If I sow a pine seed in soil with a pH of 4.3, what type of soil-related problem might occur? Would the mass of the seedling at lifting (9-months) be less than if the soil pH was 5.5? If yes, then why?
I assume you mean pH in water and that the soil has low salinity. In that case pH 4.3 is very acidic, and depending on the pine, it may tolerate strongly acidic conditions. However that does not mean that it will thrive under them. Aside from possible high concentrations of available Al and Mn, such soils are often low in available P, Ca etc.
A pH of 5.5 is a much less hostile environment.
The side effect that could decrease germination is Al toxicity but 4.3 is near the usual range of germination in soil-needle beds that is from 4.5 to 5.9. Possibly you may add a modarate amount of lime. http://www.jesc.ac.cn/jesc_en/ch/reader/create_pdf.aspx?file_no=20020120
David , we have observed a soil pH of 4.3 is very common in locations growing pine trees in India , and those trees come up excellently . Interesting , within the rhizosphere of pine trees , no other plant species come up so good , possible due to very strong acidic soil pH.
David, I agree with the first two answers above. I assume you mean southern pines like longleaf and loblolly. There are more soil fertility issues at a very low pH, including micro-nutrients, and nitrification is greatly reduced compared to higher pH levels. If you take a bale of Canadian pH, and check the pH of a slurry, it likely will be 3.8 to 4.5. The trees might tolerate the pH, but I believe the growth will be less than at a more ideal range of say 5.3 to 5.8. I worked extensively with Fraser fir and Atlantic white cedar. Fraser fir grows on isolated mountain tops in thin soils with relatively high organic matter content and low pH, say 3.8 to 4.4. Atlantic white cedar historically occurred in greatest abundance in peat soils in swamps along the East Coast, such as the Great Dismal Swamp on the VA/NC border. The pH of those organic soils is typically 3.8 to 4.4, similar to diluted vinegar. Available P is just about non-existent, and conversion of NH4 to NO3 is minimal. Yet, those species grow very well. Why? I never researched the issue, but I suspect that mycorrhizae might be involved. In mineral soils at a pH of 4.4, soluble aluminum likely would be relatively high. Southern pines, especially longleaf pine, seem to tolerate high concentrations of soluble Al fairly well. I don't know if the mechanism is one of avoidance, where tree roots can selectively exclude the Al, or if the trees have the ability to compartmentalize the Al within the cells, say in the vacuoles. I suspect both. When comparing pH 4.4 to pH 5.5, about the only advantage I can think of for the lower pH is that phytophthora root rot would not do as well. The potential for root rot goes up with increasing pH, especially above pH 6.0.
Eric... as we both know, fertilized loblolly pine and pond pine grows very well on acid, organic soils in eastern NC (at the Hofmann Forest). Regarding the growth of Fraser fir in containers, researchers at VPI would not agree that the "ideal range" is 5.3 to 5.8. Instead, they report that the ideal range for a sphagnum peat medium is pH 4.2 to 4.5.
http://hriresearch.org/Docs/Publications/JEH/JEH_1989/JEH_1989_7_2/JEH%207-2-62-64.pdf
Bryan, J.A., J.R. Seiler, and R.D. Wright. 1989.
Influence of growth medium pH on the growth
of container-grown fraser fir seedlings. J. Env. Hort.
7:62-64.
I agree with you that the potential for root rot is pH dependent. I made a nice graph showing this for longleaf pine (using Pawuk 1981 data for Pythium) and I have a reference showing the same trend with Pitch pine in containers. Do you know of another data set that shows a similar response with pine? I also suspect that in bareroot nurseries, nematodes and weeds will be less at pH 4.3 than at pH 5.8 (but I am still looking for data to support this theory).
http://forestproductivitycoop.net/wp-content/uploads/2014/12/Carlson-et-al-2014-FS-RW15-results.pdf
Anoop Kumar Srivastava.... thanks much. Here is an example of good growth of loblolly pine at soil pH below 4.5
David, is it because of the exceptionally high exchangeable Al at such low pH, other plants ( Other than pine group trees) do not flourish so well within the rhizosphere of pine trees
Anoop, if weeds do not grow well at pH < 4.5, would growing pines in a bareroot nursery at pH < 4.5 be part of an integrated weed management program? BTW, in 1946-1951, 62% of UK nurseries grew conifers at < pH (water) 4.5.
https://rngr.net/publications/tpn/60-2/optimum-ph-for-growing-pine-seedlings/at_download/file Two schools of thought address the optimum soil pH (measured in water) for growing pine seedlings (Pinus spp.) in bareroot nurseries. One school uses nutrient availability charts to determine the best pH range for growing conifers. Students of this school believe pine seedlings grow best at pH 5.5 to 6.5. In contrast, another school uses research from nursery trials to conclude that pines grow best in “very strong acid” soils (pH 4.5 to 5.0). This article compiles some of the findings from seedbed and greenhouse trials and attempts to use data to dispel a few myths about growing pine seedlings in soils with pH less than 5.0.
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