عنوان مقاله [English]
Introduction: Barley is very important to feed humans, livestock, medical, industrial uses, especially in fermentation industries. In Iran, barley crop cultivation was nearly 1.4 million hectares withits production of 1.3 million tons in 2003 (2). Barelyis the oldest crops to environmental stresses such as drought and salinity resistance (3).The different barely growth stages with extreme water requirement can benoted in germination stage, stem elongation, heading the production stage, the stage of flowering and seed production. Typically, for spring and autumn barely respectively 3 and 4 to 5 times irrigation is done during the growing season. The barley water requirement over its life is between 4 and 7 thousand cubic meters and 518 liters of water is needed to produce one kilogram of dry matter. Due to limited water resources and low rainfall in Iran, efficient use of water is absolutely essential and the maximum water utilization must be achieved by applying a minimum amount of water in agriculture. One of the ways to increase productivity in agricultural water is deficit irrigation.Deficit irrigation is an optimization strategy for water use efficiency in irrigation.The purpose of this study was to evaluate the simultaneous effect of fertilizer treatments (150, 225 and 75 kg/ ha) and water at three different levels (100%, 75% and 50% of crop water requirement) at different growth stages on leaf area index, weight fresh and dried herb and plant nitrogen concentration and the effect of irrigation and nitrogen fertilizer on yield, yield components and productivity of water use.
Materials and Method: This research was conducted in Shiraz University in fall 2012 to study the effect of interaction of deficit irrigation and nitrogen fertilizer on yield, yield component and water use efficiency and nitrogen concentration in different stages of barley (Bahman species) growth. This experiment were evaluated using a randomized complete block design with s plit-plot layout with three deficit irrigation treatments ( consisted of irrigation with 100% ,75% and 50% of crop water consumption use) and three nitrogen fertilizer treatments (included 75 kg/ha, 150 kg/ha and 225 kg/ha) with three replication. A total of 27 experimental plots were carried out. In each plot, 11-row barley with 30 cm spacing apart and 5 cm depth were planted by hand. Barley seeding rates on the basis of 200 kg per hectare were planted in each experimental plots in the first half of November.Nitrogen requirement was applied in three stages of the growth: 30% before cultivation, 40% in shooting stage and 30% in barleyclusterstage.Irrigation treatments included 100% = W1, in this treatment 100% treatment crop water requirement was estimated by neutron meter (this was the control treatment which received muchwater as neededand no water stress in all growth stages),75% = W2: in this treatment 75% of the crop water requirement was applied, and 50% = W3: the 50% of the crop water requirement plant was applied. During differentgrowth stages plant required data were collected and the parametersinclude: grain yield, biological yield, straw yield, number of grains per spike, spike per unit area, grain protein, harvest index, 1000 grain weight, number of unfilled and filled grain per spike and efficiency of water use were determined . Tests to determine the percentage of leaf nitrogen and protein was measured by kjeldahldevice(6405UV / VIS). The software SAS (version.9.1) was used to analyze data and graphs were drawn in Excel.
Results and Discussion: results showed that the highest yield,yield component was obtained on 100% irrigation and 225 kg/ha fertilizer treatments. Also it was observed that at the certain level of irrigation treatment by increasing the amount of nitrogen fertilizer the amount of this parameters will be increased.Result also showed that at the certain level of nitrogen fertilizer by decreasing water, the maximum plant response to the nitrogen fertilizer consumption will be decreased gradually in most cases, 225 kg/ha nitrogen fertilizer treatment caused most of crop yield parametersbut the differences of crop yield at this treatment with 150kg/ha nitrogen fertilizer treatment wasnot significant. Water use efficiency for 50% deficit irrigation treatment was 0.77 and for 100% irrigation treatment was 0.55. Regarding the results obtained from this study andexisting water crisis problem in Iran, it can be noted that the irrigation ofbarley should not be exceeded more than the 100% of crop water consumption use but using 75% of water requirement is suggestive. Also using 150kg/ha nitrogen fertilizer treatment is more suitable for the area.
Conclusion: This study was conducted in order to determinethe yield performance of barley (Bahmanspecies)inBadjgah (Fars Provience)using three different irrigation treatments of 100, 75 and 50 percent of crop water requirement (based on the total available water plant) and three nitrogen treatments include 225, 150 and 75 kg/ ha in the spring and autumn cultivation. In terms of deficit irrigation, during the growing season crop will interface with different intensities and durations of water stress. This tension changes in response to nitrogen fertilizer by plant that creates unpredictable and in some cases is not always the same.Statistical analysis showed that there are significant differencesbetweenthe different treatments of irrigation, nitrogen fertilizer and their interaction.Applying 75% of barley water requirement is suggestive. Also using 150kg/ha nitrogen fertilizer treatment is more suitable for the study area.