2018 Proceedings...Nitrogen planning can be especially difficult. Following a brief overview of soil nitrogen cycling, results of a multi - year on -farm study of nitrogen fertility

Horticultural Growers’

SHORT COURSE

2018 ProceedingsLower Mainland Horticulture Improvement Association

60th Annual Horticulture Growers’ Short Course

2018 Proceedings

January 25-27

Editors: Todd Kabaluk

Lisa Frey

Sponsored by:

Lower Mainland Horticultural Improvement

Association

The LMHIA acknowledges the support of the following in delivery of the 2018 Short Course:

ISSN 2560-7561

LHMIA 2017-2018 Board of Directors

Directors President: Harvie Snow

Vice President: Andrew Arkestyn-Vogler Secretary: Bruce Wisbey Treasurer: David Mutz

Jordan Alamwala James Bergen

Mike Boot Ray Bredenhof Nancy Chong Trevor Harris Jeff Husband

Brian Johnston Ed McKim

Grant McMillan Heather Meberg

Gage Neger Lydia Ryall Kerry Seale

Ria van Eekelen

Ex Officio Directors Michael Dossett

Sheila Fitzpatrick Elsie Friesen Shawn Halter

Gary Jones Todd Kabaluk

Karina Sakalauskas Ken Sapsford Susan Smith Dave Trotter

Wim van Herk Bob Vernon

Dave Woodske

Executive Director Sandy Dunn

Foreword

These Proceedings summarize three days of meetings and educational seminars at the 60th Lower Mainland Horticultural Improvement Association Short Course held in conjunction with the 20th Annual Pacific Agriculture Show from January 25-27, 2018 in Abbotsford, BC. There were 867 registered for the Short Course and 85 presenters, along with over 300 exhibitors and over 7,500 general attendees at the Pacific Agriculture Show. The Short Course provides an opportunity for participants to learn about the recent progress in research and development, sustainability and innovation, marketing, agricultural programs and policies, and the ever-changing face of the horticulture industry in BC. This event is organized by the LMHIA Board of Directors, which includes growers, agribusinesses, government and university personnel – all of whom deserve credit for its delivery. Short Course evaluations this year indicated a very high ratingfor both the choice of speakers and the topics presented. Our social media presence is at the following sitesyear-round:

Twitter: www.twitter.com/pacagshow Facebook: www.facebook.com/pacificagricultureshow Instagram: www.instagram.com/pacagshow Worldwide Web: http://www.agricultureshow.net/horticulture-growers-short-course

This volume contains summaries written by the speakers themselves. The LMHIA Board, and all others involved in the Short Course acknowledge and appreciate the widespread participation of the speakers, and in their drafting of summaries of their presentations to be included in these Proceedings. The Proceedings stand as a resource of information for the horticulture industry as a whole, and a record of the state of development of agriculture in BC. Revenue generated by the Short Course enables the LMHIA to award research projects in support of agriculture in BC, indicated at the end of this document.

We look forward to seeing you at next year’s Short Course from January 24-26, 2019.

The Editing Committee - Todd Kabaluk and Lisa Frey

The summaries presented in this volume were submitted by the presenters themselves. The BC Ministry of Agriculture, the LMHIA, and the editors of this publication do not assume liability for crop loss, animal loss, health safety or environmental hazard caused by the use of information described in this publication.

Horticulture Growers' Short Course 4

Table of Contents

Raspberries/Strawberries Strawberry and Raspberry Cultivar Development at Washington State University…….…….....11

Patrick P. Moore

Strawberry Research in the Pacific Northwest…………………..………………………..……..14 Wendy Hoashi-Erhardt

Fresh Market Variety Evaluation in Oregon…………………..…………………………..……..16 Julie Pond

Raspberry Replant Considerations …………………..……………………….…….…….……...18 Eric Gerbrandt, Tom Forge and Michael Dossett

Drip-line Fumigation and Post-plant Nematicides in Raspberry and Strawberry…….……........23 Eric Gerbrandt

High Tunnels and Low Tunnels for Strawberry Production: Plusses and Minuses…..................25 Kathy Demchak

