فهرست مطالب s. safikhani

Ignoring the spatial scale in understanding of environmental processes resulted in a vagueness in environment problems statement and incorrect decision-making in environment management. Because, connection between solutions and environmental problems in policy-making processes, require attention to suitable spatial scale of technical knowledge. Therefore in this study, focusing on descriptive-analytical approach, the role of spatial scale were surveyed in environmental policymaking. The results showed that despite the effort to understand the the environmental problems in international scale,governments focus more on environment and natural resources management in national scale. So, using of national scale is necessary for attainment to special methodological framework for solving the environment problems and transfer adequate solutions and understanding of technical knowledge to policy context. Hence, it could be suggested that providing and designing an environmental policymaking supermodel in state scale (national scale) can hemogenise its environmental macro-policies scale with scale of understanding of environmental problems. In other word, this supermodel is useful for connect technical knowledge outcomes to understanding of policymakers in national spatial scale.

In order to determine the effect of different irrigation managements on rice growth indices, an experiment was done in factorial based on randomized complete block design in Rice Research Institute of Iran, Deputy of Mazandaran, Amol during 2011. Treatments were different irrigation managements including Alternate Wet and Drying (AWD), Semi-Dry Cultivation (SDC), combining Shallow water depth with Wetting and Drying (SWD) and Traditional Irrigation (TI) and two contrast cultivars of Tarom and Fajr as native and improved cultivars, respectively. Growth indices were fitted using measuring the dry weight and leaf area over seven sampling times during rice growing stages. The results showed that IT (with an average of 7694 kg) had the highest paddy yield followed by AWD (with an average of 7056 kg), SDC (with an average of 6856/8 kg) and SWD (with an average of 6358/7 kg). Leaf area index in Tarom cultivar varied from 2.99 in the combining Shallow water depth with wetting and drying to 4.6 in alternate wet and drying regimes. By contrast, LAI in Fajr cultivar ranged from 4.1 in the alternate wet and drying to 5.6 in traditional irrigation regimes. In conclusion, the maximum leaf area index, net assimilation rate in Tarom and Fajr cultivars to AWD and SDC irrigation managements could be introduced.

To study effects of nitrogen fertilizer and sowing date on some agronomic traits of canola cultivars, a factorial split plot experiment based on randomized complete block design with four replications was conducted during growing season 2013 – 2014 at the Research Farm of Gonbadkavus University, Iran. Treatments were four canola (Brassica napus L) cultivars (C1=Hayola 401, C2=Zarfam, C3= Hayola 308, and C4=RGS003), two planting dates (D1=17 Nonvember and, D2=28 December) and three levels of nitrogen fertilizers (N1=0, N2=%50 of recommended fertilizer, N3=%100 recommended fertilizer). In this study the treatment of nitrogen fertilizer levels and planting dates were asseigned to main plots and canola cultivars to sub plots. The results of analysis of variance showed that the interaction effects between nitrogen fertilizer × planting were significant at 0.01 probability level on all evaluated traits. Interaction of planting date × cultivar effects on all yield components except seed per silique were also significantly. The fertilizer × cultivar interaction did not affect yield components significantly. The highest yield, 4.2 t/ha, was produced by the open pollinated cultivar of RGS003 using %100 recommended rate of nitrogen fertilizer at sowing date of 17 November, which represents a high potential of this cultivar under this nutrients level and sowing date.

To investigate the effect of different amounts of wheat stubbe residues and urea fertilizer levels on yield and yield components of maize (Zea mays L.) SC. 704, an experiment was carried out, at the Agricultural Research Station, University of Agriculture and Natural Resources Ramin Khuzestan, during the growing season of 2007. The experiment was split plot based on randomized complete block design with two factors and four replications. The treatments consisted of four levels of nitrogen, as main factor, and six different amounts of wheat residues, as subplot factor. Main plot treatments were: a1= 425, a2= 450, a3= 475 and a4= 500 kg/ha urea fertilizer and subplot treatments were: b1= the all wheat residues (100%), b2= 75, b3= 50 and b4= 25 % of wheat residues, b5= without straw and stubble, b6= burning of wheat residues. The resulats revealed that the effects of urea fertilizer and wheat stubble rate on all traits under study and intractions on seed number per ear and ear number per unit area weresignificant. It was also indicated that high levels of wheat residues reduced corn seed yield and its components. The results also showed that turning under the 50-75 percent residue into the soil before planting corn and not using stubble not only don’t reduce seed yield and its components , they also increase in the long run soil organic matter.