Long-term results from cultivated runoff plots from Upper Ţărnii Valley, Tutova rolling hills, Romania

Abstract

The paper presents experimental results reported for a period of 24 years, during 1985-2008, on runoff and erosion processes, measured on some runoff plots. They are located on the left hillside of the Upper Tărnii Valley, Eastern Romania, on mollisols (Cambic Chernozem), developed on top of loams, moderately eroded, with a 12% slope. The average of multiannual precipitation is 492.2 mm. From the total of eight plots, six of them are 100m2 (25×4m with 1 m border areas between them) and the other two are 150 m2 (37.5×4m). Six plots were cultivated with different crops as follows: corn, beans, soybeans, winter wheat and bromegrass. Two check plots of 100 and 150m2 were maintained like black fallow, always free of weeds. Also, annually one of the crops is cultivated both in the 100m2 and 150 m2 variants. Averages of soil losses in the study period of time were 0,16 to/ha/y for bromegrass, 0,86 to/ha/y for winter wheat, 5,60 to/ha/y for Beans, 9,30 to/ha/y for corn and 43,12 to/ha/y for black fallow. The intensity of erosion processes has been marked by some historical rainstorm events that have exceeded the value of 80 mm for which the soil losses ranged between 20 and 35 to/ha/y for the black fallow check plot. During the period of vegetation maximum peak erosion rates for winter wheat and beans were registered in May while for the rest of crops and for the black fallow maximum values were noticed in June.