Rasoul asadi; Frzad hasanpour; Mitra Mehrbani; amin baghizadeh; Fatemeh Karandish
Abstract
Using proper irrigation management leads to optimum utilization of water, soil, and fertilizer and production of high yield and quality products. In order to investigate the effect of irrigation intervals and surface and subsurface drip irrigation systems on growth indicators of Rosmarinus officinalis ...
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Using proper irrigation management leads to optimum utilization of water, soil, and fertilizer and production of high yield and quality products. In order to investigate the effect of irrigation intervals and surface and subsurface drip irrigation systems on growth indicators of Rosmarinus officinalis L., a field experiment was carried out during 2015 growing seasons at an experimental farm in Kerman city. The treatments were laid out in split plot using a Randomized Complete Block Design with three replications. The treatments comprised three irrigation levels (I 1 =25, I 2 =40 and I 3 =55 mm evaporation from class A pan) in the main plots, and two drip irrigation systems (surface and subsurface) in the sub plots. The results showed that I 2 in comparison with I 1 treatment led to 44 mm water saving. However, dry weight, height of plants, number of shoots per plant and leaf area index decreased by 12.9%, 12.6%, 13.6% and 5.3 percent, respectively, while water use efficiency increased 3.6 percent. Also, results showed that water use efficiency, dry weight, height of plants, number of shoots per plant, and leaf area index increased by, respectively, 15.1%, 18.3%, 9.7%, 12.5% and 15 percent in subsurface drip irrigation compared to surface method. Therefore, for Rosmarinus officinalis L. cultivation in Kerman area, application of I 2 in subsurface drip irrigation system is the best way to increase the water use efficiency for the drought years.
Mahdi Kalanaki; Fatemeh Karandish; Seyed Farhad Saberali
Abstract
In this research, after calibrating and validating the DSSAT-CERES Maize model, the integrated effects of modifying planting date and irrigation water depth on maize water use efficiency was investigated for four stations of Gharakheil, Babolsar, Ramsar and Noshahr in Mazandaran Province. In this regard, ...
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In this research, after calibrating and validating the DSSAT-CERES Maize model, the integrated effects of modifying planting date and irrigation water depth on maize water use efficiency was investigated for four stations of Gharakheil, Babolsar, Ramsar and Noshahr in Mazandaran Province. In this regard, the model was first calibrated and validated based on data collected in a two-year maize cropping system in Sari county under three irrigation treatments i.e. full irrigation and deficit irrigation at two levels of 55% and 75%, during 2010 and 2011 growing seasons. Then, the water-yield functions were determined for the selected cropping calendars over the period 10 April till 29 June, and for the four selected stations. Thereafter, the optimal irrigation depth, aimed at preventing significant reduction in crop yield, was determined. Based on the selected criteria and indices, the model was accurate enough for simulating leaf area index, the important morphological calendars, total dried biomass, maize grain yield and total crop N uptake. Except for Gharakheil station and regardless of the irrigation treatment, delaying planting date may reduce the optimal irrigation water depth by 14-75% due to the decreased length of the cropping cycle. Based on the 30-year average weather data, the lowest optimal irrigation water depth in Babolsar, Noshahr, and Ramsar was 366, 200 and 122 mm, respectively, which will be obtained under the cropping calendars of June 9, June 29 and June 29, respectively. Nevertheless, the difference in the optimal irrigation water depth between the full irrigation treatment and the deficit irrigation treatment will be higher under early planting date. Based on the results, irrigation water depth management and modifying the cropping calendars may result in a 1.6-22.8% water saving under maize cropping systems in Mazandaran Province. Nevertheless, validating the given results of this research requires carrying out the other field investigations in the selected sites and under the proposed cropping calendars.
moazam khaleghi; Ali Shahnazari; farzad hasanpour; F K
Abstract
The scarcity of freshwater and increasing water demand for irrigation has led to the application of new irrigation methods and also use of saline water resources. For this purpose, a field study was conducted in two crop seasons (2014 and 2015) for evaluating the effect of quantity and quality ...
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The scarcity of freshwater and increasing water demand for irrigation has led to the application of new irrigation methods and also use of saline water resources. For this purpose, a field study was conducted in two crop seasons (2014 and 2015) for evaluating the effect of quantity and quality of irrigation water on morphological attributes and quality of sunflower in the experimental farm of Sari Agricultural Sciences and Natural Resources University. Treatments were arranged as factorial based on randomized complete block design with three replications. treatments included full irrigation with fresh water (FI), full irrigation with saline water (SI), full irrigation with alternative use of saline water and fresh water (FSI), partial root zone drying irrigation with fresh water (PRD1), partial root zone drying irrigation with saline water (PRD2) and partial root zone drying irrigation with alternative use of saline and fresh water (PRD3). Saline water with an electrical conductivity of 5.4 dS/m was obtained from 20 percent mixing of Caspian seawater with fresh water. The results showed that, in most morphological characteristics, significant difference was not found between the treatments of PRD1, PRD3 and FSI compared with FI. The highest oil content (56%) was obtained from PRD2 and PRD3. SI treatment had the lowest oil content. The maximum oil yield was found in treatments FI and PRD1 with amounts of 1831 and 1783.5 kg per ha, respectively. The lowest level of oil and protein yield was found in PRD2 and SI treatments in both years. It could be concluded that in the water crisis condition and the need to use less water or saline water instead of fresh water, PRD3 and FSI methods are recommendable as the optimal management.
A D; F K
Abstract
Climate change will affect rice water requirement through changes in rice physiology and phenology, soil water balance, evapotranspiration, and green water. Adapting with this major environmental challenge is necessary to maintain or improve the current level of rice production in the future. Considering ...
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Climate change will affect rice water requirement through changes in rice physiology and phenology, soil water balance, evapotranspiration, and green water. Adapting with this major environmental challenge is necessary to maintain or improve the current level of rice production in the future. Considering the vital role of Mazandaran province in supplying rice demand of Iran, this study was conducted to quantify the effects of climate change and different cropping calendars on irrigation water requirement and amounts of green water of the province during rice growing season. Using climatic data of Babolsar, Ghaemshahr, Noshahr, and Ramsar for the base period (1980- 2010) and LARS-WG downscaling model, the weather data of 2011- 2100 were generated under different climate scenarios. Based on the minimum and maximum temperatures, the same cultivation period between current and future periods was selected. Rice water requirement was determined by Neuro-fuzzy inference system. Performance evaluation of LARS-WG model using different statistics indicated suitability of the model to simulate future climate conditions in the region. Under climate change, rice cultivation can start 2 to 23 days earlier and the number of days to physiological maturity will be reduced by one to 20 days. Despite shortening the growing period, due to the negative effects of high temperature and decrease in green water, late planting dates will increase irrigation water requirement. However, suitable cultivation time will reduce rice water requirement of the future up to 681 m3 ha-1. The results demonstrated that management of rice cultivation calendar can be an effective way to achieve sustainable agriculture under future climate condition in Mazandaran province.
M GH; A D; A M
Abstract
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 ...
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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.