Raspberries in High Tunnels—What Have We Learned? …………………..……….………….28 Kathy Demchak

To Cane Burn, or Not to Cane Burn—That is the Question…………………..…………………31 Timothy W. Miller

Application of Biodegradable Plastic Mulches in Small Fruit Production …….……..................34 Huan Zhang, Lisa DeVetter, Carol Miles, Shuresh Ghimire, Chris Benedict and Inga Zasada

Greenhouse Vegetables

Water Storage Tanks in the Horticulture Industry…………………..………………………..….38 Olaf van Marrewijk

Field Vegetables Irrigation Water Quality in the Lower Mainland…………………..………………………….…41

Justin Falardeau


Good Agricultural Practice for Monitoring Farm Irrigation Water…………………..….………44 Elsie Friesen

Herbicide Resistance: Lessons Learned From Ontario…………………..………………………46 Jichul Bae and Kristen Obeid

Field Production Practices: Sweet Potato Research in 2017 at Vineland, ON ………...………..49 Derek Pearson

Field Production Practices: Okra ……………………………….…..………………………...…55 Derek Pearson

Field Production Practices: Asian Long Eggplant ………………..………….………...………..59 Derek Pearson

Cole Crop Foliar Diseases ………………..………………………..…………………...……….64 Rishi R. Burlakoti and Renee Prasad

2017 Cabbage Storage Variety Trial ………………..………….………...……………………..67 Arlan Benn, Marjolaine Dessureault, Jen Scholefield and Kiara Jack

Noctuids Making News/Noctuids: A Challenge to Manage—Awareness is Key……………….71 Tracy Hueppelsheuser

2017 Fraser Valley Cutworm Trapping in Potato and Beet Fields…………………..…………..73 Arlan Benn, Dru Yates, Kathy Ma and Marjolaine Dessureault

The True Armyworm, Mythimna (Pseudaletia) unipuncta…………………..…………………..77 Jeremy N. McNeil

Ready or Not—Western Corn Rootworm in British Columbia .....................................................81 Tracy Hueppelsheuser

Floriculture Side Effects of Pesticides on Biological Control Agents…………………..…………………….83

Paul Koole

How Much Water Can Be Saved by Monitoring Soil Moisture …………………..…………….88 Ted van der Gulik

Agroforestry Potential of Agroforestry in the Pacific Northwest: Opportunities and Challenges .....................91

Badege Bishaw


Christmas Trees, Cattle and Forage—All Moving Together ........................................................96 Charlie Willis

Syrup Production to the Greenhouse and Back—How Sweet! .....................................................98 Pauline Gomez and Jim Fowler

Farm Business Management Exporting to the United States: How the Latest NAFTA Negotiations Affect You ....................102

Breanna Leininger

Customer Strategies That Belong on Your Radar Screen ...........................................................107 R. Gary Morton

Agriculture Water Management Economics of Rainwater Harvesting Systems for Agriculture……..………………..……..…..112

Stephanie Tam

Provincial Drought Response……..…………………………………………..………………..114 Valerie Z. Cameron

Improving Communication With Okanagan Agricultural Water Customers ……………….…116 Kellie Garcia

Salinity Monitoring in Delta ………………………………………………………………..….121 Ted van der Gulik

BC Agriculture Water Use Reporting Tool……..…………………………………………..….125 Ted van der Gulik

Potatoes Managing for Thrips in Potatoes……..……………………………..……………………...…..128

Dru Yates

Dickeya in Potatoes—What Should Growers be Aware of? ……..………………………...….129 Rishi R. Burlakoti

Managing Yellow Nutsedge and Other Weeds in Potato……..………………….…………….132 Joel Felix


Wireworm Management—Developing an IPM Solution for Potatoes……..…………….……134 Wim van Herk and Bob Vernon

Hazelnuts

BC Hazelnut Inventory 2017……..…………………………………………………….…..….141 Allyson Mittelstaedt

British Columbia Hazelnut Grower’s Production Guide……..………………………….…….145 Tom Baumann and Megan Fennerty

Performance of New Hazelnut Cultivars in British Columbia……..…………………...…..…147 Thomas E. O'Dell

