DIFFERENTIAL RESPONSE OF THE EDAPHIC ECOTYPES IN CYNODON DACTYLON (L) PERS. TO SOIL CALCIUM

Abstract

SummaryThis paper describes the differential response to calcium of the three edaphic ecotypes of Cynodon dactylon (L) Pers. growing, respectively, on non‐calcareous, moderately calcareous, and highly calcareous soils. A close correlation was discernible for the three populations with the habitats they occupy in nature. The population from a highly calcareous soil showed a better yield in calcareous soils than in non‐calcareous soils, though in highly calcareous soils it tended to decrease. The reverse was found to be the case for the population from non‐calcareous soils; the population from moderately calcareous soil showed an intermediate behaviour. Significantly different responses were found between the three populations with regard to mineral uptake in both calcareous and non‐calcareous soils. Although calcium uptake was higher in the case of plants from non‐calcareous soils compared to those from calcareous soils in experiments using calcareous and non‐calcareous soils, in extremely calcareous soil the reverse was found to be the case. The ash content and the uptake of calcium, potassium and magnesium, in general, increased with increase in soil calcium level. However, the calcium uptake of the populations from moderately calcareous or non‐calcareous soils and the magnesium uptake of the latter decreased in highly calcareous soils. It is concluded from the present studies that there are at least three ‘edaphic ecotypes’ within this species, each markedly different from the other in its physiologic‐ecological attributes and that the basis for the differentiation is chiefly due to their response to soil calcium.