Abstract

Field experiment was carried out in the years 2002 to 2004 to study the effect of soil tillage methods and weed control techniques with herbicides. Potato yield and degree of weed infestation were investigated using correlation coefficients and linear regression analysis. High negative associations were found between the number of weeds, their fresh and air dry matter, and total potato tuber yield as well as marketable fraction tuber yield. The relationships were negative linear. A higher negative influence of weed infestation on potato yield was found before harvest, compared with early stage of crop growth before closing of potato rows. The presence of weeds was increasing by 1 ton of air weed dry matter per 1 ha furthermore it reduced the marketable fraction tubers yield by, respectively, 0.94 and 1.34 t per 1 ha when recorded before closing of potato rows, and by 2.62 and 3.76 t ha^-1 when recorded before potato harvest. To conclude, weeds can affect yield and harvesting of potatoes and may encourage certain pests and diseases. Consequently weed reduction by using two techniques, either mechanical or combination of mechanical and chemical weed control is surely required.

Key words: Potato, weed infestation, yield, correlation coefficient, analysis of regression, herbicides.