The Physicochemical Properties of Soils in Tea Gardens Affected by Vermicompost and Lime Applications During Different Time Periods

Abstract

The organic matter content has significantly decreased in some of the tea gardens in north of Iran, thereforeresulting in degradation of their physical and chemical properties. An experiment was conducted in two tea gardens in order to investigate the effect of lime and vermicompost on soil's physical and chemical properties. The studied tea soils were located in Gilan province (Bazkiyagorab and Azbaram) in Iran (with clay loam and sandy loam texture). Vermicompost was applied in 3 levels of 0, 2.5% and 5% and lime was applied in two levels of 0 and 0.5%. The measurements were carried out three times (after 0, 90 and 180 days). The results showed that lime and vermicompost application has significantly affected the calcium carbonate content, pH, the electrical conductivity (EC) and the soil organic matter (SOM) content in the studied soils. Lime application significantly increased the infiltration rate (P<0.01). Comparison of the average interaction of lime with vermicompost in the Azbaram station soil showed that 5% vermicompost and 0.5% lime with an average of 5.49 (mm h-1) had the highest infiltration rate (IR) and had a significant difference with the other treatments. Comparison of the average interaction of lime with vermicompost in Basquegorob garden showed that the treatment of 5% vermicompost with 0.5% lime, the time stage of 180 days with an average density of 1.11 (g cm-3) had the lowest bulk density (BD) and was significantly different from other levels. It seems that the simultaneous presence of lime and vermicompost and their effect on improving the soil structure and increasing porosity, leads to reduction of the soil's bulk density. The results obtained in this study have clearly indicated that the simultaneous applications of vermicompost and lime is an effective way to improve soil physical and chemical properties. However, the real potential of the amendments used in this experiment should be further assessed under field conditions using a test crop.