Fertiliser and lime effects on some southern North Island hill pastures

Eruptions from Ruapehu volcano on 11 and 14 October 1995 covered large portions of the central and eastern North Island, New Zealand, with tephra, including c. 17 000 km 2 of land in primary production. The thickness and distribution of the tephra was mapped and it was chemically characterised in order to predict its effects on soil fertility. Tephra from the two eruptions contained 3.0 and 0.7 % by weight sulphur (S), respectively, 67-55 % of which was in an elemental form (S 0 ), with the remainder in the form of soluble sulphate. The S 0 in the tephras was derived from the former, hydrothermal Crater Lake system in the active vent of Ruapehu. Sulphate was derived from Crater Lake water and gases erupted with the tephra. Field and glasshouse investigations showed that the tephra significantly raised soil sulphate levels. The initial elemental S component was very fine grained (65-99% < 125 µm diameter) and oxidised rapidly causing depression of soil pH. In a transect of northern Rangitikei soil and pasture samples, S A97004

Section: Glasshouse Trialssupporting

confidence: 69%

Impact of Ruapehu ash fall on soil and pasture nutrient status 1. October 1995 eruptions

Cronin

Hedley

Smith³

et al. 1997

“…Mg concentrations in leafblades were higher on the limed hillside (except for the March harvest). Rates of lime application higher than those here (5000 kg/ha compared with 1800 kg/ha here) reduced Mg concentrations in herbage (Lambert & Grant 1980). Exchangeable Mg and Na concentrations in topsoil (shown in Table 2) were higher on the limed hillside; exchangeable K and Ca concentrations were similar for both hillsides.…”

Section: Seasonal Trendsmentioning

confidence: 77%

Element composition of ryegrass and white clover leafblades — seasonal variation in a continuously stocked pasture

Reay¹,

Waugh²

1983

Concentrations of 12 elements-organic-N, Ca, Mg, K, Na, P, Cl, Fe, Mn, Zn, Cu, and plantSi-have been determined monthly in ryegrass and white clover leafblades from a continuously stocked hill pasture. Seasonal concentration changes (up to 2-fold) were greatest for organic-N, K, Ca, Mg, Zn, and Mn in ryegrass leafblades and for Ca and Mg in clover leafblades. Leafblades of both ryegrass and clover from sheeptracks had slightly higher organic-N (about a fifth) and lower Ca concentrations than leafblades from the intervening slopes. The concentrations of organic-N, K, and P were correlated with each other and were inversely correlated with Ca and Mg. It is likely that much of the seasonal variation in element concentrations was related to variation in the seasonal supply of N.

“…1), possibly reflecting the higher vulnerability of this soil (Acidic Orthic) to sheep treading (Hewitt & Shepherd 1997). Cattle treading can have a more detrimental impact on earthworm populations (Lambert 1986) in comparison with the lower individual treading pressures of sheep (Greenwood & McKenzie 2001), and the contribution of earthworms to ecosystem services may not be observed under intensive cattle pastures.…”

Section: Discussionmentioning

confidence: 99%

Influence of phosphorus inputs and sheep treading on soil macrofauna and mesofauna in hill pastures

Schon

Mackay

Gray

et al. 2011

Earthworm abundance increased and Oribatida abundance decreased on a Brown soil with increasing inputs of phosphorus (P) fertiliser and sheep stocking rates. To determine if the same response to increasing management intensity is found in Allophanic soil, samples were collected from a long-term sheep-grazed trial with two contrasting management regimes, low and high intensity. As pastures on the Allophanic soil became more productive and were grazed with more sheep, there was a tendency for earthworm abundance to increase and oribatid abundance to decrease. Both these trends were consistent with those on the Brown soil, supporting the potential of earthworms and Oribatida as biological indicators. Oribatid mites, which produce nutrient rich faecal pellets, were positively correlated with porosity. The higher earthworm abundances in more intensive sheep grazed pastures may have a positive influence on ecosystem services such as air and water movement, and organic matter incorporation.