No-tillage and nitrogen application affects the decomposition of 15N-labelled wheat straw and the levels of mineral nitrogen and organic carbon in a Vertisol
R. C. Dalal A D , W. M. Strong B , J. E. Cooper B and A. J. King CA Department of Natural Resources and Water, Indooroopilly, Qld 4068, Australia.
B Department of Primary Industries and Fisheries, Toowoomba, Qld 4350, Australia.
C Department of Natural Resources and Water, Toowoomba, Qld 4350, Australia.
D Corresponding author. Email: Ram.Dalal@nrw.qld.gov.au
Australian Journal of Experimental Agriculture 47(7) 862-868 https://doi.org/10.1071/EA06118
Submitted: 1 April 2006 Accepted: 12 December 2006 Published: 2 July 2007
Abstract
No-tillage (NT) practice, where straw is retained on the soil surface, is increasingly being used in cereal cropping systems in Australia and elsewhere. Compared to conventional tillage (CT), where straw is mixed with the ploughed soil, NT practice may reduce straw decomposition, increase nitrogen immobilisation and increase organic carbon in the soil. This study examined 15N-labelled wheat straw (stubble) decomposition in four treatments (NT v. CT, with N rates of 0 and 75 kg/ha.year) and assessed the tillage and fertiliser N effects on mineral N and organic C and N levels over a 10-year period in a field experiment.
NT practice decreased the rate of straw decomposition while fertiliser N application increased it. However, there was no tillage practice × N interaction. The mean residence time of the straw N in soil was more than twice as long under the NT (1.2 years) as compared to the CT practice (0.5 years). In comparison, differences in mean residence time due to N fertiliser treatment were small. However, tillage had generally very little effect on either the amounts of mineral N at sowing or soil organic C (and N) over the study period. While application of N fertiliser increased mineral N, it had very little effect on organic C over a 10-year period. Relatively rapid decomposition of straw and short mean residence time of straw N in a Vertisol is likely to have very little long-term effect on N immobilisation and organic C level in an annual cereal cropping system in a subtropical, semiarid environment. Thus, changing the tillage practice from CT to NT may not necessitate additional N requirement unless use is made of additional stored water in the soil or mineral N loss due to increased leaching is compensated for in N supply to crops.
Acknowledgements
We thank the Grains Research and Development Corporation for the funding support, Mrs C. J. Holmes for field assistance, and Mrs. J. Glasby and Mrs A. Pumfrey for soil and plant analysis. We also thank the two anonymous reviewers for their comments and suggestions.
Agren GI,
Bosatta A, Balesdent J
(1996) Isotope discrimination during decomposition of organic matter: a theoretical analysis. Soil Science Society of America Journal 60, 1121–1126.
Andren O,
Rajkai K, Katterer T
(1993) Water and temperature dynamics in a clay soil under winter wheat: influence on straw decomposition and N immobilisation. Biology and Fertility of Soils 15, 1–8.
| Crossref | GoogleScholarGoogle Scholar |
Best EK
(1976) An automated method for the determination of nitrate-nitrogen in soil extracts. Queensland Journal of Agricultural and Animal Sciences 33, 161–166.
Buresh RJ,
Austin ER, Craswell ET
(1982) Analytical methods in 15N research. Fertilizer Research 3, 37–62.
| Crossref | GoogleScholarGoogle Scholar |
Crooke WM, Simpson WE
(1971) Determination of ammonium in Kjeldahl digests of crops by an automated procedure. Journal of the Science of Food and Agriculture 22, 9–10.
| Crossref | GoogleScholarGoogle Scholar |
Dalal RC,
Sahrawat KL, Myers RJK
(1984) Inclusion of nitrate and nitrite in the Kjeldahl nitrogen determination of soils and plant materials using sodium thiosulphate. Communications in Soil Science and Plant Analysis 13, 75–86.
