Tillage Effects on Soil Compactness and Wheat Root Morphology

Tillage systems influence soil physical, chemical and biological characteristics which in turn may alter, root characteristics, growth, and development. A three year study was conducted to investigate the effects of seven tillage systems on some soil (fine-loamy mixed, Typic Haplocambids) physical characteristics and wheat (Triticum aestivum L.) root morphology. Tillage treatments included moldboard plowing + disking (MD) as con-ventional tillage, chisel plowing + disk (CD), chisel plowing + rotary tilling (CR), chisel plowing (twice) + disking (2CD), plowing with a khishchi (a regional rigid cultivator) (KD), as non-inversion methods, and till planting with cultivator combined drill (TP), and no-tillage (NT) as direct drilling methods. Soil texture, bulk density (BD), organic matter (OM) and compactness (CI) were determined. At the depths 0-0.1, 0.1-0.2, 0.2-0.3 and 0.3-0.4m, root mass density (RMD) was obtained, root length density (RLD) was determined and average root diameter (RD), surface area density (RSD), and root fineness (RF) were calculated. A randomized complete block design consisting of four blocks (replications) was used. For all treatments, the upper layer (0-0.lm) contained a higher quantity of RMD, RLD and RSD, but the reverse was observed for the lower layer (0.3-0.4m). The upper layer (0-0. lm) contained almost 46 % of the total RMD (average of all treatments), while the second (0.1-0.2m) the third (0.2-0.3m) and fourth (0.3-0.4m) depths contained 23, 18.5 and 12.5 % of the total RMD, respectively. The average RLD of four depths fo