نوع مقاله : مقاله پژوهشی
نویسندگان
دانشگاه تهران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Saturated hydraulic conductivity (Ks) is one of the most important parameters for understanding water transport and retention in soil. This parameter is influenced by physical, chemical and biological factors. The aim of this study is to review some of the experimental evidence on the temporal and spatial variations of hydraulic conductivity. First, the role of tillage management, including compaction caused by agricultural machinery traffic in the field, is investigated. Here, it is shown that plowing initially causes a temporary increase in capillary conductivity but in the long term it will cause a significant decrease. Soil conservation methods maintain soil biological activities such as soil organisms and root development and macropore connectivity. Next, we will discuss soil texture and soil organic matter content. Soil organic matter content usually enhances soil hydraulic conductivity, but dissolved organic matter will cause soil degradation under certain conditions. From a chemical perspective, an increase in the percentage of exchangeable sodium and a deficiency of alkaline earth group cations lead to the dispersion of colloidal particles in the soil and a decrease in the hydraulic conductivity. The ratio of potassium to sodium, salinity and pH value in irrigation water play a decisive role in the flow of water in the soil. In another section, the role of roots and root morphology and the type of vegetation cover in changes in hydraulic conductivity is examined. Finally, the decisive role of combined physical, chemical and biological research in this matter is mentioned.
کلیدواژهها [English]
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