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

Abstract

Sulphur trials were carried out in the hill and high country of the South Island from 1986/87 to 2000/01. Initial trials showed that sulphur fortified superphosphate fertilisers are more effective products than fine elemental sulphur and sulphur bentonite prills, both in terms of dry matter production and cost effectiveness. This is because Sulphur Super products contain sulphate sulphur and finer elemental sulphur. Sulphur Super Extra (28% S) was more effective in the short to medium term than Maxi Sulphur Super (50% S) largely because it contained more sulphate sulphur. It would be a more preferable option for development, particularly when used at above maintenance rates. It is preferable to apply these products on a biennial rather than a triennial basis to maximise dry matter, maintain better sward composition and to improve the chances of coinciding application with better growth conditions, most notably summer rainfall. Residual elemental sulphur oxidises with time, reducing the dependence on biennial application, although there is still a risk of temporary sulphur deficiency and a delay in response of clover to follow up topdressing if topdressing is left beyond 2 years. Herbage sulphur levels, in conjunction with observation of pasture composition and vigour are useful to indicate when sulphur fertiliser needs to be reapplied. Keywords: sulphate sulphur, elemental sulphur, sulphur bentonite prills, wet mix Sulphur Super, Maxi Sulphur Super, anaerobic nitrogen

A summary of research results on pasture responses to fertiliser and lime in the South Island hill and high country

“…Sulphur bentonite prills were effective after 6 months from application. In a further four trials at Mt Lindis (three sites) and Wairau Valley, with soil sulphate-S levels of 2-3 ppm, Craighead and Metherell (2006) reported a similar result to the original work at Mt Lindis, whereby biennial application of S resulted in 22% more pasture production than triennial application.…”

“…In the 1970s and 1980s, the focus switched to further identification of the most effective particle sizes of elemental S according to the frequency of application (Swanney et al, 1988;Craighead et al, 1990;Boswell and Swanney 1991;Boswell 1997;Craighead and Metherell 2006). Sulphur bentonite prills, similar to the granulated elemental S products currently available, were as effective as superphosphate and wet mix S superphosphate manufactured by adding molten elemental S to superphosphate (Craighead et al, 1990, Craighead andMetherell 2006). In general, the lesser the frequency of application of elemental S, the coarser the fraction required, to an upper limit of 500 -1000 µm.…”

Impacts of Phosphogypsum, Soluble Fertilizer and Lime Amendment of Acid Soils on the Bioavailability of Phosphorus and Sulphur under Lucerne (Medicago sativa)

“…We can conclude from the negative linear relationships exhibited between shoot dry matter yields and the shoot concentration of P and S ( Table 7 ), that P and S supply may not be limiting the yield in GM soil. This explanation is supported by the observed mean nutrient concentrations in the plant shoots, which are in ‘’adequate’’ range according to Craighead and Metherell; Morton et al; Venter et al [ 37 , 41 , 42 ]. This hypothesis is also in line with the TDM yield data in GM soil where no significant differences were found between the control and treated soils with P and S either through PS or PG, except PG (R3 + Lime).…”

“…The continuous increase in shoot uptaken S per pot with PG and PS rate increase indicates that lucerne was still S-uptake responsive to S supply even at high rates and that PG can be an alternative source for S fertilization as it performed almost identically to soluble fertilizer in both soils. The sulphur concentration of shoots under different PG and PS rates exceeded the optimum range of 0.18–0.22% S, suggested by Craighead and Metherell [ 37 ] for NZ high and hill country farms.…”