Competitive Ability of Soybean and Three Species of Foxtail Setaria glauca, S. verticillata and S. viridis in Different Planting Ratios

Document Type : Research Article


1 M.Sc. Student of Aronomy, Sari Agricultural Sciences and Natural Resources University

2 Associate Professor of Aronomy, Sari Agricultural Sciences and Natural Resources University

3 Associate Professor of Agronomy and Plant Breeding, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran


Introduction: Competition for resources among plants has long been considered to generate stress for plants and to be important for determining the distribution of species, as well as their evolution. Competition can occur among the organs of a plant (intra plant competition), or negative interactions between the plants of a species (intra specific competition) or interference among different plant species (inter specific competition). Weeds have long been considered as the main competitor of crop plants. These plants can be problematic due to competition with crop plants over light, water and nutrients, decreases the quantity and quality of the product and the creation of a suitable refuge for insects and pathogens. The presence of weeds in soybean reduces seed yield and the rate of this decrease depends on weed density and stage growth stage. In agriculture areas, crop density is kept constant whereas weed density varies in accordance to local infestation degree. Therefore, variation in plant proportion of crops and weeds is established. Thus, in competition studies, it is important to measure the influence of plant density on the competitive process as well as the variation in plant proportion. There are several methodologies used to study plant competition. However, most researchers measured just the interference of weeds on crop growth and production without concerning about the competition process. Thus, it is important to use appropriate experimental designs and methods of analysis to understand the competition process not just by quantifying crop losses but in a mechanistic way. Replacement series experiments allow the control of plant density and proportion, where plant density is kept constant while plant proportion is changed for both studied species. This study aimed to investigate the response of soybeans to the interaction of three species of foxtail (Setaria glauca, S. verticillata and S. viridis) and competitions between the species of these three weeds.
Materials and Methods: These pot experiments were carried out at Sari Agricultural Sciences and Natural Resources University based on a completely randomized design in three replications. The first experimental treatments included planting ratios: 25:75, 50:50, 75:25 (soybean-weed) and pure stand of soybean and weed and in the other three experiments, each of the weeds compared in pairs with the ratios listed above. Density of soybean and weed in the sole stand was four plants per pot and in the planting ratio of 50:05 soybean-weed, two plants were considered from each plant. Also, in the planting ratio of 75:25 soybean and weed, 4 seeds were cultivated in each pot, wherein planting ratio of 75% three seeds of soybean or weed and planting ratio of 25% one seed of soybean or weed was planted. The traits studied in this experiment included seed yield, number of sub-branches, number of pods per plant, number of seeds per pod and 100- seed weight of soybeans. Weed biomass, height, number of leaves, number of spikes and number of tillers of weeds were also calculated in competition with each other. In addition, the ability of weed competition and the competition index were determined.
Results and Discussion: The results showed that the competitive ability of three species with soybean showed that the maximum soybean seed yield (15.56 g plant-1) were obtained in weed-free conditions (soybean monoculture) and increasing soybean density in interference with three species of foxtail reduce weeds biomass compare to the monoculture of weed. Although, survey competitive withstand ability of soybean to different densities of three species of foxtail showed that soybean is more tolerant to low densities (25%) of S. glauca, S. verticillata and S. viridis, but the competitive ability of soybeans compared to these three species was S. glauca > S. verticillata > S. viridis; because the increasing density of S. glauca, caused decreasing soybean yield with a gentle slope while, increasing density of S. viridis, made a decrement of soybean yield with a steep slope. The competitive ability of three species of foxtail together showed that increasing density of any species will diminished the growth index of other species when maximum height, tiller number, leaf number, spike number and biomass of all three species was observed in their monoculture.
Conclusion: The results of the competition of all three species of terns with each other show that inter-species competition has been more effective in reducing weed population life than the intra-species competition; Thus, S. viridis species could have a greater decreasing effect on S. verticillata and S. glauca species by creating more height, more tillers and leaves and as a result higher biomass production. So, the competitiveness between the three species was S. glauca <S. verticillata <S. viridis. According to the findings of the present study, by increasing the density of soybeans, weeds can be managed, especially in their low densities.


