اثر زمان رویش در خزانه و تراکم سوروف‌آبی (Echinochloa oryzoides (Ard.) Fritsch) بر قابلیت رقابت با برنج (Oryza sativa L.) (2. مطالعات انتهای فصل‌رشد: عملکرد و قابلیت ‌رقابت)

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشگاه گیلان

2 دانشگاه فردوسی مشهد

3 مؤسسه تحقیقات برنج کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، رشت

چکیده

زمان رویش و تراکم علف‌های ‌هرز اهمیت بسیاری در اثرات ‌متقابل رقابتی آن‌ها با گیاه زراعی دارد. لذا برای علف‌هرز سوروف‌آبی (Echinochloa oryzoides (Ard.) Fritsch)، به‌عنوان یک گونه نسبتاً تازه‌وارد، بررسی نقش زمان رویش در خزانه برنج (Oryza sativa L.) و در نتیجه سن گیاهچه علف‌هرز در هنگام انتقال از خزانه به زمین اصلی و نیز بررسی میزان این انتقال و در نتیجه تراکم ‌نسبی علف‌هرز در زمین اصلی ضرورت دارد. نقش سن گیاهچه سوروف‌آبی هنگام نشاکاری (10، 20 و 30 روز) و نسبت تراکم سوروف‌آبی: برنج در هرکپه (4:0، 3:1، 2:2، 1:3 و 0:4 علف‌هرز: برنج) بر صفات سوروف‌آبی و برنج در هنگام رسیدگی گیاه زراعی (90 روز پس از نشاکاری)، طی دو سال مطالعه مزرعه‌ای در قالب طرح بلوک‌های کامل تصادفی با سه تکرار مورد بررسی قرار گرفت. افزایش تعداد گیاهچه در نسبت‌های مختلف کاشت سبب افزایش عملکرد بیولوژیک، عملکرد دانه، عملکرد نسبی هر دو گونه و شاخص غالبیت برنج شد؛ اگرچه شاخص برداشت کاهش یافت. به‌جز عملکرد دانه برنج در تک‌کشتی و در نسبت 3:1 (علف‌هرز: برنج) سال دوم که تفاوت معنی‌داری با سوروف‌آبی نداشت؛ در سایر نسبت‌ها عملکرد بیولوژیک و عملکرد دانه علف‌هرز بیش‌تر از برنج متناظر بود. شاخص برداشت برنج در همه نسبت‌های کاشت بیش‌تر از علف‌هرز بود. در سال اول آزمایش، تیمار گیاهچه‌های 30 روزه سوروف‌آبی دارای بیش‌ترین عملکرد بیولوژیک، دانه و نسبی علف‌هرز، کم‌ترین عملکرد دانه و نسبی برنج، و کم‌ترین شاخص برداشت هر دو گونه بودند. در همه سنین گیاهچه ‌علف‌هرز عملکرد سوروف‌آبی بیش‌تر از برنج متناظر بود. بررسی صفات ارزیابی‌ شده و نمودارهای سری‌های جانشینی حاکی از قابلیت رقابت بالای علف‌هرز نسبت به گیاه زراعی بود که بر ضرورت توجه به گسترش این علف‌هرز در منطقه تأکید دارد.
 

کلیدواژه‌ها


عنوان مقاله [English]

Effects of Emergence Time in Nursery and Density of Watergrass (Echinochloa oryzoides (Ard.) Fritsch) on Competitive Ability with Rice (Oryza sativa L.) (II. End Season Studies: Yield and Competitiveness)

نویسندگان [English]

  • elmira mohammadvand 1
  • Alireza Koocheki 2
  • Mahdi Nassiri Mahallati 2
  • bijan Yaghoubi 3
1 university of guilan
2 Ferdowsi University of Mashhad
3 Scientific board member of Rice Research Institute of Iran, Rasht
چکیده [English]