All Berries

Mites in Berry Crops: Small Things that Matter……..…………………………………..........154 Tracy Hueppelsheuser

Weevils Know No Borders: Biology and Management……..………………………………...159 Tracy Hueppelsheuser

Vegetative Buffers: Can They Help to Moderate Interface Concerns on the Farm?…………...161 David Trotter

Direct Farm Marketing Developing Products and a Customer Base ……………………………………….……….….168

Will Bilozir

Hops Nematodes—Should Hop Growers be Concerned? ……..……….…………………….…..….171

Maria Jeffries

Downy Mildew in Hops……..……….……………………………………………….……..…176 Rishi R. Burlakoti


Blueberries Role of Pycnidia in the Epidemiology of Phomopsis vaccinii on Highbush Blueberry…….…182

Keiko Nabetani, Brandon Wood, and Siva Sabaratnam

Monitoring Townsends Voles in Blueberry Plantations in the Lower Mainland…….……..….184 Doug Ransome

Improving Farm Management for Pollinators in Highbush Blueberry……………..………….186 Kyle Bobiwash and Elizabeth Elle

Update on SWD Risk Factors and Research……………………………………………………188 Tom Peerbolt

The Blueberry Bud Set Blues……………………………………………………….………….193 Mark Sweeney

Agri-Laser Bird Management…………………………………………………..………………196 Gayle Krahn

Draper Fruit Drop Management………………………………………………..………………198 Eric Gerbrandt

Blueberry Breeding and Variety Trial Update: Introduction to Some New Genetics………….203 Eric Gerbrandt

Firmness and Fruit Quality in New Blueberry Varieties……………………………………….207 Eric Gerbrandt

Evaluating the Use of UAVs or Drones in the BC Agriculture Sector

UAV Use in BC Agriculture………………………………….………………..………………211 Thomas Elliot, Geoff Mullins and Phillip Reese

Organics Opportunities to Diversify into Organic Vegetable Seed Production .........................................224

Shauna MacKinnon

Assessing Food Safety Risks: A Good Agricultural Practice ....................................................227 for Monitoring Farm Irrigation Water

Elsie Friesen


Ecology of Weeds and Steps for Good Management .................................................................231 Jichul Bae and Kathy Ma

Tools for Evaluating Nutrient Status of Management Zones ......................................................235 for Small-Scale Vegetable Operations

Doug Collins

A New Biocontrol Solution for Loopers .....................................................................................242 Michelle Franklin

Research Project Grants Awarded by LMHIA ............................................................................246


Noctuids Making News/Noctuids: A Challenge to Manage—Awareness is Key.........................71 Tracy Hueppelsheuser

Short Course Program ..................................................................................................................247

Tools for Evaluating Nutrient Status of Management Zones for Small-Scale Vegetable Operations

Doug Collins WSU Food Systems Program & Center for Sustaining Ag and Nat Resources, Puyallup, WA

[email protected]

Several tools for evaluating and managing nutrient status on small-scale farms are discussed. Nitrogen planning can be especially difficult. Following a brief overview of soil nitrogen cycling, results of a multi-year on-farm study of nitrogen fertility on 5 organic farms is provided. Mid-season fertility testing and side dress fertilizer applications are additional tools for nitrogen management. Finally, the management zone approach to soil testing is helpful for nutrient management and directing lime applications, especially on diversified vegetable farms.

Overview of Nitrogen Cycling and Challenges for Organic Farmers

Organic farmers face a difficult problem in managing nitrogen: the magnitude and timing of nitrogen mineralization from organic matter cannot be easily predicted. Many direct-market farmers rely on organic nitrogen fertilizers that cost $5 to $9 per pound of plant available nitrogen. This can cost $1,000 to $1,800 per acre for heavy-feeding crops. Soil building practices such as incorporating leguminous cover crops and amendment with composts and manures can reduce fertilizer need. Disturbed soils and soils low in organic matter can experience dramatic increases in productivity following organic matter addition. Also, judicious use of organic amendments can maintain or enhance yields in soils with relatively high native productivity (Evanylo et al., 2008). When determining how much nitrogen to apply, producers should take into account the plant N requirement as well as contribution from any recently applied amendments or cover crops, and the nitrogen contribution from organic matter (Figure 1).

