Basics of Blueberry Production

Transcription

1 Basics of Blueberry Production Dr. Bernadine Strik, Professor of Horticulture Oregon State University Yield increases with planting age and is affected by cultivar and management (1742 plants/acre) 1 kg/plant = about 2 tons/acre Planted in October 2006 (2008 = year 2; 2014 = year 8), NWREC, Aurora, Oregon (adapted from Strik et al., 2017) University 1

2 Outline Key requirements o Good soil (that can be modified if needed) o Good water available o Adapted cultivars Basics of good management o Modification of soil properties and nutrients before planting o Proper planting design and techniques o Nutrient management o Pruning o Pollination and harvesting Blueberries are grown on two types of soils Blueberry soils Acidic High organic matter Nitrogen in ammonium form (NH 4 -N) Mineral soils Soil ph greater than 6.0 (modification needed) Low organic matter Accumulate nitrate-n (NO 3 ) over NH 4 University 2

3 Soil Requirements Soil ph of 4.5 to 5.5 High in organic matter (> 5%) Very good drainage Testing the soil Obtain representative soil sample of field take down to tillage depth Test well in advance of planting (~ 1 year) Adjust soil nutrients and ph prior to planting, if required, based on test results University 3

4 Soil ph Soil ph affects nutrient availability If ph too low or too high: Nutrients in excess or deficient or not in form plant can use Will see problems, but cause needs to be properly identified to correct them blueberry Optimum ph Modification of soil ph before planting EM 8857 PNW 599 If ph is too low, add lime If soil ph is too high then add elemental sulfur (S) to achieve target ph of 5.5 or 5.6 (upper end of adapted range) S is oxidized (with water) to acidify soil (apply in autumn generally) In high ph soils (buffered) growers may acidify irrigation water (after planting ph management) EM 9057 University 4

5 Modifying soil ph on soils highly buffered with high ph ( ) Acidify the irrigation water o Options for conventional growers include various acidifying fertilizers (fertigation), phosphoric acid, sulfuric acid, sulfur burners o Options for organic growers include OMRI-approved acetic acid, citric acid, and sulfur burners California Eastern Washington Organic matter Grow a cover crop prior to planting Incorporate organic matter like sawdust or bark Do not incorporate a high-ph material such as yard debris- or animalcomposts Amendments improve soil porosity (internal drainage) Douglas fir sawdust applied as an amendment (prior to incorporation) After incorporation University 5

6 Drainage Amendments improve internal soil drainage Rip soil Install drain tile, if necessary Plant on raised beds Impact of raised beds on growth & yield 22% greater cumulative yield on raised beds Measured improved root growth on raised beds Certified organic research study ( ). Strik et al., 2017 University 6

7 Other site requirements Be aware of any possible pest issues related to prior cropping history (fumigation?) Decide on conventional or organic production and be aware of requirements, restrictions, certification Test irrigation water and ensure adequate amount available during times of need (frost protection and plant water needs, depending on region) Choose blueberry type and cultivars adapted to your location Blueberry type and cultivar adaptation USDA cold hardiness zones range from 5b to 8a Chill hours (32-45ºF) important University 7

8 Blueberry Types Northern highbush Vaccinium corymbosum Relatively high chilling requirement ( hours) Cultivar examples: Duke, Bluecrop, Draper, Liberty, Elliott, Aurora Southern highbush Vaccinium corymbosum x V. darrowii hybrids Low chilling requirement ( hours) Cultivar examples: Star, Emerald, Jewel, Snowchaser, Kestrel, Farthing Rabbiteye Vaccinium virgatum Moderate chilling requirement ( hours) Cultivar examples: Powderblue, Ochlockonee, Alapaha, Vernon Dormex stimulates vegetative bud break in regions with insufficient chilling (e.g., Florida) No Dormex Dormex Courtesy: J. Olmstead University 8

9 Jewel treated with Dormex, Florida Factors to consider when choosing a cultivar Site factors Macro-climate (winter hardiness; chill units) Soil type Market Self pack vs someone packing for grower Fresh vs process market Wholesale vs retail market Near markets vs far Organic or conventional Ripening season Hand or machine harvest Disease and pest issues University 9

