engleski

Role of vegetation on karst on protection of soil from erosion

The paper shows the research results of grass cover and of culture Spanish broom (Spartium junceum L.) in bench terraces on the protection of soil from erosion. The research was done on experimental plots B2 and B3 in the basin of torrent Suvava near Muć. The plots have the same inclination of 16° and are build of marly lime stone on which the soil is shallow and very sceletal, calcicambisol. Medium yearly values of surface flowoff of rainfall on bare ground amount to 111, 6 mm.m-2, with coefficient flowoff 0, 076 and soil loss of 2, 14 t.ha-1, on the area under grass cover, plot B2, surface flowoff amounts to 42, 3 mm.m-2, with coefficient flowoff 0, 013 and soil loss 0, 041 t.ha-1, and on the area under culture of Spanish broom in bench terraces, plot B3, surface flowoff of rainfall amounts to 11, 2 mm.m-2 , with coefficient flowoff 0, 007 and soil loss of only 0, 003 t.ha-1. Research results showed that the surface flowoff of rainfall and soil loss on bare grounds, on areas under grass cover and culture of Spanish broom are in strong linear dependance on quantity of rainfall, its duration and intensity. Correlation coeficients are between 0, 444 under Spanish broom till 0, 803 on bare ground, the biggest correlation coefficient on bare grounds has the relation of surface flowoff of rainfall and quantity of rainfall. By univariate regression analysis the surface flowoff of rainfall on research areas, can at best be estimated on the basis of quantity of rainfall, although the other independent variables also strongly explicate this regression model, the duration of rainfall and their intensity. The quantity of rainfall on plot B2 under grass cover explains 56, 4 % of variability of surface flowoff, and 21, 2 % of soil loss. Multivariate regression models do not give much better results than univariate, especially at quantity of rainfall as the best independable estimator, where the values are nearly equal.

experimental plots B2 and B3; bare ground; grass cover; culture of Spanish broom on bench terraces; surface flowoff of rainfall and soil loss

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