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Cover crop nitrogen contribution to organic broccoli production

  • John M. Luna (a1), Dan Sullivan (a2), Amy M. Garrett (a3) and Lan Xue (a4)

Nitrogen (N) is a difficult nutrient to manage in organic farming systems, and yield reductions related to N deficiency have been reported in organic systems. Legume-based cover crops offer opportunities for biologically fixed N; however, improved quantification of N contribution is needed for cost-effective N management. A 2-yr experiment was conducted near Corvallis, OR, USA, in 2007 and 2008 to (1) evaluate biomass production and N accumulation from selected cover crop treatments, (2) compare the effects of fall-planted cover crops on broccoli [(Brassica oleraceae L. (Italica group)] yield, (3) estimate the quantity of feather meal-N replaced by cover crops. Cover crop treatments included common vetch (Vicia sativa L.), phacelia (Phacelia tanacetifolia Benth), oats (Avena sativa L.) and the mixtures phacelia plus vetch, oats plus vetch and a no-cover crop (fallow) treatment as the control. Using feather meal as an N source, four rates of N fertilizer (0, 100, 200 and 300 kg N ha−1) were randomized within each cover crop treatment in a randomized, split-plot design. Cover crop biomass and N accumulation differed between the 2 yr of the study. In 2007, total biomass accumulation ranged from 5000 to 10,000 kg ha−1, whereas in 2008, cover crop accumulation was 1500 to 5000 kg ha−1. Biomass of both phacelia and vetch (in mixtures or as sole crops) was reduced by 80% from 2007 to 2008, whereas oat biomass and weed biomass in the fallow plots was reduced by only 40% between the 2 yr. The accumulation of N was also reduced in 2008, with vetch (either as a sole crop or in mixtures) contributing less than a third of total N produced in 2007. In 2007, vetch and vetch-based cover crop mixtures increased broccoli yield compared with the fallow, providing 100–135 kg fertilizer equivalent N ha−1. But due to decreased cover crop biomass and N accumulation in 2008, vetch and vetch-based mixtures failed to increase broccoli yield, providing <20 kg N ha−1 fertilizer equivalence. In 2007, oats grown as a sole cover crop reduced broccoli yield when no supplemental N was applied. In 2008, both phacelia and oats reduced broccoli yield at all N levels, with estimated N fertilizer equivalence values of −80 to −95 kg N ha−1. Although legume and legume mixtures increased broccoli yield in only 1 yr of the experiment, addition of vetch to the mixtures reduced yield loss in both years compared with oats and phacelia grown as sole crops.

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Author for correspondence: John Luna, E-mail:
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Akemo, MC, Regnier, EE and Bennett, MA (2000) Weed suppression in spring-sown rye (Secale cereale)-pea (Pisum sativum) cover crop mixes. Weed Technology 14, 545549.
Ambrosino, MD, Luna, JM, Jepson, PC and Wratten, SD (2006) The relative frequencies of visits by predacious hoverflies, other beneficial insects and herbivores to selected insectary plants. Environmental Entomology 35, 394400.
Angustia Nova, S (1995). Impact of cover crops on weed abundance and nitrogen contribution in broccoli, Brassica oleracaea var. italica production systems in the Maritime Pacific Northwest. M.S. Thesis, Department of Horticulture, Oregon State University, Corvallis, OR 92p.
Berry, PM, Sylvester-Bradley, R, Phillips, L, Hatch, DJ, Cuttle, SP, Rayns, FW and Gosling, P (2002) Is the productivity of organic farms restricted by the supply of available nitrogen? Soil Use and Management 18, 248255.
Brandi-Dohrn, F, Hess, M and Selker, JS (1997) Nitrate leaching under a cereal rye cover crop. Journal of Environmental Quality 26, 181188.
Brennan, EB and Boyd, NS (2012) Winter cover crop seeding rate and variety affects during eight years of organic vegetables. I. Cover crop biomass production. Agronomy Journal 104, 684698.
