... small probe may have to displace soil particles of a diameter comparable to the probe. The result is that, particularly where there is an abundance of coarse sand or larger material, the ... Theoretical Biology 45,45 9-4 65. root size and frequency from one-dimensional con- HETT~ARATCH~, D,R,P, & OcALLAGHAN, J,R, 1978, solidation data -a mathematical model. Plant and Structural ... the annual rainfall, and on the nature of the crop. The soil must have sufficient mechanical strength to provide adequate anchorage for the plant throughout its development, and to prevent the...