Results of long-term experiments with growing flue-cured tobacco (Nicotiana tabacum L.) in monoculture and different types of crop rotations

In broadly conceived long-term experiments, tobacco was grown in monocultur e and with different crop rotations. This paper presents results in terms o f the yields achieved and the major yield components for the crops grown, a nd the proportion of particular tobacco quality classes obtained. In additi on to tobacco monoculture (initially only fertilized and later also unferti lized) as the key crop, different types of crop rotations included, besides tobacco, the following crops: winter wheat, maize, soybean, oil-seed rape, and red clover. Experiments involved two 2-year and two 4-year crop rotati ons, and a 3-year, a 5-year, and a 6-year crop rotation. Experiments were s et up on luvic semigley on multilayered Pleistocene sands. Average 10-year results suggest that there is an advantage of crop rotation over monocultur e for tobacco leaf yields. The influence of different crop rotation types o n yields of other crops was variable, tending towards higher values as the number of crops in rotation was increased. Values obtained for yield compon ents should be considered from two angles: some of the values were primaril y influenced by genetic factors, while others were influenced by ecological factors, including crop rotation as an overall biological buffer. With reg ard to quality classes (IB-III), the growing of flue-cured tobacco in crop rotation represents a great advancement relative to its growth in monocultu re, even in a narrower crop rotation.