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Solmaz Mokarram; Javad Behmanesh; Vahid Rezaverdinejad
Abstract
Biochar as a porous material is rich in biological carbon in a stable form. Its structure is capable to store water and nutrients. Therefore, it is used for retention of such materials, especially in sandy soils. Biochar can improve water productivity in the agricultural sector in drought stress condition ...
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Biochar as a porous material is rich in biological carbon in a stable form. Its structure is capable to store water and nutrients. Therefore, it is used for retention of such materials, especially in sandy soils. Biochar can improve water productivity in the agricultural sector in drought stress condition to achieve food security in the world. In order to study the effect of deficit irrigation and biochar on yield of coriander in a coarse-grained soil under water stress, this research was conducted using a factorial manner and a completely randomized design in the research greenhouse of Urmia University. The experimental treatments included three levels of irrigation: 100%, 75%, and 50% of the plant water requirement, and three levels of biochar application: 0, 2.5%, and 5% of the weight of each pot, which totally included 27 treatments. Irrigation was applied on the basis of plant requirement and soil water content below field capacity and the applied water was measured during the growing season. For each pot, quantitative parameters including weights of dry and wet plant, stem, leaf, and root were accurately measured. The results showed that the effects of irrigation levels and biochar on some measured parameters were significant at the probability level of 1% and 5%. The results demonstrate that by applying deficit irrigation, the measured quantitative parameters and plant yield decreased. The highest value of the parameters was obtained from the treatment of 100% water requirement and use of biochar up to the level of 2.5% of the soil. Therefore, applying suitable amount of the biochar as soil amendment improves coriander plant's growth and yield.
Mina Taheri; Vahid Rezaverdinejad; Javad Behmanesh; Fariborz Abbasi; Javad Baghani
Abstract
Water resource deficiency and the necessity of sustainable production in irrigated lands have attracted much attention to water productivity issues. In this regard, analysis, estimation, and preparation of water productivity map are necessary as an influential factor to recognize cultivation potential ...
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Water resource deficiency and the necessity of sustainable production in irrigated lands have attracted much attention to water productivity issues. In this regard, analysis, estimation, and preparation of water productivity map are necessary as an influential factor to recognize cultivation potential in irrigated lands. The aim of this study was to select a proper interpolation method for water productivity and investigate spatial changes in water productivity in Iranian wheat production centers. In this research, 241 field data were used, of which range of water productivity (irrigation water + effective precipitation) was estimated between 0.3 to 2.58 kg.m-3 with the average of 0.79 kg m-3, in 2016-2017 season. Interpolation methods used included Ordinary Kriging, Inverse Distance Method (IDW), and Radial Basis Function (RBF). Cross Validation technic was applied to evaluate methods by statistical measures such as Root Mean Square Error (RMSE), Mean Bias Error (MBE), and Mean Absolute Relative Error (MARE). Interpolation methods evaluation showed that between available procedures, typical Kriging method with exponential semi-variogram model had the most proper condition to prepare wheat water productivity zoning map. The results of the spatial analysis of water productivity confirmed that geostatistics could be used with acceptable accuracy (MBE=0.005) to provide water productivity mapping. Results of Cluster analysis of the effective factors (salinity of irrigation water, soil salinity, and crop cultivar) on wheat water productivity index showed that the areas suitable for wheat cultivation were separated into 13 independent groups (at the 5 percent level), such that the highest and lowest mean water productivity of wheat were observed in group 5 (Mean = 0.84 kg.m-3) and group 10 (Mean = 0.41 kg.m-3), respectively.
Farshad Khashaei; Javad Behmanesh; Vahid Rezaverdinejad; Nasrin Azad
Abstract
Use of subsurface drip irrigation (SDI) in row plants is increasing due to higher water and fertilizer efficiency. In order to investigate the effect of SDI levels and nitrogen fertilizer splitting on yield, yield components and water productivity of corn, a field study was conducted in 2018 as split ...
