A Greenhouse Study of Relations between Nutrient Movement and Conversion in a Sandy Soil and the Nutrition of Slash Pine Seedlings

Abstract

AbstractA greenhouse lysimeter study was made of plant‐soil‐water relations determining the availability of N, P, and K from different fertilizer sources to slash pine seedlings growing in Lakeland fine sand.Leachate analyses showed that virtually all NH4NO3 and KCl applied to the surface of the soil in bare lysimeters was leached from the upper 12 inches of the profile within 4 weeks when water was applied at the rate of 4 inches per week. At the same watering rate, urea‐formaldehyde and potassium calcium pyrophosphate showed substantially lower leaching losses. No significant leaching of P was observed.The presence of pine seedlings in the lysimeters prevented or reduced leaching of N and K at low and intermediate watering levels but at the high level the seedlings were relatively ineffective in reducing nutrient losses.Chemical analyses of the seedlings showed greater nutrient uptake over a 17‐week period from the readily soluble N and K sources at 1 and 2 inches of water per week. At the higher watering rate (4 inches per week) more N and K was taken up from the slowly soluble sources. These differences were reflected in seedling growth.Fertilized seedlings transpired from 30 to 80% more water than the controls, yet their water use per gram of dry matter produced was 25 to 50% less than that of control seedlings.