Closing the Knowledge Gap on Wisconsin Hop Fertility · Closing the Knowledge Gap on Wisconsin Hop...
Transcript of Closing the Knowledge Gap on Wisconsin Hop Fertility · Closing the Knowledge Gap on Wisconsin Hop...
Closing the Knowledge Gap on Wisconsin Hop Fertility
C h r i s t o p h er A . B ax t e r, P h . D.
Pro fe s s o r & S o i l Fe r t i l i t y a n d N u t r i e nt M a n a g e m e nt S p e c i a l i s t
U W - P l a t tev i l l e a n d U n i ve rs i t y o f W i s co n s i n M a d i s o n - E x te ns i o n
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Summary of Recent Hop Fertility Work in Wisconsin2016 – Collected preliminary data on yield, nutrient removal and soil test levels.
Verified P and K removal were within UW estimatesIndicated need for further evaluation of recommended N rates
2017&2018 – Conducted study to evaluate effect of nitrogen rate and timing on hop biomass and cone yield. Incorporated petiole nitrate tissue and sap testing.
https://buffalo.extension.wisc.edu/agriculture/barley-and-hops/
2019 – Initiated a 2-year study to determine optimum N rates for Wisconsin growers.
Included 5 N ratesContinued petiole tissue and sap testingIncluded post harvest soil nitrate samplingEvaluate effect of N rate on hop quality parameters
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
2019 N Rate TrialsSame locations as used in 2017 and 2018
Tomah, WI : Centennial and Cascade
Waterloo, WI: Chinook, Tahoma
Rosholt, WI: Magnum, Nuggett
Nitrogen TreatmentsPlots consisted of 5 “plants”
N rates: 0, 50, 100, 150, 200 lbs N/ac
All N rates split applied: at training and after majority of bines reached top wire.
N source: ammonium nitrate
Used maintenance rates of P, K, Zn, and B
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Data CollectionSoil samples collected and plots harvested at discretion of the grower (July-Sept).
Whole plants weighed before machine picking. Subsamples of machine-picked cones and bines collected for determination of moisture and nutrient content.
Soil samples collected from a subset of plots to investigate for determination of profile nitrate.
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
2019 Biomass and Cone Yield Results
Variety significantly affected bine and cone yield
0
1000
2000
3000
4000
5000
6000
7000
0 50 100 150 200
Cascades
Centennial
Chinook
Magnum
Nugget
Tahoma
Bine DM Yield
lbs/
ac
0
200
400
600
800
1000
1200
1400
1600
0 50 100 150 200
Cone Yield (adj. 10% moist.)
Suffered from Anthracnose
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Significance of N rate effect on Bine and Cone YieldLocation Variety N treatment
effect on Bine DM yield P-value
N treatment effect on Cone
yield P-value
Tomah Cascades 0.001 0.099
Tomah Centennial 0.012 0.023
Rosholt Magnum 0.015 0.077
Rosholt Nugget <0.001 0.004
Waterloo Chinook 0.014 0.37
Waterloo Tahoma 0.772 0.633
P values less than 0.05 generally indicate significant effect of N treatment.
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Overall Effect of N rate on Average Bine and Cone Yield
N Rate (lb N/ac)
Bine DM (lb/ac)
Cone Yield (adj. 10% moisture, lb/ac)
0 2735 C 841 C
50 3480 B 944 CB
100 4191 A 1141 BA
150 4430 A 1226 A
200 4501 A 1188 AMeans that do not share a letter are significantly different.
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Biomass and Cone Yield affect on N Removal
Cone yield was not a good predictor of N removal
N removal is well correlated with biomass yield
y = 0.0181x + 4.3093R² = 0.70090
50
100
150
200
0 2000 4000 6000 8000 10000
N r
emo
val (
lb/a
c)
Biomass yield (lb DM/ac)
Whole plant Biomass (DM) yield vs N removal
y = 0.0685x + 18.767R² = 0.3788
0
50
100
150
200
0 500 1000 1500 2000 2500
N r
emo
val (
lb/a
c)
Cone yield (lb DM/ac)
Cone yield vs N removal
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Petiole Tissue and Sap testing
Potentially a valuable tool for hop growers
Samples collected when bines are ½ - ¾ to top of trellis
Allows for in-season adjustment of N rates
Recommend applying 50-70% of N recommendation prior to petiole test
General Guidelines (adapted from PNW recommendations)
0-6000 ppm : Apply recommended rate plus additional 30-50lbs N
6000-10000 ppm: Apply recommended N rate
10000+ ppm: no additional N necessary
y = 1.3237x - 947.53R² = 0.7686
0
2000
4000
6000
8000
10000
12000
14000
16000
0 2000 4000 6000 8000 10000 12000Pet
iole
Tis
sue
NO
3-N
(p
pm
)
Petiole Sap NO3- (ppm)
Tissue Vs. Sap - All 2019 Samples
y = 1.0832x - 124.69R² = 0.7773
0
2000
4000
6000
8000
10000
12000
0 2000 4000 6000 8000 10000Pet
iole
Tis
sue
NO
3-N
(p
pm
)
Petiole Sap NO3- (ppm)
Tissue Vs. Sap-All Treatment Yards Excluding >10,000 ppm
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Effect on Hop Quality Parameters
3 varieties sampled for hop quality parameters, analyzed by AAR Labs
Variety significantly affected HSI, total Oils, Total A-acid, Cohumulone, Total B-acid, Colupulone, and A/B ratio. (P<0.0001)
N rate did not have a effect on any quality parameter except Colupulone. (P=0.02).
