Pastoral agriculture, a significant driver of New Zealand’s economy, based on an introduced grassland ecology and technological advances

The New Zealand economy is export-driven and heavily reliant on the productivity of the pastoral sector. The transformation of native forest and tussock grassland ecologies to temperate grasslands occurred rapidly with the arrival of Europeans. However, this transplanted ecology required the development and use of plant, microbial, animal and management technologies for successful grassland farming. These have enabled New Zealand pastoral agriculture to compete effectively in international markets, without subsidies. The extensive list of plant-based and associated microbial-based adaptations, and the management strategies that have enabled the development of highly productive grasslands are described and reviewed. Credible science is required to inform the debate on the environmental impacts of pasture production to avoid misinformation proliferating. This needs transparent and objective integrity from the science community using funding that seeks no defined or preconceived outcomes. Critically, much of the success of New Zealand pastoral farming has been due to the willingness and ability of farmers to use, adapt, adopt and integrate new ideas and technologies into their farming systems. Historic, current and future challenges, and threats that impact on the productivity and sustainability of pastoral agriculture are described and the means to achieve further technology development to manage these is discussed

Legumes, herbs or grass for lamb performance?

Paper presented at the 58th New Zealand Grassland Association Conference, 21-24 October 1996, Oamaru.Lamb performance was evaluated for three consecutive summer–early autumn periods on ryegrass (Lolium perenne), white clover (Trifolium repens), chicory (Cichorium intybus), plantain (Plantago lanceolata) or lotus (Lotus corniculatus). Lamb liveweight gains, fasted liveweights at slaughter and hot carcass weights tended to be highest on legumes and chicory and lowest on plantain and ryegrass. Greasy wool weights were significantly higher on lotus and white clover than on chicory, plantain and ryegrass. Greasy wool weight was significantly related to fasted liveweight (R²=0.94–0.99). Protein (%) in herbage accounted for 83–92% of the variability in animal performance; food intake accounted for 57–69% of the variability and was negatively correlated with hemicellulose and cellulose (R²=97.2 and 80.9%, respectively). Thus quality of feed was more important than intake alone in determining animal performance.The authors would like to thank the Meat Research Development Council and the Foundation for Research, Science and Technology for funding

Pasture species effects on carcass and meat quality

Paper presented at the 58th New Zealand Grassland Association Conference, 21-24 October 1996, Oamaru.Increasing concerns about food quality and animal fat in the human diet have promoted research into the effects of different forage species on carcass quality and fat content. This trial investigated the effect on carcass composition and the intensity of sheep meat flavour and odour of five different pure pasture species: Grasslands Lancelot plantain (Plantago lanceolata), Grasslands Puna chicory (Cichorium intybus), Grasslands Huia white clover (Trifolium repens), Grasslands Nui high-endophyte perennial ryegrass (Lolium perenne) and Grasslands Goldie lotus (Lotus corniculatus). Although pasture species did affect meat quality and fat content, there appeared to be an inverse relationship with carcass weight: larger lambs had more fat, which was related to difference in body size and relative maturity rather that pasture species. Pasture species also influenced muscle ultimate pH, sheep meat odour, foreign odours, and flavours, but did not affect sheep meat flavour.The authors would like to thank the Meat Research Development Council and the Foundation for Research Science and Technology for funding

Uptake and residual value of 15N-labelled fertilizer applied to first and second year grass seed crops in New Zealand

