Job offersmore »

Tweeting Growers

Last commentsmore »

Top 5 - yesterday

Top 5 - last week

Top 5 - last month

Exchange ratesmore »

Acidic and basic effects of floriculture species in peat-based substrate

Floriculture species differ in their effect on substrate-pH and the resulting substrate micronutrient availability in container production. The objective of a new study was to quantify effects of floriculture plant species on substrate-pH.

In a growth chamber factorial experiment, 15 floriculture species were grown in 70%:30% by volume peat:perlite substrate and fertilized with nutrient solutions containing 100 mg·L−1 N and NH4+-N:NO3-N nitrogen ratios of 0:100, 20:80, or 40:60. The relationship between substrate-pH and milliequivalents (meq) of acid or base per unit volume of substrate was quantified by titration with hydrated dolomitic lime or HCl.

After 33 days, species and solution type effects on substrate-pH and estimated meq of acid or base produced were evaluated. Final substrate-pH ranged from 4.83 for geranium in 40:60 solution to 6.58 for lisianthus in 0:100 solution, compared with an initial substrate-pH of 5.84. This change in substrate-pH corresponded with a net meq of acid or base produced per gram of tissue dry mass gain (NMEQ) ranging across solutions and species from 1.47 of base for lisianthus in the 0:100 solution to 2.10 of acid for coleus in the 40:60 solution.

With the 0:100 solution, geranium produced the greatest NMEQ of acid (0.07), whereas lisianthus produced the greatest NMEQ of base (1.47). Because all N in the 0:100 solution was in the NO3 anion form, meq of both anions and cations taken up by plant roots could be calculated based on tissue analysis. With the 0:100 solution, species that took up more anions than cations into plant tissue tended to have a more basic effect on substrate-pH, as would be expected to maintain electroneutrality.

Data were used to estimate the percent NH4+-N of total N in a nutrient solution that would be neutral (results in no substrate-pH change) for each species. This neutral percent NH4+-N of total N ranged from ≈0% (geranium) to 35% (pentas). Species were separated into three clusters using k-means cluster analysis with variables related to NMEQ and anion or cation uptake.

Species were clustered into groups that had acidic (geranium and coleus), intermediate (dusty miller, impatiens, marigold, new guinea impatiens, petunia, salvia, snapdragon, and verbena), or basic (lisianthus, pansy, pentas, vinca, and zinnia) effects on substrate-pH. Evaluating the tendency to increase or decrease substrate-pH across a range of floriculture species, and grouping of plants with similar pH effects, could help predict NH4+:NO3 ratios for a neutral pH effect and assist growers in managing substrate-pH for container production.

Access the full study at HortScience.

Publication date: 9/15/2017



Other news in this sector:

1/10/2018 US (MI): Managing substrate pH of soilless substrates
12/22/2017 Video: Phytosanitary clean peat for bulb packaging
12/12/2017 Substrate handling influences air porosity of substrates
11/29/2017 BrownGrow appoints Dr Mike Nichols as technical consultant
11/20/2017 Peat moss comes in many grades
11/2/2017 Peat and Growing medium markets: supply and demand
10/27/2017 Is all peat moss the same?
10/16/2017 US: Enroot Products ships first Ameri-Coco bagged coir
9/11/2017 Challenging year for growing media producers
9/1/2017 RHP certification for AS Tootsi Turvas
7/17/2017 RainSoil debuts new substrate enhancer at Cultivate
7/11/2017 A mixing model to predict rooting media properties
7/7/2017 US: Organic Ellepots now available at CropKing
6/5/2017 Hydroponic media: Give slab production a second look
5/31/2017 Pelemix opens Chinese branch office and warehouse
5/31/2017 Grow-Tech launches CatEyePlug
5/25/2017 "More and more applications for coco substrate"
3/23/2017 Different types of limestone to increase substrate pH
3/20/2017 Forteco corporate identity revamped
2/21/2017 Testing and corrective procedures for low substrate pH


Leave a comment: (max. 500 characters)

  1. All comments which are not related to the article contents will be removed.
  2. All comments with non-related commercial content, will be removed.
  3. All comments with offensive language, will be removed.

  Display email address

  new code