Evaluation of the Effectiveness of Iceberg Lettuce (Lactuca sativa var. Bruma Rz) Yield from Interaction of Cover Crops and Hand-Weeding

علوم باغبانی

Article 8, Volume 39, Issue 3, September 2025, Pages 487-471   

Document Type: Research Article

DOI: 10.22067/jhs.2025.90386.1386

Authors

F. Ahmadnia¹; A. Ebadi^{* 1}; M. Hashemi²

¹Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran

²Stockbridge School of Agriculture, Soil Sciences, University of Massachusetts Amherst, Massachusetts, USA

Abstract

Introduction
The most significant reduction of the commercial value and quality of leafy crops, such as lettuce, is primarily caused by weeds. The most common weeds in lettuce fields include Lambs quarters (Chenopodium album L.), Redroot pigweed (Amaranthus retroflexus L.), and wild mustard (Sinapis arvensis L.). Although using chemical inputs is considered a successful method in weed control, the risk of accumulating chemical contamination in plants and reducing human health by using these products increased the idea of using safe and environmentally friendly methods. Cover crops are an environmentally friendly strategy for controlling weeds in agricultural fields, offering numerous environmental benefits. Rye (Secale cereale L.) and chickling pea (Lathyrus sativus) are well-known worldwide cover crops. Many studies have mentioned them for their ability to control weeds, improve soil conditions, and release nutrients. Also, hand-weeding is known as one of the simple but expensive weed control methods. In our study, we aimed to explore how rye and chickling pea cover crop residues, when used in monoculture and intercropping systems, can help reduce the need for hand-weeding and improve the yield of Iceberg lettuce, considering the importance of weed control in leafy products.
 
Materials and Methods
 In the spring of 2020, an experiment was conducted using a factorial design base of RCBD with three replications. The experimental treatments included monoculture and intercropping of rye (Secale cereal L.), and chickling pea (Lathyrus sativus) cover crops, control (without cover crops), and additionally, different levels of hand-weeding were implemented (once, twice, and no hand-weeding). The amount of seed used for the rye and chickling pea monoculture was 100 and 25 kg.ha^-1, respectively. For intercropping, 50% of the recommended seed was used. F1 Iceberg lettuce (Bruma Rz.) seeds were planted in a mixture of peat moss and perlite in a 1:5 ratio. Due to the short growing season in Ardabil (20°48' E and 19°38' N), the growth of cover crops was terminated 67 days after the sowing date using paraquat. Then, lettuce seedlings were transplanted manually by 25 × 25 cm inter-row spacing. Hand weeding was conducted at three different stages: once 15 days after transplanting, twice at 15 and 30 days after transplanting, and not at all at the time of lettuce harvest. In this experiment, in addition to investigating the dry weight of cover crops and weeds, weed control efficiency index and fresh yield and lettuce yield components such as number of leaves, plant height, crown diameter, and head diameter were measured.
 
Results and Discussion
The results indicated that the highest dry weight of cover crops was obtained from the rye monoculture (530.59 ± 30.15 g.m^-2), followed by intercropping (400.21.43 ± 10.37 g.m^-2). The lowest dry weight of Chenopodium album L. and Anchusa italica Retz. weeds (0 g.m^-2) were recorded in intercropping with one- and two-times hand-weeding. The dry weight of Sinapis arvensis L. in intercropping once, twice, and without hand-weeding, rye and chickling pea monoculture without hand-weeding was 0 g.m^-2. The lowest total weed dry weight was found in the intercropping of cover crops with once hand-weeding. The highest weed control efficiency indexes (100, 86.95, and 87.72) were observed with intercropping by once and twice hand-weeding, and chickling pea monoculture without hand-weeding. The highest yield of Iceberg lettuce (3.70 ± 0.82 kg.m²) was achieved by intercropped cover crops without hand-weeding. The maximum number of leaves (21.55 ± 2.69 and 21.44 ± 1.01), crown diameter (4.15 ± 0.13 and 4.18 ± 0.23 cm), and head diameter (20. 22.12 ± 2 and 22.65 ± 2.22 cm, respectively) were obtained from the chickling pea monoculture and intercropping.
 
