The effect of species, planting date, and management of cover crops on weed community in hybrid sunflower (Helianthus annuus)

Document Type : Research Article


University of Mohaghegh Ardabili


Introduction: Studies showed that if mixed populations of annual weeds grow with the sunflower, for every 10% increase in weed biomass, seed yield would decrease by 13% (Van Gessel & Renner, 2000). In addition to control weeds using herbicides multi-stage spraying is required. In organic farming systems mulch is used to control weeds, protection, fertility and improve soil quality (Glab & Kulig, 2008; Kuchaki et al., 2001). Surface mulches from cover crops suppress weed growth by reducing light levels at the soil surface, thereby slowing photosynthesis. In return, these conditions reduce seed germination and act as a physical barrier to seedling emergence and growth (Teasdale et al., 2007).
Materials and Methods: The experiment was carried out in Ardabil Agricultural Research Station, as a factorial experiment based on randomized complete block design with three replications during 1390-1391. The first factor was considered four types of cover crops including winter rye (Secale cereal), spring barley (Hordeum vulgare), winter wheat (Triticum aestivum) and control (no cover crop, no weeding).The second factor was mulch management at two levels (living mulch and dead mulch) and the third factor was two planting dates for cover crops (synchronous with sunflower planting and 45 days after sunflower planting). Sunflower seeding performed manually on 23 May on the ridges with 50 cm row distance and spacing between plants was 25 cm in depth of 5 cm. Cover crops seeds, rye, barley and wheat, were planted between rows of sunflower. Due to the low density of weeds in study field, complete weeding and sampling of weeds in one session was performed (60 days after planting date sunflower). Statistical analysis of data performed using SAS software and mean comparison performed using Duncan's test with probability level of 5% and 1%. Diagrams drawn using Excel (Version 8.2).
Results and Discussion :
Density and dry weight of Field bindweed (Convolvulus arvensis L.): Results of the study indicated that the interaction between cover crop and planting date on density and dry weight of bindweed was significant at probability level of 5% and 1%, respectively. The best condition of reduced density of bindweed was related to the time of using rye cover crop where reduced Field bindweed density to 64% compared to control (without cover crop, no weeding). Date of simultaneous planting of cover crop, reduced bindweed density from mean 15/7% plant.m-2 to 11/62 plant.m-2, compared to 45 days after sunflower planting. Hasannejad and Alizadeh, (2005) reported that rye significantly controlled the weeds of redroot pigweed, common lambsquarters, knotgrass, russian thistle and field bindweed compared to controls with no cover crop. All three cover crops had significant effect on reducing the dry weight of bindweed. Cover crops showed the potential to reduce density and total dry weight of weeds compared to no control weeds and increase the plant yield. In a study, the density and dry weight of field bindweed in treated living rye and dead rye reduced 100% and 85% respectively (Samadani & Montazeri, 2009).
Density and dry weightof Pale bugloss (Anchusa italica Retz): The interaction (cover crop × planting date) on pale bugloss density and dry weight was meaningful in probability level of 1%.All three cover crops with simultaneous planting date showed lowest density of pale bugloss. Rye with proper ground cover in the beginning of season, and due to the long-term preservation of residues in the ground level, inhibited germination and growth of weeds for longer times. Results of the studies by (Abdollahyan Noghaby et al., 2011) on sugar beet showed that the effects of planting cover crops of triticale, wheat, rye and barley, between rows where sugar beet planted, to control weeds population would be the same as when herbicide used to control these weeds.
Density and dry weight ofRussian thistle (Salsola kali L.): Results indicated that the interaction effect (cover crop × planting date) on density and dry weight of russian thistle was meaningful at probability levels of 1% and 5% respectively. The best result on the reduced density and dry weight of russian thistle observed when rye cover crop was used. Elmore, (1980) in a study observed that rye stubble, has more potential in reducing the biomass of wide spectrum of weeds, particularly the annuals.
