Abstract

A short term grazing trial was conducted on a central Taranaki dairy farm to study the effects on milk production of regular light dressings of nitrogen fertiliser (N), when compared to a single heavy application. Fifteen paddocks were allocated to each of two treatments. Both treatments consisted of 50 kg N/ha applied as either a single heavy application (50 kg N/ha) on 10 September (50x1 treatment), or frequent light applications (10 kg N/ha), applied progressively from 10 September directly after the following 5 grazings (10x5 treatments). Grazing of herd alternated between the two treatments with 6 paddocks of one treatment being grazed for 4 consecutive days. Total milksolids (MS) production data was obtained for days 3 and 4 of each grazing period. Total net herbage accumulation from August to mid-January was similar for the two treatments even though there was a difference in the pattern of accumulation. The 50x1 treatment resulted in 28% higher net herbage accumulation between 12 November and 11 January. Botanical composition of the pastures in September, November and December indicated that 50x1 treatment increased the ryegrass content in November. Total MS production was 400 kg MS/ha between 1 October and 10 January for both treatments. The monthly MS production differences between the treatments were small. The results show there to be no advantage in terms of MS production to light regular applications of nitrogen fertiliser when compared to a single heavy application.

AB, Pleasants, and RA Barton

Proceedings of the New Zealand Society of Animal Production, Volume 52, , 303-306, 1992