Figure 1. Requirements and credits for making a nitrogen application and potential sources for gathering information. ENR= Estimated nitrogen release.

Optimizing Nitrogen Management on Organic Farms: On Farm Research Trial

It is difficult to quantify the extent to which fertilizers can be reduced based on past practices. Fast, simple, and cheap methods to predict N mineralization are desirable for farmers, especially those that rely on soil building practices such as cover cropping and manure for soil fertility. Certified organic farmers are encouraged to use these methods to build soil, and are required to use only organic sources of nitrogen for fertility. Depending on N content of organic fertilizers and amendments, only small amounts of N may be made available in the year of application while the bulk is likely to contribute to the organic matter pool (Gale et al., 2006).

plant N requirement = N from OM N from cover

crop N in

amendment + + -

Nutrient Management Guides

Oregon State Univ Cover Crop and Organic Fertilizer Calculator

ENR from Soil Testing Lab? Specialized predictive tests? Guess, observe, and test?

Horticulture Growers' Short Course

235

Organics

mailto:[email protected]

Sullivan et al. (2008) described a site-specific method for growers to estimate N mineralization potential by plant uptake over the course of a growing season using a “zero-N” plot. A more rapid method with the potential to predict N mineralization before the growing season is the Solvita™ colorimetric test for soils (Solvita Inc., Woods End, MA). This method has been correlated with other methods of determining carbon dioxide concentration (Haney et al., 2008). In addition to correlating 24-hour respiration with a 24-day incubation, Haney et al. (2001) also found strong correlation with forage uptake in fine sandy loam soil. The efficacy of these tests for predicting nitrogen mineralization has not been widely tested in field conditions, especially in western Washington.

The goals of the current study were to estimate optimum soil nitrogen fertilizer rates in organic broccoli production and to evaluate how well nitrogen mineralization predictive tests estimate available nitrogen across five organic farms.

Methods

Field Trials: An experiment to assess nitrogen contribution from organic matter and the economic benefit of five different rates of fertilizer application was performed with 5 organic farms. Two farm sites were located near Royal City in central Washington (Sites 1–2) with a semi-arid climate. Three farm sites were located in western Washington (Sites 3–5) with a maritime climate.

Fertilizer rates were determined through interviews with cooperating farmers and by consulting broccoli production guides. In 2016, organic feather meal fertilizer (11%N, 0%P, 0%K) was applied at 0, 60, 120, 180, and 240 lbs N/acre in a randomized complete block design with 3 replications at each farm. In 2017, 2 additional N rates were added: 360 and 480 lbs N/acre.

Certified organic broccoli transplants were prepared at a central location and transplanted following ground preparation and fertilizer application. Transplanting occurred mid-April in central WA and mid-May in western WA in 2016 and 2017. Plant spacing was determined by individual farmers and was similar at sites 1, 2, 3, and 5. Site 4, the smallest farm planted broccoli more densely in 2016. Weather stations were set up at each site to record air temperature for calculation of growing degree days.

Soil Analyses: Soils were sampled before planting broccoli and analyzed for bulk density (BD), water-holding capacity, organic matter (OM), total C, mineral-associated C, particulate organic C, nitrate-N, P, K, and pH. Soil nitrate-N was more intensively sampled by sampling at 0 and 28 days after transplant (DAT) and at harvest (between 71 and 91 DAT). In addition to laboratory analysis, soil nitrate was also analyzed with a field nitrate testing kit (EM Quant™). Nitrogen mineralization predictive tests were done for soils collected in spring before planting. Predictive tests included the Haney test (performed at Ward Labs, Kearney, WA) which includes both 24-hr CO2 respiration (Solvita™ test) and predicted available nitrogen calculated from Solvita™ and weak acid extraction of mineral nitrogen. Other predictive tests were 42-day aerobic nitrate (NO3) mineralization at 22 and 35 ◦C (incubated soils sampled at 0, 7, 21, and 42 days), and 7-day anaerobic ammonium (NH4) mineralization at 40◦C.

