ECOPERSIA
Volume:11 Issue: 1, Winter 2023

There are few studies on the effectiveness of this type of management on soil properties of Golestan province as the main agricultural pole in Iran. The purpose of this study is to investigate the effect of limited tillage on improving biological soil quality indicators.

Three types of operations which include No Tillage (NT), Minimum or Occasionally Tillage (OT or MT) and Conventional Tillage (CT) were selected. From each management, 30 samples were taken at depths of 0-30 cm. Microbial respiration, microbial biomass, urease, acid and alkaline phosphatase, dehydrogenase and cellulase activity were measured.

Conservation tillage (ST) which include both MT and NT increased acid and alkaline phosphatase by 1.6 to 2.5 times. The reverse trend was observed for cellulase, which showed a decrease from 37.5% in MT to 25% in NT. Urease and dehydrogenase increased by 14 and 18% in MT and decreased by 5.7 and 10% in NT. Microbial biomass and microbial respiration increased by 1.8 and 2.5 times in MT and in no tillage, operation decreased by 15 and 44%.

The emphasis is on the advice of ST, However, it seems that some points related to the promotion of this method in agricultural lands should be considered.  It seems that MT has a better condition for enzyme activity than NT. Low enzyme activity in NT conditions may reduce the availability of nutrients and thus reduce the yield, then extension experts should be inform the Farmers.

Landslide classification using a fractal model at the Tajan river basin in northern Iran is the study intended as a new approach based on 142 landslide information data set.

The obtained results were interpreted using the Depth–Number (Dp–N) fractal model and a fairly wide set of information available for each landslide class, consisting of Digital Elevation Model (DEM), rainfall, landuse, geology (lithology and fault) and drainage network data.

The log–log plot shows five classes for depth (weakly, moderately, highly, strongly, and extremely magnitude) which shows that the extremely magnitude landslides have depths higher than 19.95 m in the NE, middle, western, and SE parts of the Tajan basin. The strong (5-19.95 m) and high (2.4-5 m) magnitude landslides happened in the northern, NE, western and NW parts. The results, which were matched up to landuse, drainage network, DEM, and fault allocation patterns revealed an affirmative correlation between landslide classes and the particulars in the area. In addition, the coefficient of determination, R2, for each population shows that the classification has been done correctly using the Dp-N fractal model. Amounts of P-value obtained from paired samples t-test and ANOVA showed that the separated categories are in incongruity with each other and are significantly different (sig=0.000).

Results show that separating the populations of landslides based on a parameter as magnitude and the difference between the populations’ magnitude of landslides should be considered in landslide susceptibility zonation.

Recognition of habitat status and ecological responses of species to environmental vari - ables are prerequisites for better management and providing the ecological needs of each species. This research assessed the current status and distribution of Viburnum lantana L. It described its ecological characteristics in the lowest limit of its distribution in the Arasbaran forests.

The presence sites of Viburnum lantana L. (wayfaring trees) were se - lected based on field observations and library sources. Then, the 114 circular samples with a radius of 17.84 m were laid systematically and randomly out to collect data. Within each sam - pling area, the characteristics of each woody species, including species name, DBH (diameter at the breast height), and the height of all wayfaring trees and other species, were measured. The dominant species composition was calculated using the relative importance value.

Our results revealed 22 woody species with a height>130cm in our study area. V. lantana constitutes about 11% of the relative frequency, and its relative importance value (RIV) was 25.2, the third main species in RIV. The frequency of V. lantana showed a significant and positive correlation with the frequency of Quercus macranthera. The mean height of V. lantana was 2 m (±0.6 m). The highest number of V. lantana belonged to height class 1-2 m (47 stems per ha). Stem density per ha of V. lantana ranged between 24 and 403 in the lowest and highest elevation classes, respectively. There was no clear pattern of DBH and height of V. lantana, along with the aspect categories.

This species usually appears with Quercus macranthera as overstory species and Lonicera iberica as understory species in the wayfaring trees sites. Also, topographic factors such as slope, elevation, and aspect influenced the relative frequency, stem density per ha, DBH, and height of V. Lantana. This research is vital to inform forest managers and decision-makers about how the diversity of topographic variables differs for further planning and intervention.

The technical health of forest road surfaces has an important role in the continuation of access to the forest and the safety of vehicle traffic. The objective of this research was to investigate the effect of longitudinal slope of forest roads and climate conditions on the unpaved road surface condition.

