كليدواژه :
تناوب زراعي , جودره , گندم , مديريت علف‌هاي هرز , نخود
چكيده فارسي :
تأثير خوشه‌چيني علف هرز جودره در كشت گندم و تاريخ كاشت و راهكارهاي مديريتي در كشت نخود بر جمعيت اين علف هرز در كشت نخود در سال بعد در شهرستان خرم‌آباد طي سال‌هاي زراعي 89- 1388 و 90-1389 مورد ارزيابي قرار گرفت. آزمايش به صورت فاكتوريل اسپليت در قالب طرح بلوك‌هاي كامل تصادفي با 3 تكرار اجرا شد. خوشه‌چيني علف هرز جودره در كشت گندم به طور متوسط سبب كاهش 71 درصد تراكم و زيست‌توده اين علف‌هرز در كشت نخود در سال بعد شد. اين موضوع گوياي اهميت ريزش بذر سال جاري علف‌هرز جودره در تكميل بانك‌بذر خاك و رويش دانه‌رست در سال بعد است. با كاشت زودهنگام نخود در مقايسه با كاشت ديرهنگام، جمعيت علف هرز جودره به ميزان 75/1 درصد كاهش يافت. اين موضوع عمدتاً به عدم كارايي عمليات كاشت با شش‌خيش در كنترل كامل بوته‌هاي جودره سبز شده در تيمار كاشت ديرهنگام مربوط بود. تيمار كاشت زودهنگام نخود همراه با خوشه‌چيني جودره در كشت گندم سال قبل، به طور كامل فاقد علف‌هرز جودره بود. بر اين اساس ممانعت از ريزش بذر و تكميل بانك‌بذر خاك در سال پيشين و صرف عمليات كاشت به موقع نخود سبب كنترل كامل علف‌هرز جودره شد. بدين‌ترتيب به نظر مي‌رسد كه عمده جمعيت رويش‌يافته اين علف‌هرز به ريزش بذر در سال قبل وابسته است، به عبارتي سطح خفتگي بذر جودره اندك بوده و پويايي جمعيت آن عمدتاً به بانك‌بذر بذر گذرا و نه بانك‌بذر پايا متكي است. اين موضوع نويدبخش امكان مديريت اين علف‌هرز مشكل‌ساز و كاهش جمعيت آن به زير حد آستانه خسارت اقتصادي از طريق مديريت بانك بذر است.
چكيده لاتين :
Introduction: Transient and persistence of weed seed banks impact on weed population dynamics.
Therefore, any management tools with having a reducing role can affect weed population size. Reduction of
weed seed rain using effective control tools can reduce weed density. The seed bank density is the main factor
corresponding to seedling density. Decline of seed bank is critical to success in crop production, so that, poor
performance in weed control only for a season cause to rain weed seeds and to improve soil seed bank. Most of
the commonly used herbicides recommended for controlling weeds in wheat fields are not efficiently able to
control the wild barley (Hordeum spontaneum C. Koch). Hence, utilizing appropriate agronomic strategies to
control this weed is critical. Evaluation the effect of wild barley spike cut-off in the previous wheat field, and the
effects of chickpea planting date and chemical weed control in chickpea cultivation in rotation on wild barley
weed population in chickpea cultivation are among the aims of this study.
Materials and Methods: The effect of wild barley spike cut-off in the previous wheat field, and sowing date
and management strategies in chickpea on its population in chickpea for the following years was evaluated in
Khorramabad, Lorestan, Iran during 2009-10 and 2010-11 growing seasons. The experiment was arranged in a
factorial split plot in a completely randomized block design with three replications. The wild barley spike cutoff in wheat (at two levels: No cut-off and with cut-off) and chickpea planting date in the next season (at two
levels: early planting and late planting) were assigned into the main plots. Chickpea weed management
treatments (at five levels: pre emergence application of metribuzin at 0.7 kg per hectare, pre emergence
application of imazethapyr 0.7 litter per hectare, post emergence application of Clethodim 1 liter per hectare,
weed free treatment, and weedy infest)was assigned into the sub plots.
Results and Discussion: Wild barley spike cut-off in previous wheat reduced 71% of the density and
biomass of this weed in chickpea cultivation in the following years. This suggests the importance of recent year's
wild barley seeding rain in the completion of the soil seed bank for the next season. Early planting of chickpea
compared to late planting decreased the wild barley density by 75%. It was mainly related to the ineffectiveness
of planting operations in full control of the large wild barley plants in the late planting treatment. Early planting
of chickpea under wild barley weed spike cut-off in previous wheat crop condition, was completely free of wild
barley. Accordingly, the prevention of wild barley seed rain and the completion of the soil seed bank in the
previous year, along with the timely planting of chickpea led to full control of this weed. Triple interaction
effects of experiment factors on wild barley biomass in chickpea was statistically significant. This suggests the
difference of wild barley biomass response to weed management treatments in different planting date of
chickpea in spike cut-off and without spike cut-off of wild barley in the previous wheat crop. In addition to
manual weeding treatments in different conditions, all weed management practices, even uncontrolled weedy
check, in early chickpea planting under spike cut-off of wild barley conditions in wheat cultivation in the
previous year, did not emerged any wild barley seedling. This indicates the high efficiency of spike cut-off of
wild barley in the previous year and the prevention of seeding and the timely planting of chickpeas in the
management of this weed.
Conclusion: Thus, it seems that the major part of the growing population of this weed is dependent on
previous year seed rain. In the other words, the wild barley population dynamics is largely dependent on the
temporary transient seed bank instead of a persistent seed bank. This suggests the possibility of managing
problematic wild barley and reducing its population below the economic damage threshold through prevention of
seed rain and soil seed bank management.
