H. Ramezani Etedali; Maryam Pashazadeh; B. Nazari; abbas sotoodehnia; A. Kaviani
Abstract
Introduction: Regarding population growth rate and drought challenges, one of the effective strategies for sustainable development in agricultural sector is irrigation. In this regard, in recent years, the use of tape irrigation method has been considered in crop plants, but the use of this system will ...
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Introduction: Regarding population growth rate and drought challenges, one of the effective strategies for sustainable development in agricultural sector is irrigation. In this regard, in recent years, the use of tape irrigation method has been considered in crop plants, but the use of this system will be successful if it is to evaluate the system performance in terms of soil sustainability before it is implemented and its problems are solved. Problems in the field of sustainable agriculture are saltinification of soil resources that the tape irrigation over time and due to the continuity of its use in cultivated land, especially in warm and dry areas due to global warming, climate change and decline of the atmospheric precipitation leads to salinity accumulation in the soil.
Materials and Methods: In order to investigate the distribution and changes of salinity of soil profile in the root development zone of wheat, maize, barley and tomatoes grown in Qazvin Plain with initial salinity of 1/5 dS/m and salinity of irrigation water 1 dS/m In hot and dry climate, a type of irrigation was used (strip drip) and during the 20 years of cultivation, the AquaCrop version 5 was used. The results of simulation output were analyzed by Minitab 17 and Excel 2007 softwares.
Results and Discussion: The results showed that in all previous stuides, the amount of salinity accumulated through the tape irrigation in the soil surface is greater, but in this study, due to the time effect on salt accumulation in the soil profile in the root development area, The maximum salt accumulation below the soil surface and at depths (0/5, 1/5, 0/5 and 0/16) meter of the total root development depth of each plant, respectively, for tomato, maize, barley and Wheat has occurred. It can be said that over time, accumulated salt on the surface of the soil evaporated, re-moved with irrigation and redistributed under the soil profile. Simulation results were obtained after statistical analysis with Minitab 17 and Excel 2007 software showed that in tomato and corn products, tape irrigation with irrigation water salinity of 1 dS/m resulted in significant increase in average salinity of The root development zone from 1/5 is 4 and 4/4 dS/m over the course of 20 years (correlation significance at 5% level) and sustainable utilization of soil resources is questioned, While the increase in average salinity of root development zone in wheat and barley products due to tape irrigation over the course of 20 years has risen from 1.5 to 2/03 and 2/02 dS/m, which is not noticeable and at the level of 5% is not significance. This can be attributed to rainfall during the growing season of wheat and barley, which led to salt salting from the root zone. The correctness of this theory was tested by the significance of the correlation between rainfall and salinity in the 5% level and proved to be. Therefore, it is recommended to wheat and barley with the ability to tolerate high soil salinity are placed in the top priority for local irrigation in hot and dry areas with limited atmospheric rainfall and limited water resources.
Conclusions: From the above results, it was observed that, in products such as maize and tomatoes, tape irrigation resulted in a significant increase in the mean salinity of the root development zone over time. However, the increase in average salinity of root development in wheat and barley products due to the tape irrigation is negligible and canceled over time. In other words, the cultivation of crops such as barley and wheat in areas with scarcity of water resources and soil salinity ensures sustainable land management. These results, while using water with salinity of about 1 dS/m, and soil cultivation with an average salinity of 1/5 dS/m, have been taken. Since comprehensive and practical research has not been done on long-term salinity changes and the use of tape irrigation, after the cultivation of important crops such as wheat, barley, corn, tomato, the results of this research can be used in conducting managerial guidelines, The selection and prioritization of the appropriate cropping pattern in the warm and dry areas will be beneficial with few atmospheric precipitations.
Hossein Kheirfam; Mehdi Homaee; Seyed Hamidreza Sadeghi; Behrouz Zarei Darki
Abstract
Introduction: Land degradation and soil losses are common and universal problems which is a pose threat to food security, ecosystem health and consequently sustainable development and human well-being. Meanwhile, improving the chemical and physical properties of biological soil crusts is an effective ...
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Introduction: Land degradation and soil losses are common and universal problems which is a pose threat to food security, ecosystem health and consequently sustainable development and human well-being. Meanwhile, improving the chemical and physical properties of biological soil crusts is an effective factor in soil loss controlling. Also, the chemical properties specially soil nitrogen are the important factors for soil quality determination. To this end, various strategies on techniques of amendments have been implemented to improve soil properties and quality. Although the application of most strategieshave been verified to soil quality,but their application in real conditions is restricted due to detrimental environmental effects, instability, cost and time-consuming and less accessibility. Recently, biological soil crusts enrichment based on soil microorganism inoculation and stimulation has been raised as a biological and useful strategy in soil conservation sciences. Accordingly, the present study aimed to investigate the role of individual and combined inoculation of bacteria and stimulant nutrient material into small-scale plots on soil nitrogen variation as one of the important soil chemical component.
Material and Methods: The study soil was collected from the erosion-prone and poor biological crust of a sub-watershed from Chalusrood watershed located in Mazandaran Province. The soil sampling was carried out from the upper of the soil surface using a 5cm-diameter coring polyvinyl chloride. The sampled soils were air-dried and sieved by a 2 mm-sized mesh. The Nutrient Agar and Tryptic Soy Agar general were used to bacteria isolation. The identification of isolated bacteria was carried out based on available protocols. Effective nitrogen-fixing bacteria were selected and then purified by selective Azotobacter Agar, Modified II and DSMZ1media. The purified bacteria proliferated by LB Broth medium and then inoculated into soil small sized-plots simultaneously with stimulant nutrient material throught spraying technique. The study was conducted at plot scale with 0.5×0.05×0.5 m dimensions and the plots filled by study soil based on standard protocols. The soil samples were taken at once the 7-8 days from surface of soil plots and the amounts of soil nitrogen were measured by using Kjeldahl method. As well as, experiment period was planned about 60 days. The one-way ANOVA and Tukey HSD test were subjected to statistically analyses.
Results and discussion: The results indicated that the Azotobacter sp. and Bacillussubtilis strain were selected as the most appropriate bacteria to be applied for nitrogen fixing in soil. Also, the results showed that the average total organic nitrogen in control plots ranged from 0.082 to 0.136%, which implies the soil limitation of total nitrogen. However, the measured total organic nitrogen in the bacteria, stimulant nutrient, and combined inoculation plots varied from 0.11 to 0.241%, 0.117 to 0.204%, and 0.124 to 0.374%, respectively. These results demonstrated the positive role of inoculated treatments on fixing nitrogen in the soil. Therefore, the population of Azotobacter sp., the Bacillussubtilis strain, was considerably increased after the inoculation process, and this led to converted and fixed atmospheric nitrogen (N2) into utilizable nitrogen (NH4 or NO3) in soil by using the enzyme nitrogenase as a catalyst. The statistical analyses and evaluation results were indicative of a significant (p
