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Crop and Pasture Science Crop and Pasture Science Society
Plant sciences, sustainable farming systems and food quality
RESEARCH FRONT

C : N ratios and carbon distribution profile across rooting zones in oilseed and pulse crops

Y. T. Gan A D , B. C. Liang B , L. P. Liu C , X. Y. Wang A and C. L. McDonald A
+ Author Affiliations
- Author Affiliations

A Agriculture and Agri-Food Canada, Semiarid Prairie Agricultural Research Centre, Gate #3, Airport Road E., Swift Current, SK, S9H 3X2, Canada.

B Greenhouse Gas Division, Environment Canada, 9th Floor, Fontaine Building, 200 Sacré-Coeur, Gatineau, Québec, K1A 0H3, Canada.

C Department of Plant Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada.

D Corresponding author. Email: yantai.gan@agr.gc.ca

Crop and Pasture Science 62(6) 496-503 https://doi.org/10.1071/CP10360
Submitted: 11 November 2010  Accepted: 30 June 2011   Published: 7 July 2011

Abstract

Knowledge on the C : N ratio of crop residues is of great importance for modelling carbon (C) and nitrogen (N) dynamics of agricultural systems. This study determined (i) the C : N ratios in the seed, straw, and roots of selected broadleaf crops and (ii) the root C and N distribution in the 0–100 cm rooting zone. Three oilseed (Brassica napus canola, Brassica juncea mustard, Linum usitatissimum flax), three pulse crops (Cicer arietinum chickpea, Pisum sativum dry pea, Lens culinaris lentil), and spring wheat (Triticum aestivum L.) were grown under field conditions with low- (rainfall only) and high-water (rainfall plus irrigation) availability. Root C mass decreased substantially with rooting depth, with ~58% of root C mass in the top 20 cm of the soil, 78% in the top 40 cm, and 94% in the top 60 cm. Significant differences in root C mass between crop species occurred in the top 20 cm with canola, mustard, and wheat allocating 66% of their root C total, compared with 55% for dry pea, lentil, and flax, and 41% for chickpea. Root N mass followed a similar response to root C. Seed C : N ratios ranged between 6 and 17, whereas straw C : N ranged between 14 and 55, and root C : N between 17 and 75. Under low-water conditions, canola and mustard had a straw C : N of 33, lower than that of flax (38) and wheat (41). Under higher-water availability, however, mustard and wheat had straw C : N ratios at 55, greater than canola, mustard and flax (47). Three pulses had an average straw C : N ratio of 17, significantly lower than 41 for the oilseeds and 32 for wheat. On average, canola, mustard and wheat had greater root C : N ratios (44) than chickpea (33) and lentil (29), with dry pea having a smallest root C : N ratio (18). Root C : N ratios did not change with soil depth. These detailed measurements on the vertical distribution of root C and N as well as C : N ratios for various crops will assist in improving estimates of inputs for C and N cycling studies.

Additional keywords: oilseed, grain legumes, root carbon, C : N ratio, rooting depth, rooting zones, soil organic matter, soil nitrogen.


References

Armstrong EL, Pate JS, Unkovich MJ (1994) Nitrogen balance of field pea crops in South Western Australia, studied using the 15N natural abundance technique. Australian Journal of Plant Physiology 21, 533–549.
Nitrogen balance of field pea crops in South Western Australia, studied using the 15N natural abundance technique.Crossref | GoogleScholarGoogle Scholar |

Balesdent J, Balabane M (1996) Major contribution of roots to soil carbon storage inferred from maize cultivated soils. Soil Biology & Biochemistry 28, 1261–1263.
Major contribution of roots to soil carbon storage inferred from maize cultivated soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XmvFGnsLk%3D&md5=ba3b8bbd489fd9ccb78eb65fc619d9a2CAS |

Bengtsson G, Bengtson P, Månsson KF (2003) Gross nitrogen mineralization, immobilization, and nitrification rates as a function of soil C/N ratio and microbial activity. Soil Biology & Biochemistry 35, 143–154.
Gross nitrogen mineralization, immobilization, and nitrification rates as a function of soil C/N ratio and microbial activity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXhvFGrtbs%3D&md5=e1125b02f1ed049e32317a1ce118199cCAS |

