جستجوی مقالات مرتبط با کلیدواژه « آبیاری ناقص ریشه » در نشریات گروه « آب و خاک »

Water scarcity is the most important factor constraining agricultural production all over the world and water shortage in agriculture must be established to use the deficit irrigation. In order to study the effects of the regulated deficit irrigation and partial root zone drying on the growth traits of Rosmarinus Officinalis L., an experiment was conducted in the center of seed and plant production of IranShahr municipality in 2017. The experiment treatments were arranged as a randomized complete block design with three replications. The irrigation regimes consisted of full irrigation, regulated deficit (RDI75 and RDI55) and partial root zone drying irrigation (PRD75 and PRD55). The results showed that deficit irrigation at 75 and 55 percent of full irrigation resulted in saving 18.6 and 34.3 percent of water consumption, respectively. Comparison of full irrigation and PRD75 showed that dry weight, height of plants and number of shoots per plant were decreased by 6.7, 14.3 and 12.1 percent, respectively. However, proper development of root in PRD75 increased 12.9 percent of water productivity. Therefore, by considering the problems of water scarcity, it is possible to provide PRD75 as a superior treatment and a suitable strategy to cope with the water crisis in order to move towards a sustainable agricultural system.

Freshwater crisis and soil salinity are the most important factors that limiting agriculture in arid areas. In these conditions, cultivation of medicinal plants with considering environmental aspects can be an intelligence strategy for these areas. For this purpose, a field experiment with four treatments and three replications was conducted in randomized complete blocks design in Zahak city during 2016-2017. The treatments were consisted of full irrigation with fresh water (F.FI), partial root zone drying with fresh water (F.PRD), partial root zone drying with saline water (S.PRD) and partial root zone drying with saline and fresh water (SF.PRD). The highest values of plant height (46.1 cm), number of umbel per plant (42), number of branches per plant (10), 1000-seed weight (0.86 gr) and seed yield (293 kg ha-1) were observed in F.FI. There were non-significant differences between F.PRD, FI and SF.PRD in most traits. Results illustrated that application of PRD with alternate fresh and saline water was the best option for decreasing fresh water usage in arid climate of Sistan region.

In order to study the effects of two drip irrigation systems and deficit irrigation on the quantitative traits of Rosmarinus officinalis L., an experiment was conducted in Kerman Municipality seedling production station in 2016. The experimental treatments were laid out in split plot a randomized complete block design with three replications. The treatments consisted of five irrigation regimes (full irrigation (FI-100), regulated deficit (RDI75 and RDI55) and partial root zone drying irrigation (PRD75 and PRD55)) in main plot and two drip irrigation systems (S1= surface and S2= subsurface) in sub plot. The results showed that applying of subsurface drip irrigation system compared to use of surface drip irrigation, in addition to saving 11.4 percent in water use, increased the water productivity 21 percent. Also, the highest herbage dry weight (4404.2 kg.h-1), plant height (68.4 cm), number of shoots (128.7) and leaf area index in different stages of growth were produced by S2FI. Using S2PRD75 compared to use of S2RDI75, increased all of the Rosmarinus plant growth parameters. However, Using S2PRD75 compared to use S2FI in addition to saving 25 percent in water use, increased the water productivity 12.8 percent and dry weight, number of shoots per plant and height of plant decreased 5.3, 8.9 and 9.8 percent respectively. Simultaneous analysis of Rosmarinus’s water productivity and its growth parameters showed that it could be possible to save in irrigation water use and increase the water productivity with the lowest decrease in the Rosmarinus plant growth parameters by applying S2PRD75.