Density and dry weight ofCommon reed (Phragmites australis L.): Density of common reed on main effect of cover crop and its dry weight on main effect of cover crop and planting date showed meaningful difference with probability level of 1%. Cover crop of rye, due to the increased biomass, initial growth vigor, high tillering and in fact because of high allelopathy showed better performance in reducing density of perennial weeds such as common reed when planted simultaneously with sunflower, compared to wheat and barley. Samedani et al., (2005) reported that rye and wheat can better control the weeds due to high biomass.
Dry yield of sunflower seed: Regarding the results of data analysis, the yield of sunflower seed influenced by cover crop treatments (P≤0.05). Sunflower seed yield in treatments of rye and wheat cover crops with control 1 treatment (no cover crop, complete weeding) showed no meaningful difference. Among cover crops, highest yield of seed related to wheat with 3916/7 kg.ha-1. Cover crop of barley showed poor yield compared to rye and wheat that was likely due to lower growth of barley and the lack of producing sufficient biomass and proper control of weeds. Cover crops can have positive or negative effects on grain crop yields, depending on environment, cover crop species and management (Miguez & Bollero, 2005).
Conclusion: Results showed that cover crops, particularly rye, are very effective in reducing the density and dry weight of weeds so that the application of cover crops even resulted in increased yield of sunflower seed. Therefore, use of cover crops between planting rows of crops can be a good option to replace herbicides and conventional tillage and as a new and proper approach for sustainable management of weeds.


1- AbdollahianNoghabi M., Najafi H., and Yousefabadi V. 2011. Cover crops mulch application for sugar beet weed control in autumn seedbed preparation. 33th Iranian Sugar Beet Symposium, 26-27 Jul. 2011. Mashhad, Iran. (In Persian).
2- Blackshaw R. E., lemerle D., Mailer R., and Young K.R. 2002. Influence of wild radish on yield and quality of canola. Weed Science, 50:344-349.
3- Clark A. 2007. Managing Cover Crops Profitably, 3rd ed. Sustainable Agriculture Network, Beltsville, MD.
4- Dhima K., Eleftherohorinos I.G., and Vasilakoglou I.B. 2000. Interference between Avena sterilis, Phalaris minor and five barley cultivars. Weed Research, 40:549-559.
5- Duppong L.M., Delate K., Liebmen M., Horton R., Kraus G., Petrich J., and Chowdbury P.K. 2004. The effect of natural mulches on crop performance, weed suppression and biochemical constituents of catnip and St. John,s Wort.Crop Science, 44:861-869.
6- Elmore C.D. 1980. Inhibition of turnip (Brassica rapa)seed germination by velvet leaf (Abutilon theophrasti)seed. Weed Science, 28:658-660.
7- Fisk J.W., Heesterman O.B., Shrestha A.J., Kells J., Harwood R.R., Squire J.M., and SheafferC.C. 2001. Weed suppression by annual legume cover crops in no-tillage corn. Agronomy Journal, 93:319-325.
8- Glab T., and Kulig B. 2008. Effect of mulch andtillage system on soil porosity under wheat (Triticum aestivum). Soil and Tillage Research, 99:169-178.
9- Hasannejad S., and Alizadeh H. 2005. Winter rye appropriate option in the management of weeds in spring crops. Proceedings of the First Conference of Weed Science. Plant Pests and Diseases Research Institute, 5-6 January. 2005. Tehran, Iran. (In persian).
10- Hiltbrunner J., Liedgens M., Bloch L., Stamp P., and Streit B. 2007. Legume cover crops as living mulches for winter wheat: Components of biomass and the control of weeds. European Journal Agronomy, 26:21–29.
11- Jahedi A. 2003. The use of green manure of allelopathic plants on weed control in Potato Farm. Third National Conference on Application of Biological Development and Efficient Use Of fertilizers and Poison in Agriculture, Deputy of Education and Providing of Human Force Ministry of Agricultural Jihad, 2-4 March. 2003. Karaj, Iran. (in Persian).
