The response of certainTrifolium spp. to calcium in sand culture

Summary The response to calcium ofTrifolium incarnatum, T. pratense, T. repens andT. hybridum was determined over the range 4 to 128 ppm calcium in sand culture.T. incarnatum showed the greatest response to calcium and was severely affected by low levels of calcium.T. hybridum was the least responsive to calcium and showed no significant response over the range tested, although a gradual increase in yield with increasing calcium was apparent. The responses ofT. pratense andT. repens were intermediate and differed significantly from those of bothT. incarnatum andT. hybridum. There was no significant difference between the response ofT. pratense andT. repens.The results are considered in the light of the ecologically observed edaphic tolerances of the species, and it is concluded that there is a marked relationship between response to calcium and edaphic tolerance of the species.In view of the differences in response to calcium recently demonstrated within the speciesT. repens, the magnitude of the differences between species shown here may not strictly apply to all varieties or populations of those species.