Allelopatic effects of catch-crops aboveground mass aqueous extracts on spring barley germination and growth

Abstract

The physiologically active substances accumulating in catch-crops may have stimulative, inhibitory or a neutra! effect on subsequent crop emergence and growth. Therefore the aim of our investigations was to determine and evaluate the allelopatic influence of aqueous extracts of aboveground mass of catch-crop species (red clover {Trifolium pratense L.), Italian ryegrass (Lolium multijlorum Lam. var. Westerwoldicum Wittm.), white mustard (Sinapis alba L.) and winter rape (Brassica napus L, ssp. oleifera biennis Metzg.)) on spring barley (Hordeum vulgare L.) germination and growth. Laboratory experiments carried out at the Lithuanian University of Agriculture. Treatments of the experiment were distilled water (control) and the 5 aqueous extracts with different ratios of plant dry aboveground mass and water: 1:10; 1:50; 1:250; 1:1250; 1:6250. Plant dry mass in distilled water (1: 10) was kept at room temperature (18°C) for 24 hours. From the obtained extract by the way of dilution aqueous extracts of different ratios was prepared. Spring barley was grown in Petri dishes on filter paper and in the soil moistened with prepared aqueous extracts. It was found, that aqueous extract 1:10 of red clover, Italian ryegrass, winter rape, white mustard and its residues also inhibits intensity of spring barley germination and sprouts growth on filter paper. In soil their allelopatic influence on spring barley is weaker, and winter rape has no allelopatic effect. Growth of spring barley sprouts was stimulated by aqueous extract of winter rape (1:1250) when it was germinated on filter paper, the same like that of Italian ryegrass (1 :>50) when spring barley was germinated in soil.