Guide to High Phosphorous Levels in Soil

Plants need the following nutrients for healthy growth, nitrogen, phosphorous, and potassium. These nutrients facilitate plant growth, vegetation, and a healthy color. According to the GSFC website (owned by NASA), phosphorus is vital for plants during photosynthesis, helps plants breathe, provides energy transfer and storage, and helps plants use water in the soil. Phosphorus is a scarce nutrient, therefore, under fertilization is a key problem for plants, whereas overuse of phosphorous is a rare occurrence.

Why do plants need phosphorous in the soil?

Phosphorous is vital components for healthy plant growth, which encourages and assists in the photosynthesis process. Without proper phosphorous levels, plants cannot grow to their full potential, which translates into less than lush lawns, weak growing gardens, and stunted flower production.

Is too much phosphorous bad for plants or the environment?

According to the GSFC too much phosphorous is caused by over fertilization, as phosphorous is typically not an abundant nutrient found in soil. Over fertilization can be caused by organic and commercial fertilizers, which usually contain nitrogen, phosphorous, and potassium. However, the quantities that these nutrients come in will vary by brand, and by type of fertilizer. In an agriculture class, I took in college we studied the effects of over fertilization of phosphorous, which resulted into runoffs during heavy rain periods. Phosphorous increases the rate of which algae grow in lakes and rivers, which turns into a problem when the algae die and leave decayed matter in lakes. This is not easily cleaned via natural processes.

What happens when too little phosphorous is used during fertilization?

Plants that do not get enough phosphorous from the soil will grow weakly, have trouble reproducing, and have less crop yield. Recommended phosphorous levels for individual plant needs is determined by doing soil tests, which analyzes the nutrient levels naturally found in the soil. Commercial fertilizers have high concentrations of phosphorous, which is great for plant growth because soil typically does not contain enough phosphorous for healthy growth of mainstream crops.

What is a soil test?

Soil tests are conducted at local private soil testing labs, and at most universities that have an agriculture department. The soil test is vital for determining the levels of nitrogen, phosphorous, and potassium in your soil. Soil tests should be done three months before any major landscaping or planting project. The cost of a soil test is typically under $20, and from personal experience, much less per sample. Soil tests are costlier if you test for other elements such as pollution.

What are the differences of organic and commercial fertilizer?

Organic fertilizer comes from natural sources, but has fewer nutrients, and has a limited supply. The fewer nutrients translate into having to use more organic fertilizer than commercial. Commercial fertilizer is mass-produced and contains more nutrients per bag, thus allowing it to be less expensive for more product. Organic fertilizers are better for the environment because the risk of over fertilization is greatly reduced, whereas commercial fertilizers have more nutrients, which if not properly applied can easily lead to over fertilization.

Sources:

Personal experience taking agriculture classes in college and the pursuit of an advanced degree in agriculture economics.

http://soil.gsfc.nasa.gov/soilfert/npk.htm