ارزیابی عملکرد و کیفیت علوفه در کشت مخلوط لوبیا تپاری (Phaseolus Acutifolus L. Gray) و دو رقم ارزن

به‌منظور بررسی عملکرد کمّی و کیفی علوفه در کشت مخلوط لوبیا تپاری (phaseolus acutifolus l. gray) و دو رقم ارزن باستان (cv. bastan) و ارزن پیشاهنگ (cv. pishahang)، آزمایشی بر پایه طرح بلوک های‌ کامل تصادفی با سه تکرار در مزرعه نمونه در منطقه جیرفت، در سال زراعی 95-1394 اجرا شد. تیمارها شامل ترکیب گیاه لوبیا تپاری با دو رقم ارزن پیشاهنگ و ارزن باستان و نسبت ‌های اختلاط کشت مخلوط جایگزینی به نسبت های 75 : 25، 50 : 50 ، 25 : 75 لوبیا تپاری ارزن باستان، کشت خالص لوبیا تپاری، کشت خالص ارزن باستان، کشت خالص ارزن پیشاهنگ و همین نسبت‌های اختلاط لوبیا تپاری با ارزن پیشاهنگ و با تراکم 20 بوته در مترمربع، بودند. صفات عملکرد کل علوفه خشک، عملکرد علوفه کل تر، درصد خاکستر، قابلیت هضم ماده خشک، کربوهیدرات های محلول در آب، درصد عناصر کلسیم، منیزیم، سدیم و پتاسم مورد ارزیابی قرار گرفتند. نتایج نشان داد بیشترین عملکرد کل علوفه تر (24600 کیلوگرم در هکتار) و عملکرد کل علوفه خشک (با 4500 کبلوگرم در هکتار) از تیمار 50:50 لوبیا تپاری ارزن باستان به‌دست آمد. هرچند بهترین صفات مورد بررسی از نظر کیفیت علوفه، در نسبت های مختلف اختلاط حاصل شد، امّا برتری کشت مخلوط این گیاهان، نسبت به سیستم تک‌ کشتی آن‌ها مشاهده شد، به‌طوری که بیشترین درصد خاکستر، قابلیت هضم علوفه، کربوهیدرات های محلول در آب و میزان عناصر سدیم، پتاسیم، کلسیم و منیزیم از تیمارهای مخلوط، حاصل شد. بالاترین میزان عملکرد نسبی کل براساس عملکرد کل علوفه تر و خشک نیز از تیمار50:50 لوبیا تپاری ارزن به‌ترتیب با میزان 2.27 و 2.16، به‌دست آمد.

Evaluation of Yield and Quality Forage in Intercropping Tepary Bean (Phaseolus acutifolus L. Gray) and Millet Cultivars

Introduction[1]Intercropping agriculture is one of the pillars of sustainable agriculture that it has become popular in many countries for reasons such as increasing in the quantity and quality of agricultural products (Pakgohar Ghanbari, 2014). Currently in Iran, because of the lack quality fodder, the development of the livestock industry requires a serious approach to animal feed, which seems to be very important planting of these crops with intercropping in sustainable agriculture (Nasiri et al., 2015). Intercropping cereals and legumes is one of the kind intercropping that based on the results, it can increase the quality of forage produced (Javanmard et al., 2015). The purpose of this study was determination the total yield and forage quality obtained from intercropped Tepary bean and two millet cultivars. Materials and MethodsThe field experiment was done in a randomized complete blocks design with 30 treatment and three replications in Jiroft during 20152016 growth season. The treatments included combination of Tepary bean (Phaseolus acutifolus L. Gray) and two cultivars of millet (cv. Pishahang and cv. Bastan) and replacement intercropping ratio 75:25, 50:50, 25:75 Tepary bean Bastan millet, sole cropping of Tepary bean, Bastan millet and the same intercropping ratio of Tepary bean and Pishahang millet. The two plants were cultivated simultaneously and manually. The intra rows and inter rows were 50 and 10 cm2 respectively. The traits evaluated were dry forage yield, fresh forage, ash percentage, dry matter digestibility, water soluble carbohydrates, percentage of calcium, magnesium, sodium, and potassium. The total dry matter yield per plot was calculated from 1 m2 and the forage quality traites of the dried and milled samples in each plot was measured using infrared spectrometer such as Acid detergent fiber (ADF), Dry matter digestibility (DMD) and Water soluble carbohydrate (WSC). The amount of Na and K of forage was determined in the extracts prepared from samples of each treatment by flame Photometer and The amount of Ca and Mg in the extracts was read by atomic absorption. Data analyses were conducted using SAS ver. 12 and analysis of means was done with the Duncan’s test in significant at 5% probability level. Results and DiscussionThe results of this study showed that the highest total dry matter yield was obtained from 50:50 t of Tepary bean Bastan millet (with 87.57 and 12.59% increasement than sole cropping of Bastan millet and Tepary bean, respectively) and the same ratio of Tepary bean and Pishahang millet. It seems that the better utilization of resources, morphological differences of plants and type of cultivar in intercropping system produced more dry matter yield than sole cropping.The most of Ash, DMD, WSC, Na, K, Ca and Mg, was obtained from intercropping treatments. Also the highest Relative Yield Total (RYT) in evaluation of total dry forage yield was obtained from 50:50 Tepary bean millet treatment (2.16). Highest level of competition was observed in the relative yield of total dry forage from 75:25 Tepary bean millet (1.36). In evaluating the benefits of sorghum and bean mung bean intercropping, the researchers reported more than one relative yield total in all intercropping treatments (Shaker Koohi et al., 2014). ConclusionAccording to the results of this study the highest total forage yield obtained from 50:50 Tepary bean millet treatment. Also the quality traits of forage such as Ash, DMD, WSC and amount of Na, K, Ca and Mg were increased in intercropping treatments. Total RYT increased in 50:50 Tepary bean+ millet. Totally this result showed inter cropping of bean and millet was better than sole cropping and Therefore, it is possible to introduce intercropping of cereals and legumes as one of the effective methods for producing high quality forage.