soil moisture level influence uptake. Analysis 

 results reflect not only what is present in the 

 soil, but also how available these nutrients 

 have been to the plants. For this reason, leaf 

 tissue analysis is a much more reliable 

 indicator of nutrient levels in the plant itself. 



Effects of Water on Nutrient 

 Availability 



All important elements, even under 

 optimal conditions, must be dissolved in water 

 (in solution) in order to be taken up by roots. 

 Fertilizer application is frequently suggested 

 just before a light rain or to be watered in for 

 this reason, as well as to avoid volatilization of 

 the materials applied. Therefore, since all 

 plants require water, drought stress not only 

 weakens trees directly but also affects nutrient 

 availability. 



How Nutrients are Applied 



In general, the long-term beneficial effects 

 of fertilizers result from applications to the soil. 

 Foliar applications, which apply a nutrient 

 solution onto the leaves or fruit, generally are 

 prescribed as a rapid way to green up the 

 leaves, add calcium to fruits, or cure 

 deficiencies quickly. Also, form of the nutrient 

 element - N in the ammonium form vs. the 

 nitrate form, for example - also affects 

 availability. Crops vary in which form of what 

 element is best utilized. (This issue will be 

 discussed in "Part III" of this series of articles.) 



These are the major non-economic factors 

 that influence nutrient management for 

 peaches. Because each orchard is different, 

 programs need to be defined for individual 

 orchards and perhaps each orchard block as 

 well. 



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Fruit Notes, Volume 61 (Number 4), Fall, 1996 