Biederbeck VO, Zentner RP, Campbell CA (2005) Soil microbial populations and activities as influenced by legume green fallowing in a semiarid loam. Soil Biology & Biochemistry 37, 1775–1784.
Soil microbial populations and activities as influenced by legume green fallowing in a semiarid loam.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXlsFGjsL4%3D&md5=50a140b19b28f5827cc8a4e3a3576033CAS |

Bolger TP, Angus JF, Peoples MB (2003) Comparison of nitrogen mineralisation patterns from root residues of Trifolium subterraneum and Medicago sativa. Biology and Fertility of Soils 38, 296–300.
Comparison of nitrogen mineralisation patterns from root residues of Trifolium subterraneum and Medicago sativa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXotVarsr4%3D&md5=09994341de5ec8f292e7dd3e279020faCAS |

Bolinder MA, Angers DA, Dubuc JP (1997) Estimating shoot to root ratios and annual carbon inputs in soils for cereal crops. Agriculture, Ecosystems & Environment 63, 61–66.
Estimating shoot to root ratios and annual carbon inputs in soils for cereal crops.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXjsFyjsbw%3D&md5=0bb6c6134a01f92313d6be9651e651ddCAS |

Bolinder MA, Janzen HH, Gregorich EG, Angers DA, VandenBygaart AJ (2007) An approach for estimating net primary productivity and annual carbon inputs to soil for common agricultural crops in Canada. Agriculture, Ecosystems & Environment 118, 29–42.
An approach for estimating net primary productivity and annual carbon inputs to soil for common agricultural crops in Canada.Crossref | GoogleScholarGoogle Scholar |

Campbell CA, Vandenbygaart AJ, Grant B, Zentner RP, McConkey BG, Lemke R, Gregorich EG, Fernandez MR (2007) Quantifying carbon sequestration in a conventionally tilled crop rotation study in southwestern Saskatchewan. Canadian Journal of Soil Science 87, 23–38.
Quantifying carbon sequestration in a conventionally tilled crop rotation study in southwestern Saskatchewan.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXmt1enurc%3D&md5=bd71bfa3a89d8073c41ee69549974f5aCAS |

Campbell CA, Zentner RP, Basnyat P, De Jong R, Lemke R, Desjardins R (2008) Nitrogen mineralization under summer fallow and continuous wheat in the semiarid Canadian prairie. Canadian Journal of Soil Science 88, 681–696.
Nitrogen mineralization under summer fallow and continuous wheat in the semiarid Canadian prairie.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhs1Srt7g%3D&md5=ea4cac69bb8d2dd9ef407bdedf42f9c2CAS |

Campbell CA, Zentner RP, Liang BC, Roloff G, Gregorich EG, Blomert B (2000) Organic C accumulation in soil over 30 years in semiarid southwestern Saskatchewan – effect of crop rotations and fertilizers. Canadian Journal of Soil Science 80, 179–192.
Organic C accumulation in soil over 30 years in semiarid southwestern Saskatchewan – effect of crop rotations and fertilizers.Crossref | GoogleScholarGoogle Scholar |

Chan KY, Oates A, Swan AD, Hayes RC, Dear BS, Peoples MB (2006) Agronomic consequences of tractor wheel compaction on a clay soil. Soil & Tillage Research 89, 13–21.
Agronomic consequences of tractor wheel compaction on a clay soil.Crossref | GoogleScholarGoogle Scholar |

Elfstrand S, Lagerlöf J, Hedlund K, Mårtensson A (2008) Carbon routes from decomposing plant residues and living roots into soil food webs assessed with 13C labelling. Soil Biology & Biochemistry 40, 2530–2539.
Carbon routes from decomposing plant residues and living roots into soil food webs assessed with 13C labelling.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtFCktLjI&md5=f7732da349ce30fb946098ec7a179769CAS |

Feddes RA, Raats PAC (2004) Parameterizing the soil–water–plant root system. In ‘Unsaturated-zone modeling: progress, challenges and applications’. Wageningen UR Frontis Series, Vol. 6. (Ed. RA Feddes) pp. 95–141. (Kluwer Academic Publishers: Dordrecht, The Netherlands)

Gan Y, Liang C, Wang X, McConkey BG (2011) Lowering carbon footprint of durum wheat by diversifying cropping systems. Field Crops Research 122, 199–206.
Lowering carbon footprint of durum wheat by diversifying cropping systems.Crossref | GoogleScholarGoogle Scholar |

