بررسی وضعیت تغذیه باغات فندق (Corylus Avellana L.) استان گیلان با روش انحراف از درصد بهینه (Dop)

استان گیلان با حدود 18000 هکتار باغات فندق که 85 درصد سطح زیر کشت باغات فندق کشور را به خود اختصاص داده به عنوان بزرگترین قطب فندق‌کاری ایران محسوب می گردد. شناخت وضعیت تغذیه ای یک باغ از اولویت های اولیه تغذیه محصولات باغی می باشد که به روش های مختلفی انجام می گردد. یکی از این روش ها، روش انحراف از درصد بهینه 2(dop) می باشد. به منظور بررسی و شناخت ناهنجاری های تغذیه ای و تعیین حد مطلوب غلظت عناصر غذایی از روش انحراف از درصد بهینه استفاده شد. بدین منظور در سه شهرستان عمده تولید کننده فندق (رودسر، سیاهکل و املش) از32 باغ فندق از برگ های شاخه های یکساله در مرداد ماه نمونه برداری و میزان عناصر غذایی نیتروژن، فسفر، پتاسیم، منگنز، مس،آهن و روی در آن ها تعیین شد. باغات به دو گروه عملکرد بالا و پایین تعیین گردید، غلظت مطلوب در برگ برای عناصر نیتروژن، فسفر، پتاسیم ،آهن، منگنز، روی، مس به ترتیب 3.08  درصد،0.16 درصد،0.80 درصد،   570.38 پی.پی.ام، 175.26 پی.پی.ام، 42.93 پی.پی.ام، 17.09 پی.پی.ام بدست آمد .نتایج نشان داد در بین عناصر پرمصرف نیتروژن در 65 درصد باغات دارای شاخص منفی و در بین عناصر کم مصرف منگنز با 78 درصد بیشترین شاخص منفی را داشتند. براساس محاسبات روش dop نتایج زیر برای اولویت تغذیه باغات بدست آمد: >fe>p>zn>k>cu mn>n

Study of Nutritional Status of Hazelnut Orchards of (Corylus avellana L.) Guilan Province by Using with Deviation of Optimum Percent (DOP)

Introduction: The study of the nutritional status of orchards is one of the primary priorities for the nutrition of crops and orchards, which is done in different methods. One of these methods is the deviation from the optimum percentage (DOP). Hazelnut is one of the species of the family (Betulaceae) which is the fifth most produced nut in the world after cashews, almonds, walnuts, and oaks. Turkey is the world’s largest producer with about 70.3% of the total world production of hazelnuts and Italy with 11.9%, the United States with 4.5%, and Azerbaijan with 4.2%, Georgia with 3.8%, Spain with 2.5% of world production, respectively. Other hazelnut producing countries account for 2.8% of the world production and the world hazelnut production in 2018 was about 888,000 tons. In 2018, Iran was the eighth largest producer in the world with a production of 16,000 tons. Guilan province has 18,000 hectares of hazelnut orchards, which constitute 85% of the cultivated area of hazelnut orchards in the country. Since the leaf is the most important part of plant metabolism and the concentration of nutrients in the leaf at certain stages of plant growth and development has a great relationship with yield. Therefore, leaf analysis and interpretation of the results, provided that according to standard methods, can provide good information about the nutritional status of the plant and be used to recommend the appropriate fertilizer. Materials and Methods: The optimal Deviation (DOP) method was used to investigate and identify nutritional deficiency and determine the optimal concentration of nutrients. For this purpose, the number of nutrients such as nitrogen, phosphorus, potassium, manganese, copper, iron, and zinc were determined in 32 hazelnut orchards with growth of the following year branches in the three major hazelnut production cities (Rudsar, Siahkal, and Amlash), in July. To implement this project, 32 orchards over 10 years old were sampled from the dominant cultivars of the region (Gerd cultivar), so that they are different in terms of management and yield. Seventeen orchards in Eshkavrat region of Rudsar, seven orchards in Hazelnut areas of Siahkal, and eight orchards in the Eshkvarat region of Amlash city were selected for sampling. The orchards that had the best yield due to the great management were randomly selected to determine the standard concentration (Cref) and other lowyield and mediumsized orchards were randomly selected to determine the nutritional status. The orchards were divided into low and highyield groups in August. When the concentration of nutrients in the leaves was relatively constant, about 50 healthy young leaves were sampling in different directions and 10 trees in each orchard. Pestfree samples were transferred to the laboratory and leaf samples were first washed in water and then washed with distilled water. The samples were placed into the oven at 65 °C for drying. The dried samples were completely powdered and passed through a sieve with half a millimeter holes. In leaf analysis, nitrogen nutrients was measured in a more digestible manner by Kjeltec device, phosphorus by spectrophotometry, potassium by flame photometric, manganese, copper, iron, and zinc by dry ash method and atomic absorption spectrometry. Results and Discussion: The results showed that the average concentrations of N, P, Fe, Mn, Zn, Cu in highyield orchards were higher than the concentration of nutrients in lowyield orchards. The deviation index was calculated from the optimal percentage and the priority of the nutritional needs of hazelnut trees in each garden was determined. Indicators are positive, negative or zero numbers, zero indicates the optimal statue of concentration, a positive value indicates excess nutrient and a negative number indicates nutrient deficiency. According to the indexes of deviation from the optimal percentage, among the elements manganese, nitrogen and iron had the highest negative index, respectively, so that manganese had negative indexes in 78% of orchards and nitrogen had negative indexes in 65% of orchards, and then Iron had negative indexes in 60% of the orchards and phosphorus in 56% of the orchards, zinc in 53% of the orchards and potassium in 50% of the orchards and finally copper in 46% of the orchards had negative indexes, respectively. Conclusion: Optimal concentrations were determined for nitrogen, phosphorus, potassium, iron, manganese, zinc, copper, 3.08%, 0.16%, 0.80%, 570.38 ppm, 175.26 ppm, 42.93 ppm, ppm 17.09 in the leaves. Based on the calculations of the DOP method, the following results were obtained for the priority of feeding the orchards. Mn>N>Fe>P>Zn> K>Cu