pH of Soil and Plant Nutrients

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mirafzalkhan
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pH of Soil and Plant Nutrients

Post by mirafzalkhan » June 9th, 2011, 12:16 am

Plants need the right combination of nutrients to live, grow and reproduce. When plants suffer from malnutrition, they show symptoms of being unhealthy. Too little or too much of any one nutrient can cause problems.
Plant roots require certain conditions to obtain these nutrients from the soil. First, the soil must be sufficiently moist to allow the roots to take up and transport the nutrients. Sometimes correcting improper watering strategies will eliminate nutrient deficiency symptoms. Second, the pH of the soil must be within a certain range for nutrients to be release-able from the soil particles. Third, the temperature of the soil must fall within a certain range for nutrient uptake to occur. The optimum range of temperature, pH and moisture is different for different species of plants. Thus, nutrients may be physically present in the soil, but not available to plants.
Pakistan’s soils are mostly dry and have high concentrations of calcium carbonate and a low content of organic matter, this high concentration of calcium carbonate (lime stone) makes our soil alkaline with pH near 8 or above.

Detail Map of Soil of Pakistan

Iron, Manganese, Copper, Zinc and boron deficiencies are very common micronutrient disorders in field and horticultural crop plants grown on alkaline soils of Pakistan.
Image
Nutrient availability and soil pH. Availability is least at the pH corresponding to the narrowest part of the band and most at the widest.

Lowering Soil pH
Adding Sulfur- The drawback is that it can takes months to affect the pH. It requires the activity of soil microbes to break it down first.
Adding Aluminum Sulfate or ammonium sulfate or ferrous sulphate to the soil. These work immediately.
You can use decayed vegetable matter, compost, stable manure and straw, etc. to increase the acidity of the soil. This method allows the pH to be slowly lowered over time, while increasing microbial life and improving the structure of your soil.
My Personal experience
Two weeks ago my Ixora plant was in very bad condition, pale leaves with dark green veins and no sign of flowering; these are signs of Iron deficiency. When it comes to my knowledge that actually higher soil pH will suppress the availability of Iron, I was thinking about changing the pH of soil. I feed the plant with one tablespoon of lemon Juice in one gallon (4.5 lit) of water. The results are incredible, now the plant is looking healthy with no signs of Iron deficiency and two bunches of flower.
I am agree that without knowing pH treating plant like this is not a right way specially for developed and old plants. The best way is a pH meter for checking the pH of soil, and then goes according to resulted pH.

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Re: pH of Soil and Plant Nutrients

Post by Izhar » June 9th, 2011, 10:32 am

commendable effort Mir Sb.

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Re: pH of Soil and Plant Nutrients

Post by Muhammad Arif Khan » June 9th, 2011, 11:22 am

Changing the PH in containers is easy But changing the PH of beds not so. I think I should try ammonium sulphate/ferus sulphate.

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Re: pH of Soil and Plant Nutrients

Post by Izhar » June 9th, 2011, 11:54 am

Point of discussion:

We are talking about the soil pH, plants are unable to absorb many nutrients under alkaline pH. As Brig. Sb. mentioned that changing the pH of a container/pot is rather easy but for a bed it may become very expensive as Ferrous Sulfate and Ammonium Sulfates are costly chemicals.

However, if we apply these deficient/unavailable nutrients by foliar sprays, will it be helpful?? and with out changing the pH of soil?

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Re: pH of Soil and Plant Nutrients

Post by mirafzalkhan » June 9th, 2011, 9:48 pm

Izhar wrote:Point of discussion:
We are talking about the soil pH, plants are unable to absorb many nutrients under alkaline pH. As Brig. Sb. mentioned that changing the pH of a container/pot is rather easy but for a bed it may become very expensive as Ferrous Sulfate and Ammonium Sulfates are costly chemicals.
The adding of Sulfur or ferrous sulphate is only feasible for established plants, where you have a fear to lose the plant. For larger areas it becomes very expensive.
Amount of sulfur needed to lower pH by 1 point for one acre
  • 400Kg sulfur in case of loamy soil
  • 600kg sulfur in case of clay
  • 135 kg sulfur in case of sandy soil
For large areas change of pH is Multi prom & long term strategy. Amending the soil with compost, manure and straw, etc. using acidic fertilizer such as ammonium sulphate or sulfur coated urea will lower the pH of soil over time.
Growers can produce own compost by using straws, leaves and roots of harvested crops.
Izhar wrote:However, if we apply these deficient/unavailable nutrients by foliar sprays, will it be helpful?? and with out changing the pH of soil?
Fertilizers are plant food which gives balance nutrients to the plant; if there is an extreme deficiency of one nutrient it cannot provide the extra quantity to overcome the problem.

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Re: pH of Soil and Plant Nutrients

Post by Izhar » June 10th, 2011, 10:04 am

from this following points were deduced by me:

1) Soil structure plays a vital role in the availability of nutrients.

2) Without correcting the soil structure by adding compost/organic matter, no matter how much fertilizer we use they have only very limited affect on the plant growth.

3) Our soils are mostly on alkaline side along with our water supply.

4) Foliar fertilizer work on those plants which do not have severe deficiency symptoms.

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Re: pH of Soil and Plant Nutrients

Post by mirafzalkhan » June 10th, 2011, 7:40 pm

Izhar, the points you deduced are all valid.
We can reduce the chance of deficiencies by preparing a good potting mix.
Coco-coir has pH 5.4-5.8. So adding of coco-coir & old manure will lower the soil pH.
My recipe is a mix of 1 lit coco-coir, 1 lit old manure & 3 lit soil. For calcifuge (acid loving) plants like Ixora, gardenia, roses etc. you will increase the quantity of coco-coir.

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Re: pH of Soil and Plant Nutrients

Post by tweedle2009 » June 18th, 2011, 12:31 pm

I think rain water is always aciding with PH lower than 7.Might be a reason why plants respond well to rainy water.

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Re: pH of Soil and Plant Nutrients

Post by mirafzalkhan » June 19th, 2011, 12:37 pm

tweedle2009 wrote:I think rain water is always aciding with PH lower than 7.Might be a reason why plants respond well to rainy water.
Yes adnan you are right, rain water is acidic in nature, but Pakistan is a low rain country and our plant gets most water by irrigation not by rain. These days Rainwater Harvesting System getting popularity Image
Source:Wikipedia
Pakistan also install Country’s First Urban Rainwater Harvesting System.

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Re: pH of Soil and Plant Nutrients

Post by Muhammad Arif Khan » June 20th, 2011, 12:34 pm

Why plants respond so well to rainy water is not its PH.
Lightening in clouds produces lot of AMMONIA Which is a ready to use food for plants.

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