پديد آورندگان :
عباس پور، مجيد سازمان تحقيقات آموزش و ترويج كشاورزي - مركز تحقيقات و آموزش كشاورزي و منابع طبيعي استان خزاسان رضوي - بخش تحقيقات گياه پزشكي، مشهد , قدسي، مسعود سازمان تحقيقات آموزش و ترويج كشاورزي - مركز تحقيقات و آموزش كشاورزي و منابع طبيعي استان خزاسان رضوي - بخش علوم زراعي و باغي، مشهد
چكيده فارسي :
اين تحقيق به منظور بررسي تأثير ميزان بقاياي گياهي و مصرف علف‌كش‌ها بر كنترل علف‌هاي هرز در روش كشاورزي بدون شخم در قالب آزمايش كرت‌هاي خرد‌شده بر پايه طرح بلوك‌هاي كامل تصادفي در سيستم تناوبي جو-پنبه-گندم به مدت سه سال در سال‌هاي 1395-1393 در ايستگاه تحقيقات كشاورزي و منابع طبيعي گناباد وابسته به مركز تحقيقات و آموزش كشاورزي و منابع طبيعي استان خراسان رضوي انجام شد. تيمارهاي آزمايش شامل نه تيمار شامل مديريت ميزان بقاياي گياهي در كرت‌هاي اصلي در سه سطح 1- بدون بقايا، 2- حفظ 30 درصد بقاياي محصول (1200 كيلوگرم در هكتار از بقاياي محصول قبلي) و 3- حفظ 60 درصد بقاياي محصول (2400 كيلوگرم در هكتار از بقاياي محصول قبلي) و مهار علف‌هاي هرز در كرت‌هاي فرعي در سه سطح شامل 1-كنترل شيميايي (در جو و گندم براي كنترل علف‌هاي هرز پهن‌برگ از علف‌كش توفوردي + ام‌سي‌پي‌آ (SL 67/5%) به ميزان 1012/5 ميلي‌ليتر ماده مؤثر در هكتار و براي كنترل علف‌هاي هرز باريك‌برگ از علف‌كش پينوكسادن (EC 10%) به ميزان 150 گرم ماده مؤثره در هكتار به‌صورت پيش‌آميخته با 37/5 گرم ماده موثره از ماده ايمن كننده كلوكوئينتوست و در پنبه از علف‌كش تري‌فلوكسي‌سولفورون‌سديم (WG 75%) به ميزان 11/25 گرم ماده مؤثره در هكتار به‌صورت پيش‌آميخته با سيتوگيت 0/2 درصد حجمي، 2-وجين دستي علف‌هاي هرز و 3- بدون كنترل علف‌هاي هرز بود. كاشت گياهان زراعي با بذركار كشت مستقيم انجام شد. نتايج نشان داد وجود بقاياي گياهي محصول زراعي قبلي در سطح خاك تاثير مناسبي بر عملكرد جو، پنبه و گندم داشت و بنابراين به‌نظر مي‌رسد روش كاشت بدون شخم با حفظ حداقل 30 درصد (تا 60 درصد) بقايا در سطح خاك به همراه مصرف علف‌كش‌هاي رايج در هر محصول قابل توصيه است.
چكيده لاتين :
Introduction: Tillage is one of the most important causes of soil erosion in croplands that affects
productivity and inflates the cost of production. Recently, in order to enhance sustainability without
compromising land productivity, there has been a growing trend toward conservation agriculture. No-tillage
(NT) as one of the components of conservation agriculture is a planting system in which soil dose not disturb
and mulch cover remain from previous crop at least in 30%. It has revolutionized agricultural systems because it
allows farmers to manage greater amounts of land with reduced energy, labor, and machinery inputs. Minimum
tillage systems, such as shallow or surface tillage and direct drilling or no-tillage (NT), increase the degree of
soil cover and increase organic matter at the soil surface over time. In specific soil types and climates, this can
lead to an improvement of the soil physical condition. Improvement of the biological and physical quality of the
surface soil can also help to protect the soil resource against redistribution and erosion. NT cropping systems
frequently suffer from weed infestations, especially those of weedy annual grasses. The timing of competition in
NT systems may differ from that in conventional systems. Rottenly, a combination of relative crop yield and
specific input costs (i.e., fertilizer and pesticide) are considered as key determinants to the profitability of
adopting minimum tillage systems. Our understanding of weed community dynamics and suppression in NT
systems is limited, particularly in long-term rotations. Winter annuals, biennials, and perennials are typically
associated with NT systems because of their affinity for non-disturbed soil environments. The vertical
distribution of viable weed seeds in the soil profile is shallower in NT systems than in intensive-tillage systems.
Weed seeds remaining at or near the surface are more susceptible to predation and disease, which may deplete
the seed bank over time. NT is dependent on herbicides because of the elimination of tillage for control of
weeds.
Materials and Methods: A three-year field study was conducted to assess the efficacy of weed control in
barley-cotton-wheat rotation under no-tillage system in the agricultural research station of Gonabad, KhorasanRazavi province, Iran over 2014-2016 seasons. The experiment was arranged in a split plot design based on
completely randomized block design with three replications. The main plot was crop residue (left on the ground
from previous crop in rotation) in three levels;no residue, 30% residue (1200 kg ha-1) and 60% residue (2400 kg
ha-1. The subplot was weed control methods in three levels; (weed infest control, weed free control and chemical
control. In chemical control treatment, we applied 2,4-D+ MCPA at dose of 1.0125 lit a.i. ha-1 for controlling
broad-leaved weeds and pinoxaden (Axial® 10% EC) at dose of 67.5 g a.i. ha-1 for controlling narrow-leaved
weeds in barley and wheat, and trifluxysulfuron-sodium (Envoke® 75% WG) at dose of 11.25 g a.i. ha-1 in
cotton. For barley, the wheat residues were left from wheat planted a year before in rotation. Plots size were
3m×10m. Barley (var. Nosrat), cotton (var. Khordad) and wheat (var. Parsi) planted by direct seeding equipment
with no tillage.
Results and Discussion: Cardaria draba and Malcolmia africana in barley, Acroptylon repense and Alhagi
pseudalhagi in cotton and A. repense in wheat were dominant weed species from the beginning to the end of the
study. Results showed a remarkable change in weed flora from mostly annual weeds (like M. africana) to
perennials (like A. repense), because of the fact that no tillage system was deployed. For barley, application of 2,
4-D + MCPA significantly decreased weed dry weight and density compare to the weedy check. Residues
showed no significant effect on biological and seed yield of barley. For cotton, the effect of trifluxysulfuronsodium was significant on decreasing the density and dry weight of A. repense 30 days after spraying and in the
end of the season as well. Effect of residue levels (30% or 60%) was not significant on the density and dry
matter of A. repense in the early and at the end of the season as well. Trifluxysulfuron-sodium significantly
increased cotton dry weight compare to the weedy control. Dry weight of cotton in hand weeding control and
application of trifluxysulfuron-sodium treatments were significantly higher than that of weedy control. Residues
showed no significant effect on cotton boll dry weight. For wheat, application of 2, 4-D + MCPA significantly
decreased weed dry weight and density compared to the weedy control. Residues showed no significant effect on
biological and seed yield of wheat.
Conclusion: No-tillage system by at least 30% (1200 kg ha-1) up to 60% (2400 kg ha-1) of residues spread on
the soil surface can be recommended to be deployed besides a suitable chemical weed control management in
barley-cotton-wheat rotation in semi-arid climate conditions to enjoy the benefits of no tillage system of
agriculture.
