بررسی برخی ویژگی‌های فیزیکی و شیمیایی خاک در رویشگاه‌های گونه مورد (.myrtus communis l) در جنوب غربی ایران

یکی از گونه‌های بسیار مهم در بافت جنگل‌های غرب و جنوب کشور، درختچه مورد (.myrtus communis l) است. مورد یک گونه مدیترانه‌ای است که با توجه به وسعت و دامنه پراکنش آن، دانسته‌های کمی در رابطه با پراکنش این‌گونه در منطقه جنوب غرب کشور وجود دارد. در این پژوهش به بررسی ویژگی‌های فیزیکی و شیمیایی خاک در توده‌های m. communis در استان‌های فارس، کهگیلویه و بویر احمد و خوزستان پرداخته شد تا بتوان دانسته‌های پایه از ویژگی‌های خاک در مناطق پراکنش درختچه مورد در استان‌های جنوب غربی ایران جمع‌آوری کرد.نمونه‌برداری خاک در توده‌های مورد با استفاده از 5 پلات 25×25 متر و از لایه 20-0 سانتی‌متری انجام شد. ویژگی‌های خاک شامل نیتروژن، فسفر قابل جذب، پتاسیم قابل استفاده، کربن آلی، ph، بافت و چگالی ظاهری اندازه‌گیری شد. نتایج نشان داد که بیش‌ترین مقادیر کربن آلی و نیتروژن خاک مربوط به توده مورد شهرستان نورآباد ممسنی بود که دارای اختلاف معنی‌داری با دیگر مناطق بود. همچنین کم‌ترین مقادیر کربن آلی و نیتروژن خاک مربوط به منطقه اندیکا بود. توده‌های مورد در خاک‌های با ph خنثی تا کمی قلیایی پراکنش دارد. بافت خاک در تمام مناطق مورد بررسی ترکیبی از کلاس‌های لوم، لوم شنی و لوم سیلت بود. مقایسه میانگین آزمون t بین توده‌های مورد و مناطق مجاور مشخص کرد که مقادیر کربن آلی، نیتروژن، فسفر و پتاسیم خاک در توده‌های مورد نسبت به مناطق مجاور آن بیش‌تر بود. به‌طور کلی درختچه مورد در خاک‌های با بافت درشت و لومی و ph نزدیک به خنثی یا کمی قلیایی با حاصلخیز بالا رشد بهتری دارد.

evaluation of some soil physical and chemical properties in myrtus communis l. stands in southwest of iran

