Distance of Interference of Red Rice (Orya sativa) in Rice (O. sativa)

Journal of the Arkansas Academy of Science Volume 48 Article 20 1994 Distance of Interference of Red Rice (Orya sativa) in Rice (O. sativa) Sam L. Kwon University of Arkansas, Fayetteville Roy J. Smith Jr. U.S. Department of Agriculture Ronald E. Talbert University of Arkansas, Fayetteville Follow this and additional works at: http://scholarworks.uark.edu/jaas Part of the Agronomy and Crop Sciences Commons Recommended Citation Kwon, Sam L.; Smith, Roy J. Jr.; and Talbert, Ronald E. (1994) "Distance of Interference of Red Rice (Orya sativa) in Rice (O. sativa)," Journal of the Arkansas Academy of Science: Vol. 48 , Article 20. Available at: http://scholarworks.uark.edu/jaas/vol48/iss1/20 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact , . Journal of the Arkansas Academy of Science, Vol. 48 [1994], Art. 20 Distance of Interference of Red Rice (Oryza sativa) in Rice (0. sativa) 1 Ronald E. Talbert Dep. of Agronomy Altheimer Lab Univ. of Arkansas Fayetteville, AR 72703 RoyJ. Smith Jr. Agric. Res. Serv. U.S. Dept. Agric. Stuttgart, AR 72160 Sam L.Kwon Dept. of Agronomy Univ. of Arkansas Fayetteville, AR 72703 Abstract Three rice cultivars were grown to determine the distance at which red rice affects growth and grain yield. Red rice reduced grain yield of Lemont when rice plants grew within 71 and 53 cm of red rice in 1986 and 1988, respectively. Grain yield of Newbonnet was reduced when grown within 53 cm of red rice in both years. Grain yield of Tebonnet was reduced when grown within 53 and 36 cm of red rice in 1986 and 1988, respectively. Grain yield reduction in influenced areas averaged 35, 26 and 21% for Lemont, Newbonnet, and Tebonnet, respectively. As the distance increased at 10-cm increments from the red rice row, Lemont, Newbonnet, and Teboment grain yields increased 49 to 85, 32 to 40, and 24 to 33 g/m2,respectively. Rice straw dry weight was reduced when Lemont and Tebonnet were grown within 71 and 36 cm of red rice in 1986 and 1988, respectively. Straw dry weight of Newbonnet was reduced when grown within 36 cm of red rice in both years. As the distance increased at 10-cm increments from the red rice row, Lemont, Newbonnet and Tebonnet straw biomass increased 22 to 46, 10 to 18, and 12 to 20 g/m 2, respectively. Rice panicles/ m2 were reduced when Lemont, Newbonnet, and Tebonnet were grown within 36, 18, and 18 cm of red rice, respectively. Rice grains/panicle were reduced when rice was grown within 71, 71, and 36 cm of red rice for Lemont, Newbonnet, and Tebonnet, respectively. Published with the permission of the Director of the Arkansas Agric. Exp. Stn. Introduction Development of integrated weed management systems by a thorough understanding of the dynamics of weed populations obtained from weed interference studies (Fernandez-Quintanillia, 1988). Understanding of interference thresholds, biology, and growth habits of weeds in essential to timely, effective, economical weed control technology for profitable rice production (Smith, 1988). An integrated weed management system for rice includes a directed agroecosystem approach for the management and control of weed populations at threshold levels to prevent economic damage in current and future crops (Shaw, 1982). The objective of this study was to determine the distance at which red rice plants affected growth and yield must be supported Red rice is a competitive weed of rice in the southern U.S. A density of five plants/m 2 reduced rice grain yield by 22% (Diarra et al., 1985). Also, red rice is difficult to control in rice with herbicides because it is genetically and physiologically similar to commercial rice (Craigmiles, 1978; Hoagland, 1978) and is tolerant to most herbicides that are tolerated by rice cultivars. Weed interference can be researched by different experimental methods (Connolly, 1988; FernandezQuintanilla, 1988; Oliver, 1988; Van Groenendael, 1988). The most common methods include studies in which weed density and duration of interference are varied. Usually in the area of interference studies, the effect of individual weeds on crops is determined, but in field situations the patchy distribution of weeds should be considered in assessing crop-weed interactions. From this standpoint the method used in this interference study would be comparable to high densities in patches of red rice infestations that frequently occur in rice field. Effects of area of influence or interference have been conducted with several weed in soybeans (Glycine max L. Merr.) (Monks and Oliver, 1988), cotton (Gossypium hirsutum L.) (Bridges and Chandler, 1986), and rice (Baker et al., 1987; Smith, 1987). However, research has not been reported on the area of influence of red rice on rice. of commercial rice cultivars. Materials and Methods Field experiments were conducted in 1986 and 1988 of Arkansas Rice Research and Extension Center, Stuttgart, to determine the distance of interference of red rice on three rice cultivars. Plots were on a Crowley silt loam (Typic Albaqualfs) with a pH of 5.5 and 6.5 in 1986 and 1988, respectively, and 1% organic matter. Because growth and development of rice and red rice were injured by soil alkalinity in 1987, results for at the University Proceedings Arkansas Academy of Science, Vol. 48, 1994 Published by Arkansas Academy of Science, 1994 93 93 Journal of the Arkansas Academy of Science, Vol. 48 [1994], Art. 20 *** *^w***\iw y v^# y *r <a\*ir+%/\» jAAI *^***w\ that year are not reported. ¦ j Results Lemont, Newbonnet, and Tebonnet cultivars, with plant heights at maturity of 84, 102, and 112 cm (Ark. Coop Ext. Serv., 1990), respectively, were drill-seeded at 145, 123, and 134 kg/ha, respectively, in 18 rows with a row spacing of 18 cm in plots 3.2 m wide by 3 m long (Fig. 1). At the time of drill-seeding rice, red rice was hand seeded as a center (A) row of each plot at seeding rates equivalent to rice cultivars. In control plots the appropriate rice cultivar was substituted for the red rice in row A. The experiment was arranged as a split plot with three replications with rice cultivars in main plots and rice distance from red rice insubplots. Rice and red rice were seeded on May 14, 1986 and Vlay 16, 1988. Plants of both species emerged on May 22, 1986 and May 30, 1988 at an average density of 390 >lants/m 2 which is a higher density than normal field copulations of 220 to 320 plants/m 2 for rice (Ark. Coop. (...truncated)