No abstract

Nitrous oxide (N2O) emissions are subject to intra- and interannual variation due to changes in weather and management. This creates significant uncertainties when quantifying estimates of annual N2O emissions from grazed grasslands. Despite these uncertainties, the majority of studies are short-term in nature (<1 year) and as a consequence, there is a lack of data on interannual variation in N2O emissions. The objectives of this study were to (i) quantify annual N2O emissions and (ii) assess the causes of interannual variation in emissions from grazed perennial ryegrass/white clover grassland. Nitrous oxide emissions were measured from fertilized and grazed perennial ryegrass/white clover grassland (WC) and from perennial ryegrass plots that were not grazed and did not receive N input (GB), over 4 years from 2008 to 2012 in Ireland (52°51′N, 08°21′W). The annual N2O-N emissions (kg ha−1; mean ± SE) ranged from 4.4 ± 0.2 to 34.4 ± 5.5 from WC and from 1.7 ± 0.8 to 6.3 ± 1.2 from GB. Interannual variation in N2O emissions was attributed to differences in annual rainfall, monthly (December) soil temperatures and variation in N input. Such substantial interannual variation in N2O emissions highlights the need for long-term studies of emissions from managed pastoral systems.

No abstract

No abstract

The Kuriwao Farm Action group has followed a process of continued monitoring and evaluation to improve sheep production. Involvement in this project has given the farmers meaningful information for all members to use as part of their decision making. As a group they have evaluated options such as pasture cultivars and renovation strategies, sheep genetics, chemical topping and hogget mating. The benefit to all members has been faster progress and less costly mistakes. Many new technologies such as scanning, improved pasture species, chemical topping and improved animal genetics and nutrition are now standard practice on these properties. The farmers made bigger gains in the last five years as the impact of new sheep genetics and crossbreeding combined with a greater understanding of the importance of ewe nutrition in both lamb numbers and growth. The original objectives of the project were to improve lambing percentage, pasture performance and lamb growth. On average, lambing percentage improved by 2% per year for the last nine years (and 3% per year since 1996). Average lamb growth rate lifted by 8.6g/d/year (5% per year). Keywords: genetics, learning, nutrition, pasture improvement, pasture production, sheep production