Incidence of nodal rooting and plantlet survival in spreading red clovers

Abstract

Red clover (Trifoolium pratense L.) can provide high quality summer feed but has declined in popularity owing to its poor persistency in temperate grazing systems. From 1991 to 1996 the incidence of nodal rooting of prostrate selections of red clover was quantified and the survival of the resulting plantlets was tracked over time, under grazing conditions. Three field experiments were conducted using Astred, Grasslands Pawera, F2419 and Grasslands Turoa selections of red clover. The main experiment comprised 3 harvests (plants and plantlets dug up) of 3 red clover selections, in a randomised complete block design with no grazing. The subsidiary plantlet survival experiment followed the life and death of 160 plantlets from the three selections under rotational grazing to 5 cm, over a period of 48 weeks. The numbers of plantlets produced per parent plant of each selection were 37, 16 and 5 for Astred, F2419 and Turoa, respectively (P~O.001). Astred produced significantly larger plantlets (PcO.001, mean = 130.6 g/ DM/plantlet) over 7 months than F2419 and Turoa -(means-=.31.5.and.lO~g/DM/plantlet,.r.espec~y)~ At week 48 plantlet survival ranged from 84% (Astred) to 27% (Turoa) (P~O.001). The experiment at Ballantrae consisted of oversowing 20 kg/ha of 2 clover selections (Pawera, creeping selection) into sprayed pasture in 1991. Plant density, pasture composition and herbage accumulation were measured until 1995, with all treatments continuously stocked at 16 ewes/ha. Pawera contributed only 1.1% to herbage accumulation during the second year when oversown on hill country and ~-disappeared from the sward-soon-after.XIn-averagei the creeping selection made up 3.2% of the total sward herbage accumulation from years 2 to 5. It was concluded that the spreading red clovers represented by Astred and F2419 selections have the potential to be more persistent than crown red clovers under grazing. Keywords: nodal rooting, plantlet, spreading red clover, Trifolium pratense