The Establishment and Growth of Loblolly Pine Seedlings on Compacted Soils

Abstract

AbstractLoblolly pine (Pinus taeda L.) seedlings were grown from seed on core samples collected from surface soils of Lakeland loamy sand, Coxville loam, and Bayboro clay that had been compacted, puddled, or loosened. Seed germination was not affected by soil type or treatment, but seedlings became established with difficulty on clay cores and on heavily compacted cores of lighter texture. Top height and root length were not related to soil type, but seedlings grown on clay were significantly lighter than the other groups. Loosening the soil from its normal structure reduced growth on light‐textured soils, but stimulated it on clay soils. Compaction, whether at 3.5 or 10.5 kg cm‐2 of surface pressure, greatly reduced seedling size and weight. Small growth differences between compaction treatments indicated that even the smallest pressure applied reduced soil aeration and increased mechanical impedance to root growth to infavorable levels. There were negative linear relationships between root weight and penetration and densities ranging from 0.8 to 1.4 g cm‐3.