Cherr, CM, Scholberg, JM and McSorley, R (2006) Green manure approaches to crop production: a synthesis. Agronomy Journal 98, 302319.
Clark, AJ, Decker, AM and Meisinger, JJ (1994) Seeding rate and kill date effects on hairy vetch-cereal rye cover crop mixtures for corn production. Agronomy Journal 86, 10651070.
Colley, MR and Luna, JM (2000) The relative attractiveness of potential beneficial insectary plants to aphidophagous hoverflies (Diptera: Syrphidae). Environmental Entomology 29, 10541059.
Crews, TE and Peoples, MB (2004) Legume versus fertilizer sources of nitrogen: ecological tradeoffs and human needs. Agriculture, Ecosystems & Environment 102, 279297.
Fageria, NK, Baligar, VC and Bailey, BA (2005) Role of cover crops in improving soil and row crop productivity. Communications in Soil Science and Plant Analysis 36, 1920, 2733-2757.
Fageria, NK, Baligar, VC and Jones, CA (2010) Growth and Mineral Nutrition of Field Crops, 3rd Edn. Boca Raton, FL: CRC Press, 586 pp.
Gaskell, M and Smith, R (2007) Nitrogen sources for organic vegetable crops. HortTechnology 17, 431441.
Gavlak, R, Horneck, D and Miller, RO (2005) Soil, Plant and Water Reference Methods for the Western Region, 3rd Ed. WREP-25.
Hickman, JM and Wratten, SD (1996) Use of Phacelia tanacetifolia strips to enhance biological control of aphids by hoverfly larvae in cereal fields. Journal of Economic Entomology 89, 832840.
Hughes-Games, GA and Bertrand, RA (1991) Cover crop experience in south coastal British Columbia. In IN Hargrove WL (ed.), Cover Crops for Clean Water. Ankeny, IA: Soil and Water Conservation Society, pp. 2729. 197 pp.
Jensen, ES (1997) Nitrogen immobilization and mineralization during initial decomposition of 15N-labelled pea and barley residues. Biology and Fertility of Soils 24, 3944.
Karpenstein-Machan, M and Stuelpnagel, R (2000) Biomass yield and nitrogen fixation of legumes monocropped and intercropped with rye and rotation effects on a subsequent maize crop. Plant and Soil 218, 215232.
Kuo, S and Sainju, UM (1998) Nitrogen mineralization and availability of mixed leguminous and non-leguminous cover crop residues in soil. Biology and Fertility of Soils 26, 346353.
Lawson, A, Fortuna, AM, Cogger, C, Bary, A and Stubbs, T (2013) Nitrogen contribution of rye-hairy vetch cover crop mixtures to organically grown sweet corn. Renewable Agriculture and Food Systems 28, 5969.
Lenzi, A, Antichi, D, Bigongiali, F, Mazzoncini, M and Tesi, R (2009) Effect of different cover crops on organic tomato production. Renewable Agriculture and Food Systems 24, 92101.
Luna, JM (2009) Reducing energy inputs in Oregon vegetable production to enhance economic and environmental sustainability. Report to the Oregon Processed Vegetable Growers, Salem, OR. 15 pp.
Luna, JM and Staben, ML (2002) Strip tillage for sweet corn production: yield and economic return. HortScience 37, 10401044.
Luna, JM, Mitchell, JP and Shrestha, A (2012) Conservation tillage for organic agriculture: evolution toward hybrid systems in the western USA. Renewable Agriculture and Food Systems 27, 2131.
Magdoff, F and van Es, H (2000) Building Soils for Better Crops, 2nd Edn. Beltsville, MD: Sustainable Agriculture Network (SAN), 230 pp.
McCracken, DV, Smith, MS, Grove, JH, MacKown, CT and Blevins, RL (1994) Nitrate leaching as influenced by cover cropping and nitrogen source. Soil Science Society of America Journal 58, 14761483.