abstractmyrtus communis is one the most important mediterranean species in zagros forest. although, m. communis widely spreads in zagros forest, little information is available about its distribution in south western parts of iran. due to the lack of information on its distribution in southern zagros, in the present study soil physical and chemical properties of m. communis stands in fars, khuzestan, and kohgiluyeh and boyer ahmad provinces were determined to generate basic information about soil properties in its stands in south western provinces of iran. in each site, five 25 × 25 meter plots were selected and soil samples were taken from the 0‒20 cm layer. soil analysis included total nitrogen, available phosphorous, available potassium, organic carbon, ph, texture and bulk density. our results indicated that the highest values for soil nitrogen and organic carbon contents belonged to the m. communis stand in nourabad mamasani and were significantly higher compared to the other sites. while the lowest values of soil nitrogen and organic carbon recorded for andika, were significantly lower compared to the other sites. m. communis stands in nourabad mamasani had the highest soil fertility, compared to the other sites. besides, m. communis spreads in neutral or slightly alkaline soils. soil textures in the studied sites were loam, sandy loam and silt loam classes. independent sample t-test showed that m. communis stands had higher soil nitrogen, organic carbon, phosphorus, and potassium compared to the vicinity stands. overall, m. communis prefers coarse and loamy soils with neutral ph or slightly alkaline and high nutrients.background and objective: knowledge about forest tree species and their site demands is a fundamental topic in silviculture and forest soil productivity (kammesheidt, 2000; zolfaghari et al., 2017; ebrahimi askari et al., 2019), which can have positive effects on plantation and successful management (moradi et al., 2017). myrtus communis is one the most important mediterranean species in zagros forest. although, m. communis widely distributes in zagros forest, little information is available about its distribution in south western of iran. therefore, in the present study soil physical and chemical properties of m. communis stands in fars, khuzestan, and kohgiluyeh and boyer ahmad provinces were determined to generate basic information about soil properties in its stands in south western provinces of iran.methods: to study soil physical and chemical properties, m. communis stands in nourabad mamasani (fars province), lendeh (kohkiloye and boyer ahmad province), dezful and andika (khuzesran province) were selected. in each site, five 25 × 25 meter plots were selected and soil samples were taken from the 0‒20 cm layer. soil samples were taken from the four corners and center of each plot and pooled together, finally one pooled soil sample for each plot was transferred to the lab (moradi et al., 2022). to compare m. communis stands with the vicinity stands, soil samples were collected from the vicinity stands by the same procedure. soil analysis included total nitrogen, available phosphorous, available potassium, calcium carbonate equivalent, organic carbon, ph, texture and bulk density. to evaluate the differences between m. communis sites, one-way anova was used. besides, independent sample t-test was performed between soil variables in m. communis stands and soil variables of the vicinity sites. finally, principal component analysis (pca) was used to determine the most important soil factors in m. communis distribution.results: our results indicated that the highest values for soil nitrogen and organic carbon belonged to the m. communis stand in nourabad mamasani. while the lowest values of soil nitrogen and organic carbon recorded for andika, were significantly lower compared to the other sites. m. communis stands in nourabad mamasani had the highest soil fertility, compared to the other sites, perhaps due to the higher tree density of m. communis in the nourabad mamasani site. dezful site had the highest soil bulk density and the lowest soil porosity compared to the other sites. besides, m. communis spreads in neutral or slightly alkaline soils. studied soil textures were loam, sandy loam, and silt loam. first axis represents the soil physical properties in m. communis distribution. soil organic carbon, nitrogen, phosphorus, potassium, and tree density significantly correlated with the second axis. the results of independent sample t-test for m. communis stands and their vicinity sites showed that m. communis stands had significant higher soil nutrients, but soil ec, ph and calcium carbonate equivalent were not significantly different between m. communis stands and their vicinity sites.conclusions: based on the results, m. communis prefers sandy and loam soils with neutral or slightly alkaline ph. therefore, the most important factors in m. communis distribution are coarse-textured soils and high soil nutrients. this means in locations with such a condition, the plantation of the m. communis is recommendable. moreover, m. communis stands provide more fertile soil compared to the brant’s oak stands, agricultural lands, and wasteland.references:1. kammesheidt, l., 2000. some autecological characteristics of early to late successional tree species in venezuela. acta oecol. 21(1), 37–48. https://doi.org/10.1016/s1146-609x(00)00108-9.2. ebrahimi askari, a., moradi, m., basiri, r., mirzaei, j., ghasemi, a., 2019. evaluation of soil physiochemical properties and regeneration of prosopis cineraria (l.) druce stands in southern iran. iran. j. for. 11(2), 255–267. (in persian with english abstract)3. zolfaghari, z., moradi, m., basiri, r., ghasemi, a., 2017. evaluation of soil physicochemical properties of tecomella undulata in busher province. for. wood pro. 70(2), 273–280. https://doi.org/10.22059/jfwp.2017.62484. (in persian with english abstract)4. moradi, m., jorfi, m.r., basiri, r., yusef naanaei, s., heydari, m., 2022. beneficial effects of livestock exclusion on tree regeneration, understory plant diversity, and soil properties in semiarid forests in iran. land degrad. develop. 33(2), 324–332. https://doi.org/10.1002/ldr.4154.5. moradi, m., imani, f., naji, h.r., moradi behbahani, s., ahmadi, m.t., 2017. variation in soil carbon stock and nutrient content in sand dunes after afforestation by prosopis juliflora in the khuzestan province (iran). iforest 10, 585–589. https://doi.org/10.3832/ifor2137-010