500-meter road segments were randomly determined in Mediterranean, sub-humid and semi-arid climates. In Each climate, sample units on roads were divided into slope classes of <5% and >5% and the UPCI values were calculated in field survey. In each of road segments three soil samples were collected for California bearing ratio (CBR) analysis. Proctor and CBR tests were conducted according to ASTM standards for each slope classes.

Results indicated that in slope class<5%, UPCI value in sub-humid region was significantly lower than other climates (P<0.05). Maximum UPCI was observed for roads located in semi arid climate. In addition, an increase in slope classes from <5% to >5% can decrease UPCI by about 6.6%, 11.8% and 11.1% in Mediterranean, semi arid and sub-humid climates, respectively. There was a positive and significant correlation between soil CBR and UPCI variables in all climates. Indeed, for roads with high bearing capacity, the condition of the top layer was more suitable.

More knowledge about the effects of slope gradient and climate on road surface quality is necessary to decrease the negative effects of traffic on steep slopes in the mountainous forests.

The availability of precipitation data plays an important role in many meteorological, hydrological and applications.

In this study, to improve precipitation maps and increase the accuracy of precipitation maps, linear regression, multivariate, and Kriging subsets were used. The data from 14 meteorological stations and IMERG images in the period of 20 years (2001 to 2020), digital elevation model, Latitude and Longitude maps were used. At first, based on regression in Minitab software, the relationship between air and ground parameters was taken. Finally, with the interpolation methods and based on the error coefficients, the best equations for predicting precipitation were determined and the spatial distribution of precipitation was obtained.

According to the results, six out of 13 models were selected because of low RMSE and high R2, R, and NS. In regression models where only one climatic or edaphic parameter was used, forecast accuracy was reduced. But in the models that were used in the regression elevation, Longitude, Latitude and IMERG parameters in combination with interpolation methods, the extracted data matched the real data with a slight difference. In this study, instead of the average of the input parameters, the maps of each parameter were used, increasing the accuracy of the forecast model to R2=0.8.

results showed that combining satellite precipitation products with interpolation methods led to a more accurate estimate of precipitation in the points without recording data will be precipitated and the multivariate regression method will be more accurate than the linear gradient.

Knowledge of impacts and damages of natural and climatic disasters, besides the development of related insurance products, are among the factors that play a significant role in a better understanding of climatic threats and climate change adaptation and mitigation. Therefore, this research was carried out in order to examine the status of Iran's insurance industry in understanding the effects of climate change and developing related insurance products.

  In order to examine the international experiences of the world insurance industry in the field of climate change, library studies were used, and to examine the current situation of the Iranian insurance industry in understanding the phenomenon of climate change and insurance products, a questionnaire was used.

  Findings show, the deep and extensive attention of the insurance industry to the phenomenon of climate change, the needf for requirements such as providing detailed statistical analyxes of the number of damages and effects caused by the occurrence of climate change, clarifying the harmful effects of climate change on profitability, considering encironmental issues and biological changes in the macro polocies of the country, creating fundamental thinking and attitude regarding climate change in the country. 

The results indicate that climate change has increased customer demand for some insurance products, and the consequences of climate change have caused the need to develop and upgrade the products and use new insurance products.

Caspian locust, native to Hyrcanian forests of Iran, is one of the pioneer species, which it distributed in the moist soils of these forests. So far, the response of its seedlings to permanent and temporary flooded beds has not been reported. This study was conducted with the objective to analyze the physiological responses of Caspian locust seedlings to flooding and flooding-recovery conditions.

Flooding conditions were examined for 90 days in the greenhouse of the Tarbiat Modares University. The study was carried out in a factorial experiment as a completely randomized design with 5 treatments and 4 replications. Treatments included: (1) continuous flooding for 90 days (F90), (2) flooding for 60 days followed by a 30-day recovery (F60+R30), (3) flooding for 45 days followed by a 45-day recovery (F45+R45), (4) flooding for 30 days followed by a 60-day recovery (F30+R60) and (5) Control.

Results showed that flooding for 90 days induced a significant decrease in net photosynthesis (-91%), stomatal conductance (-77%), transpiration (-81%), Chl a (-63%), Chl b (-67%) and Chl Tot (-64%) compared to the control (p<0.05). When flooding was removed for 30-60 days, plants were able to recover gas exchange activities from 30 to 90% and Chl content by 55-90%.

Based on our results, seedlings of G. caspica can survive and grow throughout a medium period of soil waterlogging. Therefore, Caspian locust appears to be a promising species for reforestation programs in the riverine areas and temporarily flooded wetlands.