Analiza comparativă a cernoziomurilor tipice din zona de nord a Moldovei după diferiți indicatori

The purpose of this presented paper is determining the main indicators of soil fertility of typical chernozems in the Northern part of Moldova, by the Near Infrared Reflectance Spectroscopy method, used as a rapid and cost-effective analytical tool for the assessment and monitoring of their quality over time. The study was carried out in the fields of 10 districts in the northern area of Republic of Moldova. For the analysis of the agrophysical and agrochemical soil properties, a total of 16 soil profiles cultivated with different agricultural crops (winter wheat, corn, winter barley, sunflower, soybean, peas, sugar beet) and a soil profile from a fallow land were taken. Data on soil texture (clay, silt and sand fractions) do not show large differences between the sampling regions and the depth of the soil layer. On average, physical clay content is 53-64%, and fine clay content is 35-44%. The humus content varies between 3.48-4.85% in the arable soil layer and between 2.69-4.80% in the 25-50 cm sub-arable layer. The total nitrogen content in the investigated soils correlates with the humus content. The higher the humus content, the higher the total nitrogen content. Total N content ranges from 0.28% (chernozem under fallow) to 0.13% (chernozem grown with maize) in the 0-50 cm soil layer. The C:N ratio is equal to 10-11 in the 0-50 cm soil layer and 8-11 in the 50-100 cm layer. The pH values vary between 5.9-7.2 in the 0-50 cm layer and 6.8-8.1 in the 50-100 cm soil layer. Carbonates are accumulated throughout the soil profile. Comparing the results previously obtained on the typical chernozems under fallow land with the results obtained on the arable chernozems investigated in this study, showed that there is a tendency of the humus content decrease by about 2%, especially in the 0-50 cm soil layer, as a result of applied agricultural practices. Simultaneously, degradation processes are amplified, especially through erosion. In this context, the main issue is the need to monitor soil fertility to assess the impact of agricultural management applied by farmers.