كليدواژه :
بيوماس علف هرز , پانيكول , تعداد بوته - رقابت , وزن هزار دانه
چكيده فارسي :
به منظور بررسي تاثير تراكم بوته و تداخل علف هرز بر عملكرد و اجزاي عملكرد سورگوم دانه اي رقم سراوان آزمايشي به صورت فاكتوريل در قالب طرح بلوك هاي كامل تصادفي در مزرعه تحقيقاتي دانشگاه آزاد اسلامي بيرجند در سال ۱۳۹۲ با سه تكرار اجرا گرديد. تيمارهاي آزمايشي شامل سه سطح تراكم بوته (۱۰، ۲۰ و ۳۰ بوته در متر مربع) و چهار سطح تداخل علف هرز (تيمار شاهد عاري از علف هرز، تداخل تامرحله ۶-۸ برگي، تداخل تا مرحله ظهور پانيكول و تداخل تمام فصل) در نظر گرفته شد. با افزايش تراكم از ۱۰ به ۳۰ بوته در متر مربع، طول پانيكول، تعداد پانيكول در بوته، تعداد دانه در پانيكول، وزن هزار دانه، تعداد علف هرز و وزن خشك علف هرز در متر مربع به طور معني دار و به ترتيب ۷/۱، ۴۵/۵، ۱۲/۵، ۱۶/۲، ۱۲/۳، ۲۷/۶ و ۱۶/۸ درصد كاهش يافت اما تعداد پانيكول در متر مربع و عملكرد بيولوژيك ۵۴/۳ و ۵۶/۷ درصد افزايش يافت. تيمار عاري از علف هرز نسبت به تيمار تداخل تا انتهاي دوره رشد از برتري معني دار ۱۴/۳، ۲۰/۳، ۳۰/۴، ۲۷۰/۰۷، ۱۲۲ و ۱۴۹/۳ درصدي به ترتيب در طول پانيكول، تعداد پانيكول در متر مربع، تعداد دانه در پانيكول، وزن هزار دانه، عملكرد دانه و عملكرد بيولوژيك برخوردار بود. به طور كلي بر اساس نتايج اين تحقيق با توجه به اين موضوع كه رقم سراوان يك رقم دو منظوره (دانه اي- علوفه اي) است، پيشنهاد مي گردد تيمار تراكم ۳۰ بوته در متر مربع و عاري نگهداشتن مزرعه از علف هاي هرز براي زراعت اين گياه مورد توجه قرار گيرد.
چكيده لاتين :
Introduction: Weed control is a necessary element in all crop production systems. Weeds reduce yield by
competing with crops for water, nutrients, and sunlight. They also directly reduce production profit by hindering
harvest operations, decreasing crop quality, and producing chemicals which are harmful to crop plants. Crop
density is an efficient management tool to enhance yield by increasing competition ability of crops against weeds
in getting solar radiation, which can affect development of crop-weed association. Response of yield and yield
components to weed competition varies depending on crop and weeds species as well weed interference
duration. The objective of this study was to evaluate the effect of different weed interference periods and plant
density on the yield and yield components of sorghum.
Materials and Methods: In order to study the effects of plant density and weed interference on weed traits,
yield and yield components of sorghum (Sorghum bicolor L. var. Saravan), an experiment was conducted as
factorial based on randomized complete block design with three replications at the research field oflslamic Azad
University, Birjand Branch in South Khorasan province during year of2013. Factors consisted of plant density at
three levels (10, 20 and 30 plants m·2) and weed interference at four levels (crop kept weed free until the end of
growing season, interference until the 6-8 leaves stage, interference until the panicle emergence stage,
interference until the end of growing season). Measuring traits included the panicle length, number of panicle per
plant, number of panicle per m2, number of seed per panicle, I 000-seed weight, grain yield, biological yield,
density and dry weight of weeds per m2 Weed sampling in each plot was performed manually from a square
meter and different weed species counted and oven dried at 72 °C for 48 hours. MSTAT-C statistical software
used for data analysis and means compared with Duncan multiple range test at 5% probability level.
Results and Discussion: Results showed that all measured traits except grain yield were significantly
affected by plant density. Although the increase in plant density fi·om 10 to 30 plants m·' significantly decreased
panicle number per plant, number of seed per panicle and 1000-seed weight by 45.5, 16.2 and 12.3%,
respectively, but significantly increased number of panicle per m2 by 54.3%. This subject caused grain yield did
not show significant changes as plant density was changed. Also, means comparison showed that increase in
density from I 0 to 30 plants m· 2 had positive significant effect on biological yield so that it increased by 56. 7%.
Interference treatment had significant effect on all measured traits except number of panicle per plant. 1000-seed
weight, grain yield and biological yield decreased considerably by extending of weeds interference period. The
highest grain yield achieved in treatment of weed free until the end of growing season which were 18.9, 47.6 and
73 % more than interference until the 6-8 leaves stage, interference until the panicle emergence stage, and
interference until the end of growing season, -respectively. Also, weed interference until the end of growing
season of sorghum reduced biological yield by 59.9 % compared to weed free until the end of growing season.
The highest weed density with 182 plants per m2 was observed in interference until the 6-8 leaves stage.
Conclusions: This research showed that increase in plant density no increased significantly grain yield but
change of density from I 0 to 30 plants m· 2 had positive significant effect on biological yield. Moreover, the
presence of weeds in farm of sorghum is inhibitor factor for maximum production. Weed interference decreased
grain and biological yields of sorghum by decline in yield components and tillering. Saravan variety is a dual
purpose plant; both grain and forage. It is suggested that density of I 0 plants m·' and weed free unti I the end of
growing season treatment for sorghum cultivation in Birjand region.
