An investigation of the effects of added sulphur and nitrogen to S-responsive and S-non-responsive soils from Canterbury on the digestibility and chemical composition of perennial ryegrass plants (Lolium perenne L.) : A thesis submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science (Hons) in the University of Canterbury

Abstract

Several recent studies (Stewart & Porter, 1969; Baker et al, 1973) on crop plants and grass forages have shown that responses on large nitrogen (N) fertiliser applications were often limited by a deficiency of sulphur ( S). An inadequate supply of S not only affects yields, but also the quality of the herbage produced. In view of this close relationship between N and S nutrition in plants, the present study was undertaken to examine the interaction of N and S fertilisation on the yield and composition of perennial ryegrass in a pot experiment. The present study therefore attempts to determine: 1. effects of N and S fertilisation on the top and root yields of the grass ; 2. the influence of N and S on the quality of the grass herbage - as reflected by the percentage digestibility, chemical composition of N and S fractions and the amino acid composition of these plants , and 3. the S nutrition status of the grass from information concerning the quantity of N and S in the herbage.