جستجوی مقالات مرتبط با کلیدواژه « زیتوده » در نشریات گروه « آب و خاک »

The soil organic matter plays an important role in increasing agricultural products and various nutrient cycle in the soil due to its effect on the physical, chemical and biological properties of soil. There is, however, little information regarding the effect of growth promoting bacteria on biological indices and different forms of carbon in agricultural soils of the country. Therefore, this study was aimed to investigate the effect of plant growth promoting bacteria on soil respiration, microbial quotient, organic carbon, microbial carbon biomass, permanganate oxidizable carbon, cold water extractable organic C, and hot water extractable organic C under the cultivation of wheat, Chamran cultivar. The experiment was conducted in greenhouse condition as a randomized complete design with 9 replications. Treatments consisted of bacterium inoculation (without inoculation, Enterobacter cloacae Rhizo_33, Enterobacter cloacae Rhizo_R1and mixof both bacteria). During the experiment, some characteristics such as plant height and chlorophyll index were measured. At the end of the cultivation period, root and aerial part dry weight and grain yield were determined. Biological properties and different forms of carbon in the soil were measured after cultivation. The results indicated the applied plant growth promoting bacteria increased chlorophyll index, height, root and shoot dry weight and grain yield, as compared to the control. The minimum value of pH and the highest amount of each carbon forms were obtained by soil inoculation with different strains of bacteria, as compared to the control. The highest value of organic carbon was observed in the presence of the consortium of both bacteria with 22.7% increase, as compared to the control. The highest amount of microbial carbon biomass was, respectively, measured in the treatments containing consortium of bacteria, Enterobacter cloacae Rhizo_R1, Enterobacter cloacae Rhizo_33 with 87.67, 42 and 26.5% increment, as compared to the control. A positive and significant correlation was observed between cold and hot water extractable organic carbon, dissolved organic carbon and permanganate oxidizable carbon with soil respiration and there was a negative correlation between mentioned properties and the soil pH. The use of microbial inoculants increased the carbon content of the soil, which can play a positive role for improvement of  physical and chemical properties of the soil and plant yield.

Earthworms, due to their beneficial role in agroecosystems, are used as indicator species for monitoring the impact of pollutants, changes in soil structure and agricultural practices. The purpose of this study was to investigate the impact of chemical fertilizers management on the density and live weight of earthworms in the soil of an orchard.
Research was carried out in an orchard in Isfahan province. One square meter area was considered as experimental plot. After plowing and grooving at a depth of 5 centimeters per plot, common fertilizers were applied, based on the soil test. Chemical fertilizers such as urea, ammonium sulfate, diammonium phosphate, solupotas, NPK (15, 5, 25), zinc chelate, iron chelate and cow manure were used as experimental treatments with control (no fertilizer). Abundance and live weight of worms were evaluated in two stages of time and in 2 depths of 0-20 and 20-40 cm of soil. In the first stage, 20 days after the addition of fertilizers, and in the second stage, 60 days after fertilization, earthworms were sampled and their number and biomass changes were measured. Treatments were applied in three replications and the data were analyzed using two-way ANOVA (using the GLM process) by SPSS software. In addition, the means were tested with the least significant difference (LSD) at the probability level of 5%.
The assessment of the worms was accomplished at two different depths and at two different times. Sampling in 20th day of experiment showed that at soil depths of 0-20 cm, urea, ammonium sulfate, diammonium phosphate, macro fertilizer NPK and iron chelate had significant negative effect on the abundance and weight of earthworms (p≤0.05). Meanwhile, cow manure (OM) and NPK treatments increased the population and biomass of earthworms. In the depth of 20 to 40 cm, the negative role of urea, ammonium sulfate, diammonium phosphate, NPK fertilizer and iron chelate was decreased, and the NPK maintained its positive role. On the 60th day of sampling, at 0-20 cm depth, urea, ammonium sulfate, diammonium phosphate and iron fertilizer reduced the population and biomass of worms in the soil. However, NPK, OM and zinc chelate (Zn) treatments increased the number of earthworms. At a lower depth (20-40 cm) on the 60th day, the earthworm population was not affected by any of the inorganic fertilizers and nitrogen and phosphate fertilizers not only had no negative effect on the activity of earthworms but also significantly increased their biomass (p≤0.05).
The results showed that chemical fertilizers could have a significant effect on soil organisms, including earthworms. These effects could vary according to the nature and extent of fertilization, as well as the depth of fertilizer usage. Accordingly, in order to reduce the negative effects of chemical fertilizers on soil organisms, it is advisable to reduce their application in shallow soils and when applying, organic fertilizers should be used along with chemical fertilizers.