Crop Yield and N uptake: Marketable broccoli yield was taken from each plot. Additionally, three adjacent broccoli plants from each replication of each treatment were destructively harvested and combined into a single sample and analyzed for biomass, total N and total C.

Statistical Analysis and Interpretation: The average of 3 field replications was calculated for bulk density, basic soil analyses, Haney tests, 7-day anaerobic NH4 incubation, and seasonal soil NO3. The aerobic NO3 mineralization rate (lbs NO3 day-1) was calculated by attempting to fit a linear to plateau model with nitrate mineralization versus days of incubation and averaging the rate across replications.


236

Organics

Results and Discussion

Soil physical properties, days to first harvest, and plants per acre are shown in Table 1. Site 5 was a silt loam while the other sites were sandy loam, fine sandy loam, or very fine sandy loam. Soil organic matter ranged from 2.0% to 11.3% and pH ranged from 5.8 to 7.8 (Table 2). Organic matter was higher and pH was lower in the soils from the western Washington maritime climate than in the soils from the semi-arid climate in central Washington.

Table 1. Climate, soil properties, and plant density at organic farm sites in Washington State, 2016. Site Climate GDD7.2 to first

harvest Days to first harvest

Soil Type BD g cm-3

Plants acre-1

16.1 Semi-arid 701 71 Royal very fine sandy loam 1.10 14,520 16.2 Semi-arid ~7001 71 Taunton fine sandy loam 1.24 14,520 16.3 Maritime 652 71 Yelm fine sandy loam 0.93 16,228 16.4 Maritime 679 72 Alderwood gravelly sandy loam 0.89 23,522 16.5 Maritime 802 79 Nooksack silt loam 1.06 16,228 17.1 Semi-arid 91 Royal very fine sandy loam 1.10 14,520 17.2 Semi-arid 91 Taunton fine sandy loam 1.24 14,520 17.4 Maritime 81 Alderwood gravelly sandy loam 0.89 15,125

1The weather station at Site 2 was compromised, but GDD were likely similar to Site 1. GDD7.2=Growing Degree Days with base temperature of 7.2 C. There was no harvest from sites 17.3 or 17.5 in 2017.

Table 2. Basic soil analyses from each site prior to planting.

Site pH NO3-N mg/kg P mg/kg OM %

Total Org C %

Organic C (Mg ha-1)

POM-C (Mg ha-1)

C:N POM

16-1 7.7 3.2 86.9a 2.8 1.32 25.7 11.7 8.4 17-1 7.8 3.1 140 2.7 1.53 22.1 9.3 8.2 16-2 7.8 1.1 18.9a 2.0 1.18 21.9 7.5 7.4 17-2 7.7 4.7 41 2.2 1.16 22.2 6.5 8.0 16-3 6.0 3.0 206.0b 7.5 5.51 78.0 24.1 13.3 17-3 6.2 4.4 216 11.3 5.62 79.7 44.2 11.4 16-4 7.1 6.2 102.9b 7.7 4.89 66.3 22.3 14.6 17-4 6.2 7.7 143 10.1 5.28 71.6 36.3 12.5 16-5 5.8 3.0 25.2b 3.5 1.80 30.2 6.2 10.1 17-5 7.5 2.3 51 3.5 1.87 29.1 5.2 10.7

aOlsen P test, bBray P test, cOlsen K test, dNH4OAC K test

Tests to predict N mineralization varied slightly in their ranking of the soil sites. The Haney test, Solvita test, and 7-day anaerobic tests all predicted greater N mineralization from sites three and four in both years (16.3, 16.4, 17.4, 17.3). The ranking of sites with 45 d aerobic tests were similar, but site 1 was also identified as having potentially high N mineralization (Table 3).

In 2016, broccoli transplants in several plots at Site 1 were completely lost to rodent damage, so Site 1 data was not included in above ground biomass or marketable yield analyses. Similarly, harvests at sites 3 and 5 were lost in 2017. Fertilizer rate had a significant effect (p<0.05) on above ground biomass at Sites 2 and 4, but not Site 3 or 5 (Figure 1). Fertilizer rate significantly affected marketable weight at Sites 2-5 (p<0.05; Figure 2).


