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RESEARCH ARTICLE

Potential contribution by cotton roots to soil carbon stocks in irrigated Vertosols

N. R. Hulugalle A B E , T. B. Weaver A B , L. A. Finlay A B , N. W. Luelf B C D and D. K. Y. Tan B C
+ Author Affiliations
- Author Affiliations

A New South Wales Department of Primary Industries, Australian Cotton Research Institute, Locked Bag 1000, Narrabri, NSW 2390, Australia.

B Cotton Catchment Communities Co-operative Research Centre.

C Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Sydney, NSW 2006, Australia.

D Present address: Agrisearch Services Pty Ltd, 50 Leewood Drive, Orange, NSW 2800, Australia.

E Corresponding author. Email: nilanthah@csiro.au

Australian Journal of Soil Research 47(3) 243-252 https://doi.org/10.1071/SR08180
Submitted: 5 August 2008  Accepted: 12 January 2009   Published: 25 May 2009

Abstract

The well-documented decline in soil organic carbon (SOC) stocks in Australian cotton (Gossypium hirsutum L.) growing Vertosols has been primarily analysed in terms of inputs from above-ground crop residues, with addition to soil C by root materials being little studied. Potential contribution by cotton roots to soil carbon stocks was evaluated between 2002 and 2008 in 2 ongoing long-term experiments near Narrabri, north-western New South Wales. Experiment 1 consisted of cotton monoculture sown either after conventional tillage or on permanent beds, and a cotton–wheat (Triticum aestivum L.) rotation on permanent beds; Experiment 2 consisted of 4 cotton-based rotation systems sown on permanent beds: cotton monoculture, cotton–vetch (Vicia villosa Roth.), cotton–wheat, and cotton–wheat–vetch. Roundup-Ready™ (genetically modified) cotton varieties were sown until 2005, and Bollgard™ II-Roundup Ready™-Flex™ varieties thereafter. Root growth in the surface 0.10 m was measured with the core-break method using 0.10-m-diameter cores. A subsample of these cores was used to evaluate relative root length and root C concentrations. Root growth in the 0.10–1.0 m depth was measured at 0.10-m depth intervals with a ‘Bartz’ BTC-2 minirhizotron video microscope and I-CAP image capture system (‘minirhizotron’). The video camera was inserted into clear, plastic acrylic minirhizotron tubes (50-mm-diameter) installed within each plot, 30° from the vertical. Root images were captured 4–5 times each season in 2 orientations, left and right side of each tube, adjacent to a furrow, at each time of measurement and the images analysed to estimate selected root growth indices. The indices evaluated were the length and number of live roots at each time of measurement, number of roots which changed length, number and length of roots which died (i.e. disappeared between times of measurement), new roots initiated between times of measurement, and net change in root numbers and length. These measurements were used to derive root C turnover between times of measurements, root C added to soil through intra-seasonal root death, C in roots remaining at end of season, and the sum of the last 2 indices: root C potentially available for addition to soil C stocks.

Total seasonal cotton root C potentially available for addition to soil C stocks ranged between ~50 and 400 g/m2 (0.5 and 4 t/ha), with intra-seasonal root death contributing 25–70%. These values are ~10–60% of that contributed by above-ground crop residues. As soil organic carbon in irrigated Vertosols can range between 40 and 60 t/ha, it is unlikely that cotton roots will contribute significantly to soil carbon stocks in irrigated cotton farming systems. Seasonal root C was reduced by cotton monoculture, stress caused by high insect numbers, and sowing Bollgard II varieties; and increased by sowing non-Bollgard II varieties and wheat rotation crops. Permanent beds increased root C but leguminous rotation crops did not. Climatic factors such as cumulative day-degrees and seasonal rainfall were positively related to seasonal root C. Root C turnover was, in general, highest during later vegetative/early reproductive growth. Large variations in root C turnover and seasonal C indices occurred due to a combination of environmental, management and climatic factors.

Additional keywords: minirhizotron, Haplustert, wheat, vetch, rotation, permanent beds.


