نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Introduction: Soil and water salinity is one of the major environmental and agricultural challenges, particularly in arid and semi-arid regions, leading to reduced soil fertility and crop productivity. Increasing salinity of irrigation water significantly affects the physical and chemical properties of agricultural soils, causing changes and degradation in soil structure. This study aimed to investigate the effect of biochar as a soil amendment on mitigating the adverse impacts of saline irrigation water on the physical and chemical properties of two soil textures: loam and sandy loam, under different salinity levels.
Materials and Methods: A factorial experiment was conducted in a completely randomized block design under greenhouse conditions at the University of Zabol. The experiment included three factors: Soil texture: loam and loamy sand, Irrigation water salinity: at four levels (0.8, 4, 8, and 12 dS/m), and Biochar amendment: at four levels (0%, 1%, 3%, and 5% by volume mixed with the soil). The biochar used in this study was produced from one-year-old grapevine stems, which were crushed, sieved, and mixed with the soil. The measured parameters included electrical conductivity (EC), pH, bulk density, cation exchange capacity (CEC), saturated hydraulic conductivity, and the accumulation of sodium (Na), magnesium (Mg), and potassium (K) in the soil.
Results and Discussion: The results showed that increasing irrigation water salinity significantly raised soil EC, with a more pronounced increase in loam soil compared to sandy loam. Salinity had little effect on bulk density and pH but led to an increase in cation exchange capacity. Although sodium levels rose in both soil textures due to salinity, magnesium and potassium levels remained stable. Applying biochar reduced soil EC, especially in sandy loam, where 3% and 5% biochar treatments caused the greatest reduction, indicating decreased salt buildup due to biochar. Neither saline irrigation nor biochar application significantly changed soil pH in either soil type. However, biochar notably decreased exchangeable sodium at higher salinity levels in both loam and sandy loam soils. Additionally, biochar reduced soil bulk density and enhanced water retention. The greatest decrease in bulk density of the loam texture was observed in treatments with 3% and 5% biochar under irrigation conditions using water with a salinity of 4 dS/m. Additionally, the 1% biochar treatment showed a significant reduction in density under a salinity level of 12 dS/m. The highest decrease in bulk density of the sandy loam texture occurred in the 5% biochar treatment under irrigation with water having salinity levels of 4 and 8 dS/m. Biochar significantly increased soil CEC in both soil types under various salinity levels, with more substantial effects in loam soil. Hydraulic conductivity in sandy loam was significantly affected by both salinity and biochar treatments. Rising irrigation water salinity had different impacts on sodium, magnesium, and potassium accumulation in the two soils. The application of 3% and 5% biochar markedly decreased exchangeable sodium. Magnesium accumulation was higher in loam soil at higher salinity levels, and biochar's effect on magnesium depended on salinity level, biochar amount, and soil type. Notably, at 12 dS/m salinity, 5% biochar significantly reduced magnesium buildup. In contrast, potassium accumulation was unaffected by either salinity or biochar.
Conclusion: Overall, the results of this study indicate that biochar can be considered as an effective soil amendment for improving the physical and chemical properties of soil under saline irrigation conditions. Biochar application can play a vital role in managing soil salinity and enhancing plant tolerance to salinity stress, particularly in lighter-textured soils such as sandy loam.
کلیدواژهها English