Conclusion
The effectiveness of using cover crop residues for weed control depends largely on the quantity of their dry weight. In the treatments without hand weeding, the rye monoculture and intercropping reduced the dry weight of weeds. The presence of cover crop residues reduced weed growth, although hand-weeding was still a more effective method of weed control in vegetables. However, the results highlighted the impact of cover crop dry weight on reducing hand-weeding for lettuce. In terms of increasing the yield of iceberg lettuce, rye intercropping, and chickling pea were favorable for the Ardabil region's climatic conditions.
 
Acknowledgment
The authors would like to express their gratitude to the Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources at the University of Mohaghegh Ardabili, Iran, for their financial support.

Keywords

Biomass; Density; Fresh weight; Intercropping; Weed control

References

1. Ahmadnia, F., Ebadi, A., & Gudarzi, M. (2021b). Interaction effect of cover crop residues and hand weeding of weeds on Iceberg lettuce (Lactuca sativa Iceberg) yield. Journal of Crop Ecophysiology, 15(4), 555-574. (in Persian with English Abstract). https://doi.org/10.30495/jcep.2022.689806
2. Ahmadnia, F., Ebadi, A., Hashemi, M., & Ghavidel, A. (2020a). Investigating the short time effect of cover crops on biophysical properties of soil. Journal of Water and Soil Conservation, 26(6), 277-290. (in Persian with English Abstract). https://doi.org/10.22069/jwsc.2019.16172.3145
3. Ahmadnia, F., Ebadi, A., Hashemi, M., & Nabati, L. (2020b). Investigating the effectiveness of Sunn Hemp (Crotalaria juncea) and Rye (Secale cereal) in weed suppression and yield of Kohlrabi (Brassica oleracea var. Gongylodes). Journal of Agricultural Science and Sustainable Production, 31(2), 43-56. (in Persian with English Abstract). https://doi.org/10.22034/SAPS.2021.13090
4. Ahmadnia, F., Ebadi, A., Hashemi, M., Ghavidel, A., & Alebrahim M.T. (2024b). Impact of oat (Avena sativa) and Daikon radish (Raphanus sativus var. Longipinnatus) cover crops on some soil properties. Applied Soil Research, 12(2), 1-17. (in Persian with English Abstract).
5. Ahmadnia, F., Ebadi, A., Hashemi, M., Ghavidel, A., & Alebrahim, M.T. (2024a). Impact of some cover crops and hand-weeding on the yield of spinach (Spinacia oleracea). Journal of Vegetables Sciences, 15(1), 109-134. (in Persian with English Abstract). https://doi.org/10.22034/IUVS.2023.2002290.1286
6. Ahmadnia, F., Ebadi, A., Hashemi, M., Ghavidel, A., & Ghahremani, S. (2021a). Evaluation of short-term effect of oat and chickling pea cover crops in improving selected soil properties. Applied Soil Research, 9(1), 72-87. (in Persian with English Abstract). https://asr.urmia.ac.ir/article_121035.html
7. Ahmadnia, F., Ebadi, A., Hashemi, M., Ghavidel, A., Godarzi, M., & Ghahramani, S. (2019). Effect of cover crops on weed control of Kohlrabi (Brassica oleracea). Journal of Agroecology, 9(2), 151-166. (in Persian with English Abstract)
8. Akmal, M., Gupta, A.K., Shukla, D.N., & Shareef, M. (2023). Allelopathic effect of Lathyrus sativus on seed germination and seedling growth of Lens culinaris L. Agriculture Research Journal, 60(6), 882-887. https://doi.org/10.5958/2395-146X.2023.00128.X
