Effect of second pond dairy effluent applied in spring to silage regrowth of perennial ryegrass based pasture in southern Australia. 2. Changes in nutritive characteristics and mineral content
J. L. Jacobs A B and G. N. Ward AA Department of Primary Industries, 78 Henna Street, Warrnambool, Vic. 3280, Australia.
B Corresponding author. Email: joe.jacobs@dpi.vic.gov.au
Australian Journal of Agricultural Research 58(2) 145-151 https://doi.org/10.1071/AR06160
Submitted: 12 May 2006 Accepted: 3 November 2006 Published: 22 February 2007
Abstract
The 2-pond effluent systems used by the majority of dairy farmers in southern Australia result in the collection of liquid effluent in an aerobic second pond. This liquid effluent contains a wide range of nutrients that have the potential to significantly affect the nutritive characteristics and mineral content of forages.
The effect of applying second pond dairy effluent to perennial ryegrass based pasture following harvesting for silage over a 3-year period was measured. Effluent was applied at 6 rates: 0, 15, 30, 45, 60, and 75 mm following a spring silage harvest each year, with changes to nutritive characteristics and mineral content determined at each subsequent grazing.
Analysis of the effluent applied showed that on average, over the 3 years of application, the effluent contained 31, 454, 20, and 149 kg/ML of phosphorus (P), potassium (K), sulfur, and nitrogen, respectively. In addition, the effluent contained 152 kg/ML of calcium (Ca) and 225 kg/ML of magnesium (Mg).
Changes in nutritive characteristics as a result of effluent application were primarily restricted to the first grazing after application. The metabolisable energy content of herbage at the first grazing in Years 1 and 2 was unaffected by effluent application; however, in Year 3 there was a linear increase of 0.0051 MJ/kg dry matter (DM).mm of applied effluent. In contrast, effluent application had a positive linear effect on pasture crude protein (CP) content at the first grazing in all years. In Year 1, CP content increased by 0.083%/mm of applied effluent, while for Years 2 and 3 the increases in CP content were 0.044 and 0.029%, respectively. In all years, there was a negative linear effect on water-soluble carbohydrate content at the first grazing after effluent application. For Years 1, 2, and 3, responses were –0.138, –0.066, and –0.022%/mm applied effluent, respectively.
The P content of pasture was higher at the first grazing following effluent application at rates of 60 and 75 mm in each year compared with the control and the 15 mm application rate. Potassium concentrations were increased with effluent application at rates of 45, 60, and 75 mm in all 3 years in comparison with the control at the first and second grazing after application. In Year 1, Mg content of the pasture was lower for the control, 15, and 30 mm treatments than for the 2 highest application rates at the first grazing after application.
This experiment has highlighted the potential of using second pond dairy effluent following pasture harvesting for silage to maintain the CP content of pasture in late spring. The high mineral content of effluent led to increases in the concentration of several these minerals and, while the ratio of K to (Ca + Mg) was substantially increased, it is unlikely that effluent application in late spring and the concomitant increases would lead to animal metabolic problems. Coupled with the observed increases in DM yield, the increase in CP content provides greater flexibility in feeding options to bridge feed shortfalls before summer forage crops becoming available on dryland dairy farms in southern Australia.
Acknowledgments
The authors acknowledge the Victorian Government, Dairy Australia, and the Geoffrey Gardiner Foundation for providing financial assistance for this study. We also thank DemoDAIRY for the use of land on their farm to undertake the study. The technical support of Stewart Burch, Troy Jenkin, and Phillip Maskell, and biometrical analyses by Gavin Kearney are also acknowledged.
Bolan NS,
Horne DJ, Currie LD
(2004) Growth and chemical composition of legume-based pasture irrigated with dairy farm effluent. New Zealand Journal of Agricultural Research 47, 85–93.
Clarke T,
Flinn PC, McGowan AA
(1982) Low cost pepsin-cellulase assays for prediction of digestibility of herbage. Grass and Forage Science 37, 147–150.
| Crossref | GoogleScholarGoogle Scholar |
Harris DJ,
Lambell RG, Oliver CJ
(1983) Factors predisposing dairy and beef cows to grass tetany. Australian Veterinary Journal 60, 230–234.
| PubMed |
Jacobs JL,
McKenzie FR,
Rigby SE, Kearney G
(1998) Effect of nitrogen fertiliser application and length of lock up on dairy pasture dry matter yield and quality for silage in south-western Victoria. Australian Journal of Experimental Agriculture 38, 219–226.
| Crossref | GoogleScholarGoogle Scholar |
Jacobs JL, Ward GN
(2007) Effect of second pond dairy effluent applied in spring to silage regrowth of perennial ryegrass based pasture in southern Australia. 1. Dry matter yield and botanical composition changes. Australian Journal of Agricultural Research 58, 137–143.
Kemp A, Hart ML
(1957) Grass tetany in grazing milking cows. Netherlands Journal of Agricultural Research 5, 4–17.
Lautenenschlaeger W
(1989) Atomic spectroscopy advances. Microwave digestion in a closed-vessel, high pressure system. Spectroscopy 4, 16–21.
Longhurst RD,
Roberts AHC, O’Connor MB
(2000) Farm dairy effluent: a review of published data on chemical and physical characteristics in New Zealand. New Zealand Journal of Agricultural Research 43, 7–14.
McKenzie FR,
Jacobs JL, Kearney G
(2003a) Long-term effects of multiple applications of nitrogen fertiliser on grazed dryland perennial ryegrass/white clover dairy pastures in south-western Victoria. 2. Growth rates, dry matter consumed, and nitrogen response efficiences. Australian Journal of Agricultural Research 54, 471–476.
| Crossref | GoogleScholarGoogle Scholar |
McKenzie FR,
Jacobs JL, Kearney G
(2003b) Long-term effects of multiple applications of nitrogen fertiliser on grazed dryland perennial ryegrass/white clover dairy pastures in south-western Victoria. 3. Botanical composition, nutritive characteristics, mineral content, and nutrient selection. Australian Journal of Agricultural Research 54, 477–485.
| Crossref | GoogleScholarGoogle Scholar |
McKenzie FR,
Jacobs JL,
Ryan M, Kearney G
(1999) Effect of rate and time of nitrogen application in autumn to mid-winter on perennial ryegrass/white clover dairy pastures in western Victoria. 2. Pasture nutritive value. Australian Journal of Agricultural Research 50, 1067–1072.
| Crossref | GoogleScholarGoogle Scholar |
Nakashima S,
Sturgeon E,
Willie SN, Berman SS
(1988) Acid digestion of marine samples for trace element analysis using microwave heating. The Analyst 113, 159–163.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Roach CG,
Stevens G,
Clark DA, Nicholas P
(2000) Effects of effluent and urea application on groundwater, soil and pasture at WTARS. Proceedings of the New Zealand Grassland Association 62, 173–178.
Shenk JS, Westerhaus MO
(1991) Population definition, sample selection and calibration procedures for near infrared reflectance spectroscopy. Crop Science 31, 469–474.
van Soest PJ, Wine RH
(1967) Use of detergents in the analysis of fibrous feeds. IV. Determination of plant cell wall constituents. Journal – Association of Official Analytical Chemists 50, 50–55.
Wang H,
Magesan GN, Bolan NS
(2004) An overview of the environmental effects of land application of farm effluents. New Zealand Journal of Agricultural Research 47, 389–403.
Yemm EW, Willis AJ
(1954) The estimation of carbohydrates in plant extracts by anthrone. Biochemistry 57, 508–514.
