STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS

Herbage, stubble and root weights were recorded for thirteen months on various leys subjected to two treatments differing in frequency of cutting. The root‐weight per unit area of a ryegrass/white‐clover ley was not affected by the frequency of cutting, but the less frequently cut plots had fewer tillers per unit area; the root‐ and stubble‐weight per tiller was, therefore, higher on the less frequently cut plots, On a cocksfoot ley the root‐weight was not affected by the cutting treatment, but in late summer and early autumn the stubble‐weight was considerably higher on the less frequently cut plots. When cocksfoot was grown in rows 2 feet apart, the more frequent cutting decreased both the root‐ and stubble‐weight. On grass leys root‐weights were heaviest in the summer and thereafter decreased until the following spring. The root‐weight of lucerne decreased from May to July, increased to a maximum in December and then decreased in weight. The changes in root‐weight under lucerne leys were mainly due to changes in the weight of the tap‐roots. The vertical distribution of roots was recorded, and, in the case of the cocksfoot in rows, the lateral distribution of roots is also given.