Know Your Nutrients: Phosphorus

Phosphorus (P) is a primary (macro) nutrient needed for plant development and growth throughout the entire life cycle – from seedling to maturity.

A macronutrient, phosphorus is necessary for cell formation and division, and plays a key role in photosynthesis and energy transfer in the plant. Phosphorus also stimulates root development and improves plant strength, seed production and overall quality.

All crops are sensitive to phosphorus deficiency due to its restricted mobility in the soil and its ability to get tied-up with calcium, aluminum or iron, depending on soil pH.

Watch for reduced growth; crops are sometimes stunted in the early stages, showing shortened internodes, smaller leaves and reduced shoot growth. Dull, dark green leaves are often an indication of phosphorus deficiency, while purpling of the leaves is an indication of an extended deficiency. A phosphorus deficiency can result in poor tillering, and delayed maturity and seed development in cereal and oilseed crops. Pulses are also very responsive to phosphorus.

Prairie soils are often low in phosphorus, a problem compounded by poor availability when soils are cold or poorly aerated. Availability of phosphorus can also be limited in soils with a high clay content, soils with a pH less than 5.5 (Fe2+, Al3+) or greater than 7.0 (Ca2+), and mineral soils low in organic matter. 

The Solution

Getting your crop off to a good, strong start will pay off throughout the growing season, with better vigor, increased disease resistance and earlier maturity. If your soil tests indicate a phosphorus deficiency, or conditions are less-than-ideal at seeding, consider a starter fertilizer.

A liquid starter fertilizer can help you combat early season stress, particularly when seeding into cold, wet soils, by providing seedlings with a source of easily accessible phosphorus. Starter P, can be used in-furrow to encourage early root growth and development, allowing seedlings to build a strong root system able to tap into water and side-banded fertilizer. 

If you are using a granular fertilizer for your starter, treat it first with TPA to protect phosphorus from tie-up and enhance its availability to the emerging seedlings.

Talk to your retailer or OMEX sales representative for more information on how to get your crop off to the best possible start this year. 


In our next post: Potassium – an important micronutrient that regulates cell activity.

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