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Use of subsurface drip irrigation (SDI) in row plants is increasing due to higher water and fertilizer efficiency. In order to investigate the effect of SDI levels and nitrogen fertilizer splitting on yield, yield components and water productivity of corn, a field study was conducted in 2018 as split plot experiment based on a completely randomized block design with three replications at the research farm of Urmia University. The main plots of this experiment including three irrigation levels: 100%, 75% and 50% of net irrigation requirement and subplots included three nitrogen fertilizer split applications as: weekly, every other week and three times during growing season as urea fertilizer. Based on the results, the effect of irrigation levels treatment and number of fertilizer splitting on yield, yield components and water productivity were significant at 1% level. However, the effect of fertilizer splitting on water productivity was not significant. Interaction effects of the two variable treatments on plant height and leaf area index were significant at 1% level but did not significantly affect grain yield, biomass and water productivity. The highest grain yield and corn biomass were obtained with 22.39 and 39.85 ton/ha for complete irrigation, respectively. Also, the grain yield and biomass in the three- split treatments were highest with 18.47 and 32.56 ton/ha, respectively. The highest water productivity was obtained by irrigation application of 75% of net water requirement. It seems that in regions with water scarcity, applying deficit irrigation equal to 75% of the corn irrigation requirement, can be a good solution for saving water and achieving high water productivity. Also, fertilizer injection with higher amounts and less frequency especially at the sensitive growth stages, can be a more effective solution than using lower amounts with more frequent fertilizer application.
Hosein Zahedpour; Vahid Rezaverdinejad; hossin dehghani sanich
Abstract
Improving water productivity and irrigation efficiency is important in Iran due to limitations in water quality and quantity. This study was conducted to investigate and analyze application efficiency and water productivity at field scale in Nazloo-Chay plain, located in Urmia province, during 2015-2016. ...
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Improving water productivity and irrigation efficiency is important in Iran due to limitations in water quality and quantity. This study was conducted to investigate and analyze application efficiency and water productivity at field scale in Nazloo-Chay plain, located in Urmia province, during 2015-2016. For this purpose, five wheat fields, as fall planting, and five fields for spring crops i.e. maize and pumpkin (two fields of each) and sunflower (one farm), were studied. Irrigation system in wheat fields was border, while spring crops were furrow irrigated with closed end condition. To evaluate and measure the water productivity and irrigation efficiency in each irrigation event, some parameters were measured including irrigation depth, system geometry, soil water depletion in the root zone before irrigation (SMD) and the plant parameters. In the five wheat fields, a total of 21 irrigation events were performed and all of which were monitored and evaluated. The average of irrigation efficiency and standard deviation in the 21 irrigation events at these five wheat fields was about 30.9% and 19.5 percent, respectively. For the three spring crops, 27 irrigation events were evaluated and the overall average irrigating efficiencies for sunflower, pumpkin (cucurbita) and maize were about 69.3%, 51.5% and 52.5%, respectively. The average of standard deviation in spring plantings was calculated at about 13.9 percent, which indicates that the scattering of application efficiency was less in spring plantings than fall planting. Based on the results, the average of physical water productivity in wheat fields was 1.1 kg/m3. This index for sunflower, pumpkin (Cucurbita) seed and maize was calculated at about 0.27, 0.17 and 7.02 kg/m3, respectively. Average economic water productivity in wheat was 14512.4 Rial/ m3 and for sunflower, maize and cucurbita seed were 20252.6, 13463.9, and 23305.3 Rial/ m3, respectively, which indicated high economic water productivity for sunflower and Cucurbita seed. Generally, the crop management practices in all fall and spring plantings including fertilizer and pesticides applications were based on scientific recommendations, but irrigation management was poor in all farms. One of the main reasons for low application efficiency in these farms (in particular the fall plantings) was the poor field leveling that required high water depths for irrigation of the fields.