بهينه‌سازي كود دامي و تراكم بوته در گياه دارويي نعناع فلفلي (Mentha piperita L.) با استفاده از مدلسازي سطح- پاسخ

Optimization of cow manure and plant density in peppermint (Mentha piperita L.) as a medicinal plant using response surface methodolgy

بهينه‌سازي مصرف كود و تراكم بوته از جمله راهكارهاي زراعي براي بهبود كارايي مصرف نهاده‌ها و تخفيف آلودگي‌هاي زيست‌محيطي است. روش سطح- پاسخ (RSM) يكي از روش‌هاي آماري براي بهينه‌سازي نهاده‌ها است كه ميزان بهينه را بوسيله طرح مركب مركزي تعيين مي‌كند. هدف از اين مطالعه، تعيين ميزان بهينه كود دامي و تراكم بوته براي عملكرد اندام‌هاي رويشي و اسانس گياه دارويي نعناع فلفلي استفاده از مدلسازي سطح- پاسخ بود. مواد و روشها: اين مطالعه با استفاده از طرح مركب مركزي با 13 تيمار و دو تكرار در مزرعه تحقيقاتي دانشگاه فردوسي مشهد در سال زراعي 97-1396 انجام شد. سطوح بالا و پايين تراكم بوته (به ترتيب 10 و 15 بوته در متر مربع) و كود دامي (به ترتيب صفر (شاهد) و 70 تن در هكتار) به عنوان تيمار مدنظر قرار گرفتند. وزن تر و خشك ساقه، وزن تر و خشك برگ، وزن خشك كل و درصد اسانس در دو نوبت نمونه‌برداري و دو چين بعنوان متغير وابسته مورد اندازه‌گيري قرار گرفتند و تغييرات آنها با استفاده از مدل رگرسيوني ارزيابي شد. به منظور ارزيابي كيفيت و بسندگي مدل از آزمون عدم برازش و آناليز واريانس استفاده شد. معادله چند جمله‌اي درجه دوم كامل براي تعيين معني‌داري مدل و اجزاي مدل (خطي، درجه دو و اثر متقابل) و ضريب تبيين (R2) براي ارزيابي كيفيت مدل برازش شده مورد استفاده قرار گرفت. يافته ها: نتايج نشان داد كه اثر جزء خطي و درجه دو بر تمام صفات مورد مطالعه در مراحل اول و دوم نمونه‌برداري معني‌دار بود. اثر متقابل كود دامي و تراكم بوته تنها بر صفات مورد مطالعه در مرحله دوم نمونه‌برداري معني‌دار بود. آزمون عدم برازش در مورد هيچ-كداماز ﺻﻔﺎت ﻣﻌﻨﯽدار ﻧﺸﺪ ﮐﻪ ﻧﺸﺎندﻫﻨﺪه ﺑﺮازش ﻣﻄﻠﻮب ﻣﺪل رﮔﺮﺳﯿﻮن درﺟﻪ دو ﮐﺎﻣﻞ ﺑﻮد. داﻣﻨﻪ R ﺑﺮاي ﺻﻔﺎت روﯾﺸﯽ ﺑﺮاﺑﺮ ﺑـﺎ 84/62 – 64/20 درﺻﺪ و ﺑﺮاي ﻋﻤﻠﮑﺮد اﻧﺪامﻫﺎي روﯾﺸﯽ و درﺻﺪ اﺳﺎﻧﺲ در ﭼﯿﻦﻫﺎي اول و دوم ﺑﺮاﺑﺮ ﺑﺎ 63/06– 27/36 درﺻﺪ ﻣﺤﺎﺳﺒﻪ ﺷﺪ. ﺑﺎﻻﺗﺮﯾﻦ ﻋﻤﻠﮑﺮد اﻧﺪام ﻫﺎي روﯾﺸﯽ ﻣﺸﺎﻫﺪه ﺷﺪه و ﭘﯿﺶﺑﯿﻨﯽ ﺷﺪه ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺮاي ﺗﺮاﮐﻢ 12/5 ﺑﻮﺗﻪ در ﻣﺮﺑﻊ و 35 ﺗـﻦ ﮐﻮد داﻣﯽ در ﻫﮑﺘﺎر )75513 ﮔﺮم در ﻣﺘﺮﻣﺮﺑﻊ( و 15 ﺑﻮﺗﻪ در ﻣﺮﺑﻊ و 35 ﺗﻦ ﮐﻮد داﻣﯽ در ﻫﮑﺘﺎر )31992 ﮔﺮم در ﻣﺘﺮﻣﺮﺑﻊ( ﺑﻪ دﺳﺖ آﻣﺪ. ﻋﻤﻠﮑﺮد اﻧﺪام ﻫﺎي روﯾﺸﯽ در ﭼﯿﻦ دوم ﺑﺎﻻﺗﺮ از ﭼﯿﻦ اول ﺑﻮد. ﺑﺮ اﺳﺎس ﺳﻨﺎرﯾﻮي اﻗﺘﺼﺎدي، ﻣﻘﺪار ﺑﻬﯿﻨﻪ ﺗﺮاﮐﻢ ﺑﻮﺗـﻪ و ﮐـﻮد داﻣﯽ و درﺟﻪ ﻣﻄﻠﻮﺑﯿﺖ ﺑﺮاي ﻋﻤﻠﮑﺮد زﯾﺴﺖﺗﻮده ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺎ 10 ﺑﻮﺗﻪ در ﻣﺘﺮﻣﺮﺑﻊ، 23 ﺗﻦ در ﻫﮑﺘﺎر و 0/94 =d و ﺑﺮاي ﻋﻤﻠﮑـﺮد زﯾﺴﺖﺗﻮده و درﺻﺪ اﺳﺎﻧﺲ ﺑﺮاﺑﺮ ﺑﺎ 10 ﺑﻮﺗﻪ در ﻣﺘﺮﻣﺮﺑﻊ، 49 ﺗﻦ در ﻫﮑﺘﺎر و 0/96 =d ﻣﺤﺎﺳﺒﻪ ﮔﺮدﯾﺪ. ﻧﺘﯿﺠﻪﮔﯿﺮي: ﺑﻪ ﻃﻮر ﮐﻠﯽ، ﺑﻬﯿﻨﻪﺳﺎزي ﻣﯿﺰان ﻣﺼﺮف ﻣﻨﺎﺑﻊ ﺑﺎ اﺳﺘﻔﺎده از ﻣﺪﻟﺴﺎزي ﺳﻄﺢ - ﭘﺎﺳﺦ ﻣﯽﺗﻮاﻧﺪ ﺑﻪ ﻋﻨﻮان راﻫﮑﺎري ﻣﻄﻠﻮب در ﺗﻮﻟﯿﺪ ﭘﺎﯾﺪار ﮔﯿﺎﻫﺎن داروﯾﯽ ﺟﻬﺖ اﻓﺰاﯾﺶ ﺗﻮﻟﯿﺪ و ﺑﻬﺒﻮد ﮐﯿﻔﯿﺖ ﻣﺪ ﻧﻈﺮ ﻗﺮار ﮔﯿﺮد.

