The effect of reduced rates of crop protection agents and adjuvants on productivity, weed infestation and health of spring barley (Hordeum sativum L.)

A field experiment on the cultivation of spring barley was carried out in the period 2009–2011 at the Experimental Farm in Czesławice (central Lublin region) on grey-brown podzolic soil derived from loess (soil quality class II). The study included 3 rates of herbicides, growth retardant and fungicides (100%, 75% and 50%) as well as different types of adjuvant (oil, surface-active, mineral). Plots without adjuvant were the control treatment. A hypothesis was made that the reduction in rates of crop protection agents by 25–50%, with the simultaneous addition of adjuvants, would allow spring barley productivity to be maintained at a level similar to that obtained under the conditions when recommended rates are applied without adjuvant. It was also assumed that particular types of adjuvant would show different interactions with specific groups of crop protection agents. It has been proved that a rational reduction in rates of crop protection agents is up to a limit of 25%, especially when an adjuvant is added to such reduced rates. This allows spring barley productivity to be maintained at the level obtained after the application of full rates (without adjuvant). But a further reduction in rates of crop protection agents by 50%, in spite of the interaction of adjuvants, results in a significant deterioration of all spring barley yield components, since such conditions lead to increased occurrence of agricultural pests (weeds, fungal diseases) as well as increased crop lodging. Among the group of adjuvants tested in the present experiment, the oil adjuvant Atpolan 80 EC showed the best interaction with crop protection agents used

Aplikacja herbicydów nalistnych w zasiewach prosa zwyczajnego (Panicum miliaceum L.) a jakość ziarna

This paper presents the results of a study on the tolerance of proso millet to herbicides (2,4-D + fluroxypyr; tribenuron-methyl + fluroxypyr; MCPA – 2-methyl-4-chlorophenoxyacetic acid; dicamba + triasulfuron) foliar-applied at the tillering stage of proso millet, at the maximum rate (100%) and at a rate reduced by 50%. Plots without herbicide application were the control treatment. The experiment was carried out on a loess-derived soil (soil class II) under the climatic conditions of the central Lublin region, Poland. The study proved that herbicide application in millet crops was justified, because the herbicides (in particular 2,4-D + fluroxypyr and tribenuron-methyl + fluroxypyr) contributed to a statistically significant improvement in the grain chemical composition (especially to an increased content of essential amino acids, fat, selenium, and o-dihydroxy phenols). Moreover, no residues of active substances of the herbicides were found in the millet grain samples analysed. The herbicide rate reduced by 50% proved to be sufficient to ensure appropriate quality of millet grain.Praca przedstawia wyniki badań dotyczące tolerancji prosa na herbicydy (2,4-D + fluroxypyr; tribenuron-methylowy + fluroxypyr; MCPA; dicamba + triasulfuron) stosowane dolistnie w fazie krzewienia prosa, w dawce maksymalnej (100%) i w dawce zmniejszonej o 50%. Poletka bez aplikacji herbicydu były obiektami kontrolnymi. Doświadczenie założono na glebie wytworzonej z lessu (klasa II) w środkowej Lubelszczyźnie. Udowodniono zasadność zastosowania herbicydów w zasiewach prosa, ponieważ te preparaty (zwłaszcza 2,4-D + fluroxypyr oraz tribenuron-methylowy + fluroxypyr) przyczyniły się do istotnej statystycznie poprawy składu chemicznego ziarna (szczególnie zwiększenia zawartości aminokwasów egzogennych, tłuszczu, selenu, o-dihydroksyfenoli). Ponadto nie stwierdzono żadnych pozostałości substancji aktywnych herbicydów w analizowanych próbach ziarna prosa. Dla zapewnienia odpowiedniej jakości ziarna prosa wystarczająca okazała się dawka herbicydów zmniejszona o 50%