The effects of different levels of nitrogen and sulphur on the yield and composition of tussock grassland

Abstract

Nitrogen and sulphur were applied to undisturbed fescue tussock grassland to determine whether these nutrients interacted in grass production, at what levels of application the interaction occurred, and what changes in the proportions of the species took place.Total herbag~ yield for the period from March 1959 to March 1960, measured from 4 cuts, was significantly increased to the same extent by an application of either 20 Ib or 100 Ib sulphur per acre when 400 lb nitrogen per acre was also applied. The total fertiliser was applied in 2 split dressings in January and October.Where both nitrogen and sulphur were applied together, Y orkshire fog showed a superior yield response to that obtained with sweet vernal. Where sulphur was not applied and nitrogen was not limiting, sweet vernal was the superior competitor for the nitrogen and available sulphur. The combined yield of brown-top-danthonia was less than that of sweet vernal at all cuts except the final one, when this category showed a changed pattern of response to nitrogen and sulphur application. Changes in the seasonal pattern of response of the species to the fertiliser application are discussed.Reduced losses of standing herbage dry matter over the winter under high levels of nitrogen and sulphur application are recorded.

Responses of grasses to sulphur fertilisers

“…At the high level of nitrogen the low level of applied gypsum gave significant increases throughout, but the number of tillers and the weight of cocksfoot at the high level of gypsum were significantly less than at the low level of gypsum. The response to nitrogen and sulphur of resident Yorkshire fog and the response to nitrogen alone of sweet vernal were very similar to those reported by Vartha (1963) from a similar experiment on well-drained Kakahu soil in the same locality.…”

“…Walker and Williams (1963) and Jones (1963) have reported that annual grasses in Californian soils responded to sulphur after an increase in nitrogen supply. This has also been demonstrated for perennial grasses in New Zealand by O'Connor (1959O'Connor ( , 1961 and Vartha (1963), who have also shown the occurrence of interspecific competition for scarce sulphur among the resident grasses of mid-altitude tussock grasslands after improvement in nitrogen supply. This paper deals with the following aspects of sulphur nutrition: (a) comparisons among grass species in response to applied sulphur in sulphur-deficient soils; (b) influence of level of available nitrogen on the response of grasses to applied sulphur; (c) influence of form of available nitrogen on the response of grasses to applied sulphur; (d) The possible effect of mineralisation of organic sulphur after cultivation on the responses of grasses to applied sulphur.…”

“…Identical comparisons of sulphur and nitrogen fertiliser levels had been made on cocksfoot single plants in the field (Experiment 2), on cocksfoot, Yorkshire fog, and sweet vernal in pots of Kakahu hill soil (Experiment 5), and on the naturalised grasses, principally sweet vernal and Yorkshire fog, occurring on the same soil (Vartha 1963). One harvest was available from Experiment 2, two harvests from each of three grasses in Experiment 5, and three harvests of mixed herbage from the field experiment of Vartha (1963), making 10 series in all. In these 10 series, protein nitrogen content was not significantly affected by nitrogen or gypsum treatment, the mean value being 1.19 percent of dry weight.…”

“…Experiments were of three Herbage from several experiments reported here. as well as that from harvests of the field experiment reported earlier (Vartha 1963). was analysed for total nitrogen.…”

“…diameter were taken with minimum disturbance from the Kakahu hill soil site (Vartha 1963) and shaped to fit pots. Two-tillered plants of Yorkshire fog and sweet vernal were vegetatively propagated from plants collected at that site.…”