Introduction
Weed–crop competition as one of the main reasons for crop loss is often influenced by many factors including emergence time and density of competing species. Patterns of weed seedling emergence affect the outcome of weed–crop interference interactions. Information on weed seedling emergence in relation to crop seeding will assist in developing an optimum weed control program.
Weeds emerge simultaneously with a crop, have the greatest potential impact on crop production. Results from Chauhan & Johnson (2010) showed the advantage for weeds over rice in situations where these species emerge earlier in the growing season because of significantly greater biomass production comparing to those emerging later in the season. Minimal shading and competition for nutrients and soil moisture are associated with early emergence.
The importance of density in competition studies is because of the relationship among plant yield, number of individuals, and resources present. Increasing the density may enhance the plant’s share of the total resource pool and reduce resource availability for adjacent plant. Thus, to analyze competition between the crop and weeds, the variation in density should be considered. Season-long competition with watergrass at densities of 86 and 36 plants/m2 reduced rice yields by 59% and 46%, respectively.
Understanding relative aggressiveness of component species is required for the integrated weed management and it would improve weed management strategies. For watergrass as a relatively new-introduced weed species in paddy rice fields of Guilan province, it is essential to investigate the effects of the emergence time in nursery, to determine weed seedling ages at the time of transplanting, as well the amount of weed seedling translocation characterizing weed density in the field.
 Materials and Methods
Factorial arrangements of watergrass seedlings ages at the time of transplanting (10, 20 and 30 days), and plant proportions of weed:rice (0:4, 1:3, 2:2, 3:1, and 4:0) were designed as a randomized complete block with three replications to study yield characteristics and competitive ability of watergrass and rice over two years of a field experiment. Individual plants of each hill constituted as a single experimental unit. The area between individual hills was hand-weeded to avoid competition from other species. At rice maturity stage, plants were harvested, and rice and watergrass panicles were separated from stems by hand. Panicles were dried to a constant weight at 75 ℃, and weights were determined. Grain weights standardized to 12% moisture content. Biological yields of rice and watergrass were also measured after sampling their above-ground parts from an area of 1 m2 and drying at 75 ℃ until constant weight. Data were subjected to ANOVA, and means were separated using Fisher’s Protected LSD at P < 0.05. Competitiveness of the species was assessed based on the relative yield (the ratio between the production of the species in the mixture and in monoculture), relative yield total (total relative yield of the two associated species), aggressivity index and replacement series diagrams (models describing the possible outcomes of the interaction of two species when grown in a replacement series).
Results and Discussion
For each species, the greater ratio at the planting proportion, the higher biological yield, grain yield, relative yield, and aggressivity index, but the lower harvest index. When grown in monocultures, and 1 weed: 3 rice of the second year, the two species produced similar grain yield; however in the other mixtures watergrass produced more biological and grain yield compared to the rice. Harvest index of rice was greater than watergrass in all planting proportions. In the first year, trials of 30-day watergrass seedling ages represented the highest values of biological-, grain-, and relative yield, and the lowest values of grain and relative yield of rice and harvest indices of both species. Also, for all watergrass seedling ages in both years, weed production was more than rice.
Conclusion
Investigating grain and biological yield, and relative yield of both species, and aggressivity index of rice, beside replacement series diagrams exhibited higher competitiveness for watergrass comparing to rice. Therefore, it is important to maintain watergrass control in order to insure the sustainability of transplanted rice production.

کلیدواژه‌ها [English]

