جستجوی مقالات مرتبط با کلیدواژه "کشت آبی" در نشریات گروه "آب و خاک"

Determination of land suitability to achive sustainable agriculture and environmental protection is very important and essential, because of arable land decrease in the last decade. In this research, parametric approaches including Storie and Square Root and ELECTRE TRI multiple criteria method have been used for suitability evaluation of the maize cultivation under sprinkler irrigation in 12000 ha area of Dasht-e-Moghan via consideration of 167 soil profiles. After soil sampling, analysis, classification and extraction of soil properties values by weighted coefficients, finally eight properties including soil depth, lime, gypsum, pH, EC, ESP, slope and climate were selected using principal component analysis and Euclidean distance methods for calculations of the land suitability evaluation. Criteria weights via pair-wise comparison matrix method and ELECTRE TRI profiles and thresholds limits were determined using requirements table, soil and land properties data. Statistical comparison of the allocated grades, mean values to the suitability classes in the region and soil great groups showed that the results of the three methods were significantly different and ELECTRE TRI method had the best grade. Hotelling and Wilks tests of multivariate variance analysis distinguished a suitable separation accuracy of suitability classes by their P-values in ELECTRE TRI method. Also comparing the mean values of the soil and land properties via LSD test showed a significant difference among the ELECTRE TRI suitability classes that implie the high accuracy of this method due to determination of the transition suitable limits (classes between limit), appropriate values of thresholds and criteria weights as well as usage of the fuzzy logic relations and principles for performance of the calculation processes.

For proper management of soil, conducting a comprehensive assessment seems necessary and basic. Soil forming processes strongly vary among different land uses and topographies. In this study, a factorial experiment was performed in a completely randomized design with 2 factors (type of land use and soil depth) in 3 replications, in order to investigate the impacts of topography and different land uses on soil physical, chemical and mineralogical properties of soils of Chaypare, West Azerbaijan province, Iran. There were three dominant land uses including pasture (low density of vegetation cover), dry farming (mainly wheat without annual alternating crops) and irrigated farming (with annual alternating crops). In the present study, two soil profiles were dug for each land use and then clay mineralogy, along with the physico-chemical properties, were determined. The results indicated that changes in the both topography and land use influenced the soil cation exchange capacity (CEC) through affecting both the clay and soil organic matter contents. Although, there were no significant differences in physic-chemical properties among different land uses, the soils of irrigated farming showed relatively lower amounts of calcium carbonate equivalent (CCE) and sand content than the two other land uses and the amounts of organic matter content and CCE and pH were considerably dominant in the irrigated farming. The X-ray diffraction (XRD) measurements indicated that both the topography and type of land use had no significant effect on the qualitative properties of the clay minerals but they were effective on their semi-quantitative properties. Accordingly, the amount of smectite in the fine clay fraction in the irrigated farming was dominantly higher than that of the other land uses. Additionally, the status of the different cultivated crops seemed to affect the quantity of clay minerals in the both dry and irrigated farming land uses. Finally, the irrigated farming compared with the two other land uses (pasture and dry farming), revealed to be more affected by the slope and pedogenic processes.

Soil infiltration rate is the major soil hydraulic property which can be affected by the soil physical characteristics and management practices. The use of land can affect various soil properties such as physical and hydraulic properties. Differences of the hydraulic soil characteristics such as infiltration rate in various land uses can affect their potential to runoff production as well as soil loss in the catchment. The knowledge of the physical and hydraulic characteristics of various land uses can help to better management of soil and water in the catchment. It is very essential in the semi-arid catchments where vegetation cover is generally poor, the soils are often instable against erosive factors especially when the rainfalls are consecutive and intensive. Therefore, this study was conducted to investigate the soil physical and hydraulic characteristics in the TahamChai catchment, in a semi-arid region, NW Zanjan. Various land uses consist of pastures, rainfed and irrigated lands can be observed in the catchment, which cover about 62%, 33%, and 5% of the catchment area, respectively. The pastures have been covered with poor vegetation and are intensively exhausted by over-grazing. Rainfed lands are mostly under winter wheat cultivation. Soil erosion and sedimentation were the major environmental problem in this catchment.
The maps of land use and slope gradient were provided for study area. A total of 20 sites were selected based on the surface area of each land use in the catchment located between 34 46-36 53 N latitudes and 48 17-48 37 E longitudes. The study area consisted of ten sites in the pasture, seven sites in the rainfed and three sites in the irrigated lands. The geographical positions of study sites were determined by a global positing system (GPS). Soil infiltration rates were measured by double rings method at three replications in each site. Variation of soil infiltration rate was determined for each land use. Soil samples were collected at three replications from each site to determine other physicochemical soil properties. Particle size distribution, bulk density, saturation percentage, aggregate mean weight diameter, organic matter, and equivalent calcium carbonate were determined using standard methods in the lab. Mean comparisons of infiltration rate along with other physicochemical soil properties among the land uses were done using the Duncan's parametric method. The Pearson’s correlation coefficients were used to determine the relationships between soil properties and soil infiltration rate.
Based on the results, no significant difference was observed between the land uses in particle size distribution. Soil infiltration rate showed different patterns among the land uses, so that significant difference was observed among them (p Pastures with poor vegetation cover appeared the lowest soil infiltration capacity as compared to other land uses in the catchment. Decreasing soil infiltration rate was associated with increasing bulk density in the area. It seems that overgrazing in the pastures increases soil bulk density and leads to decline the soil organic matter content as well as soil aggregation and aggregate stability. According to the results, pastures have the highest potential to runoff production and soil erosion rather than the other land uses (rainfed lands and irrigated lands). Therefore, maintaining vegetation cover and preventing over-grazing in the catchment is recommended to increase soil organic matter content and decrease soil compaction. These practices improve the hydraulic soil characteristics especially infiltration rate and in consequence decrease the catchment potential to runoff production and soil erosion.