10 Planting design Affected by site (constraints such as shape of planting area, slope) Consider how to arrange planting blocks (different cultivars, ripening time) and road access Row length or access between blocks is important for managing hand pick crews and for machine harvest (unloading of fruit) Spacing between rows varies with harvest method Only use a row spacing less than 10 feet if will always be handpicked or PYO. Go no closer than 8 feet For machine harvest the minimum spacing should be 10 feet (for over-the-row machines currently used). Some growers prefer 11 feet, but this reduces yield/acre Incorporate headlands into planting design for machine harvest Plant Spacing Most common is 3 feet between plants in the row Trellis with simple wires (one per side) to improve harvest efficiency University 10

11 Nursery stock and planting Buy certified, disease-free (virus-free) planting stock from a reputable nursery For soil-grown plantings in North America, most common pot size is 3 to 4 L Smaller plants may be used in certain production systems Smaller plants lead to slower establishment time, a greater risk of plant loss, and greater plant-to-plant variability in some regions Irrigation Drip irrigation most common to provide plant water and most fertilizer (fertigation) Added low-volume overhead systems to provide cooling during fruiting (in areas with low humidity) and frost protection New planting set up with dual University 11

12 Plant water needs Depends on: o plant age (canopy and root system size) o cultivar (e.g. early vs. late-season fruiting) o stage of development (time of season) o weather o cultural practices (e.g. bare soil vs. sawdust vs. weed mat mulch) Plant water needs - ET c Plant water requirement is called crop evapotranspiration (ET c ) a combination of transpiration from plant and evaporative loss from soil ET c is affected by the environment and canopy size (season, plant size, plant age) Replace evaporative losses by crop ET c = ET r {reference ET available from weather station site} x K c {crop coefficient; from weather station} Adjust for percent canopy cover University 12

13 Mulching Helps control weeds (critical in blueberry) Conserves soil moisture Cools the soil relative to bare or plastic Organic mulches add organic matter In-row mulching options No mulch (bare soil) Organic product (e.g. sawdust) Polyethylene geotextile ( weed mat ) University 13

14 Weed mat adding organic matter underneath Adding sawdust under weed mat improved yield (Strik et al., 2017) Nutrient Management Most common nutrient management problems Soil ph not in ideal range ( ) Using the wrong type of fertilizer (nutrient source) Blueberry plants have specific requirements Excess fertilizer applied Fertilizing at incorrect time leading to undesirable effects Fertilizing with too high of a rate creating plant stress or nutrient imbalances Too little nutrient is available at key developmental times Misunderstanding of how to assess plant nutrient status Improper use of plant tissue analysis standards University 14

15 Impact of soil ph being too high Duke, soil ph above 5.8 Correct ph Soil ph above 5.5 Organic materials applied e.g. mulch, compost Fertilizers applied (ammonium NH 4+ ) granular fertilizer, fertigation Organic materials applied e.g. mulch, compost Fertilizers applied (ammonium NH 4+ ) granular fertilizer, fertigation Ammonium-N (NH 4+ ) Ammonium-N (NH 4+ ) Slow nitrification Blueberry Plant Rapid nitrification Nitrate-N (NO 3- ) Nitrate-N (NO 3- ) University 15

16 Nitrogen Rate Starting Point Adjust rates based on mulching, tissue analysis & plant growth Based on 10 ft row spacing ** Fertilizer is applied by hand per bush in year 1 and 2 for granular and using a fertilizer spreader when canopies touch in year 3+ ** Based on ft in-row spacing *Oregon: un-mulched plantings. If sawdust mulch is used add 25 lb N/acre to rate ONLY if fertilizer N applied on top of mulch (Hart et al., 2006) B.C. values from 2014 Berry Production Guide New planting - fertilization Pre-plant nutrient and ph adjustment critical to good growth in early years Rates are provided per plant Adjust for inefficiencies of fertigation or spreader if needed For nitrogen: Apply recommended rates as a starting point and observe growth Divide total fertilizer into small amounts as plants have small, shallow root systems, whether using granular or fertigating University 16

17 In older plantings: Apply granular fertilizer in the row area (broadcast band). Nitrogen in small doses. P and K in late winter/spring if needed. Granular fertilizers must be placed under weed mat if used (thus fertigation with N more common) Drip line should be under weed mat (for irrigation); then use fertigation Timing of N fertilization Nitrogen fertilizer uptake studies (using 15 N) have shown that blueberry plants take up N fertilizer from bloom through early to mid-july (Throop and Hanson, 1991; Retamales and Hanson, 1989; Bañados, 2006; Bañados et al., 2012; White, 2006). Plants use stored N prior to bloom Plants need to build reserves back up by fall University 17

