Soil microbial biomass, labile and total carbon levels of grazed sown and native pastures in northern New South Wales
G. M. Lodge A C and K. L. King BA NSW Department of Primary Industries, Tamworth Agricultural Institute, 4 Marsden Park Road, Calala, NSW 2340, Australia.
B School of Rural Science and Agriculture, University of New England, Armidale, NSW 2351, Australia.
C Corresponding author. Email: greg.lodge@dpi.nsw.gov.au
Australian Journal of Agricultural Research 57(8) 837-845 https://doi.org/10.1071/AR05337
Submitted: 20 October 2005 Accepted: 27 March 2006 Published: 9 August 2006
Abstract
Studies were conducted at 3 pasture sites in northern New South Wales to examine the effects of grazing treatments over 4 years (spring 1997 to spring 2001) on soil microbial biomass carbon (C), labile C, total C, and total nitrogen (N). These data were collected (0–0.05 m soil depth) at 9 sampling times in 2 replicates of 5 (native pastures) or 4 (a sown pasture) grazing treatments and examined for differences over time using cubic spline analyses. For each site, differences among grazing treatments were also examined in spring 2001 for herbage, litter, and root mass (kg DM/ha), ground cover (%), and perennial grass basal cover (%). Indices were also calculated for the C pool index (CPI), lability index (LI), a carbon management index (CMI), and the microbial quotient. Relationships among microbial biomass C, labile C, total organic C, CPI, LI, CMI, microbial quotient, herbage mass, litter mass, and ground cover were examined by linear regression and correlation analyses.
For each of the sites, treatment differences in the linear trend over time for soil microbial biomass C, labile C, total organic C, or total N were not significantly different (P > 0.05). In spring 2001, (4 years after treatments commenced) there were also no significant effects of treatments within sites on soil total organic C and none of the indices (lability of C, CPI, LI, CMI, or the microbial quotient) indicated any distinct trends among treatments. However, in spring 2001, there were significant (P < 0.05) treatment effects at both native pasture sites for herbage mass, litter mass, and ground cover. Similarly, in autumn 2001, herbage mass, root mass, and perennial grass basal cover were lowest (P < 0.05) in the continuously grazed high-stocking rate treatment at the sown pasture site. For all data, microbial biomass C was 10.35% of labile C and labile C was 21.60% of total C. From autumn 1998 to spring 2001, labile C was positively correlated (P < 0.05) with total C (r = 0.72) and in spring 2001, these 2 variables were also highly correlated (r = 0.98).
Additional keywords: total nitrogen, microbial quotient, grazing treatments, herbage mass, litter mass, root mass, ground cover.
Acknowledgments
We gratefully acknowledge the assistance of Tarnya Christian (in 1997 and 1998), Brian Roworth, and Michael Honess in collecting and processing the soil samples, and Steven Harden in the statistical analyses of the data. We also thank Judith Kenny, Plant Nutrition Analytical Facility, University of New England, Armidale, for analysing the labile C samples. These studies were conducted as part of the Sustainable Grazing Systems (SGS) Key Program, a joint collaboration between the NSW Department of Primary Industries (formerly NSW Agriculture), Meat & Livestock Australia, Land & Water Australia and other agencies.
Amato M, Ladd JN
(1988) Assay for microbial biomass based on ninhydrin-reactive nitrogen in extracts of fumigated soils. Soil Biology and Biochemistry 20, 107–114.
| Crossref | GoogleScholarGoogle Scholar |
Anderson TH, Domsch KH
(1989) Ratios of microbial biomass carbon to total carbon in arable soils. Soil Biology and Biochemistry 21, 471–479.
| Crossref | GoogleScholarGoogle Scholar |
Andrew MH, Lodge GM
(2003) The Sustainable Grazing Systems National Experiment. 1. Introduction and methods. Australian Journal of Experimental Agriculture 43, 695–709.
| Crossref | GoogleScholarGoogle Scholar |
Blair GJ,
Lefroy RDB, Lisle L
(1995) Soil carbon fractions based on their degree of oxidation and the development of a carbon management index for agricultural systems. Australian Journal of Agricultural Research 46, 1459–1466.
| Crossref | GoogleScholarGoogle Scholar |
Dalal RC
(1998) Soil microbial biomass—what do the numbers really mean? Australian Journal of Experimental Agriculture 38, 649–665.