  • Competition
  • Emergence patterns
  • Planting proportion
  • Relative density
De Wit, C.T., and Van Den Bergh, J.P., 1965. Competition between herbage plants. Netherlands Journal of Agricultural Science 13: 212–221.
Estorninos, Jr. L.E., Gealy, D.R., and Talbert, R.E., 2002. Growth response of rice (Oryza sativa) and red rice (O. sativa) in a replacement series study. Weed Technology 16: 401–406.
Fischer, A.J., Messersmith, C.G., Nalewaja, J.D., and Duysen, M.E., 2000. Interference between spring cereals and Kochia scoparia related to environment and photosynthetic pathways. Agronomy Journal 92: 173–181.
Forcella, F., Benech-Arnold, R.L., Sanchez, R., and Ghersa, C.M., 2000. Modeling seedling emergence. Field Crops Research 67: 123–139.
Gealy, D.R., Estorninos, Jr. L.E., Gbur, E.E., and Chavez, R.S.C., 2005. Interference interactions of two rice cultivars and their F3 cross with barnyardgrass (Echinochloa crus-galli) in a replacement series study. Weed Science 53: 323–330.
Gibson, K.D., and Fischer A.J., 2001. Relative growth and photosynthetic response of water-seeded rice and Echinochloa oryzoides (Ard.) Fritsch to shade. International Journal of Pest Management 47: 305–309.
Gibson, K.D., Foin, T.C., and Hill, J.E., 1999. The relative importance of root and shoot competition between water-seeded rice and watergrass. Weed Research 39: 181–190.
Gibson, K.D., Fischer, A.J., Foin, T.C., and Hill, J.E., 2002. Implications of delayed Echinochloa germination and duration of competition for integrated weed management in water-seeded rice. Weed Research 42: 351–358.
Gibson, K.D., Fischer, A.J., and Foin, T.C., 2004. Compensatory responses of late watergrass (Echinochloa phyllopogon) and rice to resource limitations. Weed Science 52: 271–280.
Harper, J.L., 1977. Population Biology of Plants. London: Academic Press.
Holt, J.S., 1995. Plant responses to light: a potential tool for weed management. Weed Science 43: 474–482.
Johnson, D.E., Wopereis, M.C.S., Mbodj, D., Diallo, S., Powers, S., and Haefele, S.M., 2004. Timing of weed management and yield losses due to weeds in irrigated rice in the Sahel. Field Crops Research 85: 31-42.
LeStrange, M., 1981. Competition between rice (Oryza sativa) and barnyardgrass (Echinochloa spp.): the influence of rice stature, barnyardgrass density, and nitrogen fertility. M.Sc Thesis, University of California, Davis, CA.
Mohammadvand, E., Koocheki, A., Nassiri Mahallati, M., and Yaghoubi, B., 2019. Effects of emergence time in nursery and density of watergrass (Echinochloa oryzoides) on competitive ability with rice (I. During season studies: Growth and development). Journal of Agroecology 11(3): 955-974.
Ni, H., Moody, K., and Robles, R.P., 2000. Oryza sativa plant traits conferring competitive ability against weeds. Weed Science 48: 200–204.
Ni, H., Moody, K., and Robles, R.P., 2004. Analysis of competition between wet-seeded rice and barnyardgrass (Echinochloa crus-galli) using a response–surface model. Weed Science 52: 142–146.
Ottis, B.V., and Talbert, R.E., 2007. Barnyardgrass (Echinochloa crus-galli) control and rice density effects on rice yield components. Weed Technology 21: 110–118.
Patterson, D.T., 1995. Effects of environmental-stress on weed/crop interactions. Weed Science 43: 483–490.
Perera, K.K., Ayres, P.G., and Gunasena, H.P.M., 1992. Root growth and the relative importance of root and shoot competition in interactions between rice (Oryza sativa) and Echinochloa crus-galli. Weed Research 32: 67–76.
Perez, de Vida F.B., Laca, E.A., Mackill, D.J., Fernandez, G.M., and Fischer, A.J., 2006. Relating rice traits to weed competitiveness and yield: a path analysis. Weed Science 54: 122–1131.
Radosevich, S.R., 1987. Methods of interactions among crops and weeds. Weed Technology 1: 190–198.
Ryser, P., and Eek, L., 2000. Consequences of phenotypic plasticity vs. interspecific differences in leaf and root traits for acquisition of aboveground and belowground resources. American Journal of Botany 87: 402–411.
Smith, Jr. R.J., 1968. Weed competition in rice. Weed Science 16: 252–254.
Suzuki, M., and Suto, T., 1975. Emergence of weeds in paddy rice fields 3. weed emergence and weed damage in paddy rice fields. Weed Research of Japan 20: 114–117.
Wang, G., McGiffen, Jr. M.E., and Ehlers, J.D., 2006. Competition and growth of six cowpeas (Vigna unguiculata) genotypes, sunflower (Helianthus annuus), and common purslane (Portulaca oleracea). Weed Science 54: 954–960.