Colupulone (as % of BA) decreased steadily with N rate in the Chinooks, but this decrease was not observed in Cascade or Magnum varieties.
Variety HSI Oils (mg/100g)
Cohumulone(% of AA)
A-Acid(%)
Colupulone(% of BA)
B-acid(%)
A/B
Cascade 0.24 0.19 32.45 1.41 54.14 0.98 1.55
Chinook 0.26 0.62 30.55 2.83 55.27 0.73 3.87
Magnum 0.27 0.86 25.92 4.57 45.97 2.12 2.15
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Effect of N rate on Colupulone(as % of BA) in Chinook
200150100500
58
57
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53
Nrate
Co
lup
ulo
ne
Interval Plot of Colupulone vs Nrate95% CI for the Mean
The pooled standard deviation is used to calculate the intervals.
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
N treatment effect on Soil testN treatment had no significant effect on soil test P or organic matter, but significantly (P<0.001) affected pH and soil test potassium
On average pH dropped 0.5 units and K dropped 45 ppm in 200lb/ac N rate plots compared to the 0 N plots.
4
4.5
5
5.5
6
6.5
7
7.5
0 50 100 150 200
Cascades
Centennial
Chinook
Magnum
Nugget
Tahoma
0
50
100
150
200
250
0 50 100 150 200
Soil pH Soil Test K (ppm)
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Deep Soil Nitrate samplingCollected from three varieties; Cascades (Tomah), Chinook (Waterloo), and Nugget (Rosholt).
Used truck-mounted probe to collect samples to a depth of 7-8 ft (or refusal)
Collected samples in row, ¼ distance between row, and ½ distance between row.
Sampled 0, 100, and 200 lb N/acre plots.
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Rosholt-Nugget
0 2 4 6 8
0-1
1-2
2-3
3-4
4-5
5-6
6-7
Row
0 2 4 6 8
0-1
1-2
2-3
3-4
4-5
5-6
6-7
7-8
¼ Distance between rows
0 10 20
0-1
1-2
2-3
3-4
4-5
5-6
6-7
0
100
200
½ Distance between rows
Nitrate-N (ppm)
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Waterloo-Chinook
0 2 4 6 8
0-1
1-2
2-3
3-4
4-5
5-6
Row ¼ Distance between rows ½ Distance between rows
0 2 4 6 8
0-1
1-2
2-3
3-4
4-5
5-6
0 2 4 6 8
0-1
1-2
2-3
3-4
4-5
5-6
0
100
200
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
Tomah-Cascade
0 5 10 15
0-1
1-2
2-3
3-4
4-5
Row ¼ Distance between rows ½ Distance between rows
0 2 4 6
0-1
1-2
0 1 2 3 4
0-1
1-2
0
100
200
Rocky subsoil prevented coring at most locations.
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
SUMMARY2019 growing season data suggest, on average, N rate above 150 lb/ac did not increase cone yield.
Cone yield doesn’t appear to be a good predictor of optimum N rate.
Fine-tuning N rate for hop will likely involve variety-specific adjustments for biomass production.
Petiole testing has promise for in-season adjustments of N rate – proper sampling time is important.
Most quality parameters don’t seem to be affected by N rate, but data suggest that N fertility decreases colupulone in at least one variety
Managing lime and K inputs are important considerations for hop growers
End-of season soil nitrate-N concentrations were generally low, and didn’t appear to reflect N rate.
Hop Production for the Wisconsin Craft Brew Industry, February 29, 2020 Christopher A Baxter
AcknowledgementsHannah McWhirter - UW Platteville, Class of 2019.
Fine Bine Farms – Randy and Peggy Urness
Bohica Hop Farm – Bob, Jim, & Sherry Conant
Davali Ridge Hops – Dave and Ali Buss
Carl Duley – UWEX, Buffalo County
Jerry Clark – UWEX, Chippewa County
Bill Halfman – UWEX, Monroe County
Ken Schroeder – UWEX, Portage County
George Koepp – UWEX – Columbia County
NRCS Soil Scientists – Chris Miller, Karla Petges, Natalie Irizarry
Hop harvest helpers: Walt Rasmussen, Ashley Olson, Ashley Blackburn, Kaitlyn Lance