18 Nitrogen Rate More is NOT better Long-term studies have found no advantage of higher rates of N in yield In organic production and conventional studies, plants have often performed better or just as well at low N rates High rates of N can lead to high salts (EC) in root zone and reduce growth High rates early or fertilizing with N too late in the season increases shoot growth rate and decreases fruit bud set In cold regions, late growth can delay acclimation and increase risk of cold injury Fertilizer sources Granular conventional and organic fertilizers (soil applied) o (e.g. Ammonium sulfate, urea; feather meal, cotton seed meal, soybean meal, pelletized chicken manure) Liquid conventional and organic fertilizers (soil applied or fertigated) o (e.g. liquid ammonium sulfate, urea, N-Phuric; fish solubles, various liquid products) Controlled release fertilizers (conventional) have not performed well Composts o (e.g. yard debris or animal-based use sparingly as high ph and potential high salts slow release) Humic acids (liquid, fertigated) University 18

19 Plant tissue sampling Use leaf tissue testing to assess plant nutrient status and adjust fertilizer programs Sample ALL cultivars at the same time but sample separately (Strik and Vance, 2015) Proper sampling time varies by region Standards are similar among regions Pruning University 19

20 Pruning Principles Prune at correct time of year for desired response Prune for rapid plant establishment or to improve growth Once plants mature, balance vegetative growth and fruiting to obtain a sustainable yield of high-quality fruit Prune to limit crop to the best quality (impact on size and fruiting season) Prune for efficient harvest Pruning to limit fruiting on young plants Flower buds Identify flower buds On most nursery plants, remove the flower buds Vegetative buds University 20

21 Pruning at planting prior to first growing season Before pruning After pruning Pruning at planting Impact on growth first season These plants were pruned to shape and remove flower buds. Growth in mid-may University 21

22 Pruning to limit fruiting on young plants Choose some representative plants in the block Prune these plants to the desired bud number Have pruning crew use these plants as a guide for pruning other plants with similar vigor Prune low vigor plants to remove all flower buds Impact of too much fruit on growth year 2 (Oregon) Little pruning the prior winter (Full crop) Top Shelf year 2 (July 1) Pruned prior winter to shape bush and remove flower buds (Essentially no fruit) University 22

23 New shoots Whip 1-year cane growing season (fruiting) 2-year cane End of Year 1 During Year 2 End of Year 2 2-year cane growing season 3-year cane 3-year cane growing season During Year 3 End of Year 3 During Year 4 Choosing the best fruiting wood Northern highbush blueberry What 1-year-old wood (laterals) are most productive? Best quality fruit is produced on laterals that range from 6 to 18 inches long in most cultivars Thicker diameter laterals produce bigger berries University 23

24 Pruning an establishing, still immature plant Oregon Un-pruned Pruned For good fruit production need a balanced plant with good pruning and fertilization for fruit production & growth University 24

25 Pruning Duke winter prior to year 3 (B. Strik); video not available in PDF Pruning Aurora example of thinning to the best laterals (Oregon) BEFORE Pruning University 25

26 Pruning Aurora example of thinning to the best laterals (Oregon) AFTER Pruning Pruning another example of thinning to the best laterals (Oregon) BEFORE Pruning AFTER Pruning University 26

27 POOR Pruning Adding fertilizer will not fix this problem! Too many buds left previous winter (too much fruit; too little growth) Summer pruning in southern highbush Hedging results in denser crowns over time, requiring cane renewal in older plants Photos courtesy: Jeff Williamson, Univ. FL University 27

28 Pollination Hand harvest Hand harvested for most of fresh market production Frequency of harvest depends on cultivar and weather (generally 7-10 days) University 28

29 Machine harvest Commonly used throughout North America Frequency of harvest depends on cultivar and weather (generally 7-14 days) Production system and cultivar are very important to success and harvest efficiency Substrate production (in containers) Most common for production in low latitude regions often with plants staying evergreen (low to no chill) Substrate production..who needs good soil? More rapid to come into production but..very expensive and has its own set of problems University 29

30 Key issues: Advantages: fast to production; uniform plants and fruit; no soil; adapted to many climates Disadvantages: High establishment costs; fertigation and ph and salt management more tricky; container and media choice very important; no room for error with irrigation and fertilization; winter protection in cold climates data on longevity of plantings limited Open field substrate production, northern highbush, Oregon University 30

31 Reference Publications OSU ones available at ( Northeastern publications ( Blueberry Physiology, Production Systems & Management 6-week on-line course Next class starts in late September 2019 University 31