Динаміка компонентів агрофітоценозів посівів ячменю як прояв їх конкуренції

Abstract

Упродовж 17 років у 25 дослідах у посівів ячменю в динаміці вивчали кількість і масу бур'янів. Виходячи з питомої частки бур'янів у загальній масі агрофітоценозу визначали їх конкурентоздатність. Найбільш конкурентоздатними були коренепаросткові види, амброзія полинолиста і падалиця соняшника.

В течении 17 лет в 25 опытах в посевах ячменя в динамике изучали количество и массу сорняков. Исходя из удельной массы сорняков в общей массе агрофитоценозов определяли их конкурентоспособность. Наиболее конкурентоспособными были корнеотпрысковые виды, амброзия полыннолистная и падалица подсолнечника.

Domestic plants and weeds as components of the solitary agrophytocenosis interact during vegetational season. For this reason their number and weight suffer particular changes. Yield losses mostly correlate to specific weight of weeds in gross weight of agrophytocenosis. Within this framework it is important to learn regularities of changes that happen to agrophytocenosis components over time to be able to forecast possible shortfall in yield production caused by weeds at the very start of vegetation before the chemical weeding is conducted. During 17 years and 25 tests the plant sampling collection of barley plantings was carried out three times during the vegetational season (tillering,earing, full maturity). Except of cropper the biological groups of weeds and certain hostile species and drops of the first crop (sunflower, buckwheat) were also collected. According to records the biggest number of weeds was detected during the barley ear stage that exceeded the same index during the tillering period by 26 %. During the vegetational period the average number of barley composed 336,8 and the number of weeds composed 615,8 pcs/m2 . In spite of this barley dominated with its weight, its part in gross mass of agrophytocenosis in averagecomposed 83,1 %. During the process of ontogeny all components of agrophytocenosis increased their weight. But the speeds of that process were different. Barley, having powerful edificator capability, supressed weeds very much till the midvegetational period. If during the tillering period barley’s average specific weight of agrophytocenosis composed 82,4 %, so during the earing phase it grew up to 85,0 %. At a later stage during plants ripening its leaves dried up gradually and weeds had a chance to increase thair part in formation of agrophytocenosis gross mass. And in contrast, barley decreased its specific weight in agrophytocenosis gross mass by 81,9 % during the firm-ripe stage. Perennial grasses were regard as the most serious competitors to barley, mostly weeds, their specific weight at the start of vegetational period composed 11,4 % in agrophyrocenosis gross mass. A significant danger to yield also can be constituted by ragweed and sunflower drops, their specific weight during tillering period in general gross mass of domestic plants and weeds composed 0,7 % and 0,4 % and at the end of vegetational period increased their presence up to 1,3 % and 1,0 %.