Development of sunny-facing high country using different forms of sulphur fertiliser

Abstract

<jats:p>Different forms and rates of sulphur (S) fertiliser were examined for developing oversown tussock in sunny-lying South Island high country. Sulphur significantly increased dry matter (DM) production (p = 0.0001). Soluble forms of S were most effective in the first year, and lasted 15-18 months. Sulphur bentonite prills took 6 months to be effective, but over time the higher rate (56 kg S/ha) was one of the better treatments. Elemental S on its own was ineffective even after 3 years. The combination of soluble sulphate and finely divided elemental S (56 kg S/ha as sulphur super extra) was the most effective treatment. In the first 2 years alsike clover was the most dominant pasture species. Native grasses became dominant in the third year. After retopdressing at the beginning of year 4, pasture production again improved, particularly in those treatments containing only soluble forms of S. White clover was the dominant pasture species in the fourth year. Sulphur significantly increased soil-available nitrogen levels (p = 0.0001). Keywords development, sunny hill country, sulphate sulphur, elemental sulphur, sulphur super extra, sulphur bentonite prills, available nitrogen</jats:p>

The impact of the form and frequency of sulphur on pasture yield and composition in South Island high country

“…Therefore product S release will be slightly less than wet mix SSX. 5 Product fineness varies with manufacture conditions, pre 1994 products were coarser than post 1994 products, hence a range is given 6 Particle size will vary with raw material months (Craighead et al 1990) allowing more time for coarser fractions of S 0 to oxidise. After reapplication, particle size was less important as there was still residual S 0 oxidising from previous applications, hence differences reduce with time.…”

“…Two such products were S 0bentonite clay prills (containing 85-90% S 0 and 10-15% Na bentonite), and wet mix Sulphur Supers where molten S is added to Super during manufacture so that fine S 0 is incorporated in the granule. These typically contained up to 28-30% total S. The efficacy of such commercial and experimental products has been previously reported (Craighead et al 1990;Swanney et al 1988;Sinclair & Enright 1983).…”

“…A 6 year trial (L1) compared the efficacy of a range of 'triennial (Craighead et al 1990)' S treatments including a nil S control, dry mix Sulphur Super Extra (SSX, 0-7-0-28), Tiger 90 (S-bentonite 90% S) and S 0 . A 4 year trial (L2) compared the efficacy of a wet mix SSX with Maxi Sulphur Super (Maxi, 0-5-0-50), Terrasul (Sbentonite 90% S) and S 0 applied biennially.…”

Chemical fractionation to characterize changes in sulphur and carbon in soil caused by management

“…Soil samples (0–7.5 cm depth) were collected with a 2.5‐cm diameter probe with 20 soil cores from each replicate, which were bulked. All S treatments produced marked growth responses in legume yield in the first 4 years of the trial (Craighead et al ., 1990).…”

“…They attributed this increase in C to an increased biological fixation of N 2 by legumes that were no longer deprived of S. This led in turn to an increase in pasture dry matter and hence greater organic C input to soil. At the Mt Thomas site, S fertilization markedly increased pasture production (Craighead et al ., 1990), and this has resulted in most of the applied S accumulating in organic forms. After many years of pasture improvement, the rate of accumulation of organic S in the soil decreases, and mineralization becomes a significant source of S for pasture plants (Sakadevan et al ., 1993).…”