9. Azad Shahraki, F., Naghavi, H., & Najafi Nejad, H. (2010). Effects of tillage systems and wheat residue management on soil characteristics and yield of maize in Kerman. Journal of Modern Agriculture, 8(19), 2-9. (in Persian with English Abstract)
10. Azadbakht, A., & Alebrahim, M.T. (2017). Potato Production (Emphasizing the weed, diseases and pest’s management aspects). University Jihad Publications, Ardabil, Iran. 216 pp.
11. Baudoin, W., Nersisyan, A., Shamilov, A., Hodder, A., Gutierrez, D., Pascale, S., Nicola, S., Gruda, N., Urban, L., & Tanny, J. (2017). Good agricultural practices for greenhouse vegetable production in the South East European Countries: Principles for sustainable intensification of smallholder farms. Rome: FAO, 428 p.
12. Bergtold, J.S., Ramsey, S., Maddy, L., & Williams, J.R. (2017). A review of economic considerations for cover crops as a conservation practice. Renewable Agriculture and Food Systems, Cambridge University Press, 1-15 p. https://doi.org/10.1017/S1742170517000278
13. Blanco-Canqui, H., Claassen, M.M., & Presley, D.R. (2012). Summer cover crops fix nitrogen, increase crop yield, and improve soil–crop relationships. Agronomy Journal, 104(1), 137-147. https://doi.org/10.2134/agronj2011.0240
14. Bolandi Amughin, M., Tobeh, A., & Alebrahim, M.T. (2015). The effect of species, planting date, and management of cover crops on weed community in hybrid sunflower (Helianthus annuus). Journal of Plant Protection, 29(3), 337-348. (in Persian with English Abstract). https://doi.org/10.22067/jpp.v29i3.28939
15. Campiglia, A., Mancinelli, R., Radicetti, E., & Caporali, F. (2010). Effect of cover crop and mulches on weed control and nitrogen fertilization on tomato (Lycopersicon esculentum ). Crop Protection, 29, 354-363. https://doi.org/10.1016/j.cropro.2009.12.001
16. Casadei, E., Bacha, A.L., Rodrigues, J.S., Santos, R.T.S., Alves, P.L.C.A., & Arthur, B.C.F. (2020). Redroot pigweed interference with lettuce crop. Planta Daninha, 38(e020222945), 1-8.
17. Clifford, P., Rice, Y., Aref, A., & John, R.T. (2005). Hydroxamic acid content and toxicity of rye at selected growth stage. Journal of Chemical Ecology, 31(8),1887-1905. https://doi.org/10.1007/s10886-005-5933-6
18. Doane, T.A., Horwath, W.R., Mitchell, J.P., Jackson, J., Miyao G., & Brittan, K. (2009). Nitrogen supply from fertilizer and legume cover crop in the transition to no-tillage for irrigated row crops. Nutrint Cycling in Agroecosystems, 85(3), 253-262. https://doi.org/10.1007/s10705-009-9264-9
19. Dusky, J.A., & Stall, W.M. (1995). Weed management practices for lettuce production using imazethapyr. In Proceedings of the 108th Florida State Horticultural Society, Lake Alfred, FL, USA, 22–24 October 1995. pp. 204-207.
20. Dutta, D., Thentu, T.L., & Duttamudi, D. (2016). Effect of weed- management practices on weed flora, soil micro-flora and yield of baby corn (Zea mays). Indian Journal of Agronomy, 61(2), 210-216. https://doi.org/10.59797/ija.v61i2.4350
21. Fennimore, S.A., Smith, R.F., Tourte, L., Lestrange, M., & Rachuy, J.S. (2014). Evaluation and economics of a rotating cultivator in Bok choy, Celery, Lettuce, and Radicchio. Weed Technological, 28, 176-188. https://doi.org/10.1614/WT-D-13-00051.1
