بررسي تغييرات كيفيت خاك در اثر آبياري با استفاده از مدل‌هاي شاخص تجمعي و نمورو در برخي از خاك‌هاي استان خوزستان

Study the Soil Quality Changes Indicators Using Nemoro and Integrated Quality Index Models in Some Khuzestan’s Soils

این تحقیق به منظور ارزیابی شاخص‌‌های كیفی خاك با استفاده از مدل های كمی در بخشی از اراضی استان خوزستان انجام شد. خصوصیات فیزیكی وشیمیایی نمونه‌های خاك تهیه شده از عمق 30-0 مانند بافت، جرم مخصوص، پایداری خاكدانه، رطوبت ظرفیت مزرعه‌ای نسبی، تخلخل تهویه‌ای، آب قابل استفاده گیاه، هدایت هیدرولیكی اشباع، كربن آلی، قابلیت هدایت الكتریكی، پ‌هاش، كاتیون‌های محلول، نسبت جذب سدیم، درصد سدیم تبادلی وظرفیت تبادلی كاتیونی اندازه‌گیری شد. كیفیت خاك با استفاده از دو مدل شاخص تجمعی كیفیت خاك (IQI) و شاخص كیفیت خاك نمورو (NQI) و هركدام در دو مجموعه‌ی ویژگی‌های خاك TDS و MDS ارزیابی شد. نتایج نشان داد همبستگی مثبت و معنی‌داری بین IQITDS و IQIMDS و بین NQITDS و NQIMDS وجود داشت. لذا می‌توان با اندازه‌گیری پارامترهای كمتر، برای تعیین كیفیت خاك به طور تقریبی به نتایج مشابه حاصل از سنجش TDS رسید و موجب صرفه‌جویی در وقت و هزینه ‌شد. طبق نتایج مهم‌ترین عامل محدود كننده كیفیت خاك كمبود ماده آلی، كاهش تخلخل تهویه‌ای و افزایش جرم مخصوص ظاهری خاك بود. همچنین، تراكم ناشی از تردد بیش از حد و تغییر شرایط بهینه رشد گیاه ناشی از عبور و مرور ادوات كشاورزی سنگین باعث كاهش كیفیت خاك شده است. اگر چه به واسطه كشت و كار میزان ماده آلی افزایش یافته بود با این وجود با مدیریت بهتر می‌توان از اثرات آن برای بهبود درجه كیفی خاك بهره بیشتری برد. بنابراین با عملیات مدیریت ویژه‌ای نظیر تغییر شیوه كشت، شخم، مدیریت بقایا، مصرف كود و حضور ماده آلی به مقدار بهینه و... میتوان با ایجاد ساختمان مناسب و پایدار جلوی تخریب ساختمان و در نتیجه تغییر توزیع خلل وفرج را گرفت.

Introduction: Aspects of the physical, chemical and biological are considered. Land degradation for soil quality, or improve soil quality assessment is important.This study was conducted to evaluate soil quality indicators using quantitative models in some lands of Khuzestan province (Iran).Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management. Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management. Materials and Methods: In order to evaluate the effect of crop management and cultivation on soil quality, Select several Khuzestan region and Samples were taken from the surrounding cultivated land. Physiochemical characteristics of soil samples from a depth of0-30 cm such as soil texture, bulk density (Db), mean weight diameter of wet aggregates (MWD), relative field capacity (RFC), air capacity (FA),plant available water capacity (AWC), saturated hydraulic conductivity (Ks), organic carbon (OC),electrical conductivity (EC), pH, soluble cations (Mg, Ca, Na),sodium absorption ratio (SAR), exchange sodium percent (ESP) and cation exchange capacity were determined (CEC). The soil quality was evaluated by integrated quality index (IQI) and Nemero quality index (NQI) in two data sets of soil properties including MDS and TDS. In these models, a set of characteristics that affect the quality of the soil in the form of a mathematical model incorporating and to propose a numerical quantity this number serve as general indicator of soil quality, Reflect the characteristics of the target. Results and Discussion: The results showed that there was significant correlation between IQITDS - IQIMDS and between NQITDS -NQIMDS. The results show that the NQITDS model can be saved in compire with IQI models. This can decrease the time and costs in this method. But in some regions due to low correlation with Using a set of MDS, which comprise more limited number of soil characteristics You cannot reliably determine soil quality indicators are acceptable and should use the same set of TDS. Also, the results show that the soil was compacted due to heavy traffic, and this has reduced soil quality. The most important limiting factor of quality soil was reduced soil organic matter and porosity and increased bulk density. None of the subjects in the study area are not very stable and unstable. According to the research, increased of cultivation in most soils were clay and silt and decreased sand content. The burning of sugarcane after harvesting, can be to cause reduce organic matter, Finally, reduced the cation exchange capacity related of the soil organic matter and thus increased the bulk density of soil and reduced the soil structural stability. Decreased the electrical conductivity of the saturation extract and sodium adsorption ratio under cultivation and showed increasing trend pH of soil in all the samples. Finally reduced under cultivation soil quality. Nevertheless, we can better manage the effects can be even more improved soil quality grade. Therefore, a special management operations, such as changing the way farming, plowing, residue management, fertilizer use and the presence of organic matter the optimum, Reduce negative environmental effects such as the effect of insecticides and heavy metals... By creating a suitable building could be Prevent the destruction of the building and therefore the distribution of pores. Conclusion: This investigation showed the efficiency of soil quality studies for the evaluation of present conditions of soil in agricultural and natural ecosystems. Therefore, these soils need to special management, such as minimum tillage or no tillage, addition of residues, and improve of aggregate stability can be applied for soil improvement quality. These strategies can improve soil prosity and, therefore, it can reduce bulk density under monocroping system. Therefore, special management practices seems essential in arid and semi-arid regions. Given the importance of soil quality in balancing the environment and the sustainability of agricultural systems, in addition to the chemical and physical factors, biological factors to take appropriate management programs and improve soil quality checked.