Acknowledgments

Funding for this study was provided by the Cotton Research and Development Corporation of Australia, the Australian Cotton Co-operative Research Centre and the Cotton Catchment Communities Co-operative Research Centres through grants CRC 32C, 45C, and 86C. N Luelf gratefully acknowledges the receipt of a summer scholarship (CRC grant 4.1.06SS18) from the Australian Cotton Co-operative Research Centre. Dr Stephen Milroy of CSIRO, Floreat Park, Perth, is thanked for his comments during manuscript preparation.


References


Al-Khafaf S, Wierenga PJ, Williams BC (1977) A flotation method for determining root mass in soil. Agronomy Journal 69, 1025–1026. [accessed 4 August 2008].

Carmi A, Plaut Z, Sinai M (1993) Cotton root growth as affected by changes in soil water distribution and their impact on plant tolerance to drought. Irrigation Science 13, 177–182.
Crossref | GoogleScholarGoogle Scholar | [accessed 4 August 2008].

Drew MC, Saker LR (1980) Assessment of a rapid method, using soil cores, for estimating the amount and distribution of crop roots in the field. Plant and Soil 55, 297–305.
Crossref | GoogleScholarGoogle Scholar | [accessed 4 August 2008].

Hodgson AS, Constable GA, Duddy GR, Daniells IG (1990) A comparison of drip and furrow irrigated cotton on a cracking clay soil. II. Water use efficiency, waterlogging, root distribution and soil structure. Irrigation Science 11, 143–148.
Crossref |
open url image1

Hulugalle NR , Daniells IG (2005) Permanent beds in Australian cotton production systems. In ‘Evaluation and performance of permanent raised bed cropping systems in Asia, Australia and Mexico’. (Eds CH Roth, RA Fisher, CA Meisner) pp. 161–171. (ACIAR: Canberra)

Hulugalle NR, Nehl DB, Weaver TB (2004) Soil properties, and cotton growth, yield and fibre quality in three cotton-based cropping systems. Soil & Tillage Research 75, 131–141.
Crossref | GoogleScholarGoogle Scholar | open url image1

Hulugalle N, Scott F (2008) A review of the changes in soil quality and profitability accomplished by sowing rotation crops after cotton in Australian Vertosols from 1970 to 2006. Australian Journal of Soil Research 46, 173–190.
Crossref | GoogleScholarGoogle Scholar | open url image1

Hulugalle NR, Weaver TB, Scott F (2005) Continuous cotton and cotton-wheat rotation effects on soil properties and profitability in an irrigated Vertosol. Journal of Sustainable Agriculture 27(3), 5–24.
Crossref | GoogleScholarGoogle Scholar | open url image1

Hulugalle NR , Weaver TB , Scott F (2008) Maintaining profitability and soil quality in cotton farming systems II, Final Report for Cotton Catchment Communities Co-operative Research Centre Project no. 1.04.13.

Isbell RF (1996) ‘The Australian Soil Classification.’ (CSIRO Publishing: Collingwood, Vic.)

Johnson MG, Tingey DT, Phillips DL, Storm MJ (2001) Advancing fine root research with minirhizotrons. Environmental and Experimental Botany 45, 263–289.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Knowles TA, Singh B (2003) Carbon storage in cotton soils of northern New South Wales. Australian Journal of Soil Research 41, 889–903.
Crossref | GoogleScholarGoogle Scholar | CAS | open url image1

Kottek MJ, Grieser C, Beck B, Rudolf B, Rubel F (2006) World Map of the Köppen-Geiger climate classification updated. Meteorologische Zeitschrift 15, 259–263.
Crossref | GoogleScholarGoogle Scholar | open url image1

Li Zhen Z, Wei Xing C, Si Ping Z, Zhi Guo Z (2005) Characterizing root growth and spatial distribution in cotton. Acta Phytoecologica Sinica 29, 266–273. open url image1

McGarry D , Ward WT , McBratney AB (1989) ‘Soil studies in the Lower Namoi Valley: Methods and data. The Edgeroi Data Set.’ (CSIRO Division of Soils: Adelaide, S. Aust.)

