2017 Soybean Cover Crop Trial

Transcription

1 2017 Soybean Cover Crop Trial Dr. Heather Darby, UVM Extension Agronomist Sara Ziegler, Eria Cummings, Abha Gupta, and Lindsey Ruhl UVM Extension Crops and Soils Tehniians (802) Visit us on the web at: Marh 2018, University of Vermont Extension

2 2017 SOYEAN COVER CROP TRIAL Dr. Heather Darby, University of Vermont Extension heather.darby[at]uvm.edu In 2017, the University of Vermont Extension Northwest Crops and Soils Program investigated the impat of various over rop mixtures on a subsequent soybean rop s yield and quality at orderview Researh Farm in Alburgh, VT. Soybeans are grown for human onsumption, animal feed, and biodiesel and an be a useful rotational rop in orn silage and grass prodution systems. As over ropping expands throughout Vermont, it is important to understand the potential benefits, onsequenes, and risks assoiated with growing over rops in various ropping systems. In an effort to support the loal soybean market and to gain a better understanding of over ropping in soybean prodution systems, the University of Vermont Extension Northwest Crop and Soils (NWCS) Program, as part of a grant from the Eastern Soybean oard, established a trial in 2017 to investigate the impats on soybean yield and quality of following annual over rop mixtures with a soybean rop. MATERIALS AND METHODS The trial was established at orderview Researh Farm, Alburgh, VT in the fall of The experimental design was a omplete randomized blok design with four repliations. The treatments were 10 over rop mixtures planted on 6-Sep Treatments onsisted of mixtures that would both be over-wintered and some that would be winter-killed. Cover rop treatments and seeding rates are listed in Table 2. Cover rop living biomass was determined in the fall prior to winter dormany. Cover rop was measured again in the spring just prior to soybean planting (4-May 2017). Ground over was assessed via the beaded string method (Sloneker and Moldenhauer, 1977) and biomass was olleted from a 0.25m 2 area in eah plot. The biomass was weighed and dried to determine dry matter ontent and dry matter yield. Soil was sampled within eah plot at a depth of 6 and a width of 2 on 12-May. These samples were submitted to the Cornell Soil Health Testing Laboratory (Geneva, NY) for wet aggregate stability analysis. All over rop treatments were terminated just prior to soybean planting using a moldboard plow and dis harrow (Table 1). Table 1. Trial management details, orderview Researh Farm-Alburgh, VT Soil types enson roky silt loam 8-15% slope Previous rop Annual over rop mixtures Tillage operations Moldboard plow and dis Plot size (feet) 5 x 20 Row spaing (inhes) 30 Repliates 4 Starter fertilizer (lbs a -1 ) 200 lbs a Planting dates Cover rops: 6-Sep 2016 Soybeans: 29-May 2017 Weed ontrol 1 qt a -1 RoundUp Power Max 5-Jul 2017 Harvest date 13-Ot 2017

3 On 29-May 2017, the soybeans were planted into the terminated over rop treatments using a Monosem NG-Plus 2-row preision air planter (Edwardsville, KS) at 185,000 seeds a -1 with 200 lbs a -1 starter fertilizer ( ). The variety SW1055 (maturity group 1.0, Genuity RoundUp Ready 2 Yield) soybean was obtained from Seedway, LLC. (Hall, NY) for the trial. Soybeans were sprayed with RoundUp Power Max herbiide on 5-Jul to ontrol weeds. On 13-Ot, the soybeans were harvested using an Almao SPC50 small plot ombine. Seed was leaned with a small Clipper M2 leaner (A.T. Ferrell, luffton, IN). They were then weighed for plot yield and tested for harvest moisture and test weight using a DICKEY-John Mini-GAC Plus moisture/test weight meter using a erkes Test Weight Sale. Table 2. Annual over rop mixture treatments grown in 2016 prior to soybean in Mixture # Speies Variety Cover rop over-winters Seeding rate lbs a -1 Annual ryegrass Fria yes, ryegrass 22 Tillage radish Eo-till only 3 Forage rape Dwarf Essex yes, tritiale 3 Tritiale Trial 815 only 60 Forage turnip Appin 2 yes, lover and Red lover Dynamite 3 tritiale only Tritiale Hyotane 60 Forage turnip Appin 2 yes lover and Red lover Dynamite winter rye only 1 Winter rye VNS 40 Annual ryegrass unknown 18 total no Tillage radish Arifi (premixed) Annual ryegrass unknown 24 total Crimson lover unknown no (premixed) Tillage radish Arifi Forage oats Everleaf 40 Forage turnip Appin no 2 Red lover Duration 5 Forage oats Everleaf 60 no Tillage radish Groundhog 31 Red lover Mammoth 5 Forage brassia T-Raptor yes, lover and 2 Winter pea Lynx tritiale only 20 Winter tritiale Fridge No over rop N/A N/A Yield data and stand harateristis were analyzed using mixed model analysis using the mixed proedure of SAS (SAS Institute, 1999). Repliations within trials were treated as random effets, and hybrids were treated as fixed. Hybrid mean omparisons were made using the Least Signifiant Differene (LSD) proedure when the F-test was onsidered signifiant (p<0.10).