Meisinger, JJ, Hargrove, WL, Mikkelsen, RI Jr, Williams, JR and Benson, VE (1991). Effects of cover crops on groundwater quality. In Hargrove, WL (ed.), Cover Crops for Clean Water. Ankeny, IA: Soil and Water Conservation Society, pp. 5768.
Mitchell, JP, Shrestha, A and Irmak, S (2015) Trade-offs between winter cover crop production and soil water depletion in the San Joaquin Valley, California. Journal of Soil and Water Conservation 70, 430440.
Muramoto, J, Smith, RF, Shennan, C, Klonsky, KM, Leap, J, Ruiz, MS and Gliessman, SR (2011) Nitrogen contribution of legume/cereal mixed cover crops and organic fertilizers to an organic broccoli crop. HortScience 46, 11541162.
Pang, XP and Letey, J (2000) Organic farming: challenge of timing nitrogen availability to crop nitrogen requirements. Soil Science Society of America Journal 64, 247253.
Ranells, NN and Wagger, MG (1996) Nitrogen release from grass and legume cover crop monocultures and bicultures. Agronomy Journal 88, 777782.
Rosecrance, RC, McCarty, GW, Shelton, DR and Teasdale, JR (2000) Denitrification and N mineralization from hairy vetch (Vicia villosa Roth) and rye (Secale cereale L.) cover crop monocultures and bicultures. Plant and Soil 227, 283290.
Sainju, UM, Whitehead, WF and Singh, BP (2005) Biculture legume-cereal cover crops for enhanced biomass yield and carbon and nitrogen. Agronomy Journal 97, 14031412.
SAS Institute (2008) SAS 9.2. Cary, North Carolina: Sas Institute Inc.
Schomberg, HH, Endale, DM, Calegari, A, Peixoto, R, Miyazawa, M and Cabrera, ML (2006) Influence of cover crops on potential nitrogen availability to succeeding crops in a Southern Piedmont soil. Biology and Fertility of Soils 42, 299307.
Smith, MS, Frye, WW and Varco, JJ (1987) Legume winter cover crops. Advances in Soil Science 7, 95139.
Snapp, SS, Swinton, SM, Labarta, R, Mutch, D, Black, JR, Leep, R, Nyiraneza, J and O'Neil, K (2005) Evaluating cover crops for benefits, costs, and performance within cropping system niches. Agronomy Journal 97, 322332.
Sullivan, PG, Parrish, DJ and Luna, JM (1991) Cover crop contributions to N supply and water conservation in corn production. American Journal of Alternative Agriculture 6, 106113.
Ta, TC and Faris, MA (1987) Species variation in the fixation and transfer of N from legumes to associated grasses. Plant and Soil 98, 265274.
Tonitto, C, David, MB and Drinkwater, LE (2006) Replacing bare fallows with cover crops in fertilizer-intensive cropping systems: a meta-analysis of crop yield and N dynamics. Agriculture, Ecosystems & Environment 112, 5872.
Wagger, MG (1989) Time of desiccation effects on plant composition and subsequent nitrogen release from several winter annual cover crops. Agronomy Journal 81, 236241.
Williams, IH and Christian, DG (1991) Observations on Phacelia tanacetifolia Bentham (Hydrophyllaceae) as a food plant for honey bees and bumble bees. Journal of Apicultural Research 30, 312.
Wyland, LJ, Jackson, LE and Schulbach, KF (1995) Soil-plant nitrogen dynamics following incorporation of a mature rye cover crop in a lettuce production system. Journal of Agricultural Science 124, 1725.
Wyland, LJ, Jackson, LE, Chaney, WE, Klonsky, K, Koike, ST and Kimple, B (1996) Winter cover crops in a vegetable cropping system: impacts on nitrate leaching, soil water, crop yield, pests and management costs. Agriculture, Ecosystems & Environment 59, 117.
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Renewable Agriculture and Food Systems
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