Soil + Weather + Fertilizer = Leaf Analysis

A leaf's nutrient concentration is not an exact mirror reflecting your soil's available nutrient concentrations. Think about it. A plant's the nutrient concentration is a combination of many factors: plant available soil nutrients, growing conditions and weather. These factors all affect leaf nutrient concentrations prior to you collecting a sample.

Your leaf analysis report provides you with a picture of the nutrient concentration at the time of sampling. Actively growing plant's nutrient levels are not constant. They vary from month to month, day to day and even hour to hour. Before adjusting your fertilizer program based on one tissue analysis report, consider the factors listed below. These factors can reduce or favour plant nutrient uptake. Improving your crop's growth and nutrient levels may require more than just adding more fertilizer. Following up with a second analysis can help in diagnosing trends and assist in making management decisions.

Factors reducing a plant's nutrient uptake:

• High relative humidity and reduced transpiration
  
• Soil compaction
  
• Water not draining from soil surface
  
• Plough pan
  
• Too low or too high soil pH
  
• Water logged soils
  
• Dry soils
  
• Cold soils
  
• Anaerobic soil conditions
  
• Restricted root growth
  
• Damage by mice, infestations with nematodes, and root or vascular diseases
  
• Excessive fertilizer applications salt injury or antagonism between some nutrients

Factors favouring a plant's nutrient uptake:

• High transpiration rates, low relative humidity
  
• Good soil structure
  
• Good oxygen supply to roots
  
• Optimal soil humus and adequate supply of organic matter
  
• Optimum soil pH
  
• Moist soils
  
• Warm soils
  
• Intensive rooting & deeply penetrating root systems
  
• Adequate soil available plant nutrients