Gan YT, Campbell CA, Janzenc HH, Lemked RL, Basnyata P, McDonald CL (2009a) Carbon input to soil from oilseed and pulse crops on the Canadian prairies. Agriculture, Ecosystems & Environment 132, 290–297.
Carbon input to soil from oilseed and pulse crops on the Canadian prairies.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXms1WhtrY%3D&md5=ea01d253e324bdaa744bb0d047ad5c45CAS |

Gan YT, Campbell CA, Jansen HH, Lemke RL, Basnyat P, McDonald CL (2010a) Nitrogen accumulation in plant tissues and roots and N mineralization under oilseeds, pulses, and spring wheat. Plant and Soil 332, 451–461.
Nitrogen accumulation in plant tissues and roots and N mineralization under oilseeds, pulses, and spring wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXntlGhu7w%3D&md5=f322157f80518c2b56c426c273e0b6ecCAS |

Gan YT, Campbell CA, Jansen HH, Lemke R, Liu LP, Basnyat P, McDonald CL (2009b) Root mass of oilseed and pulse crops. Canadian Journal of Plant Science 89, 883–893.
Root mass of oilseed and pulse crops.Crossref | GoogleScholarGoogle Scholar |

Gan YT, Kutcher R, Menalled F, Lafond G, Brandt SA (2010b) Crop diversification and intensification with broadleaf crops in cereal-based cropping systems in the Northern Great Plains of North America. In ‘Recent trends in soil science and agronomy research in the Northern Great Plains of North America’. (Eds SS Malhi, YT Gan, JJ Schoenau, RL Lemke, MA Liebig) pp. 277–301. (Research Signpost: Trivandrum, Kerala, India)

Jensen ES (1996) Rhizodeposition of N by pea and barley and its effect on soil N dynamics. Soil Biology & Biochemistry 28, 65–71.
Rhizodeposition of N by pea and barley and its effect on soil N dynamics.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXhtVSks7zN&md5=17c9efc23cb236527075cd7ab0988807CAS |

Kenward MG, Roger JH (1997) Small sample interface for fixed effects from restricted maximum likelihood. Biometrics 53, 983–997.
Small sample interface for fixed effects from restricted maximum likelihood.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK2svntVGitw%3D%3D&md5=720ee622b076dd5dc9aceb0945294c4eCAS | 9333350PubMed |

Kirkegaard J, Christen O, Krupinsky J, Layzell D (2008) Break crop benefits in temperate wheat production. Field Crops Research 107, 185–195.
Break crop benefits in temperate wheat production.Crossref | GoogleScholarGoogle Scholar |

Kramer C, Gleixner G (2006) Variable use of plant- and soil-derived carbon by microorganisms in agricultural soils. Soil Biology & Biochemistry 38, 3267–3278.
Variable use of plant- and soil-derived carbon by microorganisms in agricultural soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhtVagurbK&md5=f615a9acffd613810761d7e76ca65737CAS |

Krupinsky JM, Bailey KL, McMullen MP, Gossen BD, Turkington TK (2002) Managing plant diseases risk in diversified cropping systems. Agronomy Journal 94, 198–209.
Managing plant diseases risk in diversified cropping systems.Crossref | GoogleScholarGoogle Scholar |

Lemke RL, Zhong Z, Campbell CA, Zentner RP (2007) Can pulse crops play a role in mitigating greenhouse gases from North American agriculture? Agronomy Journal 99, 1719–1725.
Can pulse crops play a role in mitigating greenhouse gases from North American agriculture?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhsVGrur7K&md5=28e6159fbe944818e4f0560ef04bb134CAS |

Liang BC, Wang XL, Ma BL (2002) Maize root-induced change in soil organic carbon pools. Soil Science Society of America Journal 66, 845–847.
Maize root-induced change in soil organic carbon pools.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XlslOrur0%3D&md5=364a23139c0480ad71a240e4de1b298eCAS |

Littell RC, Milliken GA, Stroup WW, Wolfinger RD (1996) ‘SAS systems for mixed models.’ (SAS Institute, Inc.: Cary, NC)

