Journal of Water and Soil
Year:2017 | Volume:31 | Issue:4 |Papers Count:22

Introduction: In Iran, due toreduction of water resourcesandincreasing of water losses in the variousmethods of the surface irrigation pressurized irrigation methods, especially drip irrigation have got many attentions.Application of the plastic mulch method is used in cultivation of early sweet corn. Application of this technique due to its temperature provides both plant growth and early maturity and then causes the on-time delivery of product to the target market. Additionally, to reduce water consumption, the use of germinated seedlings in the greenhouse and move it under plastic on the farm, productivity will increase. The aim of this study was to evaluate irrigation levels on yield of sweet corn by using plastic mulch, and the feasibility of seedling cultivation to early crop. …

Introduction: One of the most important consequences of the future climate change is its impact on water use and water use efficiency (WUE) in agriculture which could challenge the water resources management.Khuzestan province is one of the most important areas of crops production in Iran particularly for wheat, so that 15.73 percent of total irrigated wheat production and 8.85 percent of total arable land is located in this province.Therefore, investigating climate change effects on irrigated wheat production, WUE and irrigation requirement will be necessary in the Khuzestan province. In this context, this study was conducted to simulate the growth and yield of irrigated wheat under climate change conditions, and to calculate WUE and irrigation requirement in this province. …

Introduction: Hydrological phenomena are often multidimensional and very complex. Hence, the joint modeling of two or more random variables is required to investigate the probabilistic behavior of them. To this aim, the copulas can be efficiently utilized to derive multivariate distributions. In addition, the copula functions can quantify the dependence structure between correlated random variables. …

Introduction: In drainage and irrigation network capacity design and determination, reference evapotranspiration (ETo) plays significant role. Methods applied for estimated reference evapotranspiration classified in two direct and computational methods. Amongst computational methods it might point to Penman- Monteith method. This method requires radiation, temperature, humidity and wind speed data with high reliability rate in vast ranges of climates and areas represent precise outcome from reference plant Evapotranspiration. …

Introduction: Practical problems such as rushing roots toward pot, difficulty of manually filling with water and deficit irrigation due to permeation from regular pots prevents the development of pot irrigation. With regard to increasing irrigation efficiency importance and preventing water loss to fix the problems of this irrigation method. Changing physical structure of pot could solve many problems and issues which this irrigation technique is facing. Comparison of the two major characteristics of localized irrigation hydraulic characteristics (coefficient of variation and distribution uniformity) and also using gravity pressure can achieve a solution for water and energy shortage problems. So far, with knowledge of the role of water pressure at gravitational pressures in hydraulicproperties of these methods, some effective features in these methods application is specified. …

Introduction: Wind erosion is the most important agent of environmental degradation, poverty of soil, air pollution and the dust spread. Wind erosion is causing a lot of damage to crops, buildings, facilities and vehicles.The first step of the wind erosion control is the stabilization of soil particles. Soil stabilizing methods to control wind erosion can be classified into mechanical, biological and chemical stabilization. Mechanical soil stabilization type is relatively time-consuming and costly. …

Introduction: One of the most important indicators in relation to industry, economy and environment is to achieve the most recovery with the least cost and minimum pollution. Today, the use of chemolithotrophic microorganisms is common for extraction of some metals such as cooper, uranium, gold, cobalt and molybdenum in bioleaching process of low-grade rocks. Attention to the bioleaching of heavy metals such as copper, nickel, cobalt, zinc, and molybdenum has been increased in recent years because of its application to low-grade ores. …

Introduction: Recently, destruction of soil organic matter and its has caused by continuous utilization of soil and disregarding crop rotation, especially in arid and semiarid regions such as Iran. Considering hazards and contamination caused by the application of chemical fertilizers, reducing consumption of these inputs, finding ecological methods to provide crop nutrition supplies, increasing and maintaining soil fertility is consequential.Cultivation of the appropriate pre-sowing plants, is one of these methods which can act as green manure to maintain soil fertility by recycling carbon, organic matter and total nitrogen in the soil due to increase in microbiological activity and release nutrients for plants uptake. Therefore, this study aimed to investigate the effects of integrated crop management on soil nutrients characteristics and nitrogen mineralization during the period after adding green plant residues was conducted in Karaj. …

Introduction: Among essential plant micronutrients, iron (Fe) exerts the highest restriction to crop production in Fars Province. Determination of iron chemical forms is one of the accurate methods to study the status of this element (Fe) in the soil. Assessment of the relationships between the chemical forms and soil characteristic helps to describe the chemical changes of iron in the soil. In this study sequential extraction to determine iron forms in soils was conducted in order to provide a clear understanding of elements mobility and availability to plants. Trace elements in the soil are classified into 5 groups of chemical forms. These are the water-soluble and variable, adsorbed, chelate creating with complex compounds, secondary clay minerals, forms of insoluble metal oxide minerals, and primary minerals. Trace elements in the forms of water-soluble, changeable, adsorbed or chelates improve elemental balance in the soil and are known important for plant nutrition.