22. Ghahremani, S., Ebadi, A., Tobeh, A., Hashemi, M., Sedghi, M., & Gholipuri, A. (2020). The effect of cover crops on yield and weeds control of potato (Solanum tuberosum). Journal of Crop Ecophysiology, 14(1),119-134. (in Persian with English Abstract). https://doi.org/10.30495/jcep.2020.671644
23. Ghorbani, R., Khoramdel, S., Asadi, G.H., & Afrikan, R. (2015). Evaluation the effect of weed management strategies on weed seed bank and spinach yield (Spinacia oleracea). Journal of Plant Protection, 29(4), 400-411. https://doi.org/10.22067/JPP.V29I3.34878
24. Giancotti, P.R.F., Machado, M.H., & Yamauti, M.S. (2010). Total period of weed interference prevention in Lettuce cv. Ciências Agrárias, 31, 1299-1304.
25. Giannopolitis, C.N., Vassiliou, G., & Vizantinopoulos, S. (1989). Effects of weed interference and herbicides on nitrate and carotene accumulation in lettuce. Journal Agricultural Food & Chemistry, 37, 312-315. https://doi.org/1021/jf00086a008
26. Gidesa, A., & Kebede, M. (2018). Integration effects of herbicide and hand weeding on grain yield of Soybean (Glycine max (L.) Merr.) in Assosa, Western Ethiopia. Advences in Crop Science and Technology, 6(5), 1-5.
27. Godar, A.S., Norsworthy, J. N., & Barber, T. (2024). Effect of cereal rye cover crop termination timings on weed control and corn yield under a two-pass herbicide program. Frontiers in Agronomy, 6(1419228), 1-11. https://doi.org/10.3389/fagro.2024.1419228
28. Jabran, K. (2017). Manipulation of Allelopathic Crops for Weed Control. Springer Briefs in plant Science, Springer Nature International Publishing, AG, Switzerland, p. 87. https://doi.org/10.1007/978-3-319-53186-1
29. Jahanzad, E., Barker, A.V., Hashemi, M., Eaton, T., Sadeghpour, A., & Eeis, A. (2016). Nitrogen release dynamics and decomposition of buried and surface cover crop residues. Soil Fertility and Crop nutrition Agronomy Journal, 108(4), 1735-1741. https://doi.org/10.2134/agronj2016.01.0001
30. Khan, H., Adil, B., Gul, A.K.M., & Marwat, K.B. (2015). Efficacy of aqueous extracts of different allelopathic plants on germination and growth of wheat and wild oat. Pakistan Journal of Botany, 47(SI), 181-185.
31. Kist, B.B., Santos, C.E., De Carvalho, C., & Beling, R.R. (2020). Anuário Brasileiro de Horti & Fruti. Santa Cruz do Sul: Editora Gazeta, 98 p.
32. Kruse, R., & Nair, A. (2016). Summer cover crops and lettuce planting time influence weed population, soil nitrogen concentration, and lettuce yields. HortTechnology, 26(4), 409-416. https://doi.org/10.21273/HORTTECH.26.4.409
33. Kumar, B., Prasad, S., Mandal, D., & Kumar, R. (2017). Influence of integrated weed management practices on weed dynamics, productivity and nutrient uptake of Rabi maize (Zea mays). International Journal of Current Microbiology and Applied Sciences, 6(4), 1431-1440. https://doi.org/10.20546/ijcmas.2017.604.175
34. Kumar, V., Obour, A., Jha, P., Liu, R., Manuchehri, M.R., Dille, J.A., Holman, J., & Stahlman, P.W. (2020) Integrating cover crops for weed management in the semiarid U.S. Great Plains: Opportunities and challenges. Weed Science, 68, 311-323. https://doi.org/10.1017/wsc.2020.29
35. Lanini, W.T., & Le Strange, M. (1991). Low-input management of weeds in vegetable fields. California Agriculture, 45(1991), 11–13.
