اثر تغییر کاربری بر ویژگی‌های فیزیکی و حاصلخیزی خاک‌های منطقه نهبندان

نوع مقاله: کاربردی

نویسندگان

1 گروه علوم خاک- دانشکده کشاورزی - دانشگاه فردوسی مشهد

2 علوم خاک- دانشکده کشاورزی - دانشگاه فردوسی مشهد

3 گروه علوم خاک - دانشکده کشاورزی- دانشگاه فردوسی مشهد

چکیده

در این پژوهش که به منظور بررسی اثر سه کاربری انار، زیتون و گندم بر کیفیت خاک صورت گرفت، شاخصهای کیفیت خاک در هر سه کاربری در منطقه حسینآباد واقع در 30 کیلومتری شمال شهرستان نهبندان تعیین شد. بدین منظور چهل و پنج نمونه خاک سطحی (30-0 سانتیمتر) از زمینهای موردنظر جمع‏آوری شد که سهم هر کاربری پانزده نمونه بود. سپس ویژگی‎های مؤثر بر کیفیت فیزیکی و حاصلخیزی (شیمیایی) خاک از قبیل شاخصهای پایداری ساختمان خاک و عناصر کممصرف و پرمصرف گیاه (نیتروژن، فسفر، پتاسیم، آهن، منگنز، روی و مس) اندازهگیری و تأثیر تغییر کاربری اراضی از گندم به باغهای زیتون و انار در 20 سال اخیر بررسی شد. طبق روش نمرهدهی کرنل هر سه کاربری در محدودهی 55-40 و کیفیت پایین قرار گرفتند. از بین ویژگی-های تأثیر گذار بر نمرهی کیفیت خاک به جز EC و SAR که تنها در کاربری زیتون سبب کاهش و تضعیف نمرهی کیفیت خاک شدند سایر ویژگیهایی که سبب بهبود یا تضعیف نمرهی کیفیت خاک شدهاند تا حدودی در هر سه کاربری مشترک بودند و در بین آنها مادهی آلی، آهن و منگنز نسبت به سایر عوامل تأثیر بیشتری در کاهش کیفیت خاک داشتند و ویژگیهای میانگین وزنی قطر خاکدانهها (MWD)، تخلخل تهویهای (AC)، پتاسیم و مس نسبت به سایر ویژگیها تأثیر بیشتری بر بهبود کیفیت خاک داشتند. بر اساس نتایج این پژوهش، تغییر کاربری اراضی از کشت گندم به درختان زیتون و یا انار با وجود بهبود برخی از ویژگیهای فیزیکی خاک به دلیل کاهش کیفیت خاک در منطقه مورد نظر توصیه نمیشود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

ٍEffect the changing of land use on soil physical and fertility properties in Nehbandan area

نویسندگان [English]

  • ُseyyed Mohammad Mousavai 1
  • Hojat Emami 2
  • Gholam Hosain Haghnia 3
1 Soil Science Department, Faculty of Agriculture , Ferdowsi University of MAshhad
2 Ferdowsi University of Mashhad
3 Soil Science Department- Faculty of Agriculture- Ferdowsi University of MAshhad
چکیده [English]

Extended abstract
Introduction
Knowledge about the soil quality in agriculatral lands and natural resources is essential for achievement the best management and maximum economic efficiency. The land use change is the important human activity in environmental ecosystems, which effect on some soil processes such as microbial activity, mineralization of carbon and nitrogen content. In addition, land use has an important role on temporal and spatial variation of soil properties and quality. Agricultural practices may affect positive or negative effect on soil quality. Intensive cultivation of plants decreases soil physical and quality, as a result of this yield of plants, production efficiency and environment quality decrease. In this research, the effect of three land uses on soil physical, fertility and quality properties were studied.

Materials and methods
The studied area (Hossein abad) is located 30 km far from the northern Nehbandan town (South Khorasan, Iran).To study the effect of land uses change on soil properties were selected three land uses including pomegranate (Punica granatum ), olive (Olea europaea) and wheat (Triticum aestivum ). The 45 soil samples (15 samples from each land use) were taken from surface soil (0-30 cm). Then some soil physical and fertility properties which affect the soil quality were measured and the effect of land use change from wheat cultivation to olive and pomegranate gardens during the recent 20 years were studied. In addition, soil quality in each land use was determined based on cornel university test. To compare soil properties and quality, the randomized complete block design was applied.
Results and discussion
The results showed that land use change had a significant effect on organic carbon, mean weight diameter of aggregates (MWD), water stable aggregates (WSA), macro nutrients (N, P, and K), and some micro nutrients (Fe and Mn) (P < 0.001). Comparison of means demonstrated that the difference between organic carbon content in olive and pomegranate land uses was not significant, and the content of OC in both land uses was significantly higher than wheat land use. Olive and pomegranate land uses cause to stability of soil structure increase, probably due to reduction the traffic of wheals and also somewhat increasing the organic carbon as a result of littering. Therefore, the MWD in olive land use was significantly higher than two land uses and the lowest value was obtained in what land use. Also, the value of WSA in three land uses was significantly different (P < 0.05) and their content in olive and wheat land uses were the maximum and minimum, respectively. The concentration of total nitrogen in pomegranate land use was more significant than two other land uses (P < 0.05). But the concentration of phosphorous (P), potassium (K), Fe and Mn in wheat land use was the highest content and significantly greater than other two land uses. Despite the concentrations of P, K, and Fe nutrients in pomegranate land use were the lowest value, but, there were no significant difference between the concentration of them in olive and pomegranate land uses. It seems that this variation especially P and Fe is probably due to pH and the Ca and Mg concentration and creation insoluble component of Fe, Mn and P in these land uses.
According to the results of cornel university test, soil quality in garden land uses was decreased and the range of soil quality score was varied from 49.5 (olive) to 61.2 (wheat). Among the soil properties affecting the soil quality, fertility and chemical properties such as electrical conductivity (EC), absorption sodium ratio (SAR) and somewhat pH of soil saturated extract decreased the soil quality in olive land use. Also, OM, Fe, Zn, and Mn decreased the soil quality in 3 land uses, of course in olive and pomegranate land uses, micro nutrients (Fe and Mn) had the more effect on decreasing the soil quality compared to wheat land use. In addition, bulk density (Bd), mean weight diameter of aggregates (MWD), aeration porosity (AC), P, K, and Cu contents increased soil quality in all 3 land uses.
Conclusion
In general, when wheat land use change to olive and pomegranate land uses decreased some soil properties and quality in arid area of Nehbandan, probably due to low quality of irrigation water.

کلیدواژه‌ها [English]

  • Land use
  • Soil quality
  • organic carbon
  • wheat
  • Olive
  • pomegranate