Optimization of fertilizer and plant density are management approaches to improve resources efficiency and decline environmental pollutions. Response surface methodology (RSM) is defined as a set of mathematical and statistical techniques that are used to develop, to improve or to optimize a product by using Central composite designs. In this work, optimization of cow manure and plant density on biomass yield and essential oil percentage of peppermint as a medicinal plant species using central composite design for RSM was evaluated. Materials and methods: An experiment was conducted using central composite design with 13 treatments and two replications at the Research Field of Ferdowsi University of Mashhad during the growing season of 2017-2018. The treatments were allocated based on low and high levels of plant density (10 and 15 plants.m-2, respectively) and cow manure (0 and 70 t.ha-1, respectively). Fresh weight of stem, dried weight of stem, fresh weight of leaves, fresh weight of leaves, total dried weight and essential oil percentage in two sampling times and two cuttings were measured as dependent variables and changes of these variables were evaluated by a regression model. Lack-of-fit test was used to evaluate the quality of the fitted model. The adequacy of the model was tested by analysis of variance. The full quadratic polynomial equation was tested to determine the significance of the model and the component of the model (linear, squared and first-order interaction terms) and the quality of the fitted model was judged using the determination coefficient (R2). Results: The results showed that effect of linear and square components were significant on all studied characteristics in two sampling times. Interaction between the two factors of manure and plant density was significant on the studied traits only for the second sampling stage. Lack of fit had no significant effect on the studied traits. The full square model for the response variables gave insignificant lack-of-fit indicating that the data were satisfactorily explained. In the first and the second cuttings, R2 ranges for biomass yield and biomass yield+ essential oil were 70.39-84.62% and 27.36-63.06%, respectively. The highest observed and predicted values of biomass yield were recorded in 12.5 plants.m-2+ 35 t.ha-1 cow manure (755.13 g.m-2) and 15 plants.m-2+ 35 t.ha-1 cow manure (319.92 g.m-2), respectively. The mean yield of biomass yield in the second cutting was higher than the first cutting. Optimum levels of plant density and cow manure and desirability for biomass yield were calculated with 10 plants.m-2+23 t.ha-1 and d= 0.94 and the parameters for biomass yield, and essential oil percentage were with 10 plants.m-2, 49 t.ha-1 and d= 0.96, respectively. Conclusion: In general, it seems that resource use optimization using RSM may be suitable cropping approach for sustainable production of medicinal plants in agroecosystems.