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Improvement in nutritive characteristics resulting from breeding perennial ryegrass (PRG) cultivars used in Australia from the 1970s to the present day was quantified in a grazed field experiment in south-western Victoria. The experiment was sown in May 2014 with measurements undertaken over 3 years. The experiment contained 36 PRG treatments (cultivar–endophyte combinations), which were replicated four times, with herbage nutritive characteristics measured at each grazing. The treatments differed in estimated metabolisable energy (ME), crude protein and neutral detergent fibre (NDF) concentrations at each harvest date. The decade of cultivar release had little effect on the ME or the NDF concentration of the cultivars released from 1970s onward. Early season diploids had a lower ME concentration than did later-maturing diploid cultivars (11.0 vs 11.4 MJ/kg DM), predominantly due to a lower ME concentration in late spring and early summer (10.3 vs 11.1 MJ/kg DM). The tetraploid cultivars had a higher ME concentration (11.8 vs 11.4 MJ/kg DM) and a lower NDF (480 vs 505 g/kg DM) concentration than did the mid- and late-season diploid cultivars. These differences are likely to be of economic importance at the farm level. The genetic gain in nutritive characteristics of perennial ryegrass cultivars has not been quantified in dairy environments in Victoria. This work aimed to quantify these improvements, but found that most cultivar differences could be attributed to cultivar maturity and ploidy factors, with little effect of the decade of release. These cultivar differences are likely to be of economic importance at the farm level. [ABSTRACT FROM AUTHOR]

Copper (Cu) is an important heavy metal to be considered in soil contamination, because high concentrations of copper in soil produce toxic effects and may accumulate in plant tissues. In Australia's oldest sewage irrigation farm, located in Werribee, Victoria, soil in the land filtration area is contaminated by Cu. However, Cu content in herbage tissues is in the normal range and has been trending downward since 1979. Therefore, studies on the sorption capacity and sequential extraction of Cu in soil at the Werribee Farm is of significance, not only for better understanding the mechanism of transport, chemical processes, and plant uptake of Cu, but also in providing information for the practical management of sewage farm soils. Methods of combining sorption isotherms with sequential extraction procedures were adopted, and the results showed that the soil in the land filtration area at Werribee Farm has a high sorption capacity for Cu, and distribution coefficients, K f of Cu, were 629 L kg -1 in surface soils (0–20 cm) and 335 L kg -1 in subsurface soils (20–40 cm). The sequential extraction fractions demonstrate that exchangeable and carbonate fractions are very low, only comprising 3.49 to 5.49% of total copper. The other fractions are also discussed. This characteristic of Cu in soil is related to the low concentration of Cu in plant tissues. [ABSTRACT FROM AUTHOR]