McCallum MH, Kirkegaard JA, Green TW, Cresswell HP, Davies SL, Angus JF, Peoples MB (2004) Improved subsoil macroporosity following perennial pastures. Australian Journal of Experimental Agriculture 44, 299–307.
Improved subsoil macroporosity following perennial pastures.Crossref | GoogleScholarGoogle Scholar |

Miller PR, Gan Y, McConkey BG, McDonald CL (2003) Pulse crops for the northern Great Plains: I. Grain productivity and residual effects on soil water and nitrogen. Agronomy Journal 95, 972–979.
Pulse crops for the northern Great Plains: I. Grain productivity and residual effects on soil water and nitrogen.Crossref | GoogleScholarGoogle Scholar |

Paustian K, Andren O, Clarholm M, Hanson AC, Johansson G, Lagerlof J, Lindberg T, Petterson R, Schlenius B (1990) Carbon and nitrogen budgets of four agroecosystems with annual and perennial crops, with and without nitrogen fertilization. Journal of Applied Ecology 27, 60–84.
Carbon and nitrogen budgets of four agroecosystems with annual and perennial crops, with and without nitrogen fertilization.Crossref | GoogleScholarGoogle Scholar |

Peoples MB, Herridge DF, Ladha JK (1995) Biological nitrogen fixation: an efficient source of nitrogen for sustainable agricultural production? Plant and Soil 174, 3–28.
Biological nitrogen fixation: an efficient source of nitrogen for sustainable agricultural production?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXotFals7o%3D&md5=5a83e74f7df95ca6b11ed5cc933de81cCAS |

Pietola L, Alakukku L (2005) Root growth dynamics and biomass input by Nordic annual field crops. Agriculture, Ecosystems & Environment 108, 135–144.
Root growth dynamics and biomass input by Nordic annual field crops.Crossref | GoogleScholarGoogle Scholar |

Unkovich MJ, Baldock J, Peoples MB (2010) Prospects and problems of simple linear models for estimating symbiotic N2 fixation by crop and pasture legumes. Plant and Soil 329, 75–89.
Prospects and problems of simple linear models for estimating symbiotic N2 fixation by crop and pasture legumes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXjtFGluro%3D&md5=4593876a2b38bbbd62c64e8b15ef05c4CAS |

Unkovich MJ, Pate JS (2000) An appraisal of recent field measurements of symbiotic N2 fixation by annual legumes. Field Crops Research 65, 211–228.
An appraisal of recent field measurements of symbiotic N2 fixation by annual legumes.Crossref | GoogleScholarGoogle Scholar |

White RG, Kirkegaard JA (2010) The distribution and abundance of wheat roots in a dense, structured subsoil – implications for water uptake. Plant, Cell & Environment 33, 133–148.
The distribution and abundance of wheat roots in a dense, structured subsoil – implications for water uptake.Crossref | GoogleScholarGoogle Scholar | 19895403PubMed |

Wichern F, Eberhardt E, Mayer J, Joergensen RG, Müller T (2008) Nitrogen rhizodeposition in agricultural crops: Methods, estimates and future prospects. Soil Biology & Biochemistry 40, 30–48.
Nitrogen rhizodeposition in agricultural crops: Methods, estimates and future prospects.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtF2iu7bJ&md5=730a2d9bddf128625f7e990e1d00cc95CAS |

Xu JG, Juma NG (1992) Above- and below-ground net primary production of four barley (Hordeum vulvare L.) cultivars in western Canada. Canadian Journal of Plant Science 72, 1131–1140.
Above- and below-ground net primary production of four barley (Hordeum vulvare L.) cultivars in western Canada.Crossref | GoogleScholarGoogle Scholar |

Yu GR, Zhuang J, Nakayama K (2007) Root water uptake and profile soil water as affected by vertical root distribution. Plant Ecology 189, 15–30.
Root water uptake and profile soil water as affected by vertical root distribution.Crossref | GoogleScholarGoogle Scholar |

Zentner RP, Campbell CA, Biederbeck VO, Miller PR, Selles F, Fernandez MR (2001) The search of a sustainable cropping system for the semiarid Canadian prairies. Journal of Sustainable Agriculture 18, 117–136.
The search of a sustainable cropping system for the semiarid Canadian prairies.Crossref | GoogleScholarGoogle Scholar |