scan, following the 2011 crop year.
Discussion
Some of the residue management strategies left more trash than others. This could have affected how long it took the soil to warm up, or the decomposition of the trash could have affected nutrient availability. As a result the different management strategies could have caused some of the treatments to grow faster than the others in the spring. A rapidly growing plant’s leaves would emerge faster from each tiller.  However, there was no statistical difference in the leaves to emerge count, which implies that none of the treatments increased how rapidly the crop grew in the spring.
Crop yield was very similar among all treatments.  Over the three years, the crops went through a variety of different environmental conditions. Therefore, it is also important to note that the yield of any particular treatment was not increased in any particular environmental condition.   Each individual site was studied for a two year period. It is possible that if the treatments had been repeated on one site for three, four, or five years that we may have begun to see yield differences. For example, if the residue is left on the field, it may build the soil organic matter over a longer period of time.  Had the Bio – Desolve been applied, over a longer period of time, it is possible that some of the soil health benefits may have started to effect crop yield.
Following the 2011 crop season a DNA multi-scan was taken from all treatments. “The microbes that were found in the DNA multi-scan were mostly harmful. F. solani is a phytopathogenic fungus which is an important agent in causing various crop diseases. Pythium sp. are plant pathogens which are of economic importance because of their wide host range and their ability to cause root rot. P. aphanidermatum is another organism with a wide range of hosts which can cause different plant diseases, including stem and root rot. Rhizoctonia solani is a soil-borne organism which causes various diseases infecting the pods, roots, leaves and stems of plants. P. sylvaticum again, has a wide range of host plants and can cause different diseases in grass plants.” (Martins, 2011). It was expected that, where the Bio–Desolve was applied that there would be an increase of beneficial micro-organisms. “However, only one beneficial soil microbe, Fusarium oxysporum, was found. This organism has the ability to degrade lignin and complex carbohydrates therefore, breaking down plant residues quicker”. (Martins, 2011)

Conclusion
This study shows no advantage to the application of Bio–Desolve in grass seed crops. Regardless of how growers manage their residue: bail, chop and spread, or combine twice, there was no noticeable difference in subsequent grass seed crops. No difference was found in yield, or spring emergence of the crop the following year. Therefore, when growers are deciding what to do with their residue it would be wise to consider convenience and the value of the bail, rather than what effect their decision will have on the yield of subsequent grass seed crops. Future studies looking at other residue management options such as flail chopping, and crop burning in Manitoba, would be beneficial.
Special thank you to the producers who provided land to conduct the trials on, to Agri-Food Research and Development Initiative (ARDI) for the project funding, and to the staff who contributed to the project over the past three years.

References
Martin, K. Grass Seed Residue Management. Forage Seed News, Winter 2012: 14-18.
Chastain, T.G., Kiemnic, G.L., Cook, G.H., Garbacik, C.J., Quebbeman , B.M., Crowe, F.J. (1997). Residue Management Strategies for Kentucky Bluegrass Seed Production. Crop Science Society of America. 37(6): 1836-40.

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