237

Organics

A linear to plateau model described the effect of fertilizer increase on market head weight in 2 of 4 sites analyzed in 2016. The other 2 sites did not plateau and only a linear model could be fit. In 2017, when 2 additional fertilizer rates were included, a linear to plateau model fit the 3 sites where there was a measureable harvest. Plateau N levels ranged from 152 to 457 lbs N / acre.

Fall soil nitrate levels are another indication of appropriate nitrogen application rate; leaving excess nitrate in the soil after harvest can degrade water quality. Soil nitrate at 30 ppm or greater is considered high and equates to about 105 lbs NO3-N a-1. Only one site had fall soil nitrate levels above this level and this occurred at the highest rate of N application (480 lbs N/acre).

Table 3. Results of nitrogen mineralization predictive tests.

Haney Tests 45-day aerobic incubation, 0-6inches

7-day anaerobicincubation, 0-6inches

Solvita CO2-C day-1

Predicted N min lbs acre-1 NO3 lbs a-1 day-1

NH4 mg kg soil-

1

Site 22C 35C 40 C 16.1 15.3 13.2 1.0 2.2 39.2 16.2 22.5 10.8 1.2 2.2 53.6 16.3 153.3 71 1.7 4.9 108.0 16.4 70.9 54.2 1.1 2.2 97.3 16.5 39.9 18.6 0.5 1.6 7.5 17.1 19.4 16.4 1.6 2.7 54.4 17.2 24.2 21.9 1.6 2.3 57.6 17.3 114.4 48.2 1.6 4.2 86.1 17.4 148.7 51.0 1.9 3.8 105.2 17.5 49.9 16.8 1.2 2.3 36.9

Timing of Nitrogen Availability and Pre-Side dress Nitrate Tests

Nitrogen availability is dynamic throughout the season and this further complicates management. As nitrogen is mineralized, nitrate may pool in the soil or be lost via leaching, incorporation into organic form (immobilization), or as a gas (volatilization). Most vegetables experience a period of rapid nitrogen uptake between 20 and 50 days after seeding. Organic fertilizers are generally best applied as preplant broadcast applications, but some formulations can be surface banded beside the row. Evaluation of the EMQuant field nitrate testing kit revealed it was well correlated with a traditional laboratory test, but overestimated nitrate by about 1.75 times. Mid-season testing and side dress applications are potential methods to increase nitrogen use efficiency in vegetable crops.

Management Zone Approach

Soil samples provide useful information to farmers about the nutrient status, pH, cation exchange capacity, and organic matter content of their soils. To effectively direct application of soil amendments and fertilizers based on these data, soil samples should be taken from distinct management zones. Management zones are contiguous areas that are planted to the same crop at about the same time and have the same amendments applied to them. A management zone can be as narrow as the equipment used to apply amendments, such as a tractor width.


238

Organics

The mix of plantings on diverse vegetable farms poses a challenge for linking farm management to soil sample results (Collins, 2012). To combat pests and meet market requirements farmers may plant a single field to a dozen or more different crops which have a range of nutrient needs. Because of the high spatial variation in plantings on typical small organic vegetable farms, it quickly becomes apparent that sampling each management zone each year is not economically realistic. We tested a method of sampling representative zones from each field with the goal of describing on-farm variation in soil parameters and linking soil management practices to soil nutrient values.

Sampling on a field scale—across different crops—will generalize management practices and crop effects on soil properties. If samples are taken on a management zone basis then growers can link soil test results to their management and make appropriate changes to improve profitability and environmental stewardship. Several of the management zones sampled had excessive fall nitrate levels—a water quality hazard and economic loss (Figure 2). Excess soil nitrate can be washed from the soil profile and contaminate ground and surface water. Where late-season fertilizer applications were made, average soil nitrate levels were the highest (Figure 3). A mid-season nitrate test can be an effective tool to guide mid-and late-season fertilizer applications.

