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The Evaluation of Lignocelluloses Biodegradation Ability of Some Bacteria Isolated From Various Soils and Decomposing Materials
M. Borji,
Volume 10, Issue 2 (7-2006)
Abstract
Recently, the use of microorganisms for conversion of plant biomass into many commercially valuable products has been studied. In this study, some soil samples, composting plant materials, and composted manure from different parts of Markazy province were collected to isolate and identify aerobic bacteria, which have been capable of utilizing lignin preparations as a sole source of carbon. Bacteria were isolated by using three types of lignin preparations and hot- water- extracted wheat stover and saw dusts. Two of the isolates, identified as Streptomyces sp. and Pseudomonades sp. were able to degrade wheat stover and saw dust lignin and polysaccharides. The growth rate of Streptomyces sp. and Pseudomonades sp. was higher in wheat stover fed cultures than the saw dust fed cultures. Results also showed that bacteria treatment of lignocelluloses and nitrogen supplementation of culture media had considerable effects on chemical composition of wheat stover and saw dust. All two bacteria genera increased crude protein, APPL, soluble lignin, and decreased carbohydrates and insoluble lignin of wheat stover and saw dust (P<0.01). Streptomyces showed more degradation ability than Pseudomonades, especially in culture media containing wheat stover. The utilization of yeast extract (as nitrogen source) improved degradation abilities of bacteria. The findings of this study indicate that these bacteria could be used for biological upgrading of agriculture residues in order to feed animals.
Prioritization of Erosion Prone Sub-Watersheds using MCDM Methods in Roudzard Watershed, Khuzestan Province
Mrs Soghra Bagheri, M.r. Ansari, A. Norouzi,
Volume 26, Issue 3 (12-2022)
Abstract
Soil erosion has been one of the most important problems of watersheds in the world and is considered one of the main obstacles to achieving sustainable development in agriculture and natural resources. Identifying and prioritizing regions sensitive to soil erosion is essential for water and soil conservation and natural resource management in watersheds. The present research was performed in 2021 year to prioritize the soil erosion susceptibility in 12 sub-watersheds of the Roudzard watershed in Khouzestan province using morphometric analysis and multiple criteria decision-making (MCDM) methods. In this regard, 11 morphometric parameters including shape parameters such as compactness constant (Cc), circularity ratio (Rc), form factor (Rf), elongation ratio (Re), linear parameters such as drainage density (Dd), stream frequency (Fs), drainage texture (Dt), bifurcation ratio (Rb), Basin length (L), Length of overland flow (Lg), and topographic parameter including Ruggedness number (Rn) were extracted and their relative weights were calculated using Analytic Hierarchy Process (AHP). The prioritization sub-watershed to soil erosion was performed using TOPSIS, VIKOR, and SAW methods, and the results were combined using rank mean, Copeland, and Borda methods. The final prioritization was compared with the amount of specific erosion in the MPSIAC model by determining Spearman's correlation coefficient. The result of the evaluation of morphometric parameters by using the AHP model showed that drainage density (0.161), drainage texture (0.158), and stream frequency (0.146) had the greatest effect on the erodability of the sub-watersheds. In contrast, the form factor (0.049), Elongation Ratio (0.036), and shape factor (0.026) had the least effects on erodability of the study area. In this research, the Spearman correlation coefficient between the final result of prioritizing the sub-watershed and the MPSIAC model was obtained as 0.8 in p-value<0.01. The results of prioritization of the sub-watersheds in terms of their sensitivity to soil erosion showed that sub-watersheds 11, 12, and 10 with an area of 191.83 km2 are categorized as very sensitive to soil erosion due to high value of linear parameters, low value of shape parameters, sensitive geology formation, and poor vegetation cover and located in rank 1 to 3, respectively. According to the results sub-watersheds 11, 12, and 10 have the highest amount of specific erosion equal to 16.03, 12.48, and 11.6 tons per hectare per year, respectively. Therefore, these sub-watersheds are a priority for watershed management operations. The results of the present study showed that MCDM methods and morphometric analysis are suitable tools for identifying areas sensitive to soil erosion and using the combined methods of the results and it is possible to take advantage of each of the different multi-criteria decision-making methods.

Assessment of Physical and Hydraulic Properties of Three Rockwool Types in Comparison with Wheat Straw and Sawdust as Greenhouse Growth Media
Sh. Shahmansouri, M.r. Mosaddeghi, H. Shariatmadari,
Volume 27, Issue 1 (5-2023)
Abstract
According to the rapid population growth, the challenging issue of production of economic and suitable food sources has led to greater attention to soilless culture greenhouse production systems. Components of growth media in horticulture are usually selected based on physical and chemical properties and their abilities in providing enough water and oxygen for roots. This study was conducted to investigate the feasibility of using some agricultural wastes (i.e., sawdust and wheat straw) and three rockwool types (i.e., raw, ground, ground, and sieved) as substitutes for commercial greenhouse growing media such as cocopeat and perlite. Several hydraulic, aeration, and chemical properties including easily available water (EAW), air after irrigation (AIR), water holding capacity (WHC), water buffering capacity (WBC), saturated water content (θs), bulk density (BD), total porosity (TP), water drop penetration time (WDPT), pH, and electrical conductivity (EC) were measured and scored in the growth media. Raw rockwool had larger particles compared to ground rockwool, which resulted in its faster water release. Processing of the rockwool decreased the saturated water content and saturated hydraulic conductivity due to the decrease in particle size. Four growth media were scored as very good and one was scored as good. The highest and lowest scores belonged to sawdust (34) and ground rockwool (30), respectively. The studied growth media with high TP, EAW, and WHC and low BD, EC, and WDPT can be used individually or combined with other commercial substrates for greenhouse growth media.

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