Weediness of spring barley crops depending on the forecrop in the Eastern Forest-Steppe of Ukraine

Abstract

Goal. To determine the species composition of weeds, their dominant role, and to establish the type and level of weediness of spring barley crops grown after sugar beet, corn for grain ½ + soybean ½ and spring barley as forecrops in the conditions of the Eastern Forest-Steppe of Ukraine.
 Methods. The investigations were conducted in field experiments, in a stationary field, fixed nine-course-fallow-grain-row crop rotation and in monoculture of spring barley by means of route surveys.
 results. According to our research during 2011—17, in spring barley crops 56 species of weed plants were revealed. In the conditions of crop rotation, 47 and 50 species were found, respectively, in the fields of culture after sugar beets and corn for grain ½ + soybean ½ as forecrops, and 29 species in monoculture. Spring early and late weed plants are represented in the largest number (48.0—65.5%), and the second and third places were respectively occupied by wintering, winter and biennial (24.1—32.0%), and perennial (10.4—21.3%). The main species of weeds in spring barley crops were: Setaria glauсa, Echinochloa crus-galli, Chenopodium album, Amaranthus retroflexus, Solanum nigrum, Ambrosia artemisiifolia, Polygonum lapathifolium, Stachys annua, Fallopia convolvulus, Malva neglecta, Polygonum aviculare, Cirsium arvense, Convolvulus arvensis after sugar beets as forecrop; S. glauсa, E. crus-galli, C. album, A. retroflexus, S. nigrum, A. artemisiifolia, P. lapathifolium, S. annua, Xanthium strumarium, C. arvense, C. arvensis after corn for grain ½ + soybean ½ as forecrops; S. glauсa, E. crus-galli, A. retroflexus, S. nigrum, X. strumarium, Avena fatua, C. arvense, C. arvensis after spring barley as forecrop. In spring barley crops, the largest proportion of dominance and subdominance (in total) was: A. retroflexus (72%) after sugar beets as forecrop; S. nigrum (72%) and C. arvense (71%) after corn for grain ½ + soybean ½ as forecrops; S. glauсa (72%) and E. crus-galli (71%) in monoculture. The type of weediness of spring barley crops depended on the forecrop, and the level of weediness depended on the year of research.
 Conclusions. It was established that in the conditions of the Eastern Forest-Steppe of Ukraine, the forecrop significantly affects the species composition of weeds, their dominant role and the type of weediness of spring barley crops.