This study was established to quantify the uptake of ¹⁵N-labelled nitrogen (urea) applied in the first and second years of perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea Schreb.) and browntop (Agrostis capillaris L.) seed crops, and the availability of the residual fertilizer N to a subsequent wheat (Triticum aestivum L.) crop under field conditions in Canterbury, New Zealand. Total recovery of ¹⁵N-labelled nitrogen fertilizer was approximately 100% when fertilizer was applied to the grass seed crops in spring. At harvest in year 1, grass straw and seed contained 34–47% and 6–15% of the applied N respectively; 27–35% remained in the soil (0–150 mm depth). Recovery of ¹⁵N in straw and soil was higher in fescue and ryegrass than in browntop, but recovery in roots was lower. At harvest in year 2, most of the 15N was present in the soil (30–37%) with only small amounts in the seed (0·7–1·0%), straw (3·6–4·9%) and roots (5·2–12·7%). In year 3, 2·5–3·5% of the residual ¹⁵N was recovered in the wheat and 18–26% in soil. Losses of ¹⁵N were minimal until ploughing after the second harvest, when there was an apparent loss of 11–35% of the fertilizer N applied. Losses were not directly associated with the fertilizer but indirectly following release of fertilizer N previously immobilized in plant roots and soil microorganisms. Small losses also occurred directly from autumn-applied N, probably through leaching. Despite these losses, overall there was an accumulation of fertilizer N in the soil organic pool, suggesting that ryegrass fescue and browntop seed crops have a role in contributing to the N fertility of the soil

Pasture response to fertiliser inputs under dairy grazing

Paper presented at the 58th New Zealand Grassland Association Conference 21-24 October 1996, Oamaru.Conversion of sheep and beef farms into dairy units has resulted in research on appropriate fertiliser rates and pasture species to achieve maximum productivity in minimum time. An onfarm trial involving five different mixtures of pasture species (based on fescue, prairie grass, an improved mixture, farmer mixture or original pasture), three rates of nitrogen as urea (0, 50 or 100 kg/ha of N applied half in March and half in August) and four rates of superphosphate (0, 250, 500 or 1000 kg/ha applied annually in March) was established in Canterbury on a Waimakariri sandy silt loam with border-dyke irrigation and an Olsen P of 5 pg/ml. The trial was grazed by dairy cattle as part of the general rotation; plots were not fenced individually. Pasture growth rates were measured pre- and post-grazing using a calibrated pasture probe. Botanical dissections ,were made seasonally and soil samples were taken annually. Pasture dry matter production was greatest from the prairie grass, “improved” mixture and the original pasture, reaching 13,000, 11,000 and 16,000 kg/ha in years one, two and three, respectively; production from the fescue increased with time; the ‘farmer’ mix performed poorly. Nitrogen at 50 kg/ha was generally sufficient to produce maximum yield increases. Increasing superphosphate increased production; this effect decreased with time. Change in Olsen P reflected superphosphate inputs and after three years of differential superphosphate application the Olsen P status was 8, 14, 27 or 42 (corresponding to 0, 250, 500 or 1000 kg/ha superphosphate).The Foundation for Science and Technology and the Technology for Business Growth programme

Effect of pasture species on internal parasites of lambs

Paper presented at the 58th New Zealand Grassland Association Conference, 21-24 October 1996, Oamaru.Increasing resistance of gastro-intestinal nematode parasites to anthelmintics and consumer resistance to the possibility of residues in animal products have prompted research on the effect of pasture species on nematodes and animal performance. Lambs (either infected with high rates of gastrointestinal nematodes or maintained nematode-free) were grazed on pure swards of chicory, high- or low-endophyte ryegrass, cocksfoot, tall fescue, lucerne, lotus, white clover or plantain. Infected lambs that grazed chicory had lower faecal egg counts and adult nematode populations, and higher carcass weights, than lambs grazed on plantain or the grass species; lambs that grazed legumes generally had intermediate counts, populations and weights. When kept parasite-free, carcass weights were up to 48% greater than in the nematode infected treatments. On farmlets run over 3 years, substituting 30% of the ryegrass area with lucerne or replacing the ryegrass with a multi-species mix consisting predominantly of bromes, tall fescue, phalaris, timothy and red and white clover, had no effect on gastro-intestinal nematode larvae, lamb faecal worm egg or adult nematode numbers. It is concluded that a diet of pure chicory affects internal parasite populations but the small proportion included in the farmlet studies had no effect.We wish to thank MRDC for funding Project 1 and AGMARDT for funding Project 2