Mineral Nutrients: Deficiency/Toxicity Symptoms, Sources, & Recommendations
For fruit trees, sufficient nutrients are required to maintain plant health but also to optimize fruit quality and yield. Deficiencies or excess levels can result in poor tree health and fruit quality. Soil nutrient availability to tree fruits is affected by tree characteristics (e.g. tree type, tree age, rootstock and scion), current and historic management practices, soil properties, soil type and climate conditions (i.e. moisture, temperature, extreme events and their frequency). There are also interactions among nutrients that will affect their availability. Meeting the nutrient requirements for tree fruits can be complicated. Shear and Faust (1980) can be consulted for additional details on nutrition for fruit and nut trees.
It should be noted that not all symptoms exhibited are always the result of a nutrient deficiency or toxicity. Water, temperature, mechanical injury, insects, nematodes, pathogenic diseases, herbicides and pesticide effects may cause symptoms similar to nutrition problems (Shear and Faust, 1980). The overall health of a tree must therefore be assessed before assuming problems are due to nutritional deficiency or toxicity.
There are 17 essential elements required by plants for growth (Mahler, 2004). Carbon (C), hydrogen (H) and oxygen (O) are obtained from the air, water or both. The rest are mainly taken up from the environment via the roots from the soil and thus can result in deficient or toxic levels in a tree due to the many reasons listed above. This section will cover the essential tree fruit nutrients obtained through soil and leaves:
Chlorine (Cl), Molybdenum (Mo), Nickel (Ni)
