Changes in the Physical Aspects of Soil After Four Years of Cover Cropping and Organic Soil Amendments | Whatcom Ag Monthly

Volume 5 Issue 10

Chris Benedict, Whatcom County Extension Agent
Email: chrisbenedict@wsu.edu

Objective

Evaluate measures to improve soil health including the use of ground covers and soil amendments.

Treatments

Irrigation Regime (main-plot) –

1.) Tensiometer Driven 2.) Grower Standard

Cover Crop (split-plot) –

a.) Fall planted b.) Fall + Spring Planted (site 1) c.) Perennial Turfgrass (site 2) d.) No cover crop

Soil Amendment (split split-plot) –

i.) Composted Dairy Solids (site 1) ii.) Composted Dairy Solids + Brassica Seed Meal (site 1) iii.) Separated Dairy Solids (site 2) iv.) Separated Dairy Solids + Brassica Seed Meal (site 2) v.) No amendment

Fall Cover Crop – ‘Wheeler’ rye (50 lbs/A) + oats (50 lbs/A)

Spring Cover Crop (site 1) – Oats (10 lbs/A) + ‘Piper’ Sorghum X Sudangrass (20 lbs/A) + ‘Tillage’ Oilseed radish (10 lbs/A)

Perennial Turgrass (site 2) – Dwarf tall fescue + Fine leaf fescue

Composted Dairy Solids (site 1) – 10 tons/A (d.w. basis)

Separated Dairy Solids (site 2) – 3,500 gals/A (w.w. basis)

Brassica Seed Meal – 1 ton/A

Treatments initiated in fall 2011/spring 2012.

**Table 1.** Dry matter weights and days to harvest (DTH) of covere crops planted itno res raspberry alleyways, 2012-2016 Site 1.

**Figure 1.** Alleyway soil compaction in red raspberries with/without cover crops and/or composted dairy solids. Those treatments within a year and soil depth with different letters are considered statistically different (p = 0.05).

Take Home Messages

Soil compaction was reduced by year two (CC, CDS), but differences existed between treatments. These differences were less pronounced by year five.
Infiltration and bulk density was reduced in all treatments by year five.