Introduction: Potassium (K) is the third major essential macronutrient for plant growth. Without adequate potassium, the plants will have poorly developed roots, grow slowly, produce small seeds and have lower yields.Due to imbalanced fertilizer application, potassium deficiency is becoming one of the major constraints in crop production. The concentrations of soluble potassium in the soil are usually very low and more than 90% of potassium in the soil exists in the form of insoluble rocks and silicate minerals. Soil microbes have been reported to play a key role in the natural K cycle and therefore, potassium solubilizing microorganisms present in the soil could provide an alternative technology to make potassium available for uptake by plants. Thus, identification ofmicrobial strains capable of solubilizing potassium minerals quickly can conserve our existing resources and avoid environmental pollution hazards caused by heavy application of chemical fertilizers. …

Introduction: Particle size distribution (PSD) is one of the most fundamental features of soil physics that is widely used as the most common input to predict several key soil attributes. The mathematically representing the PSD provides several benefits to soil mechanics, physics, and hydrodynamics as well as helps to convert PSD data of various particle size classification systems to the desired one. Consequently, the correct and consistent descriptions of soil PSD using mathematical functions is necessary. …

Introduction: Soil test has an important role in plant nutrition management to obtain the economical agriculture system. The nutrient concentration in soils that indicates the division between responsive and nonresponsive conditions is termed the critical level. Before any fertilizer recommendation, we should be aware of the amount of nutrient critical levels in each region. Soil test results in an area, is not applicable for other agricultural areas. Therefore, these tests should be carried out in the soils of a desired area, so that the soil test could be the base for fertilizer recommendation. ….

Introduction: Potassium is a major and essential plant macronutrient and the most abundant absorbed cation in higher plants. Potassium (K) plays an important role in the growth, metabolism, and development of plants.There are three forms of potassium found in the soilviz., soil minerals, nonexchangeable and available form. Soil minerals make up more than 90 to 98 percent of soil potassium. It is tightly bound and most of it is unavailable for plant uptake. Plants can uptake potassium only from the soil solution. …

Introduction: Fractal geometry concepts have been widely applied as a useful tool to describe complex natural phenomena, in particular, for a better understanding of soil physical systems. However, limited information is available on the fractal characteristics of soil properties or soil aggregation. A soil aggregate is made of closely packed sand, silt, clayand organic particles building upsoil structure. Soil aggregation is a soil quality index integrating the chemical, physical, andbiological processes involved in the genesis of soil structure. …

Introduction: Lead (Pb) is of great concern in environment because of its toxicity to animals and humans.Lead is a cumulative toxin and known carcinogen. Although, plants do not require Pb for growth, the bioaccumulation index of Pb in plants exceeds that of most other trace elements. It is therefore important to control Pb concentration in plants, especially in the edible parts of crops to ensure food safety. …

Introduction: Phosphorus (P) is an essential nutrient for all life forms. In aquatic environments, P is a double-edged sword. In some areas, habitat biodiversity is strongly limited by low P bioavailability, while in others, P inputs in excess of plant needs have led to pollution of water bodies and eutrophication. There is little information available on P status in river sediments by single chemical extraction and its correlation with algae growth in Iran. This study was performed to select proper single chemical extraction methods by algal bioassay. …

Introduction: Soil quality as an important part from soil resource sustainability, consistently isinfluenced by human activities. Today, the presence of accurate information about variability of soil quality properties is considered more than ever to apply this information in economic modeling, environmental predictions, accurate farming and natural resources management. Soil quality is defined as: “capacity of the soil to function, within the ecosystem and land-use boundaries, to sustain biological productivity, maintain environmental quality, and promote plant and animal health”; therefore, it is one of the most important factors in developing sustainable land management and sustaining the global biosphere. …

Introduction: Biochar is a material produced from organic matters under high temperature and low oxygen conditions. In recent years, scientific attention has been focused on its effects on soil amendment and ecological restoration. Due to its properties related to surface area and porosity, bulk density, nutrient content, stability, cation exchange capacity (CEC), pH value, and carbon content, biochar has the potential to improve physical and chemical soil properties and thus improve crop productivity and contribute to carbon sequestration. …

Introduction: Investigation of water passing through soil is one of the most important problems in soil mechanics and environmental engineering. It is an important parameter for predicting the movement of water and contaminants dissolved in the water through the soil and measured on soil samples in the lab and sometimes tests carried out in the field. Soil permeability generally depends on two factors, the first one is soil Specifications contains an empty space of soil, surface roughness of solid particles, saturation, and another one is characteristics of the fluid (water) that passes through soil. Already few efforts have been made to recognize the characteristics of anisotropy in the geotechnical designs therefore this study has been done. …

Introduction: Drought is a natural phenomenon and was described when precipitation is less than expected.Since the precipitation amounts in terms of spatial and temporal characteristics are different from one region to another, so this phenomenon is known as a multivariate phenomenon. This phenomenon often characterized by different variables such as drought duration, severity, intensity and spatial extent. Although site specific analysis can provide useful information on drought occurrences in a limited area, but these results have a fundamental uncertainty to drought risk assessment in a large region. …