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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.