Irrigation
N. Salamati; A. Danaie; V. Yaaghoobi
Abstract
Introduction Drought stress is the most important environmental factor limiting growth and development of plants worldwide. Growth reduction due to drought stress has been reported more than other environmental stresses. So far, many studies have been conducted on the relationship and correlation ...
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Introduction Drought stress is the most important environmental factor limiting growth and development of plants worldwide. Growth reduction due to drought stress has been reported more than other environmental stresses. So far, many studies have been conducted on the relationship and correlation between important agronomic traits in rapeseed, which have introduced 1000-grain weight, number of seeds per pod and number of pods per plant as the most important traits with high correlation in yield. The results showed that the application of drought stress had an effect on the yield components of sesame and the cultivars that were more sensitive to drought stress had a greater decrease in their yield. The aims of this study were to investigate (1) the effect of consumed water volume as the independent variable on other variables of the study, and (2) the effect of total independent variables (yield components and other independent factors) on yield and water productivity (dependent variables). Finally, the most important independent variables affecting water productivity and the most sensitive variables to the amount of consumed water were determined.Materials and MethodsIn order to achieve aforementioned objectives of this study, an experiment was conducted during two growing season of 2011-2011 and 2010-2011 in Behbahan Agricultural Research Station. The experiment was conducted as randomized complete block design with 4 replications. The applied amount of water in drip irrigation was composed of four levels of 50, 75, 100 and 125% water requirement in main plots and two canola varieties Hyola 401 and RGS003 in sub plots were placed.Results and Discussion The results of the analysis of variance of the regression model showed that the higher absolute value of beta coefficients and t-statistic of each independent variable caused that variable to be introduced as the most sensitive independent variable affecting the dependent variable. Therefore, the independent variable of water volume, with beta coefficient of 0.860 and t-statistic of 13.246 had the greatest effect on plant height variable. In terms of yield, the studied variables (the number of pods per plant, the number of seeds per pod, and 1000-seed weight, consumed water volume, flowering period, growth period and plant height) showed 74.1% of variation (R2 = 0.741) of dependent variable (Yield of canola). The consumed water volume with the highest absolute value of beta coefficient of 0.563 and t-statistic with 2.967 had the most significant effect on yield at the level of 1%. Among the dependent variables, the consumed water volume with the highest absolute value of beta -1.013 and t-statistic at -12.415 had the most significant effect on water productivity at the level of 1%. consumed of water volume with the highest absolute value of beta coefficient of 0.563 and t-statistic with 2.967 had the most significant effect on performance at the level of 1%. The results of Pearson correlation coefficient showed that the highest correlation between the number of pods per plant and seed per pod with both plant height were calculated to be 0.763 and 0.849, respectively, indicating that increasing plant height was effective in increasing the number of pods per plant and seed per pod.ConclusionThe results of analysis of variance of regression model showed the effect on volume of consumed water as an dependent variable through other variables (number of pods per plant, number of seeds per pod, yield, water productivity, 1000-seed weight, flowering period, growth period and plant height). Results showed a significant effect of all variables at the level of 1%, except for the variable of flowering period which had a significant effect but just at 5%. The volume of consumed water by r= 66.2% on grain yield variation in the pods, had the most significant effect on yield components. Therefore, seed number in the pods received the most negative effect from reducing water consumption due to drought stress. With increasing the growth period of canola, water productivity showed a significant decrease at 1%. The results of Pearson correlation coefficient showed that grain water productivity had a negative and significant correlation at the level of 1% with all variables. The highest correlation between water productivity (r = -0.939) was calculated with volume of consumed water, which indicates the importance of reducing water consumption in increasing canola water productivity.
F. Abbasi; A.; N. Salamati
Abstract
Introduction: Application of simultaneous nitrogen fertilizer and water as fertigation in surface irrigation systems is developing. In fertigation is possible to increase water and fertilizer use efficiency and it allows growers to apply nutrients in split and small amounts throughout the season in response ...
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Introduction: Application of simultaneous nitrogen fertilizer and water as fertigation in surface irrigation systems is developing. In fertigation is possible to increase water and fertilizer use efficiency and it allows growers to apply nutrients in split and small amounts throughout the season in response to crop needs. In this study, sugarcane furrow fertigation experiments is carried out in Dehkhoda agro-industry company to improve fertilizer management, water and nitrogen use efficiency, and reduce urea fertilizer consumption.
Materials and Methods: Large scale furrow experiments were conducted on a plant field. Field experiments were carried out as split plot with a complete randomized block design. Experimental treatments consisted of three fertilizer splits (2, 3, and 4 splits) in main plots and three levels of urea fertilizer (60, 80 and 100% of required urea fertilizer) in subplots and compared with the common method (control) used in the agro-industry fields. Experiments were conducted on a 25 hectare field in 250 meter long and blocked end furrows. Irrigation water during the crop season was applied the same for different fertigation treatments and measured using the WSC flumes in each irrigation events. Irrigation interval varied from 8 to 15 days during the crop season. Qualitative and quantitative traits (e.i., stalk height, cane yield, purity, brix, white sugar yield, and water, fertilizer, and sugar use efficiency) at harvest were measured and analyzed using the MSTATC software.
Results and Discussions: A total of 21 irrigation events during the growing season were measured. Average water consumption in each irrigation event was 865 cubic meters per hectare. Total applied irrigation water during the growing season was 18,155 cubic meters per hectare. Results showed that fertilizer split factor significantly affected the qualitative and quantitative traits at a 5% level of significance. So that, all qualitative and quantitative traits in four split treatments were significantly (P