Effects of superphosphate, lime, and stocking rate on pasture and animal production on the Wairarapa Plains

Abstract

The effects of two stocking rates (15 and 22 ewes per ha), two rates of lime (0 and 6300 kg.ha'), and two rates of superphosphate (125 and 500 kg.ha' annually) on incisor teeth wear were measured on the Wairarapa Plains near Masterton. Greater wear of teeth was incurred in ewes stocked at the higher rate, and most wear occurred during winter and spring when soil ingestion was greatest. Levels of vitamin B 12 , selenium, copper, iron, and zinc in livers were determined on four treatments on completion of the trial. Vitamin B I2 levels in the liver were higher on unlimed pastures at the higher stocking rate.

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

“…The mean yield response for the first five years ( 16%) after the high initial rate of lime was applied to a soil pH with a initial soil pH of 5.4, was similar to the response reported by Bircham & Crouchley (1976) for a grazed Wairarapa yellow-grey earth ( 17%) over a similar time period and with a similar initial soil pH. The yield response from both these grazing trials was higher than that reported from 38 mowing trials on North Island sedimentary soils (Edmeades et al 1984).…”

“…However, the relative pasture yield response to lime measured by Bircham & Crouchley (1976) under grazing on a yellow-grey earth tended to be higher than the average response from mowing trials on yellowgrey earths (Edmeades et al 1984). The two most common techniques used in fertiliser trials are mowing cages within a grazed plot or small plot mowing trials.…”

“…Previous research on yellow-grey earth (Duric palic) soils on the east coast of the North Island of New Zealand has measured good responses in pasture yield and vigour to lime (Bircham & Crouchley 1976;During 1984;Edmeades et al 1984). However, these reports gave little information on the mechanism(s) for the lime Downloaded by [UOV University of Oviedo] at 04:17 03 November 2014 New Zealand Journal of Agricultural Research, 1998, Vol.…”

Effects of lime on pasture production on soils in the North Island of New Zealand

“…Bircham et al (1977) concluded from a 5 year study that "lime had no effect on stock performance or health that could not be reasonably attributed to increased available dry matter". Similarly, Thomson (1982) found a positive correlation (r = 0.6*) between lime response in milk yield and pasture production in 3 out of 4 years, suggesting that the increase in milkfat production from liming was largely the result of increased pasture production.…”

Value of sheep pasture, and the relationship between pasture production and stocking rate

“…The values are directly proportional to GM/stock unit(SU), assumed here to be NZ$25; ifGM/SU is different, pasture values should be multiplied by (new GM/25 which is invariably less than G~-by definition, increasing a sub-optimum stocking rate (S, given the new, dashed curve) towards the new optimum (SJ, must increase GM/ha, so G~must be greater than G;. The result will be little affected by the cost of new stock, but the relative advantage of increasing stocking rate will be even greater if the proportional pasture response is greater at high than at low stocking rates (as in Bircham & Crouchley 1976). If a specific shape is assumed for the GM/ha v. stocking rate curve, then the result of increased per capita production can be compared quantitatively with that from an increased stocking rate, and a value assigned to the former.…”