جستجوی مقالات مرتبط با کلیدواژه « Rainwater harvesting » در نشریات گروه « آب و خاک »

Identifying potential sites for small rainwater harvesting can help to improve crop water productivity especially rainfed cropping systems.In present study, suitable areas for creating small rainwater collection systems in Isfahan province were determined using multi-criteria decision making models including hierarchical analysis process and network analysis process. The selected variables were annual rainfall ( 111 synoptic, climatology , evaporation and rain gauging stations), land slope, soil permeability, vegetation cover, soil fertility, distance from city and village and distance from road. The results showed that in both AHP and ANP methods, Khomeni-Shahr region with about 63% and Mobarake with about 55% of area , have the largest suitable coverage (good and very good condition) for the small rainfall collection systems construction and Aran and Bidgol (4%) and Ardestan (6%) have the lowest percentage of suitable areas, respectively. For the entire province, according to the AHP and ANP methods, about 24.8 and 21.8% of the lands are categorized as good and very good class for the creating small rainwater harvesting systems, respectively. The results also indicated that for both AHP and ANP methods, about 76.3% of lands with good and very good conditions for the construction of these systems are located in dry and semi-arid areas and 23.7% in semi-humid areas. The statistical comparison between the two approaches showed a significant difference between the provided suitable zones for constructing these systems at 0.01 level. The defference may be attributed to assigned weight of input layers.

The purpose of soil management is maximizing the supply of water and nutrients to the plant and minimizes the soil erosion, improve soil fertility and soil physical conditions. Using in-site water harvesting methods reduces runoff from the area and increases the water stored in the soil profile. Rainwater harvesting is not a new concept, but it requires the combination of native methods with modern knowledge. Because the used technology was inappropriate for special conditions of the region, some water harvesting projects have been unsuccessful or even led to the loss of the whole crop. The suitability of an area for rain water harvesting depends on its ability to supply the technical and basic needs of the system. This study introduces a method for rain water harvesting in the area with little slope or no slope, which can be Mechanized Construction for large-scale. On the other hand, a computer simulation has been preparation and introduced for precise and scientific designing of a water harvesting system, which there has not been much effort in this case. The results of simulation indicated the reduction of concentration ability of water by Kajaweh system with decreasing the size of structure. In addition, in relatively smaller sized structures under high intensity rainfall, reduction of water concentration ability by Kajaweh system was predicted by simulation. Such trend is also expected for long time rainfall times (especially in low rainfall intensity).

Present research has been executed in Chaharmahal va Bakhtiary Province during 5 years in order to investigation of impact of optimized microcatchment systems in moisture storage of soil profile for establishment and development of hillside orchards. Essential hypothesis in this research is the practicability of moisture storage in soil profile by using microcatchment systems. Towards this attempt, in a rangeland of 20 percent slope, microcatchments were made with 5 different treatments including natural surface, removed surface with gravelly filter, removed surface without gravelly filter, isolated surface with gravelly filter and isolated surface without gravelly filter, with 5 replicates and 3 cultivar of almond. Soil moisture was measured in the times of, one day after rainfall, one day befor irrigation, one day after irrigation and once in each 5 days by TDR in depth of 25, 50 and 75 centimeters of soil profile of cultivated ditch. Comparison of means of soil moisture showed that in depth of 25 centimeters of soil profile, different treatments had not effective role in soil moisture variations. In depth of 50 centimeters, the means of moisture value had significant difference between different treatments. In depth of 75 centimeters, the means of moisture value had significant difference between removed surface with gravelly filter and removed surface without gravelly filter(p<0.05) and also between isolated surface with gravelly filter and isolated surface without gravelly filter(p<0.04). So utilization of optimized microcatchment systems especially isolated surfaces with gravelly filter can be recommended for increasing of moisture storage of soil profile in hillside orchards

