COMPLEX INDICATOR FOR ASSESSING SOIL FERTILITY PUBLISHEDRadu LACATUSU, Anca-Rovena LACATUSU
The need to define more comprehensive the concept of soil fertility, but also to offer a practical tool to measure it, both for natural and agricultural soils without penalty interdictions and for soils affected by anthropogenesis processes, respectively urban soils, has led to elaboration of a complex indicator for assessing fertility (CIF). In order to quantify fertility, major soil features were grouped into two categories: potentiating and penalty indicators. The first category includes: climatic indicators (precipitation, temperature), indicators to characterize the nutritive space, also for water and air regime (edaphic volume, and the level of gleyzation and pseudo - gleyzation), physical indicators (texture, bulk density), chemical indicators (pH, humus content and the content of macro elements). The second category includes levels of salinization, alkalization, carbonation, pollution and artifacts content. Analytical values and morphological observations of each of the indicators mentioned above, are appreciated by giving points (notes) from 1-5, depending on their role in increasing soil fertility. The difference between the sum of notes granted to potentiating indicators and the sum of notes accorded to penalty indicators represents the value of complex indicator for assessing fertility (CIF). CIF values are interpreted according to a scale of values which separates soils into classes, from those with low fertility to high fertility. The calculation procedure and interpretation of CIF values for four soil types contrasting in terms of fertility level are exemplified. Three soil types, contrasting in terms of fertility, and an urban soil were selected. For each soil type, on the genetic horizons up to a depth of 60 cm, notes for each potentiating or penalty features were calculated.By summing the potentiating notes and, eventually, subtracting the amount of penalty notes was obtained the value for complex index of fertility. The results showed that: the Cambic Chernozems from Sârca has high fertility, with CIF value by 39, Fragic Alisol 1 and Gleyc Salic Vertic Cambisol have an average fertility, and with CIF value of 33, 25 respectively, and finally, Urbic Regosol has a low fertility, CIF value being only 21.
soil fertility, evaluation, complex indicator