m h; h.r s
Abstract
Estimation of seepage from water channels are necessary in evaluating water productivity in agricultural sector as affected by floodwater spreading on plains and artificial recharge of groundwater. Several empirical seepage equations have been developed for this purpose. Previous research results in ...
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Estimation of seepage from water channels are necessary in evaluating water productivity in agricultural sector as affected by floodwater spreading on plains and artificial recharge of groundwater. Several empirical seepage equations have been developed for this purpose. Previous research results in Iran have shown lots of variation in the coefficients and the empirical equations change in different areas and regions. It appears that locally calibrated theoretical equations could give satisfactory results for different conditions. For this purpose, actual measured seepage from earth channels (in the Roodasht region in Isfahan province) and Ingham empirical equation were used and compared with Wedernikow theoretical method. Differences between the measured values and estimated values of seepage in July and August were compared using RRMSE and MAE statistical indexes. The results showed that the average RRMSE and MAE statistics were 0.275 and 0.01 for the Ingham Method. But, these values were 0.145 and 0.005 for Wedernikow theoretical method. These indexes showed that Wedernikow theoretical equation gave the best result of seepage estimated values compared with empirical equations in Roodasht region channels. Moreover, the other advantage of the theoretical equation is that it can be developed and extended to various areas.
hamidreza salemi; ghasem zarei; davoud afiyuni; hamidreza sharifi
Abstract
Up to now, interactions between method and amount of nitrogen fertilizers application on plant density and variety of wheat under sprinkler irrigation systems have not been studied. Thus, this research was conducted during two years in Esfehan region with split factorial design. The treatments ...
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Up to now, interactions between method and amount of nitrogen fertilizers application on plant density and variety of wheat under sprinkler irrigation systems have not been studied. Thus, this research was conducted during two years in Esfehan region with split factorial design. The treatments of this experiment were: Three fertilizers application methods (conventional manual application at the recommended rate, fertigation method with sprinkler irrigation system at the recommended rate, and fertigation with sprinkler irrigation method at 70 % of the recommended rate), three wheat varieties (Pishtaz, Shiraz, and Bahar), and three plant densities (300, 400, and 500 seed per square meter). In this study, the amount of water use, fertilizer requirement in case of fertigation, suitable density and variety of wheat under these conditions were determined and recommended for the region. Results showed that there were no significant differences in quantity of yield among the three fertilizer application methods. Mean grain yield in F1, F2,and F3 were 6914 and 7720 kg/ha for the first and second years, respectively. The amounts of grain produced per one kg applied urea were 17.51, 17.92, and 23.44 kg for the first year and 15.39, 15.54 and 22.78 kg for the second year in the three fertilizer treatments, respectively. Therefore, the nitrogen use efficiency in fertigation with 70% of the recommended rate (F3) was high. Mean grain yield for the inestigated varieties indicated that, in sprinkler irrigation, the most suitable variety were Bahar and Pishtaz, respectively.