Evaporation loss is a key component of water resource management in arid and semi-arid regions where they are not uniformly distributed temporally. Also, due to the climate condition and physical characteristics of arid areas, a major part of rainfall will be out of reach in the form of flash floods and a few percent is recharged to groundwater aquifers. Rainwater harvesting system (RWHS) is considered as one of the most instrumental techniques that can save rainwater for domestic or agricultural uses. It is a technology used for collecting and storing rainwater in rooftops, land surfaces, or rock catchments using some simple techniques, such as natural and/or artificial ponds and reservoirs. In recent years, climate change has caused significant changes in the meteorological and hydrological components. Also, since precipitation is the main driver of RWHS, changes in its value and time can significantly change the operation of these systems. Therefore, in order to reach sustainable development, water resource management based on rainwater harvesting systems will be inevitable. These systems are moderately reliable methods to increase available water. The main aim of this study is the reliability assessment of rainwater harvesting systems designed for a future period (2017-2030) in Birjand, the center of Southern Khorasan Province, east of Iran.

Due to water shortage, increasing production by increasing cultivation area is limited in arid and semi-arid regions and approach to optimize the use of rainfall and limited irrigation to be considered, in order to increase water productivity. Development of rainwater harvesting systems and supplemental irrigation can be effective in increasing semi-irrigated cultivation area and decreasing water shortages. Rainwater harvesting is defined as a method for inducing, collecting, storing and conserving local surface runoff for agriculture in arid and semi-arid regions. The supplemental irrigation in condition which rainfall alone cannot have a good performance can be effective to improve the yield. The objective of this study was to investigate the effects of rainwater harvesting system and supplemental irrigation on water productivity index in winter barley (Hordeum vulgare L. Var. Abidar). A field experiment was conducted in a semi-arid region at Research Field of Tarbiat Modares University, located 16 kilometers of west of Tehran, Iran during the 2011-12 growing season. The land was located at 5110  E. longitude and 3535  N. latitude, at a height of 1269 m above the sea level. In order to cultivation, first it was attempted to plow to a depth of 30 cm, formed lumps were compacted using disc ,then seeds with a density of 130 kg per hectare were planted in furrows at 20 cm intra-row space and finally seeds were covered by soil using trowel so that the depth of cultivation was 4-5 cm. The size of each plot was 3×6 m considering the catchment and cultivate area ratio was 1:1. The experimental plots spacing were 1 m apart to avoid side effects. The maintenance of barley plants during the growth season was made by removing the weeds and applying fertilizer urea at a rate of 85 kg/h (half at the seeding and half in the spring). During the planting season, it was attempted to remove the weeds over the rain water harvesting catchment. The supplemental irrigation was applied during the grain filling stage. The volume of applied water was calculated based on the soil moisture deficit up to a depth of 45 cm. The amount of applied water in each plot was measured using the flow meter. The experiment was a split plot in a randomized complete block design with three replications. Irrigation treatments at five levels (twice with water, twice with treated municipal wastewater, once with water, once with treated municipal wastewater and without irrigation) as main plot and rainwater harvesting surface treatments at three levels (compacted, incompacted and natural surface soil) is defined as sub-plots and rainfed was defined as control. The analysis of variance was carried out using the generalized linear model (GLM) and after ensuring, normal distribution of residuals was tested using the SAS software. The comparison of treatment means was made using the least significant difference (LSD) at the level of 0.05. The results indicated that the use of rainwater harvesting system had increased the yield and the total water productivity in comparesion with the rainfed condition. The supplemental irrigation maximized the total water productivity (in grain and biomass yield) and increased significantly (by 6.3% and 13.2%) compared with non-irrigated plots respectively. The compacted surface plots had significantly higher values of the total water productivity in grain and biological yield (15.8% and 14.9% respectively) in comparesion with natural surface treatment. There was no significant effect of supplemental irrigation with treated municipal wastewater on the yield and yield components. The use of compacted catchment in the rainwater harvesting system caused an increase in the number of spikes m - 2 and the application of the supplemental irrigation during grain filling stage could increase the thousand grain weight by increasing the grain filling period, resulting in the desired yield. Applying the supplemental irrigation by treated municipal wastewater made the renewed pressure not exert on the surface and groundwater resources for the production of crops. Using this project can be helpful for the lands beside the smaller cities and rural areas, where there is not possibility of sustainable rainfed farming, to be planted using rainwater harvesting system and to be irrigated supplementary by the treated municipal wastewater