12- Joshi D.C., Das S.K., and Mukherjee R.K., 1993. Physical properties of pumpkin seeds. Journal of Agricultural Engineering Research, 54:219–229.
13- Kuchaki A.R., ZarifKetabi H., and NakhFroosh A. 2001. The ecological approach to weed management (translation). Mashhad University Press. (in persian).
14- LutmanP.J.W. 2002. Estimation of seed production by Stellaria media, Sinapis arvensis and Tripleurospermuminodorum in arable crops. Weed Research, 42:359–369.
15- Maldonado J.A., Osornio J.J., BarraganA.T., and Anaya A.L. 2001. The use ofallelopathic legume cover and mulch species for weed control in croppingsystems. Agronomy Journal, 93:27-36.
16- Mohammaddoost H.R., and Asghari A. 2009. The effect of crop rotation, fertilizer application and herbicide on weed control in winter rye. Journal of Science Agricultural Technology, 47:601-610 (In Persian).
17- Moonen A.C., and Barberi P. 2004. Size and composition of the weed seedbank after 7 years ofdifferent cover crop maize management systems. Weed Research, 44:163-177.
18- Mousavi S.K., Zand A., and Baghestani M.A. 2005. Effect of planting density on bean Interaction (Faseolus vulgaris L.) and weeds. Journal of Plant Pest and Diseases, 73(1):79-92. (in persian).
19- Movahedi Dehnavi M., Mazaheri D., and Bankeh saz A. 2001. The role of beans in corn weed control. Journal of wilderness, 6(12):85-71. (in persian).
20- Najafi H. 2012. The effect of autumn and spring cover crops on weed control in sugar beet. Iranian Journal of Crop Sciences, 14(4):382-370. (in Persian with English Abstract)
21- Noor Mohammadi Gh., siyadat S.A., and Kashani A. 2001. Cereal crops. shahid Chamran University of Ahvaz Press. (in persian).
22- Radfar R. 2007. Study support policies imposed by the selected countries for the development of oil seeds and edible Oil, summary articles of second seminar in the scientific application of oil seeds and vegetable oils, 22 September. 2007. Tehran, Iran (in persian).
23- Reddy K.N. 2003. Impact of rye cover crop and herbicides on weeds, yield, and netreturn in narrow-row transgenic and conventional soybean (Glycine max). Weed Technology, 17:28-35.
24- Samadani B., and Montazeri M. 2009. The use of cover crops in sustainable agriculture. Plant Protection Institute Publications, Iran. (in persian).
25- Samedani B., Ranjbar M., Rahimiyan H., and Jahansooz M. 2005. The effects of winter rye cover crops planting and hairy vetch and their mixtures on density and biomass of London rocket (Sisymbriminm irio) and Earth smoke (Fumaria villanti). Quarterly of Plant Diseases, 1:85-95. (in persian).
26- Sosnoskie L.M., Herms C.P., Cardina J. 2006. Weed seedbank community composition in a 35-yr-old tillage and rotation experiment. Weed Science,54:263–273.
27- Taleghani d. F., Sadeghzadeh S., and Msban M. 2010. Strategies for Sugar Beet Research. Institute of sugar beet seed. Iran. (In persian).
28- Teasdale J.R., Sheltone D.R., Sadeghi A.M., and Isensee A. 2003. Influence of hairy vetch residue on atrazine and metolachlor soil solution concentration and weed emergence. Weed Science,51:628–634.
29- Vahedi A. 2005. Weeds. Volume 2. Scientific coping with weeds. Astara Islamic Azad University Press. Iran. (In persian).
30- Van Gessel M.J., and Renner K.A. 2000. Redroot pigweed (Amaranthus retroflexus) and barnyard grass (Echinochloa crus-galli) interference in potatoes (Solanum tuberosum). Weed Science, 48:338- 343.