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The Effects of Phosphate on Plants & Water

By Cleveland Van Cecil ; Updated September 21, 2017
Excessive phosphorus may cause damage to water quality.

Phosphorous is one of the 17 minerals required by plants for growth and reproduction. Phosphorous is derived from phosphate rocks and added to agricultural fertilizers. Plants require phosphorous during the growing period. Plants that have shallow roots and a fast top growth, such as lettuce and legumes, require large amounts of phosphorous.

Phosphate Ions

Plants absorb phosphorous, according to the California Fertilizer Foundation, in the form of phosphate ions. This form of phosphate helps store and transfer energy throughout the plant during photosynthesis. An issue with phosphate is that it attaches itself to the soil during a process of fixation. This often prevents the leaking of phosphate into water supplies, but makes it difficult to apply phosphate, as it must be done at the correct time for the roots of the plant to absorb the material.

Effects on Plant

Phosphate ions affect plant growth by increasing early growth and root formation. Phosphate, or phosphorous, also creates new cells in the plant and helps form DNA and RNA. Phosphorous also improves the plant's ability to absorb water and other nutrients from the soil. Phosphorous also encourages flower or fruit production.

Water Quality

Phosphorous, according to the University of Missouri Extension, is carried out of crop fields due to agricultural run off water. Phosphorous dissolves into water quickly and travels along with the flow. Excessive phosphorous in water causes eutrophication. Eutrophication, says Oklahoma State University, is the changing of the natural life balance in water. Phosphorous runoff causes increased algae growth, reduced water clarity, an unpleasant odor and taste to the water and toxins from blue algae. The increased algae population in the water may lead to a scarcity of oxygen in the water, which kills fish and other plants.