| Crossref | GoogleScholarGoogle Scholar |
Dalal RC,
Henderson PA, Glasby JM
(1991) Organic matter and microbial biomass in a Vertisol after 20 years of zero-tillage. Soil Biology and Biochemistry 23, 435–441.
| Crossref | GoogleScholarGoogle Scholar |
Haynes RJ
(1999) Labile organic matter fractions and aggregate stability under short-term, grass-based leys. Soil Biology and Biochemistry 31, 1821–1830.
| Crossref | GoogleScholarGoogle Scholar |
Hutchinson KJ, King KL
(1982) Microbial respiration in a temperate sown grassland grazed by sheep. Journal of Applied Ecology 19, 821–833.
| Crossref |
Insam H,
Parkinson D, Domsch KH
(1989) Influence of macroclimate on soil microbial biomass. Soil Biology and Biochemistry 21, 211–221.
| Crossref | GoogleScholarGoogle Scholar |
Joergensen RG, Brooks PC
(1990) Ninhydrin-reactive N released by the fumigation-estimation method as a measure of microbial biomass under field conditions. Soil Biology and Biochemistry 22, 1023–1027.
| Crossref | GoogleScholarGoogle Scholar |
Kennedy AC, Smith KL
(1995) Soil microbial diversity and the sustainability of agricultural soils. Plant and Soil 170, 75–86.
| Crossref | GoogleScholarGoogle Scholar |
King KL
(1993) The potential for avermectins to affect the nutrient economy of grazed pastures. Veterinary Parasitology 48, 261–271.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
King KL, Hutchinson KJ
(1976) The effects of sheep stocking intensity on the abundance and distribution of mesofauna in pastures. Journal of Applied Ecology 13, 41–55.
| Crossref |
King KL, Hutchinson KJ
(1983) The effects of sheep grazing on invertebrate numbers and biomass in unfertilized natural pastures of the New England Tablelands (NSW). Australian Journal of Ecology 8, 245–255.
Lefroy RDB,
Blair GJ, Strong WM
(1993) Changes in soil organic matter with cropping as measured by organic carbon fractions and 13C natural isotope abundance. Plant and Soil 155/156, 399–402.
| Crossref | GoogleScholarGoogle Scholar |
Lodge GM,
Mason WK,
Andrew MH,
Anderson CA, Muir LL
(2003a) Sustainable grazing systems: building financial, social and natural capital for livestock producers. Australian Journal of Experimental Agriculture 43, 663–1082.
| Crossref |
Lodge GM, Murphy SR
(2006) Root depth of native and sown perennial grass-based pastures, North-West Slopes, New South Wales. 1. Estimates from cores and effects of grazing treatments. Australian Journal of Experimental Agriculture 46, 337–345.
| Crossref | GoogleScholarGoogle Scholar |
Lodge GM,
Murphy SR, Harden S
(2003b) Effects of continuous and seasonal grazing strategies on the herbage mass, persistence, animal productivity and soil water content of a Sirosa phalaris–subterranean clover pasture, North-West Slopes, New South Wales. Australian Journal of Experimental Agriculture 43, 539–552.
| Crossref | GoogleScholarGoogle Scholar |
Lodge GM,
Murphy SR, Harden S
(2003c) Effects of grazing and management on herbage mass, persistence, animal production and soil water content of native pastures. 1. A redgrass-wallaby grass pasture, Barraba, North-West Slopes, New South Wales. Australian Journal of Experimental Agriculture 43, 875–890.
| Crossref | GoogleScholarGoogle Scholar |
Lodge GM,
Murphy SR, Harden S
(2003d) Effects of grazing and management on herbage mass, persistence, animal production and soil water content of native pastures. 2. A mixed native pasture, Manilla, North-West Slopes, New South Wales. Australian Journal of Experimental Agriculture 43, 891–905.
| Crossref | GoogleScholarGoogle Scholar |
Mazzarino MJ,
Olivia L,
Abil A, Acosta M
(1991) Factors affecting nitrogen dynamics in a semiarid woodland (Dry Chao, Argentina). Plant and Soil 138, 85–98.
| Crossref | GoogleScholarGoogle Scholar |
McGill WB,
Cannon KR,
Robertson JA, Cook FD
(1986) Dynamics of soil microbial biomass and water-soluble C in Breton L after 50 years of cropping to two rotations. Canadian Journal of Soil Science 66, 1–19.
