SULFUR NUTRITION REQUIREMENTS OF PEACH-TREES

Changes in fertilizer and pesticide formulations plus success in reduc ing sulfur (S) emissions to the air from industrial operations have re duced the availability of S to peach trees in some locations. Peach (P runus persica L. Batsch) trees on highly leached acid sands have shown responses to S fertilization. The levels of total S required for S su fficiency is important to determine fertilizer needs. The 100 ppm S0(4 )-S requirement offered by some sources has been misinterpreted. Green house experiments with Nemaguard, Lovell, Montclar and Nemared rootsto ck seedlings resulted in the establishment of levels representing S de ficiency and sufficiency. The foliage and growth rates of rootstock se edlings in this experiment showed severe deficiency symptoms at 550-99 0 mu g S g(-1) DW. Sufficiency was achieved at 1400-2500 mu g S g(-1) DW.