4 Variations in yield and quality an our beause of variations in genetis, soil, weather, and other growing onditions. Statistial analysis makes it possible to determine whether a differene among hybrids is real or whether it might have ourred due to other variations in the field. At the bottom of eah table a LSD value is presented for eah variable (i.e. yield). Least Signifiant Differenes (LSDs) at the 0.10 level of signifiane are shown. Where the differene between two hybrids within a olumn is equal to or greater than the LSD value at the bottom of the olumn, you an be sure that for 9 out of 10 times, there is a real differene between the two hybrids. In this example, hybrid C is signifiantly different from hybrid A but not from hybrid. The differene between C and is equal to 1.5, whih is less than the LSD value of 2.0. This means that these hybrids did not differ in yield. The differene between C and A is equal to 3.0, whih is greater than the LSD value of 2.0. This means that the yields of these hybrids were signifiantly different from one another. RESULTS Weather data was reorded with a Davis Instrument Vantage Pro2 weather station, equipped with a WeatherLink data logger at orderview Researh Farm in Alburgh, VT (Table 3). Overall, the season was ooler and wetter than normal. More than 1.5 inhes of rain fell within 10 days following planting. Unseasonably ool temperatures and above average rainfall persisted through August followed by above average temperatures and below average rainfall in September and Otober. The dry warm weather in the fall provided good weather for the soybeans to mature and to be harvested at optimal moisture ontent. Overall, a total of 2335 growing degree days (GDDs) were aumulated June-Otober, 209 above the 30- year normal. Despite these unusual growing onditions, the soybeans appeared relatively unharmed and produed very well. Table 3. Weather data for Alburgh, VT, Alburgh, VT June July August September Otober Average temperature ( F) Departure from normal Preipitation (inhes) Departure from normal Growing Degree Days (base 50 F) Departure from normal ased on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger. Historial averages are for 30 years of NOAA data ( ) from urlington, VT. Hybrid Yield A * C 9.0* LSD 2.0 Table 4 summarizes the over rop prodution and soil health harateristis in the spring for eah treatment. The treatment that produed the most biomass in the fall was treatment 1 (annual ryegrass/tillage radish) whih produed 2104 lbs a -1. This was statistially similar to six other treatments. Treatments 3 and 4, whih both inluded turnip, red lover, and a winter grain (tritiale and winter rye respetively), both produed the lowest biomass but were statistially similar to one another. Of the five treatments that survived the winter, treatment 9, whih ontained red lover, forage brassia, winter pea, and tritiale,

5 produed the most biomass with 1494 lbs a -1. In reality only the tritiale and lover survived the winter and produed that spring biomass. It is interesting that this treatment, despite having a lower seeding rate of tritiale ompared to treatment 2 (tritiale/rape) produed signifiantly more biomass in the spring. Furthermore, winter rye is traditionally regarded as the speies that produes the most biomass in this region, however, treatment 4, the only treatment ontaining winter rye, was one of the lowest produing treatments in the fall and produed half the biomass of treatment 9 in the spring. Treatments did not differ in the perent ground over that they provided. This suggests that, even over rops that winterkill in our region an provide substantial ground over in the spring to help protet the soil surfae from the impats of rainfall. Treatments also varied signifiantly in terms of soil aggregate stability. The highest aggregate stability was obtained by treatment 5 (annual ryegrass/tillage radish) with 33.4% aggregate stability. This was statistially higher than any other over rop treatment. The next highest treatment was the oat/turnip/lover treatment with 26.5% aggregate stability. Table 4. Cover rop and soil health harateristis, Cover rop mixture Fall biomass Spring biomass Ground over Aggregate stability -----DM lbs a % * * * * * * LSD (p = 0.10) NS 5.01 Trial Mean *Varieties that did not perform signifiantly lower than the top performing variety in bold are indiated with an asterisk. NS No signifiant differene. Soybeans were harvested on 13-Ot Table 5 summarizes the yield and harvest harateristis of soybeans from eah over rop treatment. Despite relatively wet and ool weather onditions through most of the growing season, the soybeans produed high yields with all produing at least 58 bu a -1. The highest yielding treatment was treatment 6 (annual ryegrass/rimson lover/tillage radish) whih produed 4541 lbs a -1 or 75.7 bu a -1, an inredible yield, espeially for a region with suh a short growing season. This was statistially similar to the ontrol and treatment 5 (annual ryegrass/tillage radish). The lowest yielding treatment was treatment 3 (tritiale/turnip/red lover) whih only produed 3481 lbs a -1 or 58.0 bu a -1. Cover rop treatments did not signifiantly impat harvest moisture or test weight. Of the 10 over rop treatments examined, five (mixtures 5, 6, 7, 8, and 10) did not produe living vegetation in the spring while the other five treatments did. Overwintering treatments produed on average 4073 lbs a -1 or 67.9 bu a -1 while the treatments that had living spring biomass produed on average 3625 lbs a -1 or 60.4 bu a -1 (Table 6). These data suggest that soybean yields may be negatively impated by preeding overwintering over

