Influence of preplant and vegetable crop rotation links on carrot yield and damage of pests.

At the Lithuanian Institute of Horticulture in 2003-2007 there were investigated the most suitable plants for green manure and evaluated their influence on ecologically grown carrot yield and damage of pests. Experiments were carried out in the experimental field for ecological vegetable growing, in calcaric epihypogleyic luvisol of sandy loam on light loam. It was established that biomass of the plants grown for green manure left in the ploughing layer uneven amount of organic matter. Pea and oat mixture produced the biggest amount of organic matter (43.2 t ha-1), barley - the least one (24.5 t ha-1). All the sideral plants influenced humus positively. All the preplants increased carrot yield. The biggest carrot yield (correspondingly 40.4 and 41.2 t ha-1) was obtained growing them after barley and pea-oat mixture for green manure. In the first year after harvesting of the plants for green manure, when carrot yield was gathered, there was found only very small amount of root-crops damaged by pests (Psila rosae Fabr. and Pemphigus phenax Born et Blunck). At the end of rotation, i. e. in third year after plant ploughing for green manure, the percent of carrot root-crops damaged by pests increased. The least amount of damaged root-crops was found in carrot, which preplant in the beginning of rotation was barley for green manure. [ABSTRACT FROM AUTHOR]