جستجوی مقالات مرتبط با کلیدواژه « بیوچار » در نشریات گروه « اکولوژی »

The effect of biochar and cultivation pattern on essential oil yield and nutrient content of thyme under different local irrigation methods were the most important objectives of this study.

This experiment was performed as a factorial split based on a randomized complete block design with three replications during the two crop years of 1397-1396 and 1398-1397 in the farm of Karaj Branch of Azad University. Irrigation at three levels (irrigation of all furrows, irrigation of furrows as one-intermediate and one intermittent variable), as the main factor and biochar at two levels (no use and application of biochar), and planting pattern (one-row and two-row cultivation on the ridge) as Sub-factors were considered.

The percentage of essential oil and its yield increased significantly under water stress conditions. The highest essential oil yield with 22.14 kg.ha-1 was obtained in the treatment of furrow irrigation as a constant intermediate + application of biochar + cultivation of two rows of thyme. Furrow irrigation treatments, both fixed and variable, increased the yield of essential oil by significantly increasing the percentage of essential oil. Biochar also had a significant effect on all studied traits. Water stress reduced the levels of calcium, magnesium, and iron,

Due to the positive effects of biochar in improving organic matter, physical and chemical properties as well as the availability of soil nutrients, less irrigation through constant one-intermediate furrows irrigation and application of 8 tons per hectare of biochar.

This experiment was performed to evaluate the effect of organic amendment and growth-promoting bacteria on phytoremediation of maize under cadmium (Cd) stress.

This experiment was performed in the form of factorial in a completely randomized design with 4 replications. Experimental factors were: 1- biochar as a soil organic amendment at two levels (non-application and application (20 g.kg-1 soil), 2- Pseudomonas putida at two levels (non-inoculation and inoculation of bacteria) and 3- heavy metal levels (0, 25, 50, 75 and 100 mg Cd. Kg-1 soil). 

Cadmium in all concentrations had reduced the dry weight of roots and shoots, while biochar application and bacterial inoculation increased these traits; when the maximum shoot dry weight (9.43 g per plant) was observed by biochar application and inoculation of Pseudomonas putida and no cadmium contamination, which increased 45.30% compared to the control. The highest amount of available cadmium in soil, roots and shoots were 23.29, 33.90 and 36.25 mg/kg, respectively, which all three were obtained in the concentration of 100 mg Cd/kg soil. The lowest amount of bioconcentration factor (0.75) and bioaccumulation factor (1.03) were related to the synergistic treatment of biochar and Pseudomonas putida at the concentration of 25 mg Cd/kg soil, which decreased up to 17.90 and 10.62% compared to the control, respectively.

