پديد آورندگان :
رنجبر، محمدحسن دانشگاه علوم كشاورزي و منابع طبيعي گرگان - گروه زراعت , قرخلو، جاويد دانشگاه علوم كشاورزي و منابع طبيعي گرگان - گروه زراعت , سلطاني، افشين دانشگاه علوم كشاورزي و منابع طبيعي گرگان - گروه زراعت
كليدواژه :
سرعت اسيميلاسيون خالص , سرعت رشد گياه , سرعت رشد نسبي , شخم حفاظتي
چكيده فارسي :
توليد ارقام جديد نمي تواند به تنهايي باعث افزايش محصولات كشاورزي شود بلكه در كنار پيشرفت هاي به نژادي بايد روش هاي زراعي مناسب
جهت توليد به كار گرفته شده تا حداكثر عملكرد حاصل شود. هدف اصلي از اجراي روش هاي خاك ورزي حفاظتي، نگهداري مقادير مناسب بقايا در
سطح خاك جهت كنترل فرسايش آبي و خاكي مزارع، كاهش انرژي و حفاظت از منابع آب و خاك مي باشد. مطالعه پيش رو به منظور بررسي تأثير
تيمارهاي مختلف خاك ورزي بر روي عملكرد ذرت علوفه اي، در سال 1392 انجام شد. آزمايش در قالب طرح آشيانه اي در سه قطعه زمين مجزا انجام
شد. صفات اندازه گيري شده شامل سطح برگ، وزن خشك برگ، وزن خشك ساقه، وزن خشك بوته و ارتفاع بوته و آخرين مرحله فقط وزن تر بود.
نتايج تجزيه واريانس آماري حاكي از آن بود كه بين نظام هاي خاك ورزي از نظر سطح برگ، وزن خشك برگ، وزن خشك ساقه و وزن خشك بوته ي
ذرت اختلاف معني داري وجود نداشت. در بين نظام هاي خاك ورزي با وجود اختلاف غير معني دار در عملكرد وزن خشك ذرت، مقدار عملكرد علوفه ي
تر ذرت در نظام خاك ورزي متداول از نظر آماري بيشتر از دو نظام ديگر بود. بيشترين عملكرد علوفه ي تر با مقدار 71 تن در هكتار در نظام
خاك ورزي متداول و كمترين عملكرد با مقدار 64 تن در هكتار براي نظام بدون خاك ورزي به دست آمد كه با دو نظام خاك ورزي ديگر اختلاف
معني داري داشت. نتايج اين مطالعه نشان داد كه نظام هاي خاك ورزي اثر معني داري بر وزن خشك بوته ي ذرت نداشت اما عملكرد علوفه ي تر در
سيستم خاك ورزي و كمترين عملكرد با مقدار 64 تن در هكتار براي نظام بدون خاك ورزي به دست آمد كه با دو نظام خاك ورزي ديگر اختلاف
معني داري داشت. نتايج اين مطالعه نشان داد كه نظام هاي خاك ورزي اثر معني داري بر وزن خشك بوته ي ذرت نداشت اما عملكرد علوفه ي تر در
سيستم خاك ورزي متداول به مقدار هفت تُن در هكتار از سيستم بدون خاك ورزي و چهار تُن در هكتار از سيستم كم خاك ورزي بيشتر بوده است كه
دليل اين اختلاف عملكرد افزايش دسترسي به آب يا دسترسي به آب بيشتر و توسعه مناسب و بهتر ريشه در سيستم خاك ورزي مرسوم ميباشد.
چكيده لاتين :
Introduction: The maize as the oldest cultivated plant, is ranked second and first in terms of cultivated area
and amount of production, in the world respectively. Although, researchers have improved the yield of corn by
introducing new lines and hybrids, new genotypes alone cannot increase agricultural production, and it is
necessary that appropriate and advanced agricultural techniques also be used to maximize corn yield. Maize is
one of the most important crops in Golestan province, which is planted in more than 5000 hectares of
agricultural land. In Golestan Province, different tillage systems are used for planting maize. Conservation tillage
is a new and widespread method in this province, which many farmers use this method every year for cultivating
their crops. The main objective of this study was to investigate the effects of different tillage systems on growth
indices and yield of maize.
Materials and Methods: To study the effects of different tillage systems on qrowth indices and forage yield
of corn, an experiment was conducted using a Nested design at Azadshahr city. Treatments included no-tillage,
minimum-tillage and conventional tillage. Each treatment was carried out in a separate 30 × 50 m plot. Cultivar
770 was planted in all plots with row spacing of 75 cmand the distance between plants on the ridges was 14 cm.
Sampling was done by a 1*1 m2 quadrate in six phenological stages of maize including two leaf-stage (9 days
after planting), six-leaf stage (26 days after planting), flowering (55 days after planting), (71 days after planting),
(85 days after planting) and 86 days after planting. At each stage, 15 quadrates were randomly sampled in each
plot. Leaf area and dry weight, height of each plant and total fresh and dry weight of maize was measured at
laboratory.
Results and Discussion: Net assimilation rate decreased following a quadratic equation in all treatments.
Although the amount of NAR was estimated 13.5, 13.16 and 13.11 g.m-2.day-1 for conventional, minimum and
no tillage, respectively but there was not significance different between the tillage systems in this regard. The
maximum amount of NAR occurred at 17.3, 17.4 and 17.5 days after planting for conventional, minimum and no
tillage, respectively. The value of this index at the end of the growing season (86 days after planting) was
estimated as 0.41, 0.45 and 0.47 g.m-2.day-1 for conventional, minimum and no tillage, respectively.
Relative growth rate decreased following a quadratic trend for all tillage systems. In conventional tillage,
RGR declined from 0.24 g.g-1.day-1 at the beginning of the growing season to 0.01 g.g-1.day-1 at the end of the
growing season. There was no difference between estimated RGR of the tillage systems both at beginning and at
the end of growing season.
Maximum crop growth rate occurred at 54 days after planting in all three tillage systems. The maximum
value of CGR was estimated 41, 41 and 40 g.m-2.day-1 for maize in conventional, minimum and no tillage
systems, respectively. CGR was estimated as 3 g.m-2.day-1 at the beginning of the growing season for all
treatments; this index was estimated 15, 15 and 14 g.m-2.day-1 at the end of the growing season, for conventional,
minimum and no tillage systems, respectively.
Result showed that although tillage systems did not effect on dry weight of maize, forage yield of maize in
conventional system (71 ton.ha-1) was significantly more than minimum (67 ton.ha-1) and no tillage (64 ton.ha-1)
systems.
