Sodium fertilizer application to pasture. 9. The effects of combined or separate applications of sodium and sulphur fertilizers on herbage composition and dairy cow production

An experiment was conducted to examine the response of herbage grazed by da iry cows to sodium fertilizer applied with or without sulphur fertilizer. T he residual effects of applying sodium fertilizer in the previous year were also evaluated. The application of sodium or sulphur fertilizer did not af fect herbage growth or height, but the application of sulphur fertilizer in creased crude protein content of herbage. The increase in sodium content wi th application of sodium fertilizer was small, but was greater when sodium fertilizer had also been applied in the previous year. Herbage potassium wa s increased when sodium fertilizer was applied in the year of the experimen t, but only if sodium had not been applied in the previous year. Applicatio n of sulphur fertilizer increased herbage sulphur content and reduced the c ontents of boron, chromium, molybdenum and nickel. Cows grazing pasture tha t had received sodium fertilizer had increased milk yields and the content of lactose in milk, whereas those grazing pasture that had received sulphur fertilizer application had reduced milk yields and the content of milk fat .