عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Using deficit irrigation management has an important role in increasing water use efficiency in areas that are faced with water shortage. Alternate furrow irrigation is one of the deficit irrigation strategies which improve water use efficiency without significant effect on crop production. Results of different research demonstrated that alternate furrow irrigation has been widely used to reduce water use up to 50%. Application of integrated management of irrigation as alternate furrow irrigation at the critical growth stages of maize can be used both to save water and increase water use efficiency. So, this management with regard to the critical stages of maize development in different regions (with different soil textures, including loam, clay loam and silty clay)was studied, Also, combined effects of reducing water consumption and increase water use efficiency were investigated.
This research was conducted in Soil and Water Research stations (Karaj, Darab and Isfahan) for 2 years. The randomized complete block design with three replications was considered in this research project. Irrigation timing was determined based on allowable depletion of soil moisture (50% deficit) and irrigation water depth was considered based on refilling soil moisture content till field capacity in rootzone for all treatments. In this regard, irrigation management was conducted in six treatments, included: (T1) full irrigation in total period (Control); (T2) alternate furrow irrigation in total period; (T3) full irrigation in development stage and irrigation during an alternating among other stage; (T4) full irrigation in flowering stage and alternating irrigation in other stage; (T5) full irrigation in development and flowering stage and alternating irrigation among other stage; (T6) full irrigation in flowering and getting stage and alternating irrigation among other stages. The treatments were done in different areas with different soil textures (The soil textures of Karaj, Darab and Isfahan were Loam, Clay loam and Silty Clay, respectively). Water use efficiency index expresses the relation between obtained yield and total amount of water applied. In this research, variation between irrigation treatments on maize production including dry biomass, grain yield and water use efficiency has been demonstrated.
Results in all locations showed that irrigation treatments have significant effect on dry biomass, grain yield and water use efficiency of maize. Using alternate furrow irrigation management in other growth stages with full irrigation in flowering stage (T4) for Clay, Clay loam and Silty clay soil textures, respectively decreased water consumption by 38, 25 and 37%. Grain maize production in full irrigation treatment (T1) was about 9510 kg/h in loam soil (Karaj). Statistical analysis showed that T2 (with 5850 kg/h of grain yield) and T3 (with 6090 kg/h of grain yield) treatment were in the same group but T4, T5 and T6 (with respectively 7563, 8040 and 7770 kg/h of grain yield) were located in another group that produced higher grain yield than T2 and T3 in Karaj site with loamy soil. Also, results in Darab with Clay loam soil showed that grain yield of control treatment (T1) was 9412 kg/h. Grain yield reduction in T4 treatment (full irrigation in flowering stage and alternating irrigation in other stage) was about 10% comparing to the control treatment in Darab site. While, application of alternate furrow irrigation in all stages of maize, decreased the grain yield about 19 %, comparing to T1. In Isfahan, results showed the significance difference between irrigation treatments on grain yield. The maximum grain yield was about 8690.3 kg/h in control treatment and the minimum of grain yield was related to T2 treatment (alternate furrow irrigation in total period), which was about 6848.8 kg/h. In this site with silty clay soil texture, the grain yield of T2, T3, T4, T5 and T6 were decreased about 21,18,16,14 and 12%, respectively. Considering T4 in all sites, water use efficiency increased as 25, 21 and 30% in the soil textures of Loam, Clay loam and Silty Clay, respectively. Using alternate furrow irrigation management in other stages with full irrigation in flowering stage (T4) decreased water application about 35% and increased water use efficiency about 25%, in average, comparing to the full irrigation treatment. The most critical stage of maize, that is better to be fully irrigated, is flowering so we can use alternate furrow irrigation in the other growth stages except flowering (Full irrigation in flowering stage for more water saving and achieving higher water use efficiencies). This reflects the importance of full irrigation at critical stages of flowering and ripening. Hence, with this irrigation management, we can increase cultivated area and achieve more total yield with higher water use efficiency. Therefore, alternate furrow irrigation is a valuable strategy for dry region, where water is the limiting factor in crop cultivation.