Milne RM, Haynes RJ
(2004) Soil organic matter, microbial properties, and aggregate stability under annual and perennial pastures. Biology and Fertility of Soils 39, 172–178.
| Crossref | GoogleScholarGoogle Scholar |
Murphy SR, Lodge GM
(2002) Ground cover in temperate native perennial grass pastures. I. A comparison of four estimation methods. The Rangeland Journal 24, 288–300.
| Crossref | GoogleScholarGoogle Scholar |
Orchard BA,
Cullis BR,
Coombes NE,
Virgona JM, Klein T
(2000) Grazing management studies in the Temperate Pasture Sustainability Key Program; experimental design and statistical analysis. Australian Journal of Experimental Agriculture 40, 143–154.
| Crossref | GoogleScholarGoogle Scholar |
Pankhurst CE,
Hawke BG,
McDonald HJ,
Kirby CA,
Buckerfield JC,
Michelsen P,
O’Brien KA,
Gupta VVSR, Doube BM
(1995) Evaluation of soil biological properties as potential bioindicators of soil health. Australian Journal of Experimental Agriculture 35, 1015–1028.
| Crossref | GoogleScholarGoogle Scholar |
Robertson FA,
Myers RJK, Saffigna PG
(1993) Distribution of carbon and nitrogen in a long-term cropping system and a permanent pasture. Australian Journal of Agricultural Research 44, 1323–1336.
| Crossref | GoogleScholarGoogle Scholar |
Robertson FA,
Myers RJK, Saffigna PG
(1994) Dynamics of carbon and nitrogen in a long-term cropping system and a permanent pasture. Australian Journal of Agricultural Research 45, 211–221.
| Crossref | GoogleScholarGoogle Scholar |
Roper MM, Gupta VVSR
(1995) Management practices and soil biota. Australian Journal of Soil Research 33, 321–339.
| Crossref | GoogleScholarGoogle Scholar |
Sanford P,
Cullen BR,
Dowling PM,
Chapman DF,
Garden DL,
Lodge GM,
Andrew MH,
Quigley PE,
Murphy SR,
King WMcG,
Johnston WH, Kemp DR
(2003) SGS Pasture Theme: effect of climate, soil factors and management on pasture production and stability across the high rainfall zone of southern Australia. Australian Journal of Experimental Agriculture 43, 945–957.
| Crossref | GoogleScholarGoogle Scholar |
Scott JM,
Hutchinson KJ,
King K,
Chen W,
McLeod M,
Blair GJ,
White A,
Wilkinson D,
Lefroy RDB,
Cresswell H,
Daniel H,
Harris C,
MacLeod DA,
Blair N, Chamberlain G
(2000) Quantifying the sustainability of grazed pastures on the Northern Tablelands of New South Wales. Australian Journal of Experimental Agriculture 40, 257–265.
| Crossref | GoogleScholarGoogle Scholar |
Sparling GP,
Speir TW, Whale KN
(1986) Changes in microbial biomass C, ATP content, soil phosphor-monoesterase and phosphor-diesterase activity following air-drying of soils. Soil Biology and Biochemistry 18, 363–370.
| Crossref | GoogleScholarGoogle Scholar |
Stirling GR, Lodge GM
(2005) A survey of Australian temperate pastures in summer and winter rainfall zones: soil nematodes, chemical and biochemical properties. Australian Journal of Soil Research 43, 887–904.
| Crossref | GoogleScholarGoogle Scholar |
Verbyla AP,
Cullis BR,
Kenward MG, Welham SJ
(1999) Analysis of designed experiments and longitudinal data by using smoothing splines (with discussion). Applied Statistics 48, 269–312.
White PF
(1990) The influence of alternative tillage systems on the distribution of nutrients and organic carbon in some common Western Australian wheatbelt soils. Australian Journal of Soil Research 28, 95–116.
| Crossref | GoogleScholarGoogle Scholar |
White RE,
Helyar KR,
Ridley AM,
Chen D,
Heng LK,
Evans J,
Fisher R,
Hirth JR,
Mele PM,
Morrison GR,
Cresswell HP,
Paydar Z,
Dunin FX,
Dove H, Simpson RJ
(2000) Soil factors affecting the sustainability and productivity of perennial and annual pastures in the high rainfall zone of south-eastern Australia. Australian Journal of Experimental Agriculture 40, 267–283.
| Crossref | GoogleScholarGoogle Scholar |
Williams CH, Donald CM
(1957) Changes in organic matter and pH in a podsolic soil as influenced by subterranean clover and superphosphate. Australian Journal of Agricultural Research 8, 179–189.
| Crossref | GoogleScholarGoogle Scholar |