اثر نوع شخم، سطوح کود اوره و کاربرد قارچ میکوریزا بر خصوصیات فیزیکی خاک و عملکرد و اجزای عملکرد ماش (vigna radiata l.)

سطوح خاک‌ورزی و مصرف کودهای شیمیایی و زیستی نقش مهمی در رشد و عملکرد گیاهان دارند که به‌منظور بررسی تاثیر نوع شخم، سطوح اوره و کاربرد قارچ میکوریزا بر عملکرد و اجزای عملکرد ماش (vigna radiata l.)، آزمایشی در دو سال زراعی 1396 و 1397 در مزرعه تحقیقاتی مرکز تحقیقات کشاورزی دره‌شهر استان ایلام به‌صورت اسپلیت اسپلیت پلات در قالب طرح بلوک‌های کامل تصادفی با سه تکرار انجام شد. نوع شخم با سه سطح متداول (برگردان‌دار)، حفاظتی (قلمی) و بدون شخم به‌عنوان عامل کرت اصلی، کود اوره با چهار سطح عدم مصرف (صفر درصد)، 33، 66 و 100 درصد کود توصیه شده به‌عنوان عامل کرت فرعی و کاربرد و عدم کاربرد با قارچ میکوریزا (glomus mosseae) به‌عنوان عامل کرت فرعی فرعی مد نظر قرار گرفتند. عملکرد دانه و صفات مرتبط با آن و نیز صفات وزن مخصوص ظاهری خاک، رطوبت خاک، شاخص مخروطی خاک و کربن آلی خاک اندازه‌گیری شد. طبق نتایج تجزیه مرکب دو سال آزمایش اثرات ساده سال، نوع شخم کود اوره و کاربرد میکوریزا بر تعداد دانه در غلاف، تعداد غلاف در بوته، عملکرد دانه، شاخص برداشت، کربن آلی خاک، شاخص مخروطی خاک و درصد رطوبت خاک و اثر متقابل نوع شخم و کود اوره بر عملکرد دانه و شاخص مخروطی خاک و نیز اثر متقابل نوع شخم و کاربرد میکوریزا بر شاخص برداشت و درصد رطوبت خاک معنی‌دار بود. طبق نتایج آزمون مقایسات میانگین بالاترین عملکرد دانه از تیمار شخم حفاظتی و کاربرد 100‌ درصد کود اوره با 2941 کیلوگرم در هکتار با اختلاف معنی‌دار از سایر تیمارها به‌دست آمد. بیشترین وزن هزار دانه (57.5 گرم) از تیمار بدون شخم و بیشترین تعداد دانه در غلاف (10.6) و غلاف در بوته (61) از تیمار شخم حفاظتی به‌دست آمد. بیشترین وزن هزار دانه، تعداد دانه در غلاف و تعداد غلاف در بوته از تیمار 66 درصد کود اوره به‌دست آمد. بیشترین شاخص مخروطی خاک 2.25 مگاپاسکال از تیمار بدون شخم و مصرف 66 درصد کود اوره توصیه شده و کمترین آن 1.07 مگاپاسکال از تیمار شخم متداول و عدم مصرف اوره به‌دست آمد. بدون شخم و شخم متداول به‌ترتیب با مقادیر 0.68 و 0.32 درصد بیشترین و کمترین میزان کربن آلی خاک را دارا بودند. به‌طور کلی، شخم حفاظتی همراه با کاربرد 66 درصد کود اوره توصیه شده و تلقیح با میکوریزا، از نظر عملکرد دانه و اجزای آن بر سایر تیمارها برتری معنی‌دار داشت. به‌علاوه در این تیمار شاخص مخروطی خاک، درصدر طوبت خاک و محتوای کربن آلی نیز بهبود یافت.

Effects of Different Tillage Systems, Nitrogen Fertilizer Rates, and Mycorrhiza Inoculation on some Soil Physical Properties and Yield of Mung Bean (Vigna radiata L.)

IntroductionTillage intensity and tillage system can affect biological, physical, and chemical properties of the soil. Suitable soil management is essential to achieve sustainable agricultural production especially in droughtprone regions. More application of machineries in a tillage system will result in more soil compaction which in turn increases soil bulk density and decreases its air and water permeability. Additionally, it has been well documented that the compact soil hampers the downward growth of the crop roots. The soil with good physical quality will provide aeration and water as well as nonimpeditive mechanical resistance for root proliferation. Moldboard plowing is currently applied in around 65% of tillage practices although the agricultural extension services have tried to convince farmers to apply reduced tillage system by replacing moldboard plow with chisel plow to mitigate adverse effects of moldboard plowing especially in arid and semiarid regions. Conservation tillage practices, especially reduced tillage, have been introduced to Iranian farmers since 1999. Mycorrhiza is the product of an association between a fungus and plant root that enhance the tolerance levels of plants against the drought, salinity and high heavy metal contents. The aim of the present study were to evaluate the effects of tillage systems, nitrogen levels, and mycorrhiza inoculation on yield and yield components of mung bean and soil criteria.Materials and MethodsThe experiment was conducted in Darehshahr research field in two growing seasons (2017 and 2018). The experimental layout was split plot based on a randomized complete block design with three replications. Treatments consisted of three tillage systems as conventional, conservation and no tillage as main plot, four nitrogen levels including 0% (as control), 33%, 66% and 100% of recommended fertilizer as sub plot, and two levels of mycorrhiza fungi inoculation (Contains arbuscular mycorrhiza fungi of Glomus mosseae strains, counting 107 to 108 (CFU / g.) Prepared by Soil and Water Research Institute) (no symbiosis (as control) and with symbiosis) as subsubplot. Studied traits were yield components (such as 1000seed weight, No. of seeds per pod, No. of pods per plant), seed yield and harvest index of mung bean and moisture content, cone index and organic carbon percent of soil. For analysis of variance SAS 9.4 was used. All the means were compared according to Duncan test (p≤0.05).Results and DiscussionThe results revealed that the highest 1000seed weight (57.48 g) was obtained from notillage and the highest number of seeds per pod (10.64 seeds per pod) and the number of pods per plant (61.04 pods per plant) were obtained from conservation tillage. The highest seed yield was obtained from conservation tillage + application of 100% N fertilizer with 2941 kg.ha1. The highest seed weight, number of seeds per pod, and number of pods per plant were obtained from 66% N fertilizer application. Mycorrhiza inoculation increased harvest index, seed yield and its components. The soil bulk density in the notillage system had the highest value. The maximum and the minimum soil moisture contents were observed for nontillage and conventional tillage systems, respectively.The highest soil cone index (2.25 MPa) was obtained from notillage and 66% N fertilizer and the lowest (1.07 MPa) was for conventional tillage system+ without nitrogen application. The highest and the lowest soil organic carbon were related to notillage and conventional tillage systems with 0.68% and 0.32%, respectively.ConclusionIn general, the conservation tillage system+ application of 66% N fertilizer and inoculation with mycorrhiza had a relative advantage impact on yield and related traits. In addition, the soil physical traits and organic carbon content were improved affected as declined tillage systems. The longterm field experiment points out the beneficial impacts of reduced tillage and no tillage systems that, in addition to preserving both soil physical (such as cone index) and chemical criteria (and organic carbon), fertility and biological activity, could increase yield and exhibit a comparable yield over a longterm period as in conventional plough. Currently, there is no mung bean variety appropriate to Iran. Improving some varieties with higher yield which are tolerant to warm climate and water deficiency seems essential to improve the sustainability of local seed production. Investigating into the effect of mung bean tillage and fertilizer consumption on the weed type and density is also suggested for future studies.