Conventional tillage systems disturb the soil in the long term and obstruct farmland sustainability. Hence, adoption of conservation tillage systems, for example no tillage and reduced tillage has been widely accepted in the last two decades.
The use of chemical fertilizers has increased in intensive farming systems, but this brings with environmental problems. Nowadays, due to the problems of chemical fertilizers, the use of organic fertilizers such as manure and biochar has been more prevalent in agriculture. Biochar is the product of incomplete combustion of biomass in the absence of oxygen. Its presence in the soil is reported to improve physical and chemical properties and crop yield. In order to evaluate the effect of nutrition management on yield and yield components of corn (Zea mays L.) under different tillage systems, a field experiment was carried out at research farm of Shahrood University of Technology in 2015. The experiment was conducted as a split plot arranged in a randomized complete block design with three replications. The main plots were tillage systems (conventional tillage and reduced tillage) and subplots were control, chemical fertilizer (300 kg.ha-1 urea and 100 kg.ha-1 triple superphosphate), manure (20 t.ha-1), biochar (20 t.ha-1), chemical fertilizer + manure (150 kg.ha-1 urea and 50 kg.ha-1 triple superphosphate and 10 t.ha-1 of manure), chemical fertilizer + biochar (150 kg.ha-1 urea and 50 kg.ha-1 triple superphosphate and 20 t.ha-1 biochar) and manure + biochar (20 t.ha-1 biochar and 10 t.ha-1 of manure). After adding manure, biochar and triple superphosphate, corn was planted on 10 days and urea was used in stages three. At full maturity 10 plants were randomly selected and the biological yield, grain yield, 100-grain weight, ear weight, number of row per ear, number of grains per row, ear length, ear diameter, height and stem diameter were measured. The results showed that the effect of tillage systems and the interaction of tillage systems and nutrient management were not significant on any of the measured traits. Tillage systems affect yield mainly by altering water and nitrate content in soil. The water content and nitrate concentration in the soil had no significant difference between tillage systems (data not shown). As well as tillage systems are site-specific, so the degree of their success depends on soil, climate and management practices. The nutrition management had significant effect on grain nutrients, grain protein, ear characteristics, 100-grain weight, biological yield, grain yield and harvest index. The highest and lowest grain nitrogen, ear weight, biological yield and grain yield were obtained in chemical fertilizer and control, respectively. The chemical fertilizer + manure increased grain nitrogen, ear weight, biological yield and grain yield 13.89, 56.19, 47.04 and 60.41 percent compared to the control, respectively. As well as chemical fertilizer + biochar increased grain nitrogen, ear weight, biological yield and grain yield compared to control 14.81, 52.78, 42.69 and 56.32 percent, respectively. Crops respond to nitrogen fertilization mainly by increasing aboveground and root biomass production. As a result of increasing nitrogen doses, the photosynthetic activity, leaf area index (LAI) and leaf area density (LAD) increase. Providing organic matter and nutrients create better conditions for photosynthesis and plant growth. The increased maize yield in biochar amended soil could be attributed to increased nutrient availability and to improved soil physical properties indicated by decreased soil bulk density. Based on results, the effect of nutrition management was significant on height, stem diameter, grain nutrients, grain protein, ear characteristics, 100-grain weight, biological yield, grain yield and harvest index. Maximum and minimum of stem diameter, grain nitrogen, grain protein, ear characteristics, 100-grain weight, biological yield, grain yield and harvest index were obtained in chemical and control, respectively. Although using of chemical fertilizer had the highest amount of traits, it had no significant difference with chemical fertilizer + manure and chemical fertilizer + biochar. Also, there were no significant effect between conventional tillage and reduced tillage. Therefore, due to the excessive use of nitrogen fertilizer and also due to the negative effects of conventional tillage on the physical, chemical and biological properties of soil, it can be concluded that use of reduced tillage and chemical fertilizer + manure and chemical fertilizer + biochar for corn production is recommended for similar conditions with the study area to reduce both chemical fertilizer and environmental pollution.

Water and soil contamination by petroleum compounds are important due to their toxicity and carcinogenic. The objective of this study was to evaluate the effect of biochar and compost on phytoremediation of heavy metal and total petroleum hydrocarbons (TPH) by Ziziphus spina-christi (L.) Willd.  In this study, one-year old Z. spina-christi seedlings were selected and 0, 1 and 2 percent of biochar and compost were used to evaluate the phytoremediation. Experiment were performed total randomized block design with three replications. One way ANOVA (Analysis of variance) was used for analysis. Our results indicated the significant effect of biochar and compost on phytoremediation ability of Z. spina-christi. The largest and the smallest values of soil TPH were belonged to control and two percent compost, respectively. Also, concentration of nickel in soil was the smallest in one percent biochar compared to the other treatments. While, the largest value of nickel belonged to the control. Furthermore, the least and the highest values of vanadium belonged to one percent compost and control, respectively. Our result indicated the importance of soil biochar and compost to improving Z. spina-christi phytoremediation of petroleum contaminated soils.

