Mohammad Amin Zakery-Asl  Shahin Oustan 《Archives of Agronomy and Soil Science》2013,59(6):785-792

Suaeda aegyptiaca is an important native annual halophyte in salt-affected soils around coastal areas of the Persian Gulf. In order to study the effects of different levels of saturation paste soil salinity (10, 20, 40, 60, and 80 dS m^?1) and nitrogen supply (25, 50, and 75 mg kg^?1 N as urea) on growth and physiological characteristic of S. aegyptiaca, a greenhouse factorial experiment in completely randomized design was conducted with three replications. Salinity treatments were established after early growth of plants and nitrogen was applied in two steps. Results showed that increasing salinity up to 20 dS m^?1 led to increase in dry weight (DW) of plants and this decreased by increasing salinity. Also, DW of plants was significantly increased by application of 75 mg kg^?1 nitrogen. Increasing salinity significantly decreased plant height, chlorophyll index, and total nitrogen content; while proline content and total soluble solids (TSS) were significantly increased. The electrolyte leakage (EL) and sodium concentration were increased under salinity stress. However, further increase in salinity decreased these two parameters. By increasing the nitrogen levels, relative water content (RWC), chlorophyll index, proline, and total nitrogen contents were increased, whereas EL was decreased.  相似文献   

    

Mohammad Valipour  Mirkhalegh Ziatabar Ahmadi  Mahmoud Raeini-Sarjaz  Mohammad Ali Gholami Sefidkouhi  Ali Shahnazari  Ramin Fazlola 《Archives of Agronomy and Soil Science》2013,59(5):657-678

The present paper aims to estimate the areas equipped for irrigation and desirability of agricultural water management in the world. For this purpose, all necessary information was gathered from Food and Agriculture Organization and checked using World Bank Group. The selected 18 indices were analysed for all 26 regions in the area studied, and the extent of area equipped for irrigation to cultivated area was estimated by 2 different formulas and other 9 indices. In addition, an average index was calculated using various methods to assess region conditions for agricultural water management. The results show that Central Asia is the best region for agricultural water management and the value of relative error is less than 20%. The capability of irrigation and drainage systems was studied using other eight indices with more limited information. The results indicated that trial-and-error policies should be avoided and expert comments be applied to irrigation systems for any crop.  相似文献   

    

Mohammad Bannayan  Sara Sanjani 《Agricultural and Forest Meteorology》2011,151(12):1589-1598

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Ali Akbar Moosavi  Ali Reza Sepaskhah 《Archives of Agronomy and Soil Science》2013,59(1):11-38

Irrigation with low-quality water may change soil hydraulic properties due to excessive electrical conductivity (EC_w) and sodium adsorption ratio (SAR_w). Field experiments were conducted to determine the effects of water quality (EC_w of 0.5–20 dS m^?1 and SAR_w of 0.5–40 mol^0.5 l^?0.5) on the hydraulic properties of a sandy clay loam soil (containing ～421 g gravel kg^?1 soil) at applied tensions of 0–0.2 m. The mean unsaturated hydraulic conductivity [K(ψ)], sorptive number (α) and sorptivity coefficient (S) varied with change in EC_w and SAR_w as quadratic or power equations, whereas macroscopic capillary length, λ, varied as quadratic or logarithmic equations. The maximum value of K(ψ) was obtained with a EC_w/SAR_w of 10 dS m^?1/20 mol^0.5 l^?0.5 at tensions of 0.2 and 0.15 m, and with 10 dS m^?1/10 mol^0.5 l^?0.5 at other tensions. Changes in K(ψ) due to the application of EC_w and SAR_w decreased as applied tension increased. Analysis indicated that 13.7 and 86.3% of water flow corresponded to soil pore diameters <1.5 and >1.5 μm, respectively, confirming that macropores are dominant in the studied soil. The findings indicated that use of saline waters with an EC of <10 dS m^?1 can improve soil hydraulic properties in such soils. Irrigation waters with SAR_w < 20 mol^0.5 l^?0.5 may not adversely affect hydraulic attributes at early time; although higher SAR_w may negatively affect them.  相似文献   

    

Ali Reza Sepaskhah  Arash Tafteh 《Archives of Agronomy and Soil Science》2013,59(1):93-103

The specific surface area (SSA) of a soil is crucial for the interface of ions and water molecules with the soil particles. Therefore, many physical and chemical properties of a soil are determined using its total SSA. Measurement of SSA is time-consuming and laborious, and its estimation using pedotransfer functions is therefore preferred. The objectives of this study were to: (1) analyze the pore–solid interface fractal dimension (D) in soils with different textures from thesouthern part of Iran using estimated improved particle-size distribution (PSD) from the soil primary particles, i.e. clay, silt and sand; (2) develop a multivariate pedotransfer function to estimate D based on PSD; and (3) develop a multivariate pedotransfer function to link the values of D to the SSA. As a result, two pedotransfer functions are presented for estimation of D and SSA. To estimate SSA, the value of D is first obtained using the presented pedotransfer function and these estimated D values are then used in another pedotransfer function to estimate SSA. The pedotransfer functions were validated and it is concluded that they are able to predict the values of D and SSA accurately.  相似文献   

    

Reza Ghasemi-Fasaei  Abdolmajid Ronaghi  Esmaeil Farrokhnejad 《Archives of Agronomy and Soil Science》2013,59(10):1171-1178

