Soil erosion and conservation measures in Moldavian Plateau

Abstract

The long-term experiments carried out at the Agricultural Research Station of Podu-Iloaiei, Iaşi County, Romania, tried to establish some fertilization systems for getting efficient yield increases, which maintain or increase the content of organic carbon from soil. These trials were set up on a 16% slope field, with a cambic Chernozem soil, which has a clayey-loam texture, a neuter to weakly acid response and a mean supply in nutrients. Analyzes performed on soil profiles after 44 years, on land with a slope of 16% and slope length of 310 m, shows that the entire length of slope soil fertility were very different, being influenced by processes of erosion and silting. Soil organic carbon, the depth of 0-20 cm, was between 45.94 t / ha, the foot slope and 27.45 t / ha in the mid-slope area with strong erosion. From the results obtained on erosion in different crop rotations, we have found out that in 16% slope fields from the Moldavian Plateau, soil losses by erosion were diminished below the allowable limit of 3-4 t/ha/year only in case of 4 year-crop rotations with two reserve fields, cultivated with legumes and perennial grasses, which protect soil. Annual soil losses by erosion, registered during the last 30 years, in the Moldavian Plateau, were between 0.246 t/ha in perennial grasses, on the second year of vegetation, and 8.976 t/ha in sunflower. The fertilization of wheat and maize crops at the rate of N80P80 + 60 t/ha manure has determined the increase with 5.5 t/ha (7.8%) in the content of organic carbon from soil, as compared to the rate of N140P100.