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Application of Biodegradable Plastic Mulches on Tissue Culture Red Raspberry

Volume 6 Issue 9

Huan Zhang1, Lisa DeVetter1, Carol Miles1, Shuresh Ghimire1, Chris Benedict1, Inga Zasada2

1Washington State University; 2United States Department of Agriculture, Agricultural Research Service


• Tissue culture (TC) plugs are hard to establish and are weak competitors with weeds.
• Plastic biodegradable mulches (BDMs) can be comparable to polyethylene mulch (PE) for weed management, increasing soil temperature and moisture, promoting crop growth, and enhancing crop yield.
• Plastic BDMs are used in annual vegetable production systems.
• Few studies have tested plastic BDMs in perennial crop production systems, like red raspberry. There is potential that plastic BDMs promote raspberry establishment when planted as TC plugs.

Figure 1.  Spring-planted raspberry TC trial, 18 May 2017.


  1. Evaluate weed incidence with BDMs and PE mulch in comparison to bare ground (control treatment) in establishing TC red raspberry in both spring and fall planted systems in northwestern Washington.
  2. Monitor surface and in-soil degradation of BDMs in spring and fall planted raspberry systems.
  3. Evaluate growth, establishment, plant nutrient and moisture status, and yield of raspberry grown with BDMs and PE mulch in comparison to bare ground.
  4. Monitor soil temperature and moisture across BDM, PE, and bare ground treatments.
  5. Assess populations of root lesion nematodes (Pratylenchus penetrans; RLN) in the soils and roots of raspberry before and after using BDMs and PE mulch; populations will be compared to the bare ground treatment.


  1. Organix 0.5 mil (BDM)
  2. Organix 0.6 mil (BDM)
  3. Bio 360 0.5 mil (BDM)
  4. Bio 360 0.6 mil (BDM)
  5. PE 1.0 mil (non-BDM)
  6. Bare Ground Control

Cultivars are ‘WakeField’ and ‘WakeHaven’ for the spring- and fall-planted trials, respectively. 

Preliminary Results (only spring-planted trial results)

Figure 2.  Plant height (in) on 30 August 2017.

Figure 3.  Comparison of plant height on 15 August 2017; bare ground (A) and BDM treated (B, Organix 0.5mil).

Figure 4.  Primocane number/hill on 30 August 2017.

Figure 5.  Average daily soil temperature (values averaged over 24-hours period at a 4 inch depth; 15-27 July 2017).

Figure 6. Downloading soil moisture and temperature data.

Figure 7.  Average daily soil moisture (values averaged over 24-hours period at a 4 inch depth; 15-27 July 2017).

Data Collection

Figure 8.  Measuring plant height.

• Weed number and weight (monthly)
• Soil and root samples for RLN population assessment
• Machine harvestable yield (in 2018)
• Mulch degradation (PSE)
• Plant height and primocane number (once per month, May-Oct)
• Soil temperature and moisture (logged every 15 minutes with a Decagon logger)
• Photosynthesis rate (once a year, between mid-July to mid-August)
• Leaf water potential (once a year, between mid-July to mid-August)
• Plant and soil nutrient content

Figure 9.  Counting primocane number.


• Technical assistance from Sean Watkinson, Edward Scheenstra, Clara Tevelde and Matt Arrington, WSU NWREC.
• Funding from Washington Red Raspberry Commission and Washington State Commission on Pesticide Registration.
• Special thanks to grower cooperators.

WSU Small Fruit Horticulture Program:
Biodegradable Mulch: