USE OF ROOT PRESSURES IN DETERMINING INJURY TO ROOTS BY CULTIVATION

Abstract

A rapid method is desirable for determining the injury to roots caused by cultivating plants in different ways and with different implements. No satisfactory procedure of studying injury to roots by cultivation has been developed. Cultivators form such irregular patterns, in cultivating soil, that direct determination of injury to roots is difficult. The method to be described is comparative. Positive root pressures are used in the method. Manometers are used to measure the pressures at which water is forced into the xylem. If some roots are cut, the pressure will drop until the rate of entry of water is sufficient to maintain a certain pressure, and in addition, to maintain a certain rate of water flow from the cut roots into the soil. It is logical to suppose that the degree of injury to roots (amount of xylem cut) would affect both the rate at which water is lost from the cut roots, and the root pressures. The writer is aware that the method is neither entirely satisfactory nor perfect. It is assumed, however, that the principles upon which the method Tests are sound, and that the results can give a better insight into injuries to roots resulting from cultivation than has previously been possible.