a four - year field experiment (1999-2002) was conducted on a silty clay loam soil at laklak research field of hamedan to determine the effects of crop residue management and plowing depth on soil fertility and wheat yield in a maize-wheat rotation. in this investigation, four corn residue managements were used consisting of 1) stalk shredding by maize stalk shredder 2) stalk shredding by disk ...

to assess the effects of livestock grazing on soil compaction (density changes), the trampling action of livestock was simulated. the research field was located to the south west of nazarabad in savojbolagh district, south west of tehran province. samples were annually collected based on a completely randomized design. from the triple regions (reference, key and critical) 36 cylindrical cores w...

Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addition, it can deteriorate the performance of water treatment process including coagulation, adsorption, and membranes. NOM also reacts with chlorine in the chlorination process and may form disinfection by-products. The present study was carried out in laboratory-scale in a batch system using a cylind...

Several factors effect on sorption of polycyclic aromatic hydrocarbons (PAHs) in soil. Coexistence of metals and organic matter of soil are among important affecting factors on sorptive behavior of PAHs. This research investigated the effect of organic matter content and heavy metals (lead, nickel and zinc), on sorption of phenanthrene onto kaolinite. For this purpose, sorption of the organic m...

Organic matter was studied in radiation fogs in the San Joaquin Valley of California during the California Regional Particulate Air Quality Study (CRPAQS). Total organic carbon (TOC) concentrations ranged from 2 to 40 ppm of C. While most organic carbon was found in solution as dissolved organic carbon (DOC), 23% on average was not dissolved inside the fog drops. We observe a clear variation of...

digestibility if the models are to accurately simulate organic matter transformations in fish ponds. This is especially true for pond management systems that utilize non-conventional feed and fertilizer sources. Munsiri and Boyd (1995) showed that, with the use of a single first-order rate constant to model organic matter degradation, equilibrium conditions were reached in a relatively short ti...

in order to study the effects of micronutrients application on some morphological traits associated with seed quantity and quality of sugar beet cultivar shirin, an experiment was conducted in 2001-02 at ardabil agricultural research station. based on soil test results, soil ph was 7.62-7.80 with 0.49- 0.53% organic matter content, and the quantity of absorbable p, total n, and k amounts were f...

background: this study assessed the removal of organic material and nutrients from full-scale subsurface flow (ssf) constructed wetlands (cws) followed by anaerobic stabilization ponds under environmental conditions. methods: the effluents were distributed evenly in 12 reed beds. samples were taken twice monthly for a total of 6 months from several points in the wetland. biochemical oxygen dema...

abstract soil organic matter and its components are important factors in formation and stability of aggregates and subsequently soil structure. however data regarding organic matter distribution in soil aggregates is scarce, particularly in arid soils of central iran. the objective of this study was to investigate the distribution of organic carbon (oc), total nitrogen (tn), and carbohydrates i...