590 Journal of Food, Agriculture & Environment, Vol.8 (2), April 2010 www.world-food.net Journal of Food, Agriculture & Environment Vol.8 (2): 590-593. 2010 WFL Publisher Science and Technology Meri-Rastilantie 3 B, FI-00980 Helsinki, Finland e-mail: info@world-food.net Different irrigation regimes affect water use, yield and other yield components of safflower (Carthamus tinctorius L.) crop in a semi-arid region of Iran Houshang Ghamarnia * and Salomah Sepehri Department of Irrigation and Water Resources Engineering, Faculty of Agriculture, Razi University, P.O. Box: 1158, post code: 6715685438, Kermanshah, Iran. *e-mail: hghamarnia@razi.ac.ir, sepehri_saloome@yahoo.com Received 14 October 2009, accepted 2 April 2010. Abstract Water shortage during crop planting in Iran, especially in the west parts of the country, is very serious. Therefore, for this research an experiment was performed in a research field belonging to Irrigation and Water Resource Engineering Department in College of Agriculture, Razi University in Kermanshah (west of Iran) in year 2007 to investigate the effects of different irrigation treatments on water use efficiency, yield and yield components of safflower (Carthamus tinctorius L.) crop. The experiment was in complete randomized blocks design with different levels of irrigation water amounts (33%, 66% and 100%) of cumulative evaporation from Class A pan with surface drip (SD), subsurface drip (SSD) and surface furrow (SF) (with 100% ET), supplementary irrigation and dry farming treatments. The results showed that the effects of different irrigation treatments on water use efficiency were significant (P<0.01). The highest and lowest water use efficiency based on grain and oil yield (5.2 and 2.423, 1.58 and 0.690 kg/ ha/mm) were achieved for SSD and SF (100% ET) treatments, respectively. The results also showed that the treatment with SD (66% ET) was acceptable for conditions where there is a shortage in water resources. Although grain and oil yield of safflower under this treatment was significantly (P<0.01) lower than SSD (100%ET) treatment, no significant difference between various treatments was found. The results also showed that under conditions of a severe water resource shortage, the SD irrigation with (33%ET) seems to be applicable, because water use efficiency compared to SD (66%ET) and SSD (100%ET) treatments was acceptable. Key words: Surface drip, subsurface drip, furrow irrigation, water use efficiency. Introduction Deficit irrigation is one way of maximizing water use efficiency (WUE) for higher yields per unit of irrigation water applied. In this method, crop is exposed to a certain level of water stress either during a particular period or throughout the whole growing season 8 . The expectation is that any yield reduction will be insignificant compared with the benefits obtained through diverting saved water in order to irrigate other crops 7 . However, the growers need to know in prior about crop yield responses to deficit irrigation. The province of Kermanshah has an area of 24,500 km 2 and lies in the west of Iran (33°26’ -35°15’N, 45°24’- 49°20’E). The climate in this province is warm in western parts and cold in the rest of it. The average daily temperature is 15.6°C in spring, 25.3°C in summer, 11.3°C in autumn and 3.3°C in winter. The average annual rainfall is approximately 496 mm. The region is climatologically semi-arid with no rain during summer. In Kermanshah province, safflower mostly grows under dry land condition while farmers are almost unfamiliar with growing techniques in different parts of the province where vast land and water resources and facilities exist. Also, some parts of area in this province are suffering from a shortage of water resources. Thus, researches need to identify the areas where cultivation of safflower in low rainfall regions of this province has taken place along with areas in shortage of water resources during safflower growing period. Because farmers lack necessary knowledge on oil seed cultivation such as safflower in areas with enough or in shortage of water resources have not been defined. Early experiments have indicated that no oil seed crop is better adapted than safflower to the low rainfall and water stress condition of cold dry lands 17 . Iran is considered to be one of the most suitable regions where safflower as a drought and salt-tolerant crop grows 1 . Thus, it can be a suitably alternative crop in marginal areas 15 . The latest investigation on safflower production showed that it is a sensitive crop to water 1, 16 . Also, yield response to water and water use efficiency of safflower under deficit irrigation treatments have been investigated 14 . The effect of water stress imposed at different development stages on seed yield, seasonal evapotranspiration, crop-water relationships, yield response to water and water use efficiency of safflower (Carthamus tinctorius L.) for winter and summer sowing also been investigated 11 . The present research was initially conducted to study and evaluate the effects of water deficit on yield, oil yield and the other yield parameters in safflower production across the semi-arid regions in Kermanshah province in west of Iran. Materials and Methods Field experiments were performed in Irrigation and Water Resources Engineering Research Field Station (47° 9’N and 34° 21’E, elevation 1319 m) of the Faculty of Agriculture, Razi University of Kermanshah, west of Iran, during one year winter/autumn crop growing season lasting from March to August, 2007. The