جستجوی مقالات مرتبط با کلیدواژه "هیدروچار" در نشریات گروه "آب و خاک"

In the present study, the effects of biochar (produced by slow pyrolysis process) and hydrochar (produced by hydrothermal carbonization process) of cypress cones application on nickel (Ni) stabilization in a soil spiked with this element were investigated. For this purpose, the raw cypress cone and its biochar and hydrochar are added separately at 1.5 and 3% (w/w) to a Ni-spiked calcareous soil (350 mg kg-1) and after 3 months of incubation process, under field capacity moisture condition, desorption kinetics and chemical forms of Ni, in the laboratory of environment department, graduate university of advanced technology, Kerman (2020), were measured and investigated. According to the results, hydrochar had higher specific surface area and functional groups containing reactive oxygen, as well as more irregular porosity morphology compared to biochar. The values ​​of final desorbed Ni in the treated soils showed a decrease of 27-37% and 11-16.5% of desorbed Ni in the soil treated with hydrochar and biochar, respectively, compared to the control sample. The fitness of the two first-order reaction model on Ni desorption data in all treated samples showed the high accuracy of this model (coefficient of determination>99%) in predicting Ni desorption. Evaluation of Ni mobility factor obtained from the Ni chemical forms shows a decrease in this factor in samples of soils treated with hydrochar (29.2-30.2%) and biochar (31.9-33.3%) in comparison with control soil sample (38.8%). In general, the presence of functional groups containing reactive oxygen and higher specific surface area of ​​hydrochar compared to biochar has resulted in more stabilization of Ni in the soil compared to treated soils with biochar. Due to lower production costs and reduced production of destructive greenhouse gases in hydrochar production compared to biochar, the need for more attention to hydrochar and engineered hydrochar application is required in future studies of heavy metals stabilization in the soil environment.

To evaluate the effects of different levels of sewage sludge and sewage sludge-derived hydrochar a greenhouse experiment was performed in a factorial combination based on a completely randomized design with three replications and three factors of organic matter at three levels (control, 10g sewage sludge, and 10 g sewage sludge-derived hydrochar per kilogram), nitrogen at two levels (0, and 250 mg per kg soil as urea), and copper at three levels (0, 10, and 250 mg Cu per kilogram as copper sulfate). The results showed that by applications of sewage sludge and its hydrochar, the dry matters of shoot and root, tillers number, spikes number, leaves number, leaf length, leaf width, plant height, and stem diameter were significantly increased as compared to the control and the amount of this increase in the presence of sewage sludge was greater than that of hydrochar. Also, the using of 250 mg N per kilogram increased the mentioned characteristics relative to the control. The soil contamination Cu significantly reduced the tillers number, spikes number, leaves number, and root dry matter as compared to the control. The use of sewage sludge hydrochar and N fertilizer reduced the Cu toxicity and increased rice tolerance to Cu toxicity by reducing the Cu concentration in rice shoot. To achieve rice optimum growth in both Cu contaminated and non-contaminated conditions, the use of 10 g sewage sludge or sewage sludge-derived hydrochar and 250 mg N per kilogram soil can be recommended at similar conditions.

In the modern world, it is necessary to have a sustainable agricultural system in which natural resources are utilized and at the same time does make any harmful to the environment. Nitrogen leaching is one of the most important problems in intensive farming for high crop production. Application of organic matter lead to reduce chemical inputs and achieve sustainable agricultural goals. Application of modified materials such as biochar and hydrochar can play an important role in creating optimal conditions for growth, increasing plant yield and reducing water consumption, as well as reducing nitrate leaching. In the present study, the effect of biochar and hydrochar, derived from sugar cane bagasse, on crop yield, water productivity and nitrogen leaching in maize cultivation under two irrigation levels of full and dificit (up to 30%) and two fertilization levels of 200 and 160 kg/ha of nitrogen for each sources of urea, biochar and hydrochar were investigated. Adding biochar and hydrochar to the soil increased the yield and water productivity and reduced drainage outflow and nitrogen leaching. In contrast to hydrochar,  biochar has a more effective role for the above mentioned parameters due to its high porosity and specific surface area. In comparison with urea application, using biochar and hydrochar at the optimum moisture conditions reduced drainage outflow 9.2 and 3.1% and nitrogen leaching 2.6 and 3.4%, respectively. Therefore, the use of biochar and hydrochar could be considered as an effective solution to reduce the negative effects of agriculture.

