ارزیابی شاخص ‌های رقابتی و عملکرد کشت مخلوط تریتیکاله (triticosecale wittmack ×) و نخود (cicer arietinum l) تحت تاثیر کود زیستی- آلی در شرایط تنش ‌آبی

به منظور ارزیابی تاثیر منابع مختلف کودی بر عملکرد و شاخص های رقابتی تریتیکاله (triticosecale wittmack ×) و نخود (cicer arietinum l) در کشت مخلوط تریتیکاله و نخود تحت شرایط تنش آبی، آزمایشی به‌ صورت اسپلیت فاکتوریل در قالب طرح بلوک های کامل تصادفی در سه تکرار در مزرعه پژوهشی دانشکده کشاورزی و منابع طبیعی داراب- دانشگاه شیراز در سال زراعی 1399 1398 انجام شد. تیمارها در دو سطح آبیاری [1 مطلوب: آبیاری بر اساس نیاز آبی گیاه و 2 تنش آبی: آبیاری تا مرحله شیری] به عنوان عامل اصلی و سه منبع کودی [شیمیایی: (50 کیلوگرم فسفر بر هکتار + 150 کیلوگرم نیتروژن بر هکتار)، زیستی- آلی: (40 تن کود گوسفندی بر هکتار + تلقیح با سودوموناس فلورسنس (pseudomonas fluorescens) و آزوسپیریلوم براسیلنس (azospirillum brasilense)] و تلفیقی: (25 کیلوگرم فسفر بر هکتار + 75 کیلوگرم نیتروژن بر هکتار + 20 تن کود گوسفندی بر هکتار + تلقیح با باکتری های سودوموناس فلورسنس و آزوسپیریلوم براسیلنس)، و سه الگوی کشت [کشت خالص تریتیکاله، کشت خالص نخود و کشت مخلوط تریتیکاله و نخود (1:1)] به عنوان عوامل فرعی بودند. نتایج نشان داد، تنش آبی  شاخص نسبت برابری زمین هر دو گیاه وکل را افزایش داد. همچنین، بیشترین نسبت برابری کل در تیمار تلفیقی مشاهده شد. شاخص بهره وری سیستم به‌واسطه تنش آبی کاهش یافت که کمترین کاهش (17 درصد) در تیمار کود زیستی رخ داد. همچنین، شاخص نسبت رقابتی برای تریتیکاله در تیمار کود شیمیایی و برای نخود در کود زیستی بیشترین مقدار (به ترتیب 1.37 و 1.02) را داشت. برهم‌کنش تیمار آبیاری × سامانه کودی برای تریتیکاله و نخود نشان داد که بیشترین عملکرد دانه نخود و تریتیکاله در تیمار آبیاری مطلوب و کود تلفیقی به ترتیب (3544 و7450 کیلوگرم بر هکتار) به دست آمد. همچنین، باتوجه به اینکه کمترین کاهش عملکرد دانه نخود و تریتیکاله به‌واسطه تنش آبی در تیمار کود زیستی (به ترتیب 27 و 31 درصد) مشاهده شد، کشت تریتیکاله و نخود با کاربرد کود زیستی جهت تعدیل اثرات منفی تنش آبی توصیه می شود.

evaluation of competitive indices and grain yield of triticale (× triticosecale wittmack) – chickpea (cicer arietinum l.) intercropping as affected by bio-organic fertilizer and water stress

introductiontodays, efforts to increase crop yields have led to the indiscriminate use of chemical fertilizers, especially nitrogen (n) and phosphorus (p) fertilizers. it has caused soil and groundwater pollution and the destruction of soil microbial communities. therefore, researchers should look for ways to replace n fertilizers and reduce their side effects. intercropping of cereals and legumes due to differences in the distribution and depth of roots in the soil profile can reduce competition for water and the survival of these plants in water shortage conditions. among the methods that may reduce the use of n and p fertilizers and thus reduce sensitivity to water stress is the intercropping of cereals and legumes. using growth-promoting n-fixing bacteria such as azospirillum brasilense and phosphorus solvents such as pseudomonas fluorescens as biofertilizers can be another way to reduce the use of n and p fertilizers and the adverse effects of water stress. therefore, the aim of this study was to investigate the effects of different fertilizer systems [chemical, integrated, and biological] on yield and competitive indices in triticale (× triticosecale wittmack) - chickpea (cicer arietinum l.) intercropping under water stress conditions in southern iran (fars province).materials and methodsthis experiment was performed as a split factorial on a randomized complete block design with three replications in the research farm of the darab faculty of agriculture and natural resources-shiraz university in the 2019-2020 growing season. experimental treatments included two levels of irrigation (ir) [normal: irrigation based on plant water requirement (irn) and water stress: irrigation based on plant water requirement up to the milking stage (ws)] as the main factors. the sub-factors included three sources of fertilizer (f) [chemical: 50 kg p.ha-1 +150 kg n.ha-1, bio-organic: 40 tons of manure sheep ha-1 + inoculation with pseudomonas fluorescens and azospirillum brasillens, integrated: 25 kg p ha-1 + 75 kg n.ha-1 + 20 tons of manure sheep ha-1 + inoculation with pseudomonas fluorescens and azospirillum brasilens] and three types of cropping systems (cp) [monoculture of triticale, monoculture of chickpea, and intercropping of triticale-chickpea (1:1)]. the crops grain yield were measured, of the crops was measured and competitive indices including land equivalent ratio (ler), aggressivity (a), competitive ratio (cr), and system productivity index (spi) were computed. the sas 9.1 software was used to analyze the data, and the means were separated using the least significant difference (lsd) test at a 5% probability level.results and discussion the results showed that the cessation of irrigation after the milking stage put severe stress on the triticale and chickpea during the grain filling period and reduced grain yield of both plants. the ir × f interaction for triticale and chickpea grain yield showed that the lowest reduction of their grain yield (31% and 27%, respectively) were obtained in bio treatment due to water stress as compared to irn. furthermore, the ir × cp interaction for triticale and chickpea grain yield showed that the water stress reduced their grain yield. however, the reductions were lower in intercropping system of triticale (38%) and chickpea (24%) as compared with their sole cropping. late season water stress increased triticale, chickpea and total ler as compared with irn conditions by 40, 65 and 51%, respectively. furthermore, the ir × f interaction showed that the highest and the lowest reductions (55% and 17%, respectively) of spi were achieved in chemical and bio treatments as a consequence of water stress conditions. conclusions based on the results obtained from this study, it can be concluded that the intercropping system of triticale and chickpea is superior to their monocropping under late season water stress conditions. also, the lowest reduction of chickpea and triticale grain yields as a consequence of water stress was obtained by the application of bio and integrated fertilizers. therefore, the use of azospirillum brasiliens and pseudomonas fluorescens with sheep manure fertilizer not only mitigates the negative effects of water stress, but also reduces the excessive use of n-p chemical fertilizers and their harmful environmental effects and it can be an effective step for sustainability of agricultural systems.