Root Development of Intensively Cultivated Slash Pine

Abstract

AbstractRoot development of 12‐year‐old airlayers and seedlings of Pinus elliottii Engelm. was investigated after 10 years of cultural management on a moderately deep sandy soil. Cultural treatment included a factorial arrangement of irrigation vs. no irrigation, fertilization vs. no fertilization, and disking vs. a legume cover crop. Root surface area and root distribution were estimated from soil core samples, soil pits, and root excavations. Intensive culture significantly altered root surface area and root distribution. Airlayers and trees grown from seed did not differ significantly in total root surface area or in shoot growth. However, all seedlings had well‐defined taproots, while most airlayers had one to three heavy sinkers arching from the root collar to the maximum depth of rooting. Overall, 50% of the total root surface area was in the surface 0.3 m of the soil, while 6% was below 1.35 m. However, within a horizontal distance of 1 m from the bole of a tree, 42% of the roots were in the surface 0.3 m and 24% were below 1.35 m. Roots less than 2 mm in diameter made up 50% of the total root surface area. Results indicate that vegetative propagules develop equally as well as seedling stock and that both root profusely to a depth of 2.5 m.