جستجوی مقالات مرتبط با کلیدواژه « intermittent irrigation » در نشریات گروه « آب و خاک »

Due to the lack of water resources, increasing of the water productivity index in a strategic and high water consuming cultivation like as rice is getting more important. Planting date and irrigation program are important factors in increasing the productivity of rice. This study investigates the effect of transplanting date on irrigation programe and rice yield and provides an acceptable strategy for determining the appropriate planting date with respect to climatic conditions and field characteristics. Therefore, SWAP model was calibrated in the Astaneh-Koushfahan plain with data of three paddy fields (Hashemi variety) and validated with data of two other paddy fields. The R2 index greater than 0.98 and RMSE-N less than 10% indicated that the model had acceptable accuracy for rice growth simulation. After validation, the optimummanagement of intermittent irrigation was obtained in planting dates 1, 5, 10, 15, 20 and 25 May. The results showed that in 2011 1 May was the suitable planting date due to higher irrigation water productivity. At this date, 9% allowable moisture depletion and 7 days irrigation intervals were proposed. Also, in this plain, the maximum and minimum moisture allowable depletion was 15 and 2%, respectively in clay and sandy loamy clay soil texture.

 In Khuzestan province, waste water release from various sources, especially from agricultural farms, is a serious problem. The volume of drainage water resulting from irrigation and drainage networks of the Karun river basin is about two billion cubic meters per year, considering sugarcane agro-industries and fish farming as the main sources of drainage water. Time-Averaged salinity of this drainage water, with source of sugarcane agro-industries, is about 6 dS/m which is valuable to irrigate salt-tolerant crops or aquaculture with saline water as part of the solutions for drainage water management and providing sustainable environment. This can also affect the amount of water allocated to irrigation networks and sugar cane industries. In this regard, reusing of agricultural drainage water to produce rice salinity resistant varieties and lines as a high-yielding strategy in Khuzestan, especially in the central and southern areas with high water demand, can be very useful. 

This study was conducted at farm code L08-20, in Mirza Koochak-Khan Agro-Industry Company, using split plot in a randomized complete block design with two factors and three replications. Irrigation interval with saline water daily, one-day and two-day alternations were main factors and three salinity-tolerant rice lines were sub factors. Subsequent selections from the International Treasury of rice cultivars, four salinity-tolerant breeding lines, one international control line and local cultivar were subplots. The amount of water applied to the plots was measured throughout the growing season and samples for determination of physical and chemical properties of soil and drainage water before planting until harvesting time for soil monitoring and soil salt balance analysis were collected. In this study, grain yield, biomass and harvest index were determined. Finally, water productivity was estimated as yield per cubic meter of water.  

Due to the average salinity of irrigation water, 6 dS/m, the volume of water consumed during the growing season was estimated to be 30,000 m3/ha, based on water requirement calculations. Based on irrigation management, applied volume of water was estimated about 37500 m3/ha for treatment I0, 19500 m3/ha for treatment I1 and 13200 m3/ha for treatment I3. The average salinity of soil saturated extract was measured about 4 dS/m before cultivation. Except for the first 15 days, when irrigation was carried out with full irrigation for transplanting stage, the trend of soil salinity changes was decreasing, during the rest of the growing season until harvesting. Salinity of soil increased in all three irrigation managements. The rate of salinity changes varied from 50% in the daily irrigation round to 100% in the two-day irrigation round, compared to pre-cultivation soil salinity. During the crop growth from the transplanting, daily, one-day and two-day rounds irrigation managements caused enterance of 190, 99 and 66 tonnes of salt in the top 100 cm of soil profile. Increased salinity over growing time for daily, one-day and two-day round irrigation treatments, were 6, 6.5 and 7.2 dS/m respectively, according to soil salinity, 4 dS/m, before planting. Assuming the  porosity of soil equal to 51%, it could be concluded that 7.6, 9 and 11 tonnes of salts stored in the upper 60 cm of soil profile for daily, one-day and two- day round irrigation management and the rest of the solutes extracted from soil profiles through underground drainage system. This behavior illustrated the importance of drainage, especially underground drainage system, in agricultural drainage reclamation and saline operations for soil conservation. The results showed significant decrease of farm applied water in daily irrigation water management relative to two-day and three-day intervals. Farm yield increased 6% from I0 with an average of 2139.3 to 2248 kg, I1 and then decreased by 30% in the three-day irrigation period. 

