What's the most important nutrient for a plant?

The answer to this question is the one that is the most limiting at any given time. This is the law of minimum which means growth is dictated not by the total quantity of nutrients available, but by the scarcest.

Crop plants require 16 essential nutrients to complete their life cycle. Essential plant nutrients are divided into macro and micronutrients. Plants require macronutrients such as nitrogen (N), phosphorus (P), and potassium (K) in greater amounts compared to micronutrients which include zinc, copper, and molybdenum.

From the plant’s point of view, all nutrients are important for growth. Three macronutrients make up 90 to 95 percent of a plant by weight: carbon, hydrogen, and oxygen, and are supplied to plants by air. You could say that plants get most of their nutrients not from the soil but from the atmosphere, and as such, supply to plants is not a problem.

Ideally, the remaining 13 nutrients should be present in the soil in adequate amounts and proportion as required for optimum plant growth.

A nutrient deficiency in crops and pasture can occur for several reasons: when there are insufficient nutrients in the soil, where pH is significantly high or low, a notable nutrient imbalance exists, or when a lack of absorption or utilisation of nutrients by plants is a result of unfavourable environmental conditions.

The impact of a nutrient deficiency ultimately results in a loss of yield if not remedied. Where a poorly performing crop or pasture is identified, there may be a need to look at foliar nutrition.

The purpose of foliar nutrition is not to replace granular soil fertilisation as this is usually the most effective and economical means of supplying a plant’s macronutrient needs such as N and P. Rather, foliar nutrition is an excellent method of supplying plant requirements of micronutrients, while supplementing any N, P and K needs for short-term growth. Foliar nutrition can be a quick and effective management tool used to favourably influence the growth of plants that have been compromised by environmentally induced stresses such as adverse growing conditions and/or poor nutrient availability.

BENEFITS OF FOLIAR NUTRITION

• Rapid correction of a nutrient deficiency from the immediate uptake of applied nutrients.
• Accurate and even application of tiny amounts of key elements.
• Providing plants with micronutrients that may not be readily available in the soil.
• Can be combined with other selected foliar chemicals, minimising application costs.

Contact your local PGG Wrightson Technical Field Representative for advice on suitable foliar nutrition solutions for your crops.