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hassan osooli; Ahmad Karimi; Hossin Shirani
Abstract
The use of organic waste in the form of biochar in order to ameliorate soil is a novel approach in the management of organic waste. In previous studies, researchers mostly focused on the amount of biochar that was added to the soil. However, the aim of this study was to investigate the characteristics ...
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The use of organic waste in the form of biochar in order to ameliorate soil is a novel approach in the management of organic waste. In previous studies, researchers mostly focused on the amount of biochar that was added to the soil. However, the aim of this study was to investigate the characteristics of biochars prepared from different feedstock (wheat straw, vermicompost and apricot firewood) and the interaction effects of amounts and particle sizes of biochars on yield and water use efficiency (WUE) of winter wheat. In a factorial experiment with a randomized complete block design with three replications, the effects of these three biochars in the amount of 0.5% (R1), 1.5% (R2) and 3% (R3) with a particle size of ≤0.5 (S1), 0.5-1 (S2) and 1-2 (S3) mm were evaluated in two consecutive cropping years. The studied biochar were added to the soil only in the first year to a depth of 0-15 cm. A control plot was considered in each replication. The interactions of experimental factors (except interaction effect of year and biochar amount) on yield and WUE were significant. Comparison of average yield and WUE in each type of biochar showed that, in the first and second year, wheat straw biochar treatment of R3 S2 had the highest yield (5,200 kg ha-1 and 6664.3 kg ha-1, respectively) and WUE (1.6 kg m-3 and 2.1 kg m-3, respectively). In the first year, in vermicompost biochar treatments, the highest yield (4517.7 kg ha-1) and WUE (1.4 kg m-3) were observed in the R2 S3. In the same year, in apricot wood biochar, treatment R3 S3 had the highest yield (3871.7 kg ha-1) and WUE (1.2 kg m-3). In the second year, in vermicompost treatments, the highest yield (6615.7 kg ha-1) and WUE (2.04 kg m-3) was observed in the R3 S2 and, in the same year, in apricot wood biochar treatments, the highest yield (5263.7 kg ha-1) and WUE (1.6 kg m-3) was observed in the R2 S3. The highest yield and WUE (in the two years) was observed in wheat straw biochar with the R3 S2. These results showed that in addition to the type of biochar, the interaction of the amount and size of biochar particles had a decisive effect on increasing the yield and water use efficiency of wheat.
Samira mesry; Shoja Ghorbani; Hossin Shirani; Abolghasem Kamkar; hamidreza motaghian
Abstract
Soil water is an important factor in the growth of the plant. There are different methods for soil moisture estimation. It is time-consuming to obtain volumetric soil moisture in a laboratory. This study was performed to evaluate estimate of soil moisture by different in situ methods including the electrical ...
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Soil water is an important factor in the growth of the plant. There are different methods for soil moisture estimation. It is time-consuming to obtain volumetric soil moisture in a laboratory. This study was performed to evaluate estimate of soil moisture by different in situ methods including the electrical resistance of Werner electrode arrangement and ground penetration radar (GPR) from 700 MHz antenna, and two humidity sensors, namely, thetaml2 and sm300. These were used in 72 soil samples with different textures (loam, sandy clay loam and silty loam, silty clay, silty clay loam, clay loam) in parts of Shahrekord Watershed.The results showed that the coefficient of correlation between soil moisture and electrical resistance was 0.85. Also, the correlation coefficient between the values obtained from subsurface radar method, sm300 sensor and thetaml2 with the results obtained from laboratory measurements were 0.86, 0.94, 0.86, with CRM index values of -0.52, -0.75 and –1.22. By comparing the results of electrical resistivity, moisture from the GPR and the sm300 and thetaml2 sensors with volumetric moisture, the Root Mean Squared Error (RMSE) values were 8.41, 4, 5.3 and 8.6; and RRMSE were 10, 31, 29, and 26, respectively. Duncan test of moisture content showed that the difference between the sensors and the laboratory moisture content was significant at 5% level (p<0.05). According to the value of RRMSE All sensors had a good estimate of soil moisture. In conclusion, electrical resistivity and GPR method, due to higher sampling density, could be used as a rapid, cost effective, and non-destructive technique to estimate profile of soil water content at scales of field to sub-watershed.