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Tree Fruit Soil Health Long Term Agroecological Research & Extension Site

Printable Handout Station 6 – Soil Health LTARE – WSU USDA Sunrise field day 2025

Problem

Droughty soils, soil borne disease and nematodes, and compaction restricting root growth affect fruit quality and productivity.

Project Goal

Investigate organic matter additions to buffer environmental stress and improve fruit quality.

Treatments

Standard

  • Typical synthetic nutrients and pesticides

Mulch

  • Chipped apple wood.
  • Chip size 0.25-0.5 by 2.5-6 in.
  • Aged at 131 F 15 days turning 3 times.
  • 2 to 3 in depth (93 yd-3 acre-1).
  • Raked back from trees.

High Carbon

  • Compost: 10 tons per acre. 19.5% C ~ 2 ton per acre C 1.7% N – 0.81% P – 2.02% K
  • Mown-and-blown grass clippings

Integrated Organic

  • Same as high carbon
  • Plus cultivation (Kult Kress Finger weeder)

Map of farm experiment with plots outlined.

Results

Soil Carbon

Soil carbon for Standard Mulch Organic Carbon and Standard plus treatments where Mulch is slightly higher than standard, organic and carbon but not significantly different.

Water Infiltration


Figure of water infiltration in years 1 and 2 where mulch is 0.6 min versus 4 min in other treatments.

Tree Growth

Tree growth for years 1 and 2. The growth for the mulch treatment was higher in year 2 than in other treatments.

Fungal Community Composition

Figure showing a scatter plot of the fungal community. Orange dots representing the fungal community in mulch are off to the right hand side far away from those of standard, organic, high carbon and plus which overlap.

Thank you to funders

Washington Soil Health Initiative

Washington Department of Agriculture

Contacts

Tianna DuPont, WSU Extension, Tianna.dupont@wsu.edu

Tracey Somera, Jessica Waite, Devin Rippner USDA-ARS

Lee Kalcsits, Chad Kreuger, WSU

 

Washington State University