Organic residues processing and their reversion to soil is helpful to build up a sustainable agriculture. Biochar is product of organic residue pyrolysis. Biochar chemical and physical characteristics are significantly affected by pyrolysis temperatures and its feedstocks. Therefore an experiment was conducted to evalute some properties of biochar produced from four feedstocks viz: sugarcane bagasse, rice straw, wood sawdust and conocarpus leaves, which processed by three pyrolysis temperatures vis: 400, 700 and 900°C .The treatments replecated three time and laid out in a factorial experiment with the completely randomized design. Results showed that each group of treatments separatelye as well as their interaction had significantly different effect on biochar pH, EC, CEC, specific surface area, C/N ratio and total element concentration as well as pb and cationic micronutrients availability. Increasing the pyrolysis temperature from 400 to 900°C, decreased CEC in biochar drived from rice straw, conocarpus leaves, sugarcane bagasse and wood sawdust by 73/9, 37/7, 36/0 and 21/9 cmol﹈, respectively. But increasing temperature from 400 to 900°C, improved specific surface area of bagasse, rice straw, sawdust and conocarpus leaves biochar by 153/3, 241/1, 283/9 and 21/2 m2/g, respectively. It is suggested that at pyrolysis temperatures of 400°C with prioritize of biochar derived from conocarpus leaves, 2- rice straw, 3- sugarcane bagasse and 4- wood sawdust can be used to improve cation exchange capacity as well as improving available nutrients reservoir.

