Мульчування як захист енергетичної верби від бур'янів

Abstract

Species composition of weeds in energy willow plantations was under the effect of such factors as current land use, soil conditions and weed seeds stock. Thus, in control treatment dominated the following species (number of plants per m 2 ): (i) dicots – goosefoot ( Chenopodium album L.) 13.8 and green amaranth ( Amaranthus retroflexus L.) 10.4, with their proportion in total weeds of 30.5%; (ii) monocots – barnyardgrass ( Echinochloa crus-galli L.) 7.6 and foxtail grey ( Setaria glauca L.) 11.5. Together these four weed species accounted for 64.0%. Other dicot species presented in the field were field pennycress ( Thlaspi arvense L.) 5.1 (6.4%), catchweed ( Galium aparine L.) 4.2 (5.3%), black nightshade ( Solanum nigrum L.) 3.4 (4.3%), wild buckwheat ( Polygonum convolvulus L) 7.4 (9.3%), spotted ladysthumb ( Polygonum persicaria L.) 3.2 (4.0%), other 5.3 (6.7%). Total number of weeds in the control treatment made up about 79.6. When using winter wheat straw as a screening material (layer thickness 5 cm) the total number of weeds decreased significantly to 16.8. High efficiency of the mulching marked sprouts of goosefoot, green amaranth (within 90%) and monocots species (85-86%). Whereas the number of black nightshade sprouts (2.6) and field pennycress (1.9) decreased by only 49 and 44%, respectively. The number of spotted ladysthumb (1.3) decreased by 60%. In a treatment with 10 cm of mulching straw, weed sprouts number decreased to 3.3. Dicots reduced their number by 87.5-97.3% and monocots by 97.4-99.1% compared with control treatment. Under these conditions, the number of field pennycress plants was 0.9, green amaranth, barnyard grass and spotted ladysthumb 0.4. When applying 15 cm of mulching straw there were few sprouts of green amaranth, field pennycress (0.1 and 0.2, respectively) left, which impose no significant damage to energy willow plantations. Green mass of weeds on 20-91 July in the control treatment made up 2418 g/m 2 . To this, the most contributing species were wild buckwheat (417 g/m 2 ), black nightshade (336 g/m 2 ) and barnyardgrass (324 g/m 2 ). When applying 5 cm straw, green mass of weeds decreased by 7.7 times (to 314 g/m 2 ). Goosefoot produced the above-ground mass of 117 g/m 2 , which exceeded all other species by more than 3.0 times as much. Covering inter-row space with 10 cm straw reduced weed green mass to 116 g/m 2 , whereas 15 cm straw ­­ to 3 g/m 2 . Treatment with 5 cm straw provided reducing weeds number 4.7 times compared to the control treatment. However, the number of weeds in the growing season made up 16.8 per m 2 . Better results provided screening with 10 and 15 cm of straw, which significantly reduced both the number of weeds and their weight, which makes it possible to prevent energy willow plantations from weed infestation.