پروین ذوالفقاری

Rice is one of the important food products that is generally transplanted. The rice “dry seeding method (DSM)” is a new approach that has provided an opportunity to increase water productivity. In this research, changing the cultivation method from transplanting to DSM and using pressurized irrigation instead of flooding method was studied in 5 rice fields in Golestan Province. The field with flood irrigation method was considered as the control treatment. Other fields were cultivated in dry soil and irrigated by drip and sprinkler methods. The results showed that, in all parameters related to grain yield and yield components, the field with flood irrigation method had higher values. Economic study at the different growth stages with different irrigation methods showed that by changing the planting method and removing the puddling in rice field, 4000 to 7000 cubic meters of water can be saved. Comparison between different irrigation methods showed that the sprinkler irrigation had a higher average yield (4998 kg/ha) than drip irrigation) 4426 kg/ha(. With 30% yield reduction, this method saved 61% in water use, which is a significant amount. The highest and lowest physical (0.53 and 0.3 kg/m3) and economical productivity rates (141,791 and 82,704 Rials/m3) were related to sprinkler irrigation and flood irrigation, respectively, which show very low water productivity in the rice fields of the province. This shows the need to increase water productivity under the current climatic conditions of the country.

The recommended strategies in intensifying water shortage condition is changing the surface irrigation system to drip irrigation، in which case notification of the root system of mature trees for drip irrigation management is essential. The goal of this study was to investigate the effects of surface irrigation، automatic drip irrigation and traditional drip irrigation on olive tree root growth. The soil texture was sandy loam with 50% gravel. The fresh weight، dry weight and fresh volume of root were measured within 30 cm of tree under tree shadow area for 80 cm soil depth. The results showed that percent of fresh weigh was reduced 40% to 5% and 5 to 4 gr with increasing of depth and tree trunk distance to 240 cm، respectively. Also existence of gravel in soil was effective in root development، and fresh weigh and fresh volume density were decreased with increased of gravel. The olive root development was affected by irrigation system and dripper layout. The results showed that، changing of surface irrigation system to drip irrigation system for mature olive trees is possible; however، need to consider root growth system under previous irrigation system.