Acid soils(low ph) have less calcium and high ph soils normally have more. As the soil ph increases above ph 7.2, due to soil calcium the additional free calcium is not absorbed onto the soil. Much of the free calcium forms nearly insoluble compounds with other elements such as phosphorus thus making Phosphorus less available.
Plants take up basic cations such as K+, Ca++, and Mg++. When these are removed from the soil, they are replaced with H+ in order to maintain electrical neutrality.
The main reason for soil acidity in the backyard food garden in the tropics is rainfall. Rainfall affects soil pH. Water passing through the soil leaches basic cations such as calcium (Ca2+), magnesium (Mg2+), and potassium (K+) into drainage water. These basic cations are replaced by acidic cations such as aluminum (Al3+) and hydrogen (H+). For this reason, soils formed under high rainfall conditions are more acid than those formed under arid conditions...................................................................................
Post has been added to New e-book; barry@barrydaly.com.au
"Growing Herbs, Fruit & Vegetables in a warm climate"
$10 Book contents Packed full of first hand knowlege, 24 Chapters include;
Chapter 1 Let's Get Started
How to set up and maintain your food garden, to ensure success
Chapter 2 Rotating Your Veggies
Why rotating your veggies works
Chapter 3 Pest Control & Balance
How to minimise the use of pesticides
Chapter 4 Soil Guide & Building Your Soil
Get to know your soil – you'll be glad you did
Chapter 5 Storing Seeds
Improve your success rate with properly store seeds Here's How
Chapter 6 Tastes Better Home Grown
Why is that?
Chapter 7 Green Manure / Beans
Maintain fertility like the ancient Romans
Chapter 8 Snake Beans Dwarf & Climbing
Great Addition to a tropical Garden
Chapter 9 Keeping Chickens
Why they're such an asset to your garden
Chapter 10 Okura
Easy to grow, not to mention the health benefits
Chapter 11 Soya Beans “Eda Mame”
Eaten the Japanese way taste great and good for you
Chapter 12 Paw Paw or Papaya
30 Kg of the nutritious you have to have one in your garden, this is how to grow it
Chapter 13 Capsicum in the tropics
There's nothing like watching capsicum fruit form in your garden pure joy
Chapter 15 Corn
Corn is easy when you know how
Chapter 16 PH Testing
How to measure your soil PH and what is PH
Chapter 17 Growing Bananas
Some great tip on the best backyard bananas
Chapter 18 Dolomite & Garden Lime
Which is best to use why and how
Chapter 19 Egg Plant
Grafting onto wild egg plant for extended growth
Chapter 20 Mignonette Lettuce
Open leaf lettuce like mignonette is the best lettuce for warm climates
Chapter 21 Growing Tomatoes From Garbage
Great tomatoes from garbage, learn how
Chapter 22 Growing Herbs in the tropics
Yes it's possible see what to grow and how
Chapter 23 Some Working Gardens
Some gardens from people who have a lot of experience, Italians, Greeks, and Bougainvillea.
Chapter 24 Take Out The Misery & Bring Back The Muck
A final word
Friday, March 12, 2010
Subscribe to:
Post Comments (Atom)
2 comments:
Hi Barry,
Limestone and dolomite are indeed good ways of balancing the acidity added in some organic materials and by natural acidification in a wet climate. The pH of acids like hydrochloric acid depends on their pH; the more concentrated the lower the pH. The most concentrated hydrochloric acid you can buy (10 M) has a pH of -1! It's an historical accident that the cations Na+, K+, Ca2+ and Mg2+ have been called 'basic cations'. Rather unfortunate because they actually aren't basic at all. All the good modern textbooks no longer call them 'basic', but rather the unwieldy, but correct term 'non-acidic'. Unlike the cation Al3+, which is acidic, and which only exists in acidic soils, with pH less than around 5.5. At pH values above this the Al is stable in mineral forms that are not acidic (all clay minerals have a high Al content).
Calcium carbonate (limestone) and calcium/magnesium carbonate (dolomite) have similar effects on pH. Dolomite is more soluble and thus has higher pH. However, the main thing driving their liming effect is their particle size and the pH of the soil (the more acidic the soil the more quickly the limestone or dolomite will dissolve). Dolomite contains Mg, so that is an advantage if Mg is required, but the Mg content of dolomite varies, depending on the source. I'm not sure about incorporating it to 6-8 inches though; it'll work much better if you incorporate it to 15-20 cm!
Gypsum is good for improving sodic soils or impermeable clays but not for saline soils.
Paul Nelson
Hi Paul,
Thanks for bringing your knowlege to Backyard food.
Barry
Post a Comment