Adsorption and release are the most influential reactions controlling zinc (Zn), manganese (Mn) and copper (Cu) availability in soils. Characteristics of native Zn, Mn and Cu release by ethylenediaminetetraacetic acid (EDTA) in two calcareous soils for periods from 1 min to 24 h were studied. The pattern of Zn, Mn and Cu release from both soils fitted well with power function, Elovich and parabolic diffusion models. The magnitude and rate of release was greatest for Mn, followed by Zn and Cu, respectively. This trend suggests a higher ability of the studied soils to replenish soil solution Mn, compared with Zn and Cu. The results showed that higher Mn release in clay soil compared with sandy loam soil was considerably related to higher initial Mn release rates in the former compared with the latter. However, Cu release rates of the two soils at initial times were not significantly different. Higher Cu release in clay soil was, therefore, attributed tohigher Cu release rates at subsequent time intervals. It is assumed that the different Zn release rates of these soils were due to consistent differences in Zn release rates throughout the release periods.  相似文献   

    

Seyed Hamid Ahmadi  Ali Reza Sepaskhah 《Archives of Agronomy and Soil Science》2013,59(11):1303-1316

A new empirical-based scaling method is introduced to predict saturated hydraulic conductivity (K _s ) of compacted soils. This method is an improvement of the former non-similar media concept (NSMC) model that is generalized for tilled and untilled conditions. In this method, geometric mean particle size diameter (d_g ), geometric standard deviation (σ _g ) and saturated soil water content (total porosity) are successfully incorporated in the empirical-based scaling factor of K _s . Results showed that the scaled model overestimated K _s by ～18%, whereas the NSMC model underestimated K _s by ～21%. However, the scaled model based on the similar media concept (SMC) failed to predict K _s . Because of the complexity and high uncertainty in determining the shape factor parameter in the NSMC model, it is suggested that the new scaled model might be used reliably in practical cases to predict K _s in the various layers of compacted soils irrespective of the tillage condition. Further assessment of the new scaling model in other areas, in which new collected data are available, is recommended.  相似文献   

    

Khosro Mohammadi  Gholamreza Heidari  Mohsen Javaheri  Mohammad Tahsin Karimi Nezhad 《Archives of Agronomy and Soil Science》2013,59(7):899-910

Tillage systems and fertilization have important effects on soil microorganism activity. Information regarding the simultaneous evaluation of long-term tillage and fertilization on soil microbial traits in sunflower fields is not available. Therefore, this study was conducted to determine the best tillage and fertilization system for soil microbial parameters. The experimental design was a split plot based on a randomized complete block design with three replications. Main plots consisted of the long-term tillage systems (1999–2011) including: no tillage (NT), minimum tillage (MT) and conventional tillage (CT). Six methods of fertilization, including farmyard manure (N1), compost (N2), chemical fertilizers (N3), farmyard manure + compost (N4); farmyard manure + compost + chemical fertilizers (N5), and control (N6) were arranged in subplots. Results showed that the highest amount of microbial biomass was observed in treatment NTN4. The highest and lowest values of enzyme activities (acid, alkaline phosphatase, urease, dehydrogenase and protease) were found in organic fertilizers + NT and chemical fertilizers + CT plots, respectively. Highest basal and induced respiration values were found for NTN4 treatment. Correlation coefficients between enzyme activity, respiration and microbial biomass carbon were significant.  相似文献   

    

Tarek G. Ammari  Sa'id Al-Hiary  Mohammad Al-Dabbas 《Archives of Agronomy and Soil Science》2013,59(3):367-375

Vegetative bioremediation of saline calcareous soil (EC_1:1 11.01 dS m^?1) was practised through growing fodder beet (Beta Beta vulgaris var. magnum) and millet (Panicum spp.) in soil columns. Beet was grown at a planting density of 4427 plants m^?2, whereas millet was grown at two planting densities: 5202 (M1) and 8928 (M2) plants m^?2. Some plants were irrigated with 233 μ S cm^?1 water throughout the experiment (70 days), while for others non-saline water was replaced with saline water (2.52 dS m^?1) at the middle of the experiment. The control was leaching of uncropped soil. Beet had higher ash content and efficiently extracted higher amount of salts (particularly Na and Cl) along with their aboveground biomass than millet under the two irrigation regimes. Millet grown at high planting density had higher ash content and extracted higher amount of salts (particularly Cl) than those at low planting density. Bioremediation, particularly in the case of millet (M1), considerably enhanced soil hydraulic conductivity as compared with leaching treatment; thus, facilitating the removal of some soluble salts beyond the root zone. Accordingly, soil electrical conductivity was considerably decreased by 54–69% compared with the untreated soil. It is concluded that mainly fodder beet is a potential candidate for efficient bioremediation of saline calcareous soils.

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Mohammad Valipour 《Archives of Agronomy and Soil Science》2013,59(9):1247-1271

The aim of this paper was to study the land use index (equipped area for irrigation per cultivated area, AI) and irrigation management in Asia and Oceania during past decades. For this purpose, all necessary information was collected from Food and Agriculture Organization of the United Nations (FAO). Among all presented data in the FAO database, 10 indices were selected. These indices were analysed for all 64 countries in Asia and Oceania, and the extent of AI was estimated by two different methods and other 9 indices. The results show that using all the 9 indices, the value of relative error will be less than 20%. Prioritization of the indices has shown that national rainfall index (NRI) and the difference between NRI and irrigation water requirement had a highlighted effect on the estimation of AI.  相似文献