Substrate pH Affects Nutrient Availability in Fertilized Douglas Fir Bark Substrates

Abstract

An experiment was conducted to determine how pH and nutrient availability in douglas fir bark (DFB) substrates respond to lime and sulfur (S) rates. The treatment design was a two-by-nine factorial arrangement with two substrate types and nine pHaltering amendments. The two substrates were 100% DFB or 75 DFB:15 sphagnum peatmoss:10 pumice (by volume). Substrate pH-altering amendments included elemental S amended at either 0.6 or 2.4 kgÁm -3 ; calcium carbonate amended at 0.6, 1.5, and 5.9 kgÁm -3 ; calcium hydroxide amended at 4.4, 8.9, or 23.7 kgÁm -3 ; and a nonamended control. All substrates were amended by incorporating 0.9 kgÁm -3 Micromax micronutrients before potting and topdressing 8 g/pot of 14N-4.2P-11.6K Osmocote controlled-release fertilizer after potting. A group of controls was also maintained for each substrate that received no fertilizer amendment (no S, lime, Micromax, or Osmocote). Four containers of each treatment were randomly selected and harvested 4 and 8 weeks after potting. Amendment with S decreased pH with increasing rate, whereas both lime types increased pH with increasing rate. The two substrates in general responded similarly to S and lime amendments, although there were some significant effects and interactions caused by substrate type. Ammonium-N and NO 3 -N both decreased exponentially with increasing substrate pH, whereas water-extractable phosphorus decreased linearly with increasing pH. Water-extractable potassium, calcium, magnesium, and sodium responded quadratically to increasing pH by initially decreasing and then increasing. The micronutrients boron and iron decreased with increasing pH, whereas DTPA extractions of manganese, zinc, and copper initially increased and then decreased over the range of observed pH.

Substrate pH and Butterfly Bush Response to Dolomitic Lime or Steel Slag Amendment

“…Leachate P concentration decreased linearly with increasing DL rate at 1 WAP, but did not respond to DL rate thereafter (Table 3). This agrees with other studies that have shown a decrease in leachate P with increasing DL rate and a concomitant increase in pH (Altland et al 2008;Chrustic and Wright 1983;Midcap 1999). In contrast, leachate P concentration decreased with increasing SS rate throughout the experiment.…”

Investigating the Benefits of Tectonite Dust as an Amendment for Bark Substrates and Dryland Crops

“…aged DFB; (3) Madras loam mineral soil gathered near Agency Plains (AP) in Jefferson County, Oregon (44.69, −121.19); (4) a Maupin loam mineral soil gathered near Juniper Flats (JF) in Wasco County, OR, USA (GPS 45.17, −121.19). DFB is the most common soilless substrate used in container production in Oregon [ 33 ]. The PM was used as a “standard” to create a benchmark for physical properties that is acceptable in containerized specialty crop production.…”

Remediation of saline soils by a two-step process: Washing and amendment with sludge

“…A plausible explanation could rely on the following: because at lower pH the availability of most nutrients should be greater as suggested in Altland et al (2008). They also reported that there was no single pH range ideal for all crops.…”