ECOPERSIA
Volume:2 Issue: 3, Summer 2014

Understanding the development of gully volumes requires the empirical relations between gully volume (V) and length (L) to be established in the field. So far, such V–L relations have been proposed for a limited number of gullies/environments and were especially developed for ephemeral gullies.In this study, V–L relations were established for ephemeral gullies in southern Ilam. In order to take the regional variability in environmental characteristics into account, controlling factors of gully cross-sectional morphology were studied for 90 cross-sections. The results indicated that the soil properties were the most important controls of gully cross-sectional shape and size. Cross-sectional size could be fairly well predicted by their drainage area. The V–L relationship for the complete dataset was V=15.45 L 0.12 (n = 90, R2=0.06). In addition, gully volume was also related to its catchments area (A) and catchment slope gradient (Sc). This study demonstrated that the V–L and V–A×Sc relations were not suitable to assess ephemeral gully volume.

A field study was undertaken with four farming systems (FS) such as; grasses and fodders, agro-forestry, agriculture (new farming systems) and shifting cultivation (old practice), to investigate the effect of land use on the soil properties, erosion and crop productivity on a loamy acidic Alfisol. Besides crops, the livestock were also kept and their dropping were incorporated in the respective watersheds. Soil sampling was done during first week of May every year from 0-20 cm depth, with auger. A significant increase in soil organic carbon (SOC) up to 0.99%, available P up to 17.2 mg kg-1, K up to 170 mg kg-1 of soil, pH up to 6.3, was found after 10 years of study over their initial values of 0.46%, 2.7 kg-1, 105 kg-1 of soil and 4.9, respectively, in the new FS. In shifting cultivation, K status increased up to three years of study and then subsequently decreased. Diethylen etriamine penta acetic acid (DTPA) extractable Zn, Mn, Fe and Cu decreased in all the farming systems. Exchangeable Al content decreased from 117 to 37 mg kg-1 of soil, in new FS. The study showed that about 91.1% to 99.1% rainwater could be retained depending on the vegetation cover in new FS, as against 66.3% in the shifting cultivation. New FS ameliorated the soil by decreasing exchangeable Al and Fe and enhancing soil pH. Soil and nutrient losses were significantly less and crop productivity higher in new FS compared to shifting cultivation.

Determining landslide size could be a difficult and expensive task. In this research, size parameters of 142 landslides recognized in Tajan River Basin, northern Iran, have been assessed. The dataset was prepared through the extensive field surveys and using the satellite imagery available via Google Earth. Dependence between landslides area (A-m2), volume (V-m3), and depth (D-m) was appointed by the Pearson correlation coefficient (r) at 0.05 and 0.01 levels. Then, the relation between the area and volume variables has been investigated using 10 curve estimation (CE) models. Coefficient of determination (R2), F statistic, and RMSE were calculated to compare the models with each other. Results showed that the power law fit the data better than other CE models. Although, the quadratic and cubic relationships have represented high R2 and low RMSE, they have resulted negative estimated volumes, and also their F statistic is less than its value in power law. To achieve a better result, the estimated volumes were compared with the observed ones using paired test. Results indicated that the estimated volumes were in conformity with the observed ones and there was no statistically significant difference between them (R2=0.801, sig=0.633). Although, the estimated depths were significantly different from the observed ones. The mean depth was estimated 5.5 m which was close to mean of the actual depths (5.53 m).