6 rops (Figure 1). However, to fully understand this interation, more data needs to be olleted, suh as nutrient ontent of the over rop biomass and availability, as differenes between mixture omposition would likely impat soybean yields differently. Table 5. Soybean harvest harateristis by over rop treatment, Cover rop mixture Harvest moisture Test weight Seed 13% moisture % lbs bu -1 lbs a -1 bu a * 67.5* * 75.7* * 68.1* LSD (p = 0.10) NS NS Trial Mean *Varieties with an asterisk performed similarly to the top performer in bold. NS No signifiant differene. Table 6. Soybean yields by over rop overwintering status. Overwinter Soybean yield lbs a -1 bu a -1 Yes No LSD (p = 0.10) Trial mean The top performing treatment is indiated in bold. DISCUSSION Overall, soybeans produed high yields in Preeding a soybean ash rop with a over rop an help retain exess nutrients that would otherwise be lost from the soil. However, using a mixture that inludes a winter grain, suh as winter rye or tritiale, an present management onsiderations in the spring as they will overwinter and an produe a lot of biomass early in the spring. These data suggest that overwintering over rop mixtures an redue the yields of a following soybean rop. This may be due to the immobilization of nitrogen or other nutrient dynamis in the soil when the soybean rop is establishing. However, these dynamis were not investigated in this study. Further analysis will be onduted in order to determine potential differenes between the mixtures, both that winterkill and overwinter, to identify best over ropping praties that support high yielding soybeans in this region.

7 Cover rop dry matter yield (lbs a -1 ) Soybean yield (bu a -1 ) 4000 A 80.0 Fall CC yield Spring CC yield Soybean yield 3500 A A b a b AC A A A A A A C C 10.0 D Cover rop treatment 0.0 Figure 1. Soybean and over rop yield by over rop mixture treatment, Treatments that share a letter performed statistially similarly to one another. Letters presented for over rop yield indiated differenes in total biomass.

8 REFERENCES Sloneker, L. L. and W. C. Moldenhauer, Measuring the amounts of rop residue remaining after tillage. J. Soil Water Conserv. 32:23 l-236. ACKNOWLEDGEMENTS UVM Extension Northwest Crops and Soils Program would like to thank Eastern Soybean Region oard for the funding for this trial. We would also like to thank Roger Rainville and the staff at orderview Researh Farm for their generous help with this researh trial. We would like to aknowledge Nate righam, John rue, Eria Cummings, Kelly Drollette, Hillary Emik, Amanda Gervais, Freddie Morin, Matthew Sanders, and Stuart Wolff-Goodrih for their assistane with data olletion and entry. We would also like to thank the seed ompanies for their seed and ooperation in these study. The information is presented with the understanding that no produt disrimination is intended and no endorsement of any produt mentioned or ritiism of unnamed produts is implied. UVM Extension helps individuals and ommunities put researhbased knowledge to work. Issued in furtherane of Cooperative Extension work, Ats of May 8 and June 30, 1914, in ooperation with the United States Department of Agriulture. University of Vermont Extension, urlington, Vermont. University of Vermont Extension, and U.S. Department of Agriulture, ooperating, offer eduation and employment to everyone without regard to rae, olor, national origin, gender, religion, age, disability, politial beliefs, sexual orientation, and marital or familial status.