The AquaCrop model is a powerful tool for the simulation of crop response to the different quantitative and qualitative management of irrigation that advanced by FAO. In this study, the latest version of this model (v. 6) was evaluated for simulating sunflower yield, water productivity and soil salinity under different irrigation management using saline water. Field data were collected in order to calibration and validation of model during two crop years (2014 and 2015). The experiment was conducted as a factorial design in completely randomized blocks including two factors: the quantitative irrigation management in two levels (full irrigation and partial root zone drying irrigation in 75%) and the qualitative irrigation management in three levels (non-saline water, saline water and non-saline and saline water alternation), with three replications. While a significant reduction of 3.1-32% in grain yield were observed under water-saving irrigation treatments compared to FI (4706.7 and 4367.2 kg ha-1 in 2014 and 2015, respectively), the PRD1 treatment resulted in a slight reduction of 3.1% and 5% in grain yield, in 2014 and 2015, respectively. FI had the highest WPET (0.90 and 0.89 kg m-3 in 2014 and 2015, respectively), and PRD1, PRD3, FSI, SI and PRD2 treatments ranked next. Sensitive analysis result showed that the model sensitivity to the volumetric soil water content at soil saturation and field capacity point, maximum canopy cover, HIO, time to flowering, time to CCx and CGC is more than other input parameters.

In order to investigation the root distribution and plant growth of Rosmarinus Officinalis L., an experiment was conducted in a completely randomized design with three replications under using subsurface irrigation system in 2016. In this study treatments are full irrigation (FI), regulated deficit (RDI75 and RDI55) and partial root zone drying irrigation (PRD75 and PRD55). The results showed that deficit irrigation at 75 and 55 percent of full irrigation resulted in saving 17.1 and 32.6 percent water consumption respectively. Comparison of FI and PRD75 showed that dry weight, height of plants and number of shoots per plant decreased 5.3, 9.8 and 8.9 percent respectively. However, proper development of root in PRD75 increased 12.8 percent of water productivity, 7.3 percent of root fresh weight, 2.7 percent of root depth and 10.7 percent of root volume. Therefore, considering the problems of water scarcity, it is possible to provide PRD75 as a superior treatment and a suitable strategy to cope with the water crisis, to move towards a sustainable agricultural system.

Soil cardinal temperatures are one of the affective factors on biological properties of crops and highly affect root growth and consequently, water and nutrient uptake. Since soil water content has a considerable contribution in controlling soil temperature, predicting the probable consequences of applying a specific irrigation strategy may help with selecting a suitable method aiming at increasing water and nutrient use efficiency. Therefore, in this research, HYDRUS2D was applied for dynamical assessment of the influence of different irrigation strategies on the spatial and temporal pattern of soil temperature variations and the projected uncertainties through the simulation approach. Simultaneous soil water content and soil temperature data was collected by using IDRG SMS T-2 sensors installed in maize rooting zone under full irrigation (FI), deficit irrigation (DI) and partial root-zone drying (PRD) during 2010 growing season. Simultaneous soil water content and soil temperature data was collected by using IDRG SMS T-2 sensors installed in maize rooting zone. The calibration process was done using the continues data collected after 10 irrigation events in all treatments, and the validation process was carried out using daily variations of soil temperature. Finally, the model uncertainty was assessed by calculating the spatial and temporal error variance. Based on the root mean square error (RMSE) and model efficiency (EF) in the validation process, HYDRUS2D could accurately simulate soil temperature (RMSE=0.02-0.42 oC, EF=0.71-0.92) and the minimum and maximum RMSE in estimation soil thermal regimes was corresponded to FI and PRD treatments, respectively. the lowest uncertainty domain for simulating soil temperature under FI, PRD and DI treatments was observed in 60-80 cm soil depth, and the estimated errors for these treatments were, respectively, 0.6±0.2, 5.9±2.3 and -5.4±2 percentage, respectively. Moreover, the highest uncertainty domain for FI, PRD and DI treatments was corresponded to 20-40 cm, 0-20 cm and 60-80 cm soil depth, respectively, and accounted for 9±5, -0.6±3.04 and 13.7±5.3 percentage, respectively. Based on the results, applying PRD would decrease the number of stress days through controlling soil cardinal temperatures in the domain of 9-28 oC which led to providing a better condition for root growth especially in the soil depths beyond 40 cm.