The results showed that the highest and lowest water productivity were found in I2 and I0 irrigation treatments, respectively, with values of 0.128 and 0.057kg/m3. ESP monitoring showed that at the end of growing season, soil profile was not sodic and remained in saline condition for two irrigation regimes I0 and I1. However, in I2 irrigation regime, the soil profile status approached to the sodic state, with 17% increasing in ESP and 100% increasing in salinity relative to planting time. The reason for this behavoir was driness of land between two irrigation events which caused salinity moving upward to soil surface layers, so it could be addressed by considering the percentage of leaching at the end of the growing season.   Acknowledgement  The authors gratitude Mirza Koochak-Khan Agro-Industry Company, Khuzestan Water and Power Authority (KWPA), Agricultural Engineering Research Institute (AERI), Rice Research Institute of Iran )RRII), Khuzestan Agricultural and Natural Resources Research and Education Center  for their  overall supports to accomplish the study.

Irrigation is known as one of the most important factors in the production of grains in dry climate. The present irrigation method used for wheat and alfalfa production is mainly surface irrigation (Basin, Border, and furrow) and this method consumes more water and has less water efficiency than innovative irrigation methods. Using pressurized irrigation systems can both save water and increase water use efficiency. The purpose of this study is to investigate the feasibility of using strip drip irrigation in winter wheat. In order to determine the most suitable distance between irrigation tapes and find out the effect of Alternate Partial Root Drying (APRD) on water use efficiency, yield and components of wheat yield , a factorial experiment with 6 treatments and three replications was conducted in Pelband plain-Khorasan Razavi province- in 2016-2017. Then, water consumed, yield and its component yield were compared in traditional flooding method - conventional flooding. The treatments applied in this research consisted of drip-tape irrigation with distance of 50 cm (I1) and 60 cm (I2) and 70 cm (I3) and three intermittent drip-tape irrigation with spacing of 50 cm (I4) and 60 cm (I5) And 70 cm (I6) and all of them with three repetitions. The results of mean square variance analysis showed significant difference in tape irrigation distance and wheat component on, yield and water use efficiency was significant at 1% level, and irrigation interval on number of pancakes, number of seeds in the cluster, stem height, Yield and water use efficiency were significant at 1% level and significant differences were observed on 1000 grain weight at 5% level. And the interaction effects on 1000 grain weight and grain number per cluster was not significant, but there was a significant difference between the number of pancakes and the level of 1%. Also, stem height and yield and water use efficiency at 5% level were statistically significant Had The highest yield and water use efficiency related to the irrigation bar spacing 50 and fixed irrigation type were 4958 kg / ha and 1. 57 kg / m3, respectively, and the least irrigation bar spacing were 50 with alternating irrigation it is equal to 3005 kg / ha and 95 / kg / m3 respectively. The performance and efficiency of water use in irrigation were measured at 5030 kg / ha and 1.05 kg / m3 respectively. The results of this study showed that irrigation intervals of 50, 60 and 70 cm with irrigation method were recommended for wheat cultivation in the study area. the irrigation bar spacing 50 with fixed type is more better than furrow irrigation in drought years, because of saving water around 1620 cubic meters and less than 500 kilograms decrease performance .

