Fall organics application and info. for alkaline soil
Thanks, Krista, for advising me to apply manure and slow-released organic fertilizers in the fall, before the ground freezes. I found data from Canadian wheat agriculture that supports Krista's good tip. Optimal pH of wheat is 6.5, same as roses.
The site is: http://www.agricocanada.com : "It is easier to apply Nitrogen on frozen ground early so that we do not miss this stage due to wet soils. The amount of Nitrogen to apply at this time would be 35 to 40% of the total Nitrogen required for this crop. If all of the Nitrogen is applied to the crop after the tillering stage it will only promote vegetative growth and might increase disease pressure."
Some info. from Colorado State to help people like me growing roses in alkaline soil with free lime: "Soils with a pH of 7.5 and higher typically have a high calcium concentration that binds P as calcium-phosphate creating an insoluble compound that is not available to plants. Therefore, it is necessary to amend agricultural soils with available forms of P.
Apply manure in the fall. It takes 3-6 months for phosphorus to be available. Rock phosphate is not readily available for plant use in soils with pH above 7. For this to be available, the acidity of the soil solution must dissolve the Phosphorus. Bone meal should be used ONLY when the pH is below 7... The major problem with high pH is iron chlorosis. Soils with a pH above 7.3 and/or with free lime (calcium carbonate) can be amended with acid peat moss at the rate of one to two cubic feet per plant. This only last for a few years. To test for free lime, place a tablespoon of dry soil in a cup. Moisten it with vinegar. If the soil-vinegar mix bubbles, the soil has free lime."
The Florida State U. Extension stated that lowering pH with sulphur only lasts for 1 year. Another site added that lowering pH with sulphur or raising it with lime only lasts for 1 year. Which means I have to make frequent trips to Starbucks for acidic coffee grounds for my white pines, azaleas, rhododendrons, and roses.
Plants like wheat and roses with optimal pH of 6.5 can't extract phosphorus from soil as well as plants with higher pH preference. The Aussie achieved success with increasing wheat yield through applying liquid phosphorus, along with other elements. Rose growers also reported success with alfalfa tea.
At first I blamed my alkaline soil on lime stones (calcium carbonate). Then I had my soil tested professionally by EarthCo. with the result of 7.7 pH, super-high magnesium, but adequate in calcium. When I tested pH of various stuff using red cabbage juice, the control cabbage color didn't change a bit with calcium citrate, but shot way up to the alkaline zone when tested with magnesium oxide (even more green than baking soda).
I once read a book by a gastroenterologist, M.D., who recommends people to take a magnesium supplement rather than Tums for acid stomach and heartburn. It finally made sense when I tested the pH of mangesium supplement (mixed in distilled water) with fish-tank litmus paper, again, it shot way up past 8.4 alkaline zone.
Here is a link that might be useful: Phosphorus and alkaline calcareous soil