Soil sampling: Jorba
The garden of Jorba is located on a mid-slope close to the valley bottom around the village of Senan. According to the fieldwork results and the studying of geological and soil maps, the type of soil in Jorba can best be characterized as “Emprius” described by the Institut Cartogràfic i Geològic de Catalunya (ICGC). Emprius-type soils are moderately deep, well-drained and of medium texture, with some coarse elements. They have developed on lutites or sandstones from colluvial detrital sediments in gentle and moderate slopes of the Segarra.
The soil profile shows a soil depth of over one meter and three distinct soil horizons with no organic layer on the ground. However, it has a soil is covered with grasses and mosses. According to the general descriptions of the Emprius soil, the A-horizon is usually 20 to 30 cm thick and shows a color from dark brown to yellowish brown. By drilling in the soil, the team revealed that the A-horizon at Jorba is thinner than expected with only around 8 cm.
The B-horizon of the Emprius soil is 30 to 50 cm thick with a color of orange to yellowish brown. This fits well to the 42 cm the team revealed by drilling up the soil. Below that, a C-horizon with a depth of more than 40 cm was discovered which shows a much brighter color than the colors above. The Munsell soil chart reveals that the soil color is light brown.
The soil texture of the A-horizon analyzed in the field and in the lab does not align well with the general descriptions of the soil texture of the soil type Emprius. The team found out that the texture in the garden is much less clayey than expected. Although the fieldwork tests revealed a rather clayey soil, the lab analysis showed a silt-loam texture for the A-horizon.
Photos of the exact sample site and its context in Jorba. © Chair of Being Alive, 2022.
Speaking of, the lab analysis in a depth of 10 cm in the A-horizon reveals that the soil is basic, with very high calcareous levels, not saline and with a low macronutrient content (except for the potassium that is average). The content of organic matter is medium (2.3%) and presents average levels of micronutrients, except for sulfur and zinc (low contents).