Rice is one of the cereals that are widely used food in the world as staple.Rice is the largest consumer of water among agricultural products.At the field level, rice receives up to 2–3 times more water per hectare than other irrigated crop for producing of one kilogram of rice.Accordingto water resources limitation in Iran, According to water resources limitation in Iran, careful planning is essential to optimal use of water resources in agriculture as the largest consumer. One of the methods to reduce water consumption in rice cultivationis changing the traditional irrigation methods (flooding) to periodic irrigation. Change of management from traditional water-logging irrigation to unsaturated improves the irrigation water use efficiency. Due to water scarcity problems, the aim of this study was to evaluate controlled drainage and the impact of irrigation management on growth characteristics and yield components of rice in the arid and semi-arid.
To Considering the effect of water table level on water productivity in rice cultivation, the study was done in Shahrekord university. The experiments conducted in pots with 40 cm diameter and 45 cm hight. The experiment was arranged following a completely randomized design with four treatments (water table level) and five repetitions. The water table managements including: control water table 2 cm on the top of the soil (FI),the control water table 20 cm below the soil surface (CD20), control water table 36 cm below the soil surface (CD36) and Intermittent irrigation(AI). Tocontroll the water level, two tanks were used, one as stabilizer water table and another to measure the amount of water used. The Treatmentsares are completely water logging for a week, in second week treatments were applied. Sampled four times during the growing season was performed to determine the dry matter content of leaf, stem and leaf relative swelling and at the end of the growing season, the volume of water consumed, harvest index, the amount of grain produced and thousand grain weight was measured and recorded. The data obtained were analyzed using SAS software and LSD test was performed for comparison of means.
The results showed reduced yield treatments for CD20, CD36 and AI for each unit reduction in water consumption respectively as much 0.36, 0.46 and 0.38 units. Also results showed irrigation management caused significantly decrease in swelling relative only in the first and Second measuring stages respectively at the 5 percent level and in the fourth measuring stages at 1 percent level. Dry matter productive also was reduced under irrigation management in the Second and fourth measuring stages respectively in 1st and 3rd measuring stages at the 5 percent level. The impacts of irrigation management are no statistically significant on the rice harvest index and thousand grain weights but water consumption was reduced in CD20, CD36 and AI. Resulted to increment 5 percent water use efficiency based on performance and a significant increase 1 percent in the efficiency of water use was based on biomass. The highest and lowest harvses index belongs to FI (39.1) and CD36 (35.4) respectly. The highest and lowest thousand grain weights belong to FI (1247 kg/ha) and CD36 (1101 kg/ha) respectly.
High water Stress causes roots gone to sleep and their growth will slow after re-watering. Water scarcity is not only the hinder root growth but causes the root fuzzy and reduce its ability to absorb substances. The results showed that water reduction, a significant decrease in grain yield not occurred, Lack significant differences in grain yield mean that the water supply was adequate at all levels and in none of irrigation regimes, the plant was not affected by water stress and plant roots grown have enough at critical stages that needs greater water and has access to available water at greater depths. Results showed that T2 (control water table level at 20 cm below surface of soil) for each unit reduction in water consumption, 0.36 units reduces seed productionand 16% reduction in the amount of dry matter, That these lowest values are in the between treatments. With this irrigation management and reduce water consumption by 23% compared to control treatment area under cultivation can increased by as much as 30% and the grain production increase from 3424 to 4210 Kg per hectare.

Intermittent irrigation is a method to increase water productivity of rice (Oryza sativa L.). In this study, the effects of this type of irrigation combined with two periods of midseason drainage on growth parameters of two rice cultivars were investigated in subsurface drained paddy fields. The experiment was laid out as split plot in a randomized complete block design with three replications during 2014 growing season. The main factor consisted of drainage systems in the study field including three conventional subsurface drainage systems with drain depths and spacing of, respectively, 0.9 m and 30 m (D0.9L30), 0.65 m and 30 m (D0.65L30), and 0.65 m and 15 m (D0.65L15). In addition, a bi-level subsurface drainage system with drain spacing of 15 m and drain depths of 0.65 and 0.9 m as alternate depths (bilevel), and a treatment without subsurface drainage (control) were included in the study. Sub-factors including rice cultivars Hashemi and Daylamani Tarom were planted in the study area. Midseason drainage was conducted in two periods of 10- day (25 to 34 days after transplanting) and 5-day (43 to 47 days after transplanting). During the growing season, sampling was done to determine leaf area index (LAI), total shoot dry weight (TDW), crop growth rate (CGR), relative growth rate (RGR), leaf area ratio (LAR) and net assimilation rate (NAR). Conducting such water management through subsurface drainage systems increased most of the studied parameters of Hashemi cultivar so that significant differences were found between CGR, NAR, and RGR of D0.9L30 and the control treatment. Maximum dry weights of Hashemei and Daylamani cultivars were 858.8 and 1006.6 g m-2 related to D0.65L15 treatment and maximum leaf area indexes of these cultivars were 4.87 and 5.43 related to bilevel and control treatments, respectively. However, there were not significant differences among different treatments for each cultivar. Based on the results, two periods of midseason drainage through subsurface drainage would improve rice growth characteristics if proper drainage time is selected.