Soil science
O. Toorajzadeh; H. Piri; A. Naserin; M.M. Chari
Abstract
IntroductionAppropriate and practical use of agricultural waste reduce the pressure on the environment. Recently, there has been significant promotion of biochar utilization in agricultural lands. It serves as a valuable source of organic material for enhancing plant growth and as an effective soil amendment ...
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IntroductionAppropriate and practical use of agricultural waste reduce the pressure on the environment. Recently, there has been significant promotion of biochar utilization in agricultural lands. It serves as a valuable source of organic material for enhancing plant growth and as an effective soil amendment to improve soil properties. Due to its unique chemical and physical properties, biochar can be used as a soil conditioner and has many benefits for optimal agricultural and environmental management. Studies have shown that biochar is a useful amendment for improving the physical and chemical properties of soil and effective in maintaining organic matter and soil moisture. Materials and Methods This research was conducted with the aim of investigating the effects of biochar on the physical and chemical properties of soil under conditions of water stress and irrigation using saline water. The experiment was carried out in a factorial based on a completely randomized design with three replications in greenhouse conditions. The treatments include three irrigation water treatments (60, 80, and 100 percent water requirement of the plant, respectively, I1, I2, and I3), three treatments of biochar prepared from northern forest trees at a temperature of 300 degrees Celsius (0, 2, and 4 percent by weight of potting soil, respectively, B1, B2, and B3) and three water quality treatments (with electrical conductivity 1, 4 and 7 dS/m, respectively, S1, S2 and S3). The pots were weighed every other day and at each level of biochar and salinity, the water deficit up to the agricultural moisture level was calculated based on the changes in the pot's weight. After harvesting (in the first half of April 2022), in order to investigate the effect of biochar on the amount of soil nutrients and some physical and chemical parameters of the soil under the conditions of water stress and irrigation water salinity, sampling was done from the soil of each pot. The samples were taken to the laboratory and parameters of apparent and actual specific gravity, acidity and salinity of the soil, percentage of nitrogen, phosphorus and potassium absorbable of the soil were measured in the laboratory. Referring to the yield to irrigation water ratio, water productivity is obtained by the following relation (Payero et al., 2009): WP=Y/IR, where, WP represents water productivity (kg/m3), Y denotes the yield (kg/ha), and IR shows the amount of irrigation water (m3/ha). Analysis of variance for the results obtained from different treatments was conducted using SAS software (SAS 9.1, SAS Institute, Cary, NC, USA). The mean values of the main factors and interactive effects were compared using the Duncan method at the 1% and 5% levels of significance. Results and DiscussionThe results showed that the amount of biochar, irrigation water and water salinity and their mutual effects had a significant effect on the measured parameters at the probability level of one and five percent. Adding 2 and 4 mass percent biochar to the soil increased the amount of phosphorus (35 and 60%, respectively), potassium (57% and 61%), nitrogen (83% and 91%), pH (13% and 13%) and electrical conductivity (EC) (13% and 57%) of the soil. By adding 2% and 4% of biochar to the soil, the actual specific gravity of the soil decreased by 13% and 21%, respectively, and the apparent specific gravity decreased by 11% and 22%, respectively. The actual and apparent specific gravity of the soil decreased by adding biochar to the soil. Decreasing the depth of irrigation water and increasing water salinity increased the amount of phosphorus, potassium, nitrogen, pH and EC of the soil. The amount of irrigation water had no significant effect on the apparent and actual specific gravity, however, the salinity of the irrigation water caused a significant increase in the apparent and actual specific gravity of the soil. Although the addition of biochar to the soil increased the nutrients required by plants in the soil, high amounts of biochar in the soil should be used careful, because the addition of this organic matter to the soil at high levels increased soil EC significantly. Based on the findings derived from the research, the utilization of biochar is recommended as a viable approach for enhancing both the chemical quality and productivity of nutrient-poor and sandy soils.