McKenzie DC , Shaw AJ , Rochester IJ , Hulugalle NR , Wright PR (2003) ‘Soil and nutrient management for irrigated cotton.’ NSW Agriculture AGDEX 151/510, no. P5.3.6. (NSW Agriculture: Orange, NSW)

Nehl DB , Allen SJ (2002) Managing disease with rotations. In ‘Proceedings of the 11th Australian Cotton Conference’. 13–15 August 2002, Brisbane, Qld. pp. 695–698. (ACGRA: Wee Waa, NSW)

Polomski J , Kuhn N (2002) Root research methods. In ‘Plant roots: the hidden half’. 3rd edn (Eds Y Waisel, A Eshel, U Kafkafi) pp. 295–321. (Marcel-Dekker: New York)

Rayment G , Higginson R (1992) ‘Australian laboratory handbook of soil and water chemical methods.’ (Inkata: Melbourne and Sydney)

Rochester IJ, Constable GA (1996) Retain your cotton stubble – burning can reduce yields. Australian Cottongrower 17(1), 62–64. open url image1

Rochester IJ, Constable GA, Saffigna PG (1997) Retention of cotton stubble enhances N fertilizer recovery and lint yield of irrigated cotton. Soil & Tillage Research 41, 75–86.
Crossref | GoogleScholarGoogle Scholar | open url image1

Rochester IJ, Peoples MB, Constable GA, Gault RR (1998) Faba beans and other legumes add nitrogen to irrigated cotton cropping systems. Australian Journal of Experimental Agriculture 38, 253–260.
Crossref | GoogleScholarGoogle Scholar | open url image1

Rochester IJ, Peoples MB, Hulugalle NR, Gault RR, Constable GA (2001) Using legumes to enhance N fertility and improve soil condition in cotton cropping systems. Field Crops Research 70, 27–41.
Crossref | GoogleScholarGoogle Scholar | open url image1

Sadras VO (1996a) Population-level compensation after loss of vegetative buds: interactions among damaged and undamaged cotton neighbours. Oecologia 106, 417–423.
Crossref | GoogleScholarGoogle Scholar | open url image1

Sadras VO (1996b) Cotton compensatory growth after loss of reproductive organs as affected by availability of resources and duration of recovery period. Oecologia 106, 432–439.
Crossref | GoogleScholarGoogle Scholar | open url image1

Schwab GJ, Mullins GL, Burmester CH (2000) Growth and uptake by cotton roots under field conditions. Communications in Soil Science and Plant Analysis 31, 149–164.
Crossref | GoogleScholarGoogle Scholar | CAS | open url image1

Smit AL , Bengough AG , van Noordjwijk M , Pellerin S , van de Geijin SC (Eds) (2000) ‘Root methods: a handbook.’ (Springer-Verlag: Berlin, Heidelberg, New York)

Soil Survey Staff (2006) ‘Keys to Soil Taxonomy.’ 10th edn (USDA-Natural Resources Conservation Service: Washington, DC)

Terry J (2007) Cotton yield and soil carbon under continuous cotton, cotton-corn, cotton-vetch-corn and cotton-wheat rotations. BSc (Agric.) Hons Thesis, University of Sydney, NSW, Australia.

Tisdall JM, Hodgson AS (1990) Ridge tillage in Australia: A review. Soil & Tillage Research 18, 127–144.
Crossref | GoogleScholarGoogle Scholar | open url image1

Van Dam NM , Bezemer TM (2006) Chemical communication between roots and shoots: towards an integration of aboveground and belowground induced responses in plants. In ‘Chemical ecology: from gene to ecosystem’. (Eds M Dicke, W Takken) pp. 127–143. (Springer: Amsterdam)

Vervoort RW, Minasny B, Cattle SR (2006) The hydrology of Vertosols used for cotton production: II. Pedotransfer functions to predict hydraulic properties. Australian Journal of Soil Research 44, 479–486.
Crossref | GoogleScholarGoogle Scholar | open url image1

Ward KJ, Klepper B, Rickman RW, Allmaras RR (1978) Quantitative estimation of living wheat-root lengths in soil cores. Agronomy Journal 70, 675–677. open url image1

Zamora DS, Jose S, Nair PKR (2007) Morphological plasticity of cotton roots in response to interspecific competition with pecan in an alleycropping system in southern United States. Agroforestry Systems 69, 107–116.
Crossref | GoogleScholarGoogle Scholar | open url image1









1Bulk densities used in these estimates were calculated using the pedotransfer functions described by Vervoort et al. (2006).

2Genetically-modified varieties which carry an insecticidal gene from Bacillus thuringiensis and are resistant to attack by Helicoverpa spp.