Organic matter is considered as the main element for soil fertility by improving the condition of agglomeration, porosity and soil permeability. One of the most useful ways to use plant debris is to turn it into Biochar and Hydrochar. Biochar is a kind of coal produced from plant biomass and agricultural waste that is burned in the presence of low oxygen content or its absence. The hydrothermal process involves heating the biomass or other materials in a pressurized in the presence of water at a temperature between 180 and 250 C, and the result of this reaction is coal (Hydrochar) and soluble organic matter. Biochar and Hydrochar have several advantages such as climate change mitigation through carbon sequestration, soil cation exchange capacity (CEC) increasing, soil fertility, plant growth and root development, improved soil structure and stability, increased soil moisture storage capacity and soil pH adjustment. Coarse soils have large pores and they have low ability to absorb the water and nutrient. The aim of this research was to determine the optimum temperature of wheat straw Biochar and Hydrochar production, and to investigate the effect of these materials on bulk density, total porosity and moisture curve of Sandy Loam soil.
In order to produce biochar, at first the wheat straw was washed and dried in the oven. Then it was grinded and was made at different temperatures (200 to 600 C) inside a furnace for four hours. Similar to biochar, for producing hydrochar, after washing and drying the wheat straw it was grinded into particles ranges from 0.5 to 1 mm. Then it was placed in a stainless steel autoclave with deionized water. The autoclave was heated at different temperatures between 140-230 C for four hours. The optimum temperature for producing of biochar and hydro-char was determined by using stable organic matter yield index (SOMYI), and it was used in this study. The pH and EC of the biochar and hydro-char samples were measured by combining 1 g of a sample with 20 mL DI water. The cationic and anionic exchange capacity were determined by replacing sodium nitrate with hydrochloric and potassium chloride (Chintala et al., 2013). Surface area was obtained using methylene blue method. A CHNSO Elemental Analyzer (Vario ELIII- elementar- made in Germany) was used to determine the content of C, N, H, S and O in the samples. Potassium and sodium content were measured by flame photometer and calcium and magnesium were measured by titration with EDTA. Biohchar and hydrochar treatments were applied at three levels of 2, 5 and 10 mg / kg soil in three replications in 21 lysimeter. The bulk density, total porosity and moisture curve of soil were measured after four-month irrigation period.
According to the calculated value of stable organic matter yield index (SOMYI) at various temperatures in this study, the maximum thermal constancy of wheat straw biochar was 16.20 at temperature of 300 C and for hydro-char was obtained as 6.13 at the temperature of 200 C. So, the temperatures of 300 and 200 ̊C were determined as the optimum temperature of sustainable carbon biochar and hydro-char production and were used to continue the experiments of this study. The results showed that addition of HW2, HW5, HW10, BW2, BW5 and BW10 to soil compared to control treatment significantly decreased the bulk density of the soil, 8.97, 11.77, 15.17, 7.9, 10 and 13.10 percent respectively. Also, results showed that addition of HW2, HW5, HW10, BW2, BW5 and BW10 to the soil as compared to control treatment increased soil porosity by 8.8, 11.48, 15.77, 6.48, 9 and 22.13 percent, respectively. The reason for reducing the soil bulk density and increasing the total porosity of soil can be due to the mixing of the soil with materials with a lower bulk density and the effect of increasing the organic matter of the soil due to the use of Biochar and Hydrochar. Based on statistical analysis, wheat straw Biochar and Hydrochar had a significant effect (P