Effects of soil air-filled porosity, soil matric potential and soil strength on primary root growth of radiata pine seedlings

Abstract

The effects of soil air-filled porosity, soil matric potential and soil strength on primary root growth of radiata pine (Pinus radiata D. Don) seedlings were examined in four soil textures ranging from coarse to fine. At low penetrometer resistance ( 0.20 m3 m−3. This relationship was independent of soil texture. Root elongation rate was half its maximum at a penetrometer resistance of 1.3 MPa. Increasing bulk density has a greater effect of increasing soil strength in coarse soil than in fine soil but decreasing soil water content has a greater effect on increasing soil strength in fine soil than in coarse soil.