Main Subjects

  • AbdullahiW., Nasrollah Zadeh S., Dabagh Mohammadi Nasab A., Zahtab Salmasi S., and Pourdad S. 2014. Study on effect of weed interference and nitrogen fertilizer on performance of chickpea in intercropping with wheat. Agricuitural Science and Sustainable Production 23(4): 85-100. (In Persian)
  • Adcock T.E., and Banks P.A. 2009. Effects of pre emergence herbicides on the competitiveness of selected weeds. Weed Science 39: 54-56.
  • Aguyoh J.N., and Masiunas J.B. 2003. Interference of redroot pigweed (Amaranthus retroflexus) with snap beans. Weed Science 51: 202-207.
  • Akbari A., Zand E., and Mosavi K. 2011. Evaluation the effect of row space and weed management approaches on biomass, chickpea (Cicer arietinum) yield, and yield components in Khorramabad dryland conditions. Crop Production 3(3): 1-21. (In Persian)
  • Asghari M., and Armin M. 2014. Effect of weed interference in different agronomic managements on grain yield and yield components of chickpea (Cicer arietinum). Crop Ecophysiology 8: 32(4): 407-422. (In Persian)
  • Bakhtiari Moghadam M., Vazan S., Asfyny Farahani M., Azizkhany S., and Rezaei K. 2012. Study of time and location management of weed control on yield and some agronomical traits of chickpea (Cicer arietinum ). Journal of Agriculture and Plant Breeding 8: 87-96. (In Persian)
  • Bilgili U., Sincik M., Uzan A., and Acikgoz E. 2003.The influence of row spacing and seeding rat on seed yield and yield components of forge turnip (Brassica napus ). Journal of Agronomy and Crop Science 189(4): 250-254.
  • Blackshaw R.E., Stobbe E.H., and Sturko A.R.W. 1981. Effect of seeding dates and densities of green foxtail (Setaria viridis) on the growth and productivity of spring wheat (Triticum aestivum ). Weed Science 29: 212-217.
  • Chaab A., Bakhshandeh A., Zand E., Ebrahimpour F., Shafeinia A., and Anafjeh Z. 2010. Effect of competition of wild mustard (Sinapis arvensis ) on yield and yield components of canola (Brassica napus L.) in pot and field conditions. Electronic Journal Crop Production 3(2): 33-48. (In Persian)
  • Challaiah O., Burnside C., Wicks G.A., and Johanson V.A. 1986. Competition between winter wheat (Triticum aestivum) cultivars and downy brome (Bromus tectorum). Weed Science 34: 689-693.
  • Defelice M. S. 2002. Green foxtail, Setaria viridis (L.) P. Beauv. Weed Technology 16: 253-257.
  • Dhanput K., Singh K., Kumar D., and Sinugh K. 2002. Stabbility analysis for seed yield and its components over different plant densities in soybean. Legume-Research 25(3): 222-224.
  • Douglas B.J., Gordon T.A., Morrison I.N., and Maw M.G. 1985. The biology of Canadian weeds. 70. Setaria viridis (L.) Beauv. Canadian Journal of Plant Science 65: 669-690.
  • Fereydoni N., Rafei M., and Khorgami A. 2010. Effect of planting, application of nitrogen fertilizer and weed interference on corn yield and morphological characteristics of a Single Cross 704. Journal of Crop Physiology 2(2): 85-95.
  • Ghamari H., and Ahmadvand G. 2013. Effect of different periods of weed interference and weed control on height, yield and yield components of common bean. Journal of Crop Production and Processing 3(9): 71-80. (In Persian)
  • Golestani Far F., Mahmoodi S., Zamani Gh.R., and Sayyari Zahan M.H., 2016. Effect of inter and intra-specific competition on morphological and growth characteristics of wheat (Triticum aestivum) and rye (Secale cereale L.) under drought stress conditions. Environmental Stresses in Crop Science 9(3): 241-256.
  • Gozubenli H. 2010. Influence of planting patterns and plant density on the performance of maize hybrids in the eastern mediterranea conditions. International Journal of Agriculture and Biology 12: 556-560.