Considering limited water resources in arid and semi-arid climate of Iran, deficit irrigation is one of the strategies for efficient use of water, increasing water productivity and water use efficiency in agricultural district. Regulated Deficit Irrigation (RDI) and Partial Root Drying (PRD) are among deficit irrigation methods aiming to limit using of irrigation water. PRD is a new approach for irrigation management due to increasing water use efficiency and non-significant decreasing yield. The objective of this study was to investigate the effect of different levels of irrigation water and nitrogen fertilizer on water productivity and water use efficiency of Sugar beet.
This research was conducted in the agricultural land of Karafs plain on Hamadan province, at latitude 35° 18̍ N, longitude 49° 20̍ E and altitude 1915 m above sea level. This study was conducted in a split block with a randomized complete block design. In the main blocks Irrigation levels included: Conventional irrigation (CI), three levels of partial root drying: 85 (PRD85), 75 (PRD75) and 65 percent (PRD65) and regulated deficit irrigation at three levels: 85 (RDI85), 75 (RDI75) and 65 percent of the crop water requirement (RD 65). Also, in the sub blocks two fertilizer levels were applied: 100 (f100) and 75 percent of fertilizer requirement (f75).
The results showed that the impact of irrigation treatments on water productivity and water use efficiency of all studied traits were significant at one percent level (P The results showed that water productivity and water use efficiency indexes of root and sugar yield of PRD85 irrigation treatment was more than other irrigation treatments. Due to the non- significant differences between the PRD85 with CI treatment in terms of root and sugar yield and also saving 15 percent of water irrigation in PRD85 treatment, under such study conditions, applying PRD85 treatment is recommended. Also, f100 fertilizer treatment was root yield, sugar yield, water productivity and water use efficiency indexes of biomass, root and sugar yield more than f75 treatment. Therefore, PRD85 and f100 were selected as the best treatments.

An experiment was conducted in order to investigate the effect of deficit irrigation method on yield, yield components and water use efficiency of forage maize (KSC 704) an experiment was conducted during 2013 and 2014 growing seasons in mashhad. A factorial experiment based on randomized complete blocks design with four replications was carried out. Treatments included full irrigation treatment, deficit irrigations (regulated deficit irrigation and replacements of 80 and 60% of total water requirement, variable PRD at 100, 80 and 60% of water requirement and fixed PRD at 100, 80 and 60% of water requirement). Deficit irrigation resulted in water use saving at the rates of 14-28 %. Results showed that plant height, ear height and stem diameter decreased by deficit irrigation. The highest fresh forage yield (75095 kg/ha) was produced by full irrigation treatment. There was no significant difference between fresh forage yield of full irrigation treatment and plants which grew at 80% water replacement and variable PRD method (P≤0.01). The highest water use efficiency was 2.27 kg/m3 which belonged to variable PRD by 80% of water requirement.There was no difference between replacing 100 and 80% of water requirement by applying variable PRD. Overall, results showed that application of variable PRD method saved water by 14% compared with full irrigation treatment without significant reduction in yield and yield components of forage maize.

This study was carried out as a complete block design with three treatments including, full irrigation, partial root-zone drying in two levels at 75% and 55% of full irrigation to evaluate three Geostatistical methods including Kriging, CoKriging and Weighting Moving Average for interpolating the values of soil electrical conductivity, as the best index for soil salinity. Soil electrical conductivity (EC) was measured using Decagon 5TE TDR sensors. Then zone classification maps of the EC were prepared using a linear relation between EC and soil water content values measured by IDRG SMS T2 sensors. Results of the variograms analysis showed that the effective range of variograms was higher than the maximum space between observed points in the all treatments. Comparing the observed and Geostatistical estimated values of EC based on the evaluation criteria including root mean square error (RMSE), mean bias error (MBE), mean absolute error (MAE) and index of agreement (d) showed that there was a good agreement between observed and estimated EC values. Duncan test at 5% probability level showed that values of the evaluation criteria for the Kriging method were significantly lower than those for the other methods at the all treatments, and CoKriging method ranked as the second method (p≤0.05). Also there was no significant difference between the Cokriging methods by simultaneous consideration of the electricul conductivity with one of the temperature or soil moisture covariates as the model input.