The goal of the experiments carried out at the Podu-Iloaiei Agricultural
Research Station, Ia?i County, was the study of water runoff and soil losses, caused by
erosion, in different crops and the influence of water and soil erosion on the losses of
organic matter and mineral elements from soil. The results on water runoff and soil
losses in different crops from the Moldavian Plateau have shown that in the last seven
years, of the total amount of 608.4 mm rainfall, 387.5 mm (63.7%) produced water runoff, which was between 8.5 mm in
perennial grasses, in the second year of vegetation, and 34.9 - 36.8 mm, in maize
and sunflower crops. The annual soil losses due to erosion, recorded at the same period,
were between 0.190 t/ha/year in perennial grasses, and 4.079 - 4.451 t/ha/year in maize
and sunflower crops. Erosion has affected soil fertility by removing once with eroded
soil, high amounts of organic carbon and mineral elements, which reached 10.71 -
11.26 kg/ha nitrogen, 0.56 ? 0.64 kg/ha phosphorus and 0.98 - 1.11 kg/ha
potassium, in maize and sunflower crops. The crop structure, which determined the
diminution in mean soil losses by erosion until 1.383 t/ha included 20 % straw cereals,
20% annual legumes, 20% row crops and 40 % perennial grasses and legumes. On land
with a slope of 16%, lowering the percentage of weeding plants from 60% to
20% has reduced the amount of eroded soil by 49%.
