The effect of sulphur fertilisation on grass growth and animal performance

Abstract

A previous study of S deficiency in Irish grassland was based on cutting trials carried out at 150 locations throughout the country. In order to determine if S deficiency would occur under grazing and affect animal performance, a grazing experiment with beef cattle was carried out on an S-deficient soil between 1981 and 1985. Results showed that when S was applied to pasture, the stock-carrying capacity was in creased, especially in late season. Samples of herbage taken prior to each grazing, together with data from a cutting experiment carried out nearby, showed that S fertilisation increased herbage yield by about 20% and also improved herbage quality as measured by its N / S ratio. These factors were probably responsible for the extra stock-carrying capacity of the S-treated areas. Sulphur fertilisation significantly decreased the molybdenum concentration in herbage from 1.85 to 0.87 mg/kg and significantly decreased blood copper of the grazing cattle from 0.56 to 0.49 |xg/ml.