نشریه تحقیقات منابع طبیعی تجدید شونده
سال پنجم شماره 3 (پیاپی 17، پاییز 1393)

The aim of present study was to evaluate the effects of different levels of dietary Phytogenic combination (Biomin PEP 1000) on nutrition and growth performance and survival rate of grass carp (Ctenopharyngodon idella) fry which has done for 56 days. The experiment was completely randomized design consisting four levels 0 (Control group), 1, 2, and 3 g of Biomin PEP 1000 kg-1 diet in four treatments with three replications. Twenty five specimens of grass carps fry with initial mean weight 0.51 ±0.02 g were distributed in 12 small tanks with 100 liters volumes filled with 80 liters water and fed up to satisfy. Growth parameters such as final weight, body weight increase, specific growth rate, daily food intake, feed conversion ratio and protein efficiency ratio were measured. The results were analyzed by one-way analysis of variance (ANOVA) and Duncan test. According to the results, phytogenic combination (Biomin PEP 1000) addition had no significant effect in Feeding, growth performance and survival rate in any experimental levels (P>0.05).

The aim of this study was to provide Poplar’s wood-polymer composite to improve the physical properties and practical use in industry. Accordingly, a sample test was done with monomer methyl methacrylate with the method of filled cell saturation and then heating in an oven to be polymerized at 140 and 150 °C and times of 4 and 5 h. After providing poplar’s wood-polymer composite, the physical characteristics of poplar wood such as water adsorption, special gravity, dimensional change were analyzed. The results of one-way analysis of variance showed significant changes in all experimental variables. In temperature changes, only the percentage of polymer establishment was significant, while no significant difference was found in the changes. In the analysis of factorial variance, the dependent effect of temperature and time, the only significant effect was percentage of polymer establishment and water adsorption. The results showed that all the physical properties including water absorption, dimensional change and specific gravity in this study were improved compared to the control.

This study aimed to identify, evaluate and compare the ecological density of phytoplankton populations during two season spring and fall in Asalouyeh harbor, Persian Gulf. Sampling was conducted at six stations on April 2013 and October 2014. Ecological parameters such as temperature, salinity, turbidity, conductivity, dissolved oxygen, pH, and TDS were also measured at different time sampling time. According to the results, 5 groups of phytoplankton including bacillariophyta (86.14%), pyrrophyta (3.38%), chlorophyta (2.76%) cyanophyta (7.68%), and euglenophyta (0.02%) were identified. Bacillariophyta was the most abundant group, while the minimum frequency group refered to the Euglenophyta. Except turbidity, there were positive but not significant correlation between physico-chemical parameters and phytoplankton density (p>0.05).

The present study was conducted to assess the effect of pre-heat treatment on the wood particle of Carpinus betulus for the manufacturing one-layer particleboard to increase dimensional stability, decrease water absorption, and improve mechanical properties. Carpinus betulus wood-particles were pre-steamed with a reactor system 160 °C at 20, 40 min. The boards with 6% phenol formaldehyde were manufactured by laboratory hot press instrument. After production of particel boards, the physical and mechanical properties including water absorption, thickness swelling, MOR, MOE, and internal bonding (IB) were tested. The results of thickness swelling, and water absorption showed that pre-heat treatment boards after 24 hours immersing in water had a significant decrease from 65.65 to 77.60%, respectively, compared to untreated boards (92.31%). After two hours of immersing, only the thickness swelling showed a significant decrease. The results showed that by increasing the amount of pre-heat treatment time to 40 min, MOE reduced to 2046 MPa, although its reduction was not significant. Pre- heat treatment caused a significant increase on the internal bond amounting to values of 0.618, 0.514 MPa.

In this study, the effects of recreation and conversion use of forested land to forest parks on soil physical and chemical properties followed by the biodiversity of Blouran forest park, Kuhdasht County was investigated. Three zones including non-recreation, extensive recreation and intensive recreation were chosen. In each area, 30 sample plots in a systematic random design (100 × 150 m) were established. In each plot, three soil samples were taken from 0-20 cm depth and a mixed sample was transferred to soil laboratory. For consideration of woody plants biodiversity current indices of diversity Simpson and Shannon wiener, evenness Camargo and Shannon wiener and richness with Margalef were assessed respectively. For data analysis, ANOVA and Duncan test was used. Results showed that some soil physical and chemical characteristics including pH value and bulk density of recreational areas has been increased but the amount of organic carbon, total nitrogen, absorbable phosphorous, exchangeable potassium, soil porosity, and litter depth in intensive recreational areas has been dropped. Indices of diversity, uniformity and richness in non-recreation zone had also significant differences with extensive recreation and intensive recreation zones. Thus, it is concluded that recreational activities cause high damages to forest, hence rational planning and management should be conducted for reducing these damages.

Because of shortage of woody forest resources and increasing uses of agricultural residues in wood industry, this study was conducted to investigate the effect of sunflower peel content on physical and mechanical properties of particleboard made from combination of sunflower peel and wood particles of poplar (Populus alba). The main physical and mechanical properties including swelling thickness in 2, 12, and 24 hours followed by modulus of rupture (MOR), modulus of elasticity (MOE), and internal bonding strength were tested. The results showed that swelling thickness of 2, 12, and 24 hours immersion in distilled water decreased modulus of rupture (MOR). Modulus of elasticity (MOE) and internal bonding strength significantly were decreased by increasing sunflower peel content in the particleboard. Based on the present findings none of the manufactured particleboard panels made from the combination of wood and sunflower’s peel particles didn’t meet the EN 312-4, EN 312-3, and EN 312- 2 standards.