什么是土壤pH值?

Soil pH is the measure of the acidity or alkalinity of soil from an extremely acid pH of 0 to an extremely alkaline pH of 14. A soil pH of 7 is neutral, neither acid not alkaline. Knowing the pH of your garden soil is important because soil pH controls the availability of nutrients and the number of microorganisms that improve soil structure. Plants can only absorb nutrients as electrically charged “ions” that attach themselves to clay and organic matter ions with the opposite electrical charge. Depending on the level of acidity or alkalinity of soil, varying amounts of different nutrients can be taken up by plant roots. At some pH levels, nutrients can become bound to other elements, or to soil, and become “locked out” and unavailable to plants. All the major nutrients are only freely available to plants within a narrow soil pH range of 6.5 to 7.5, where essential trace elements are also available, and aluminium is locked out. (见pH值见下表如果生长在pH值范围6.0-7.0),大多数蔬菜和外来仍将保持健康,但土豆和草莓做的最好,当pH值在5.5左右,和芸苔属植物和甜菜需要的pH值接近中性。然而,当土壤pH值低于4.5,其中主要营养成分的严格限制和微量元素有毒数量变为可用,或9.0以上,其中钙变得不溶一些植物才能生存。
On the pH scale, the “p” stands for potential, and “H” is the chemical symbol for hydrogen. The more acidic your soil is, the more hydrogen ions in your soil. As hydrogen ions are replaced by calcium ions on the charged sites, soil pH rises. Just to make it confusing, the pH scale is shown as a negative logarithm so that the more hydrogen ions in topsoil, the lower the pH number. Because soil pH is expressed as a logarithm, a pH of 6.0 is ten times more acid than a pH of 7.0, and a pH of 5.0 is a hundred times more acid than 7.0. Adjusting pH without the buffering effect of decomposed organic matter is difficult.
Testing for pH level
The only way to find the exact pH of garden soil is to test it. The Manutec Test Kit is quite economical to use, is available from most large nurseries. I’ve found this test kit to be very reliable and have used it since it was first developed by the CSIRO.
Testing involves taking samples of topsoil from across the growing area, and mixing themthoroughlyin a bucket. A small sample of the mixture is placed on a supplied sheet and moistened with a liquid dye. The damp mixture is then dusted with barium sulphate, and the resulting colour matched to a pH range on the kit’s colour chart.
***所有花园土壤应当至少每年测试,因为从植物根渗出物和有机物质释放氢离子的分解到土壤中,替换钙离子和酸度增加。

3回复“土壤pH值是什么?”

  1. Hi,
    I am setting up an above ground organic garden. I have bought expensice organic soil but the PH is around 8. How do you lower the PH levels?JB
    Elemental sulphur (sometimes sold as flowers of sulphur) is the easiest way to lower the pH of slightly alkaline soil. The following amounts will lower the pH of topsoil approximately 1 pH unit.
    If you have sandy soil apply 25 grams sulphur to each square metre of bed.
    对于质量好的壤土,适用于50克p.s.m.,并为重粘土,适用于100克p.s.m.在几个星期的再次测试土壤。如果土壤的pH值是高于7.5,挖通了顶部土壤一些马或牛粪。由于粪便发生故障,会释放氢离子,将取代钙离子对土壤交换点和降低pH值 - 但是这不会在一夜之间发生。- 林恩

  2. Hi! I’ve been reading your weblog for a long time now and finally got the bravery to go ahead and give you a shout out from Kingwood Texas! Just wanted to mention keep up the great work!

  3. I didn’t know that you could test your soil’s pH levels by placing your topsoil into a bucket and mixing it. Now that my brother has recently inherited our uncle’s farm, he would like to prepare the used soil so that he can start growing crops next year. Maybe he should learn how to manipulate his soil’s pH levels effectively.

发表评论

Your email address will not be published.Required fields are marked*