فهرست مطالب amirabbas rostami ajirloo

Using the AquaCrop model, this research simulated the grains and biological yields of soybean cultivars (M9, Zan and Williams) under different irrigation treatments and future climatic conditions. To this end, whether data of the LARS-WG model were used as input data related to 1970-2010 period in Pars abad of Moghan Plain using AOGCM of HadCM3 based on scenarios of AR4 (A1B, A2 and B1) and NCAR based on scenarios of AR5 (RCP2.6 and RCP 8.5) to study periods of 2011-2030 and 2046-2065. Results showed, compared to the historical period, the statistical periods of 2011-2030 and 2046-2065 would show increases in average monthly minimum temperatures for all scenarios. These periods would also reveal decreases in average monthly maximum temperatures as well as average monthly precipitations for scenarios of RCP8.5, A2, A1B, RCP2.6, and B1, as well as scenarios of B1, RCP2.6, RCP8.5, A2, and A1B, respectively. According to the findings of RMSE and NMRSE, the AquaCrop was a good model for performance evaluation and simulation. The values of grain and biological yield would increase more for A1B and RCP8.5 than for the other scenarios during future periods. These findings indicate that soybean is an acceptable plant for the future climate of Pars abad of Moghan. In conditions of sufficient water and deficient water, Williams and Zan, respectively, exhibited lesser growth reduction and higher grain and biological yields than M9.

Determining appropriate deficit irrigation regimes and varieties under these conditions is necessary to optimize the use of available water in arid and semi-arid regions. In this regard, field experiments were carried out for two years (2014-2015) at the Moghan plain, Iran. The experimental design in each year was split plot based on randomized complete blocks with three replications. The main plots consisted of four irrigation levels: normal irrigation, 80% of maximum daily crop evapotranspiration (ETc), 70% ETc and 50% ETc. Three maize hybrids (SC704, SC703, SC705) were arranged in the sub-plots. Mean comparisons showed that deficit irrigation caused a significant decrease in grain yield and other agronomic traits, physiological characteristics (chlorophyll a, b and relative water content) and growth parameters (leaf area index, crop growth rate, relative growth rate). On the other hand, leaf rolling percentage increased due to the water deficit stress. By increasing deficit irrigation intensity (especially at 50% ETc), chlorophyll a, b and relative water content decreased in SC705 more than the other two hybrids (SC703, SC704) and the leaf rolling percentage at the severe stress condition reached to 60% in SC705. The highest grain yield (8.51 t/ha) and biomass (19.36 t/ha), averaged over two years, were observed under normal irrigation for the SC705 hybrid. However, this hybrid had minimum grain yield and biomass at 50% ETc. By increasing water deficit from normal irrigation to 50% ETc, significant decrease was observed for leaf area index, plant growth rate, relative growth rate and net photosynthesis rate of SC705. Due to the sensitivity of physiological characteristics and growth parameters to the deficit irrigation and the influence of grain yield from these traits, it seems necessary to prevent the occurrence of water deficit at critical stages of maize growth. In conclusion, due to the sensitivity of the SC705 to water shortage, this hybrid is not recommended to water deficit conditions and it would rather be planted when enough irrigation water is available. On the other hand, SC704 seems suitable for the water deficit environments, especially at the severe water stress condition (50% ETc).