Since the change of land use accrued in the Iran, especially in northern Iran, this research aims tocompare the spatial variability of soil properties in three adjacent land uses including cultivated by wheat lands, grazing lands and forest Lands covered by juniperus sp, fagus orientalis, quercus castanifolia, and acer velotinum species in kiasar region, Mazandaran Province, northern Iran. Some of soil features, i.e. pH, CaCO3, total nitrogen (TN), soil organic carbon (SOC), electric conductivity (EC), percentage of silt, clay and sand contents and saturation moisture content(SM) were measured at a grid with 20 m sampling distance on the top soil (0 – 30 cm depth). Accordingly, total of 147samples were taken from 49 soil sites. The normality of data was examined by the tests of normality. Then, data were analyzed by using of geostatistics approach. The results showed that spatial distribution of many soil properties could be well described by spherical model in the forest and exponential model in the cultivated and grazing lands. Spatial dependences were the highest for SOC, EC and the lowest for silt, (SOC and silt) in the forest method and grazing lands, respectively. Deforestation and conversion to cultivated and grazing lands decreased spatial dependence of soil properties.

We investigated the response of Sea Buckthorn to drought in a nursery experiment that has been studied for the first time in the world for Iranian Sea Buckthorn. Biomass and physiological differences in response to drought were compared between four Elaeagnus rhamnoides seedlings inhabited in Qazvin Province origin seeds of Iran. The experimental design included four water regimes including 2, 4, 8 and 12 days irrigation and three blocks. Water Use Efficiency (WUE), Relative Water Content (RWC), Water Potential (WP), Water Saturation Deficit (WSD), Root and shoot weight of fresh leaves were determined at the end of the watering treatment (four months). We found that drought tolerance was highly related to the plant physiology in E. rhamnoides. With the extension of drought stress from 2 to 12 days, E. rhamnoides seedlings WUE was increased; between one and second treatment, also between third and fourth treatments we observed significant difference. RWC gradually was declined with decreasing water supplies. WP was decreased, while drought was increased from first to last treatment. WSD gradually was increased by accelerating drought in all treatments. WSD values did not differ significantly between treatments three and four. Significant differences at 0.05 levels were not observed between 8 and 12 days-irrigated in both of R and S weight, but in all treatments was decreased toward drought. Our results provided new clue and new insight to study the drought-tolerant mechanism for the study species.

The objectives for this study were first to understand and estimate energy consumption in each stage of production and processing of milk using regional data and second, suggesting improvement opportunities. A cradle to gate assessment of market milk was performed by separating the system into three stages: agronomy, animal farm and processing plant. Data were collected from multiple sources e.g. questionnaire, published papers, national and international databases, and the processing plant database. Throughout the study, ISO framework and International Dairy Federation guideline on life cycle assessment were used. The functional unit (FU) was one liter of pasteurized milk packaged in plastic pouch at the processing plant gate. The average energy demand for producing 1 kg of fat-protein corrected milk at farm-gate was 10.8 MJ, although for the final packaged milk, it was 12.5MJ. Main stages in overall energy use of FU were agronomy 68 %, animal farm 19 % and processing plant 13%. The average energy use for raw milk production was 2-5 times higher than previous European reports. To enhance efficiency in this sector, we need to assess other regions’ potentials for feed and milk production and then to focus on agronomy stage for lower energy use by optimization of irrigation, or even importing energy intensive feed such as barley and alfalfa from other countries.

Soil and Water Assessment Tool model, SWAT, uses different layers of watershed data which out of soil layer is the important one. Soil layer data should be extracted from detailed soil maps. In most developing countries including Iran, these detailed maps are not available except for irrigation districts and rarely for dry land farming areas and also for some strategic places of development purposes. For larger plains, the available soil maps information are reduced to semi-detailed scale which adds uncertainty in data required for catchments and hydrologic modeling. This research studied the relations between land use (LU) maps, land suitability for agricultural activities (LS) and physiographic soil unit (PU) on one hand and detailed soil maps and their embedded data on the other hand. The research has focused on the replacement of data derived from the detailed soil maps (from large scale soil map information) with those of readily available LS, PU and LU maps. Using these two sets of data for modeling of hydrologic system with SWAT on a 5793 Km2-watershed in west of Iran showed no significant difference between the simulated discharges at the watershed outlet. So the available LS map for the whole country may be used for both plains and catchments in SWAT simulation.