تاثیر روش‌های مدیریتی بر خصوصیات فیزیکی و شیمیایی خاک در بوم‌نظام‌های کشاورزی استان اصفهان

به‌منظور بررسی تاثیر روش‌های مدیریتی بر خصوصیات فیزیکی و شیمیایی خاک در بوم نظام‌های کشاورزی تحقیقی در سال زراعی 91-1390 در سطح مزارع شهرستان های استان اصفهان انجام گرفت. ابتدا در هر یک از 23 شهرستان استان اصفهان، شش مزرعه انتخاب و به‌منظور گروه‌بندی مزارع موردمطالعه، پرسش‌نامه ای تنظیم و از طریق مراجعه به زارعین تکمیل گردید. سپس براساس اطلاعات پرسش‌نامه ها، مزارع به سه گروه (مزارع کم نهاده، متوسط نهاده و پرنهاده) طبقه‌بندی شدند. در هر شهرستان دو مزرعه از هر گروه نهاده انتخاب و مورد بررسی قرار گرفت. عملیات نمونه‌برداری خاک مزارع به‌ازای هر هکتار، ازچهار نقطه مزرعه به‌صورت تصادفی انجام و خاک تا عمق 30 سانتی‌متری نمونه‌برداری گردید. سپس با اختلاط نمونه‌های هر مزرعه، یک نمونه مرکب از هر مزرعه تهیه و با هدف تعیین خصوصیات فیزیکی وشیمیایی به آزمایشگاه منتقل گردید. نتایج نشان داد که پایداری خاک‌دانه‌ها، هدایت الکتریکی محلول خاک و میزان ماده آلی در بین سه نظام کشت (کم نهاده، متوسط نهاده و پرنهاده) مقادیر متفاوتی داشت و این تفاوت از لحاظ آماری معنی‌دار (p<0.01) بود. پایداری خاک‌دانه‌ها در نظام های زراعی کم نهاده دارای بیشترین مقدار (0.72) و در نظام های زراعی پرنهاده دارای کمترین مقدار (0.42) بود. خاک نظام‌های کم نهاده و پرنهاده به‌ترتیب دارای بیشترین وکمترین درصد ماده آلی (2.05% و 1%) بود. ph نمونه‌ها در بین سه نظام زراعی تفاوت آماری معنی‌داری نشان نداد.

The Effects of Management Practices on Soil Physical and Chemical Propertiesof Esfahan Agroecosystems

IntroductionIn parallel with the population growth, increasing food production using modern agricultural methods seems necessary. Application of chemical inputs and biodiversity reduction in agroecosystems lead to artificial ecosystems, requiring human intervention. Soil is an essential part of agroecosystems and the key to soil fertility is preserving the ecological biodiversity of the system. The use of management methods based on field hydrone inputs reduces the consumption of thorny inputs and reduces environmental degradation. The size and stability of the aggregates indicate the balance between the constituent and destructive factors of the aggregates. Different tillage methods are based on the soil physical and chemical properties. The purpose of this study was to investigate the effect of management methods on the physical and chemical properties of farm soil of the cities in Isfahan province.Materials and MethodsWe investigated the effect of management practices on physical and chemical properties in field soils in Esfahan province during 20112012. First, 6 fields are selected in each of 23 counties, and evaluation was conducted using questionnaires filled by farmers. Accordingly, the fields were classified in three groups (low input, medium input and high input). Two fields of each group input were selected and evaluated. Four points (30 centimeters of depth) at each hectare of field were randomly sampled. By mixing, one complete sample was obtained and carried to laboratory for further analyses. Soil texture was determined by hydrometric method, and electrical conductivity and pH were determined in saturated extract. Wet oxidation method was used to measure soil organic matter. To determine the stability of aggregates, soil samples were evaluated by wet sieving method.Results and Discussion Results indicated that soil texture, aggregate stability, electrical conductivity and rate of organic matter in three management practices (low input, medium input and high input) were significantly different (p < 0.01). The aggregate stability in low input fields had the highest value (0.72) and in high input fields had the lowest value (0.42).The soils in low and high input fields include maximum and minimum organic matter (2.05% and 1%), respectively. The field management methods had a significant effect on the amount of organic matter. The pH of soil samples did not show a significant difference. The electrical conductivity of the soil solution was different between three planting systems analyzed. In high input fields, the electrical conductivity values of the soil solution had the highest values. It seems that excessive consumption of chemical inputs in high input fields increased the electrical conductivity of soil solution. Other researchers have reported that the soil solution electrical conductivity depends on several factors such as the fertilizer type and their consumption, irrigation method and soil type. ConclusionReduced chemical fertilizers consumption and less entry of machinery increase the stability of aggregates in low input fields. The reduced or nontillage methods in fields that preserve more crop residues on the soil surface increase the aggregates’ consistency and thus improve their stability. Application of conventional plowing, chemical inputs, and no crop rotation reduce soil organic matter content.AcknowledgmentI would like to express my sincere gratitude to the professors, staff, and students of the Faculty of Agriculture of Ferdowsi University of Mashhad who helped me in carrying out this research.