36. Lemessa, F., & Wakjira, M. (2015). Cover crops as a means of ecological weed management in agroecosystems. Journal of Crop Science and Biotechnology, 18(2), 123-135. https://doi.org/10.1007/s12892-014-0085-2
37. Majidi, M.R., Mirshekari, B., Samedani, B., Hajinajari, H., & Frahvash, F. (2018). Effect of four cover crop species on weed control and population changes in Karaj region. Iranian Journal of Weed Science, 14(1), 11-22. (in Persian with English abstract). https://doi.org/10.22092/IJWS.2018.1401.02
38. Mennan, H., Jabran, K., Zandstra, B.H., & Pala, F. (2020). Non-chemical weed management in vegetables by using cover crops: A review. Agronomy, 10, 257. https://doi.org/10.3390/agronomy10020257
39. Mohammadi, G.R. (2010). Weed control in irrigated corn by hairy vetch inter seeded at different rates and times. Weed Biology and Management, 10, 25-32. https://doi.org/10.1111/j.1445-6664.2010.00363.x
40. Mohammadi, K.H., Nabiolahi, K., Alikhani, M., & Kharmali, F. (2009). Effects of tillage systems on soil physical properties and yield and yield components of wheat. Journal of Plant Production, 16(4), 77-91.
41. Nabati Souha, L., Alebrahim, M.T., Ahmadnia, F., & Rostami Yangjeh, M. (2021). Investigating of the ability of some cover crops to weeds control. Journal of Crop Ecophysiology, 15(2), 281-298. (in Persian with English Abstract). https://doi.org/10.30495/jcep.2021.683387
42. Obopile, M., Munthali, D.C., Matilo, B. (2008). Farmers’ knowledge, perceptions and management of vegetable pests and diseases in Botswana. Crop Protection, 27, 1220-1224. https://doi.org/10.1016/j.cropro.2008.03.003
43. Olsen, S.R., & Sommers, L.E. (1982). Phosphorus. In: Page AL. (ed), Methods of Soil Analysis, Agronomy. No. 9, Part 2: Chemical and microbiological properties, 2^nd, American Society Agronomy, Madison, 403-430 p.
44. Osipitan, O.A., Dille, J.A., Assefa, Y., & Knezevic, S.Z. (2018). Cover crop for early season weed suppression in crops: Systematic review and meta-analysis. Agronomy Journal, 110, 2211-2221. https://doi.org/10.2134/agronj2017.12.0752
45. Pannacci, E., Lattanzi, B., & Tei, F. (2017). Non-chemical weed management strategies in minor crops: A review. Crop protection, 96(2017), 44-58. https://doi.org/10.1016/j.cropro.2017.01.012
46. Parven, A., Meftaul, I.M., Venkateswarlu, K., & Megharaj, M. (2025). Herbicides in modern sustainable agriculture: environmental fate, ecological implications, and human health concerns. International Journal of Environmental Science and Technology, 22(2025), 1181-1202. https://doi.org/10.1007/s13762-024-05818-y
47. Pereira, L., Tejada, J.L., Cecílio Filho, A.B., Alves, P.L.D.C.A. (2023). Lettuce weed control with prior soil solarization. Comunicata Scientiae Horticultural Journal, 7(14), 1-7. https://doi.org/10.14295/CS.v14.3906
48. Planisich, A., Utsumi, S.A., Larrip, M., & Galli, J.R. (2021). Grazing of cover crops in integrated crop-livestock systems. Animal, The international Journal of Animal Bioscience, 15(1), 100054, 1-7. https://doi.org/10.1016/j.animal.2020.100054
49. Plastina, A., Liu, F., Miguez, F., & Carlson, S. (2020). Cover crops use in Midwestern US agriculture: Perceived benefits and net returns. Renewable Agriculture and Food Systems, 35, 38-48. https://doi.org/10.1017/S1742170518000194