Among wide variety of soil pollutants including heavy metals, acidic precipitation and other toxicants, the importance of heavy metals due to their pollution capacity has received growing attention in recent years. These metals enters into soil through municipal and industrial sewage as well as direct application of fertilizer and pesticides. High cadmium and lead concentration in soil lead to severe environmental pollution. Such pollution not only has a destructive effect on crop yield but also endangers human being and other creatures’ health after entering in their food chain. Several physical, chemical and biological methods used to reduce the adverse effect of high concentration of heavy metals in soil. In spite of the hight cost, these methods are not always suitable for reclamation of small area and mostly have side effect on physico-chemical and biological characters of soil, after application. Biochar produced by thermal decomposition of biomass in the absence or presence of low oxygen. These material due to their high spacific surface area and high cation exchange capacity may have great ability to absorb charged material including heavy metals. Therefore in this study attempt is made to evaluate the effect of sugarcane bagasse –derived biochar in improving maize plant growth in cadmium and lead contaminated soils.
Material and This study was carried out during the year 2014 in two separate experiments in Shahid Chamran university. The treatments in each case consisted of two levels of sugarcane bagasse made biochar (0 and 4 percent by weight) in combination with each soil, properly contaminated with 50 and 100 mg cadmium per kg soil in first experiment and 500 and 1000 mg lead per kg soil in the second. The treated soils were applied to pot and arranged in a complete randomized block designe and replicated 3 times. Prior to introduction of soil to pots, the heavy metal contaminated soils with moisture content around 70 percent of F.C. were incubated for 30 days. During incubation period sugarcane bagasse was dried, milled, sieved, compacted and subjected to traditional furnace at 550 oc for 3 hours on low pyrolysis. The furnace temperature was controlled manually using lesser thermometer. The furnace cooled down and the collected sugarcane bagasse made biochar sieved again. The incubated soil mixed with proper amount of sugarcane bagasse made biochar and incubated under previous condition for 45 days. The treated soils were poured to the labeled pots and 3 maize seeds were sown in each pot and two weeks after emergence thinned to one plant per pot. Nineteen days after sowing, the height of the plants and chlorophyll index were recorded and plants were harvested and leaf area of each plant was recorded, maize root content of each pot were carefully separated from soil and along with shoot property washed, dried, weighed and after milling subjected to chemical analysis. Prior to sowing maize seeds some of physic- chemical properties of untreated soil were estimated. Furthermore few charactoristics of sugarcane bagasse made biochar including pH and EC in 1 : 10 solution of biochar to water recorded. N, C, H, O concentration were estimated by elementary analyzer. Cation exchange capacity of sugarcane bagasse made biochar was measured by ammonium acetate method. Moreover its functional group determined by FT-IR method. Specific surface area estimated as per Branuar Emmet Teller (BET) method. Sugarcane bagasse made biochar image was obtained from scanning electron microscope. Cadmium and lead concentration in root and shoots were estimated by atomic absorption spectrometer after wet digestion. SAS software was used for statistical analysis data which fallowed by Duncan test to compare the mean values.
The results showed that implementation of cadmium and lead led to decrease in chlorophyll index, leaf area, height of plant and root and shoot dry weight significantly. But the sharp decline in the concentration of cadmium and lead in root and shoot after sugarcane bagasse made biochar application improved chlorophyll index, leaf area, height of plant, root and shoot dry weight. Application of 4% Sugarcane bagasse made biochar, decreased transfer factor (TF) and bioaccumulation factor (BF) of these elements compared to control. The results showed high capability of sugarcane bagasse made biochar to absorb cadmuim and lead and reduce their availability to plant respectively. In fact application of sugarcane bagasse made biochar dwindled cadmium and lead absorption as well as their transfer factor and bioaccumulation factor, and hence improved plant growth.
The results obtained after sugarcane bagasse made biochar application mainly initiated due to high cation exchange capacity of which eventually was created by large number of functional groups in its high specific surface area (table 2) to stabilize cadmium and lead and render them unavailable to plant and hence improve its growth.

Considering limited water resources in arid and semi-arid climate of Iran, deficit irrigation is one of the strategies for efficient use of water, increasing water productivity and water use efficiency in agricultural district. Regulated Deficit Irrigation (RDI) and Partial Root Drying (PRD) are among deficit irrigation methods aiming to limit using of irrigation water. PRD is a new approach for irrigation management due to increasing water use efficiency and non-significant decreasing yield. The objective of this study was to investigate the effect of different levels of irrigation water and nitrogen fertilizer on water productivity and water use efficiency of Sugar beet.
This research was conducted in the agricultural land of Karafs plain on Hamadan province, at latitude 35° 18̍ N, longitude 49° 20̍ E and altitude 1915 m above sea level. This study was conducted in a split block with a randomized complete block design. In the main blocks Irrigation levels included: Conventional irrigation (CI), three levels of partial root drying: 85 (PRD85), 75 (PRD75) and 65 percent (PRD65) and regulated deficit irrigation at three levels: 85 (RDI85), 75 (RDI75) and 65 percent of the crop water requirement (RD 65). Also, in the sub blocks two fertilizer levels were applied: 100 (f100) and 75 percent of fertilizer requirement (f75).
The results showed that the impact of irrigation treatments on water productivity and water use efficiency of all studied traits were significant at one percent level (P The results showed that water productivity and water use efficiency indexes of root and sugar yield of PRD85 irrigation treatment was more than other irrigation treatments. Due to the non- significant differences between the PRD85 with CI treatment in terms of root and sugar yield and also saving 15 percent of water irrigation in PRD85 treatment, under such study conditions, applying PRD85 treatment is recommended. Also, f100 fertilizer treatment was root yield, sugar yield, water productivity and water use efficiency indexes of biomass, root and sugar yield more than f75 treatment. Therefore, PRD85 and f100 were selected as the best treatments.