Figure 2. Box plot distributions of selected soil parameters across four farm sites in 2010. N=29

pH

4.8

5.0

5.2

5.4

5.6

5.8

6.0

6.2

6.4

6.6

Org

anic

mat

ter,

%

2

4

6

8

10

12

14

16

18

20

Nit

rate

, ppm

0

5

10

15

20

25

30

35

40

Phos

phor

us, p

pm

0

10

20

30

40

50

60

Pota

ssiu

m, p

pm

50

100

150

200

250

300

350

Calc

ium

, ppm

400

600

800

1000

1200

1400

1600

1800

Boro

n, p

pm

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Cati

on E

xcha

nge

Capa

city

, meq

/100

g

4

6

8

10

12

14

16

18

Mag

ness

ium

, ppm

0

50

100

150

200

250

300

350Li

me

requ

irem

ent,

t/a1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

Low

Med

Low

Med

High

Low

Med

Low

Med

High

Low

Med

High

Low

Med

High

Ext. High

pH

4.8

5.0

5.2

5.4

5.6

5.8

6.0

6.2

6.4

6.6

Org

anic

mat

ter,

%

2

4

6

8

10

12

14

16

18

20

Nit

rate

, ppm

0

5

10

15

20

25

30

35

40

Phos

phor

us, p

pm

0

10

20

30

40

50

60

Pota

ssiu

m, p

pm

50

100

150

200

250

300

350

Calc

ium

, ppm

400

600

800

1000

1200

1400

1600

1800

Boro

n, p

pm

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Cati

on E

xcha

nge

Capa

city

, meq

/100

g

4

6

8

10

12

14

16

18

Mag

ness

ium

, ppm

0

50

100

150

200

250

300

350Li

me

requ

irem

ent,

t/a1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

Low

Med

Low

Med

High

Low

Med

Low

Med

High

Low

Med

High

Low

Med

High

Ext. High


239

Organics

Figure 3. Fall soil nitrate levels by timing of fertilizer application across 4 farm sites in 2010. Mid-season = May–June; Early-season = March–April. Bars are SD.

Late-season Mid-season Early-season No fertilizer

NO3-

N pp

m

0

10

20

30

40

Number of samples

Average total N application (lbs/a)

10

100

7

91

8

41

4

0

Late-season Mid-season Early-season No fertilizer

NO3-

N pp

m

0

10

20

30

40

Number of samples

Average total N application (lbs/a)

10

100

7

91

8

41

4

0

Many western WA soils are excessively acidic and soil tests indicated a median lime requirement exceeding 3 t/A (Figure 2). Lime applications at Oxbow farm between spring 2012 and spring 2013 effectively raised soil pH and reduced lime requirement in all management zones tested (Figure 4). Future applications can be tailored by specific needs indicated by soil test results.

Figure 4. Buffer pH and lime applications by management zone at Oxbow Farm, Carnation, WA between 2010 and 2013.


Organics

References

Collins, D.P. 2012. Soil testing: A guide for farms with diverse vegetable crops. Washington State University Extension Fact Sheet. EM050E.

Evanylo, G., C et al.. 2008. Soil and water environmental effects of fertilizer-, manure-, and compost-based fertility practices in an organic vegetable cropping system. Agriculture, Ecosystems & Environment 127:50–58.

Gale, E.S., D.M. Sullivan, C.G. Cogger, A.I. Bary, D.D. Hemphill, and E.A. Myhre. 2006. Estimating Plant-Available Nitrogen Release from Manures, Composts, and Specialty Products. Journal of Environment Quality 35:2321.

Haney, R.L., W.F. Brinton, and E. Evans. 2008. Soil CO2 Respiration: Comparison of Chemical Titration, CO2 IRGA Analysis and the Solvita Gel System. Renewable Agriculture and Food Systems 23:171–176.

Haney, R.L., F.M. Hons, M.A. Sanderson, and A.J. Franzluebbers. 2001. A rapid procedure for estimating nitrogen mineralization in manured soil. Biology and Fertility of Soils 33:100–104.

Sullivan, D., J.P.G. McQueen, and D.A. Horneck. 2008. Estimating nitrogen mineralization in organic potato production. Oregon State University Extension EM 8949-E.


Organics

Documents

2018 Proceedings...Nitrogen planning can be especially difficult. Following a brief overview of soil nitrogen cycling, results of a multi - year on -farm study of nitrogen fertility