مسعود تدین نژاد

The large area of saline soils in Iran and decreasing in quality of these soils require that the effectiveness of conservation tillage systems in such lands be investigated. This project aims to determine changes in soil physical properties in three different types of tillage system and plant residue management, including: 1) conventional tillage system and removal of crop residues from soil surface, 2) reduced tillage system and preservation of crop residues, and 3) no tillage system and preservation of crop residues in rotation of barley and safflower in a saline soil with irrigation water salinity of 5.35 dS/m for four years. Some soil physical properties such as bulk density and porosity, and aggregate stability indices of mean weight diameter (MWD) and geometric mean diameter (GMD) were measured in soil samples prepared from the layers of 0-10, 10-20 and 20-30 cm. After each crop rotation period, water infiltration into the soil was measured and the modified Kostiakov model was fitted to obtain the optimized parameters. The results of variance analysis of the data in the four years of the experiment showed that the difference in most of the soil properties at the end of the experiment was significant due to the tillage treatments compared to the control. The highest MWD and GMD (2.53 and 1.90 mm, respectively), porosity (51.2%) and final infiltration rate (31 cm/h) were observed in the no-tillage system. while the lowest MWD and GMD (2.02 and 1.29 mm, respectively), porosity (47.8%) and final infiltration rate (3.5 cm/h) were recorded in the conventional tillage system. Overall, our findings showed that the increment in the soil organic matter due to the implementation of conservational tillage treatments improved the stability of soil aggregates and increased soil porosity and water infiltration into the soil.

One of the most important problems in arid and semi-arid regions is the salinity of water and soil. poplars, which are native to Iran, are found in many climates. In crossbreeding programs, the transfer of salinity traits and resistance to salinity stress from P.euphratica, and on the other hand, the transfer of good quality trait form of the trunk and high growth of spruce, bruised are special importance. For this purpose  this study was conducted to evaluate the rate of resistance to salinity stress and growth of four poplar colonies (Populus alba 58.57, Populus alba 44.9, Populus euphratica, P. euphratica x P. alba 44/9) in the form of complete randomized block design with three replications and was performed for 3 years in Rudasht salinity research station. For this purpose, P.euphratica, P.alba and Hybrid of P.euphratica trees were cut down and planted. The physiological characteristics of the leaf, including proline, sugar, chlorophyll a and b, carotenoid, total protein, peroxidase value and relative moisture content were measured according to standard methods. The results of the physiological characteristics of the leaf showed that poplar colonies had significant differences in terms of proline, total protein and relative humidity percentage but carotenoids, chlorophyll a and b, total chlorophyll and chlorophyll a / b ratio did not show a statistically significant difference. However, the highest amount of chlorophyll a, b and total chlorophyll was obtained in the leaf of hybrid clone. However, the highest amount of chlorophyll a, b and total chlorophyll in the leaf was related to hybrid clone and were equal to 0.76, 0.36 and 1.12 mgg-1 dry matter, respectively. Growth characteristics of seedlings including living percentage, diameter, height, leaf area, leaf thickness, leaf area and leaf dry matter percentage were also measured. The results of analysis of variance of vegetative characteristics of poplar colonies showed that the coefficients of percentage of survival, diameter and height are statistically significant at the level of 5%. The average comparison test showed that P.euphratica with 93% and Colon Hybrid with 85% had the highest survival rate compared to bruised colonies. In addition, P.euphratica species with a diameter growth of 3.8 cm and a height of 160 cm had the highest amount of vegetative growth. In general, according to the vegetative and physiological characteristics of seedlings, Pede species and hybrid clone can be recommended under salinity stress.