Evaluation of net primary productivity and carbon allocation to different organs of corn under nutrient management and tillage systems
IntroductionAgriculture operations produce 10 to 20 percent of greenhouse gases. As a result of conventional operations of agriculture, greenhouse gases have been increased (Osborne et al., 2010). Therefor it is necessary to notice to carbon sequestration to reduce greenhouse gases emissions. In photosynthesis process, plants absorb CO2 and large amounts of organic carbon accumulate in their organs. Biochar is produced of pyrolysis of organic compounds. Biochar is an appropriate compound for improved of soil properties and carbon sequestration (Whitman and Lehmann, 2009; Smith et al., 2010). Conservation tillage has become an important technology in sustainable agriculture due to its benefits. So the aim of this study was to evaluate the effect of nutrient management and tillage systems on net primary production and carbon allocation to different organs of corn in Shahrood.
Material and methodsThis study was conducted at the Shahrood University of Technology research farm. Experiment was done as split plot in randomized complete block design with three replications. Tillage systems with two levels (conventional tillage and minimum tillage) were as the main factor and nutrient management in seven levels including (control, chemical fertilizer, manure, biochar, chemical fertilizer manure, chemical fertilizer biochar, manure biochar) were considered as sub plot. At the time of maturity of corn, was sampled from its aboveground and belowground biomasses. Carbon content of shoot, seed and root was considered almost 45 percent of yield of each of these biomasses and carbon in root exudates almost 65 percent of carbon in the root. Statistical analysis of the data was performed using SAS program. Comparison of means was conducted with LSD test at the 5% level.
Results and discussionEffect of nutrient management was significant on belowground and aboveground biomasses, total weight and net primary productivity. Maximum and minimum of shoot, seed, total weight and aboveground net primary productivity were obtained in chemical fertilizer and control respectively. Nitrogen plays a key role in several physiological crop processes. As a result of increasing N doses, the photosynthetic activity, leaf area index (LAI) and leaf area density (LAD) increase. Maximum and minimum of root weight and belowground net primary productivity were obtained in chemical fertilizer manure and control respectively. Manure and biochar increased root weight 56/03 and 54/31 percent compared to control respectively that had no significant different to chemical fertilizer. Manure increased root growth, possibly through improved physical properties and increased nutrient and water availability. Manure decreases soil compatibility with increasing of stability of soil structure and soil resilient. Impact of adding manure on improving of root length density has been reported by Mosaddeghi et al. (2009). The increased maize yield in biochar amended soil could be attributed to increased nutrient availability (Chan et al. 2008; Zhang et al. 2010) and to improved soil physical properties indicated by decreased soil bulk density.
ConclusionsThe results showed that nutrient management had significant effect on belowground and aboveground biomasses, total weight, below and aboveground net primary productivity and carbon allocated to different organs of corn. Maximum and minimum of belowground and aboveground net primary productivity was obtained in chemical fertilizer, manure chemical fertilizer and control respectively. Manure and biochar increased belowground net primary productivity 54/91 and 53/21 percent compared to control respectively that had no significant different to chemical fertilizer. Tillage systems had no significant effect on measured traits. The results showed that with application reduced tillage and manure and biochar can increase belowground net primary production and carbon allocation to belowground organs and by adding root residues to the soil can retain roots carbon and prevent its release into the atmosphere. Therefore with reduction of CO2 amount in atmosphere, climate change and global warming be reduced.

Biochar has received great attention by many researchers recently due to its potential to improve soil fertility and immobilize contaminants and is proper as a way of carbon sequestration and therefore a possible carbon sink. In this work, a series of biochar were produced from wheat straw by slow pyrolysis at different temperatures (300, 400, 500, 600 and 700 ◦C) and their physicochemical properties were analyzed. Biochar yield, ash content, the amount of nutrients and other physicochemical properties in the all treatment of the raw material for the effect of temperature on the wheat straw biochar and to determine the best temperature pyrolysis temperature for converting wheat straw to biochar with agricultural usage. As temperature increased incrementally from 300 to 700◦C, biochar yield, total N content and organic carbon (OC) decreased while pH, EC, ash content and OC stability increased. The generated biochars production caused yields 28.34-58.32 % of feed mass, stable OC % 65.32-92.14 and pH 7.4-10.9. The maximal transformation of feed OC into biochar recalcitrant OC occurred at 500 ◦C. There were reductions in the amount of functional groups as pyrolysis temperature increased for wheat straw biochar. However, total acidity of the functional groups increased with pyrolysis temperature increased for wheat straw biochar. To produce agricultural-use wheat straw biochar, 300 ◦C should be is suggested in pyrolysis process and for carbon sequestration biochar 500 ◦C is recommended.