Urea and Ammonium Sulfate Fertilization of Potted Slash Pine under Two Soil Moisture Regimes

Abstract

Two‐year‐old slash pine seedlings grown in lysimeter pots, filled with a Spodosol, received three levels of N from two sources, (NH2)2CO and (NH4)2SO4, under two soil moisture regimes. Tree growth was greater when soil matric suction limit was set at 170 cm than at 500 cm of water. Slash pine growth response was greater to (NH2)2CO than (NH4)2SO4. Urea fertilization resulted in greater nutrient uptake by the seedlings during a 9 month period. On the other hand, (NH4)2SO4 favored higher nutrient leaching losses. In general, where growth response was best, nutrient uptake was greatest and leaching losses were least.