Effect of lime and form of superphosphate on productivity of dryland pastures

Abstract

The effect of initial high lime (7500 kg ha-1), annual low lime (200 kg ha-1 yr -1 ), and no lime (all with 200 kg ha -1 yr -1 superphosphate) and dicalcic superphosphate (400 kg ha -1 yr -1 ) was compared over six years under sheep grazing and mowing on a low rainfall (800 mm), low pH (5.4), phosphorus (P) responsive (Olsen P 5) Matapiro yellow-grey earth (Duric palic) soil near Hastings, Hawke's Bay, New Zealand. High lime significantly increased pasture dry matter yield compared with other treatments in the first three years of the trial under both grazing and mowing. There were no differences in annual yield between the other treatments. The response to high lime in relation to no lime in the first 3 years was greater under grazing (21%) than mowing (12%). There was a greater A97032 number of legume plants per m 2 under mowing than grazing. The increase in pasture yield from high lime in the grazing trial was because of an increase in grass rather than legume yield. Legume yield averaged over all years was similar for the other treatments. There was no significant difference in the P concentration of grasses between treatments. Compared with low lime, high lime resulted in an initial increase of 0.9 pH units. Low lime and dicalcic superphosphate maintained the initial soil pH. The initial low Olsen P levels were only slightly increased by the low rates of P fertiliser used.After six years, P applications ceased on the dicalcic and low lime treatments, and the high lime plots were split into no P and P (20 kg ha -1 yr -1 ) applied. During the residual effect phase (Year 7-17), there was no difference in annual yield between no lime and high lime when P applications continued. For all treatments, where P was withheld, annual yield was lower than where P was maintained.Application of high initial rates of lime in this environment resulted in a short-lived (3 year) response in pasture yield despite a large increase in soil pH. At equivalent rates of P there was no difference in the effectiveness of single and dicalcic superphosphate. The liming effect of dicalcic was matched by applying the equivalent low rate of lime as a dry mix in addition to superphosphate.

Soil and pasture responses to lime on dry hill country in central Hawke's Bay, New Zealand

“…The application of 1.25 t lime ha -1 reported by O'Connor et al (1981) resulted in an increase in soil pH from 5.5 to 5.7 over 3 years, which was similar to the increase of 0.2-0.3 pH units from 1t lime ha-1measured in our trial. The lower rate of 0.2 t lime ha -1 used at the low rainfall Hawke's Bay site under sheep grazing (Morton et al 1998) only maintained soil pH at about 5.6 and had no significant effect on pasture DM production. Where lack of soil moisture limits legume growth, both soil pH and soil Al needs to be measured, and if soil Al is above the critical level, it can be corrected from application of 1t lime ha -1 or greater.…”

“…Application of an initial 6.3 t lime ha -1 to new pasture on a Pallic soil on the Wairarapa Plains (average rainfall 786 mm yr -1 ) increased soil pH to 6.3 and resulted in an average 19% response in pasture production over 5 years (Bircham & Crouchley 1976). On a flat site at Summerlee Station in coastal Hawke's Bay with old pastures (average rainfall 838 mm yr -1 ), 7.5t lime ha -1 applied initially to a Pallic soil increased soil pH from 5.5 to 6.3 and resulted in a 21% response in pasture production over 3 years (9% over 7 years) (Morton et al 1998). On steep hill country on a Brown soil with pH 5.5 under high rainfall (average 1400 mm yr-1 ) at Te Kuiti, 1.25 t lime ha -1 resulted in economic responses in ewe and lamb live weight and ewe fleece weight in the second and third year after application (O'Connor et al 1981).…”

Lime and Gypsum as Source Measures to Decrease Phosphorus Loss from Soils to Water

“…Morton et al (1998) and Fernandes and Coutinho (1999)). Although organic forms of P are not taken up directly by plant root systems, enzyme-labile organic P can be a large soil P pool and an important source of P for plants (Asmar et al 1995;George et al 2002;Hayes et al 2000;McDowell and Koopmans 2006;Shand and Smith 1997).…”

The agronomic effectiveness of lime‐reverted and dicalcic superphosphates: A review

“…7 9 11 Years 13 15 17 Fig. 2 Effect of superphosphate plus lime (squares) and dicalcic superphosphate (circles) on pasture production (Morton et al 1998). …”

“…The site was P responsive (Fig. 2) (Morton et al 1998) and the trial was balanced with respect to total lime and P inputs, (dicalcic superphosphate (50:50,400 kg ha ' yr 1 ) and low lime (200 kg ha" 1 yr') plus P (20 kg P ha"•' yr 1 )). From Year 8 the fertiliser inputs ceased, allowing the residual effects of the treatments to be examined.…”