M Gorji, H Eshghizadeh, A Khosh Goftarmanesh, A Ashrafi, A Moalem, N Poursakhi, N Pourghasemian, A Miladi,
Volume 12, Issue 46 (1-2009)
Abstract
Iron deficiency is a worldwide nutritional constraint in agricultural lands especially in calcareous soils. Cultivation of crops tolerant to Fe-deficiency is an approach to combat Fe deficiency. The aim of this investigation was to evaluate Fe-efficiency of selected important crops in Iran. A completely randomized block design in triplicates was conducted at IUT research greenhouse in fall 2006. Sweet corn (Hybrid K.S.C. 404), grain corn (Hybrid S.C. 500), safflower (cvs. S3110, S-411), sunflower (Hybrid Hyson) and durum wheat (cv. Shuga) were grown in a nutrient solution at two Fe levels (1 and 10 µM Fe-EDTA). The results showed significant (P < 0.01) variation among the studied crops in Fe-efficiency. Corn hybrids were more sensitive to Fe deficiency (FeE = 26%) as compared to other studied crops, and the greatest reduction was observed in their shoot dry matter at 0.1 mM Fe- EDTA treatment. In contrast, the lowest decrease in root and shoot dry matter weight under Fe-deficient condition was found for durum wheat (FeE=94%). Comparing the calculated Fe-efficiency using different indices showed that Fe concentration and content in the whole plant, shoot and root had no relationship with crop tolerance to Fe deficiency.
H. Asadi, M. Aligoli, M. Gorji,
Volume 20, Issue 78 (Winter 2017)
Abstract
This study aimed to investigate the dynamic changes of rill erosion and evaluate the ability of Hairsine-Rose model in estimation of sediment concentration. The experiments were carried out at the Soil and Water Conservation Research Station of Tehran University in Kuhin, Qazvin. Four flow rates were tested at three slopes in trapezoidal hand-made rills of 3 m long and 5 cm base width. Outflows were sampled periodically to determine changes in sediment concentration. The experiments were repeated in early autumn and mid spring. Sediment concentration showed a dynamic change with time which was affected by flow rate, slope and season. The sediment concentration was high in the first few minutes of the experiment but over time, dropped and finally reached a more or less stable state. The effects of flow rate and slope were more detectable on sediment concentration at the early unsteady conditions than at the final steady conditions. Though the temporal trends were similar, the sediment concentration was generally higher in autumn than in spring. Hairsine-rose model showed a better performance at lower flow stream powers but generally over predicted sediment concentration showing a systematic error probably due to model formulation.