Dalal RC,
Henderson PA, Glasby JM
(1991) Organic matter and microbial biomass in a Vertisol after 20 yr of zero-tillage. Soil Biology & Biochemistry 23, 435–441.
| Crossref | GoogleScholarGoogle Scholar |
Dalal RC,
Strong WM,
Weston EJ,
Cooper JE,
Lehane KJ,
King AJ, Chicken CJ
(1995) Sustaining productivity of a Vertisol at Warra, Queensland, with fertilisers, no-tillage or legumes. 1. Organic matter status. Australian Journal of Experimental Agriculture 35, 903–913.
| Crossref | GoogleScholarGoogle Scholar |
Dalal RC,
Strong WM,
Weston EJ,
Cooper JE, Thomas GA
(1997) Prediction of grain protein in wheat and barley in subtropical environment from available water and nitrogen in Vertisols at sowing. Australian Journal of Experimental Agriculture 37, 351–357.
| Crossref | GoogleScholarGoogle Scholar |
Dalal RC,
Strong WM,
Weston EJ,
Cooper JE,
Wildermuth GB,
Lehane KJ,
King AJ, Holmes CJ
(1998) Sustaining productivity of a Vertisol at Warra, Queensland, with fertilisers, no-tillage or legumes. 5. Wheat yields, nitrogen benefits and water use efficiency of chickpea-wheat rotation. Australian Journal of Experimental Agriculture 38, 489–501.
| Crossref | GoogleScholarGoogle Scholar |
Freebairn DM,
Ward LD,
Clarke AL, Smith GD
(1986) Research and development of reduced tillage systems for Vertisols in Queensland, Australia. Soil and Tillage Research 8, 211–229.
| Crossref | GoogleScholarGoogle Scholar |
Fuentes JP,
Flury M,
Huggins DR, Bezdicek DF
(2003) Soil water and nitrogen dynamics in dryland cropping systems of Washington State, USA. Soil and Tillage Research 71, 33–47.
| Crossref | GoogleScholarGoogle Scholar |
Jalota RK,
Dalal RC,
Harms BP,
Page K,
Mathers NJ, Wang WJ
(2006) Effects of litter and fine roots composition on their decomposition in a Rhodic Paleustalf under different land uses. Communications in Soil Science and Plant Analysis 37, 1859–1875.
| Crossref | GoogleScholarGoogle Scholar |
Radford BJ,
Key AJ,
Robertson LN, Thomas GA
(1995) Conservation tillage increases soil water storage, soil animal populations, grain yield, and response to fertilisers in the semi-arid subtropics. Australian Journal of Experimental Agriculture 35, 223–232.
| Crossref | GoogleScholarGoogle Scholar |
Robinson D
(2001) δ15N as an integrator of the nitrogen cycle. Trends in Ecology & Evolution 16, 153–162.
| Crossref | GoogleScholarGoogle Scholar |
Schomberg HH, Steiner JL
(1999) Nutrient dynamics of crop residues decomposing on a fallow no-till soil surface. Soil Science Society of America Journal 63, 607–613.
Sims JR, Haby VA
(1971) Simplified colorimetric determination of soil organic matter. Soil Science 112, 137–141.
Strong WM,
Dalal RC,
Cooper JE, Saffigna PG
(1987) Availability of residual fertiliser nitrogen in a Darling Downs black earth in the presence and absence of straw. Australian Journal of Experimental Agriculture 27, 295–302.
| Crossref | GoogleScholarGoogle Scholar |
Strong WM,
Dalal RC,
Weston EJ,
Cooper JE,
Lehane KJ, King AJ
(1996a) Nitrogen fertiliser residues for wheat cropping in subtropical Australia. Australian Journal of Agricultural Research 47, 695–703.
| Crossref | GoogleScholarGoogle Scholar |
Strong WM,
Dalal RC,
Weston EJ,
Cooper JE,
Lehane KJ,
King AJ, Chicken CJ
(1996b) Sustaining productivity of a Vertisol at Warra, Queensland, with fertilisers, no-tillage or legumes. 2. Long-term fertiliser needs to enhance wheat yields and grain protein. Australian Journal of Experimental Agriculture 36, 665–674.
| Crossref | GoogleScholarGoogle Scholar |
Turpin JE,
Thompson JP,
Waring SA, Mackenzie J
(1998) Nitrate and chloride leaching in Vertisols for different tillage and stubble practices in fallow-grain cropping. Australian Journal of Soil Research 36, 31–44.
| Crossref | GoogleScholarGoogle Scholar |
Wang WJ,
Dalal RC, Moody PW
(2004) Soil carbon sequestration and density distribution in a Vertisol under different farming practices. Australian Journal of Soil Research 42, 875–882.
| Crossref | GoogleScholarGoogle Scholar |
