تاثیر سیستم‌های مختلف خاک‎ورزی و مدیریت بقایای گیاهی بر حفاظت آب خاک، عملکرد و اجزای عملکرد گندم

به‌منظور بررسی تاثیر سیستم‌های مختلف خاک‎ورزی و مدیریت بقایای گیاهی بر میزان آب خاک، اجزای عملکرد و عملکرد گندم، آزمایشی مزرعه‎ای در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد طی سال زراعی 97-1396 انجام شد. آزمایش به‌صورت کرت‌های خرد شده در قالب طرح بلوک کامل تصادفی با سه تکرار اجرا شد. شیوه‌های مختلف خاک‎ورزی شامل شیوه متداول خاک‎ورزی و کاهش‌یافته به‌عنوان کرت‌های اصلی و سه مدیریت بقایای گیاهی شامل حفظ صفر، 30 و 60 درصد بقایای گوجه‌فرنگی به‌عنوان کرت‌های فرعی در نظر گرفته شد. نتایج نشان داد که اثر سیستم خاک‌ورزی بر میزان آب خاک در عمق 20-0 سانتی‌متری در دو روز پس از آبیاری چهارم و عمق 40-20 سانتی‌متری در دو روز پس از آبیاری پنجم، ششم و هفتم، تعداد سنبله در متر مربع، تعداد دانه در سنبله، عملکرد دانه و بیولوژیک گندم معنی‌دار بود و بیشترین مقادیر این صفات از تیمار خاک‌ورزی کاهش‌یافته حاصل شد. اما اثر مدیریت بقایای گیاهی بر هیچ‌یک از صفات مورد مطالعه معنی‌دار نبود. نتایج اثر متقابل نشان داد تنها میزان آب خاک در عمق 20-0 و 40-20 سانتی‌متری خاک به‌ترتیب دو روز پس از آبیاری چهارم و سوم، تعداد دانه در سنبله، وزن هزار دانه و عملکرد دانه تحت تاثیر سیستم خاک‌ورزی و مدیریت بقایای گیاهی قرار گرفتند. حداکثر میزان آب خاک (22.10% و 17.57% در عمق 20-0 و 40-20 سانتی‌متری خاک به‌ترتیب دو روز پس از آبیاری چهارم و سوم) و وزن هزار دانه (38.44 گرم) در سیستم خاک‌ورزی کاهش‌یافته و حفظ 60 درصد بقایای گیاهی به‌دست آمد و تیمار خاک‌ورزی کاهش یافته و حفظ 30 درصد بقایای گیاهی بیشترین تعداد دانه در سنبله (61.90) و عملکرد دانه (7120.67 کیلوگرم در هکتار) را به خود اختصاص داد. با توجه به نتایج حاصله اعمال خاک‌ورزی کاهش یافته و حفظ 30 درصد بقایای گوجه‌فرنگی جهت حصول به عملکرد بالاتر، مطلوب به نظر می‌رسد.

Effect of Tillage Systems and Residue Management on Soil Water Conservation, Yield and Yield Components of Wheat

Introduction;Soil is one of the most important components of production, food security, selfsufficiency and national economy. Soil of semiarid regions, which most of Iran 's agricultural lands are located in these areas, are poor in terms of organic matter. The soil tillage operations are carried out by means of moldboard plow and removal of plant residue in most of the agricultural systems. This operation, called conventional tillage, requires not only high energy but also damages to soil physical properties and erosion in the longterm. Conventional tillage does not provide good environmental conditions to maintain moisture in the soil due to the impossibility of managing plant residue in the soil surface. In addition this tillage increases the evaporation and losses of soil water content and reduces the soil organic carbon as a result conventional tillage reduces the physical, chemical and biological characteristics of the soil. The objective of this study was investigation of effect of conventional and reduced tillage systems and management of tomato residue on soil water content, yield and yield components of wheat.;Materials and Methods;The experiment was conducted as split plot based on randomized complete block design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad, during growth season 201718. Tillage system (in two levels i.e. conventional and minimum tillage) and tomato residue retention (0, 30 and 60%) were in main plots and sub plots, respectively. The sowing date was 11th November in 2017.Sampling was done at harvest time and included plant height, spike number.m2, spike length, grain number per spike, 1000 grain weight, grain yield, biological yield and harvest index. During the growing season, soil water content in 020 and 2040 cm depth was measured by the soil moisture meter (PMS714 model) two days after irrigation. Data were analyzed with R software; obtained averages compared with Duncan’s multiple range test at the 5% probability level.;Results and Discussion;The results showed that the effect of tillage system was significant on soil water content in 020 cm depth two days after forth irrigation, soil water content in 2040 cm two days after fifth, sixth and seventh irrigation, spike number.m2, grain number per spike, grain and biological yield. Maximum of this traits were obtained in reduced tillage due to increased soil nutrition, improved physical condition of the soil and soil water status. However, the effect of management of tomato residue on any of the studied traits was not significant. This could be due to reducing microbial activity, in complete decomposition of plant residues and reducing available nitrogen.;The interaction effect between tillage system and tomato residue was significant on soil water content in 020 and 2040 cm depth two days after forth and third irrigation, respectively, grain number per spike, 1000 grain weight and grain yield. Reduced tillage and 60% of tomato residue showed that maximum of soil water content and 1000 grain weight (38.4 g).Maximum of grain number per spike (61.9) and grain yield (7120. 7 kg.ha1) were obtained in treatment of reduced tillage and 30% of tomato residue.;Conclusions    ;The results of this study indicate that in order to achieve maximum grain yield and less damage to the physical and chemical properties of soil, the implementation of reduced tillage and maintenance of 30% of tomato residue is recommended in the studied area. In general, due to climate change and water resource constraints in the country, conservation tillage and residue management practices are a good way to maintain resources and sustainability.;