50. Rajput, R.L., & Kasana, BS. (2019). Integration of chemical and cultural methods for weed control management in soybean (Glycin max). Legume Research, 3944, 1-4. https://doi.org/10.18805/LR-3944
51. Riva, N.B., Biffe, D.F., Nalin, D., Mendes, R.R., Silva, V.F.V., Ferreira, L.A.I., & Constantin, J. (2021). Sensitivity of lettuce cultivar Lucy Brown to pre-planting herbicide application. Horticultura Brasileira, 39, 305-311.
52. Riva, N.B.D., Biffe, D.F., Nalin, D., Mendes, R.R., Ferreira, L.A. I., Silva, V.F.V., & Constantin, J. (2023). Weed interference periods in lettuce crop. Horticultura Brasileira, 41, 2566, 1-9.
53. Roberts, H.A., Hewson, R.T., & Ricketts, M.A. (1997). Weed competition in drilled summer lettuce. Horticulture Research, 17(1997), 39-45.
54. Santos-Naressi, R., Santos-Pimentel-Oliveira, L., Santos, E.H., Francisco, J.P., & Lopes, A.D. (2022). Iceberg lettuce cultivated in different systems of planting and sources of fertilizer. Brazilian Journal of Biology, 84, e255421, 1-8.
55. Shem-Tov, S.H., Fennimore, S.A., & Thomas Lanini, W. (2006). Weed management in lettuce (Lactuca sativa) with preplan irrigation. Weed Technology, 20(4), 1058-1065. https://doi.org/10.1614/WT-05-085.1
56. Sias, C., Wolters, B.R., Reiter, M.S., & Flessner, M.L. (2021). Cover crops as a weed seed bank management tool: A soil down review. Italian Journal of Agronomy, 16, 1852, 1-9. https://doi.org/10.4081/ija.2021.1852
57. Silva, G.C., & Bagavathiannan, M. (2023). Mechanisms of weed suppression by cereal rye cover crop: A review. Crop Ecology and Physiology, 115(2023), 1571-1585. https://doi.org/10.1002/agj2.21347
58. Sturm, D.J., Peteinatos, G., & Gerhards, R. (2018). Contribution of allopathic effects to the overall weed suppression by different cover crops. Weed Research, 58(5), 331-337. https://doi.org/10.1111/wre.12316
59. Thiem, T.T., Thu, T.T.P., & Loan, N.T. (2020). Effect of plant density and hand weeding on weed control and yield of the vegetable corn. Vietnam Journal of Agricultural Sciences, 3(4), 784-797. https://doi.org/10.31817/vjas.2020.3.4.02
60. Tiwari, S., Sindel, B.M., Smart, N., Coleman, M.J., Fyfe, C., Lawlor, C., Vo, B., & Kristiansen, P. (2022). Hand weeding tools in vegetable production systems: An agronomic, ergonomic and economic evaluation. International Journal of Agricultural Sustainability, 20(4), 659-674. https://doi.org/10.1080/14735903.2021.1964789
61. Uchino, H., Iwama, K., Jitsuyama, Y., Ichiyama, K., Sugiura, E.R.I., Yudate, T., Nakamura, S., & Gopal, J.A.I. (2012). Effect of inter seeding cover crops and fertilization on weed suppression under an organic and rotational cropping system 1. Stability of weed suppression over years and main crops of potato, maize and soybean. Field Crops Research, 127, 9-16. http://doi.org/10.1016/j.fcr.2011.10.007
62. Urbano, V.R., Mendonça, T.G., Bastos, R.G., & Souza, C.F. (2017). Effects of treated wastewater irrigation on soil properties and lettuce yield. Agricultural Water Management, 181, 108-115. http://dx.doi.org/10.1016/j.agwat.2016.12.001

• Vaezi Rad, S., Valadabadi, S.A., Pourousef, M., Seifzadeh, S., & Zakerin, H.R. (2020). Evaluating of forage yield increase of sorghum (Sorghum bicolor L.) and weed control by its intercropping with forage legumes. Journal of Crop Ecophysiology, 14(1), 101-118. https://doi.org/10.30495/jcep.2020.671643