  • Habibi F., and Sorkhi F. 2011. Effect of wild oats density on morphological characteristics and yield of winter wheat. Journal of Research in Crop Sciences 13(4): 41-50. (In Persian)
  • Holm L.G., Plunknett D.L., Pancho J.V., and Herberger J.P. 1991. The world's worst weeds. Distribution and Biology. Krieger Publishing Company, Malabar, Florida.
  • Jozarian Z., Yadavi A., Movahedi Dehnavi M., and Maghsodi E. Effect of row spacing and plant density on yield quality and quantity of soybean under weed competition. Agroecology 6(4): 857-848. (In Persian)
  • Jozarian Z., Yadavi A., Movahedi Dehnavi M., and Maghsodi E. 2018. Effect of planting patterns on grain yield and morphological characteristics of soybean (Glycine max) in the competition with weeds. Plant Ecophysiology 10(33): 138-148. (In Persian)
  • Kiani, Movahedi Dehnavi M., and Yadavi A. 2012. Interaction effects of planting date and weed competition on yield and yield components of three white bean cultivars in Semirom. Journal of Crop Production and Processing 2(3): 17-29. (In Persian)
  • Lythgoe B., Norton R.M., Nicolas M.E., and Conner D.J. 2001. Compensatory and competitive ability of tow canola cultivars. International Journal of Agronomy 2: 1-8.
  • Masuda T., and Goldsmith P. 2009. World soybean production: area harvested yield, and long-term projections. International Food and Agribusiness Management Review 12: 143-162.
  • Mirshekari B., Frahvash F., and Javanshir A. 2010. Phenology and grain yield of maize cv. Hybrid 604 at interference with lambsquarters (Chenopodium album ). Seed and Plant Production Journal 2-26(4): 365-385. (In Persian)
  • Mohammadi G.R., Javanshir A., Rahimzadeh-Khoie F., Mohammadi A., and Zehtab-Salmasi S. 2004. The effect of weed interference on shoot and root growth and harvest index in chickpea. Iranian Journal of Crop Sciences 6: 24-33. (In Persian)
  • Mousavi M.R. 2008. Integrated Weed Management (Principles and Methods). Miad Publisher. p.468. (In Persian)
  • Naseri R., Fasihi K Hatami A., and Poursyahbidi M.M. 2010. Effect of planting pattern on grain yield, yield components, oil and protein contents in winter safflower cv. sina under rainfed condition. Journal of Crop Science 12(3): 227-238.
  • Nikcheh M., Mohammad Esmaili M., Nakhzari Moghaddam A., and Bahmanesh B. 2018. Study of competition between two rangeland species Bromus tomentellus, Poa pratensis in order to protect them in rangeland ecosysteme. Journal of Plant Ecosystem Conservation 6(12): 123-134. (In Persian)
  • Rajcan I., and Swanton C.J. 2001. Understanding maize-weed competition: resource competition, light quality and whole plant. Field Crop Research 71: 139-150.
  • Sebastian J., Wong M.K., Tang E., and Dinneny J.R. 2014. Methods to promote germination of dormant Setaria viridis PLoS One 9: 95-109.
  • Sorkhi Lellahlo F., Dabbagh Mohammadi Nasab A., and Javanshir A. 2008. Evaluation of leaf characteristics and root to shoot ratio on the interference of underground and shoot organs in wheat (Triticum aestivum) and different density of wild oats (Avena fatua). Journal of Sciences and Technology of Agriculture and Natural Resources 45: 435-446. (In Persian)
  • Stefan S., Cragi E.A., and Michael H.D. 2004. Forage soybean yield and quality responses to plant density and row distance. Agronomy Journal 96: 966-970.
  • Tepe I., Erman M., Yergin R., and Bükün B. 2011. Critical period of weed control in chickpea under non-irrigated conditions. Turkish Journal Agriculture and Forestry 35: 525-534.
  • Watson P.R., Derksen D.A., Van Acker R.C., and Blrvine M.C. 2002. The contribution of seed seedling, and mature plant traits to barley cultivar competitiveness against weeds. Proceedings of the National Meeting- Canadian Weed Science Society 14: 49-57.