Pokus s različitim varijantama suzbijanja korova u usjevu kukuruza proveden je u 2021. godini na lokaciji pored naselja Markovo Polje na praškasto ilovastom tlu. Primijenjene su tri varijante ...suzbijanja korova: 1. mehaničko suzbijanje korova između redova kukuruza motokultivatorom, a unutar redova ručno okopavanje motikom, 2. mehaničko suzbijanje korova samo između redova kukuruza motokultivatorom bez suzbijanja unutar redova, 3. bez ikakvog suzbijanja korova. Na pokusnom polju je pronađeno 14 različitih vrsta korova od kojih su prevladavali Amaranthus retroflexus (običan štir), Ambrosia artemisiifolia (ambrozija), Chenopodium album (bijela loboda) i Sorghum halepense (divlji sirak). Najmanja zakorovljenost pokusnih parcela očekivano je bila na parcelama gdje je primijenjena varijanta 1 suzbijanja korova, kod varijante 2 je prosječna masa korova po 1 m2 bila 223%, a kod varijante 3 čak 334% veća u odnosu na varijantu 1. Prinosi kukuruza su bili obrnuto proporcionalni sa zakorovljenosti pokusnih parcela, najviši prinosi su ostvareni kod varijante 1 s prosjekom od 6015 kg ha-1, kod varijante 2 prosječni prinos je bio 2907 kg ha-1, a kod varijante 3 1242 kg ha-1. Kombinacija mehaničkog suzbijanja korova i ručnog okopavanja može biti alternativa korištenju herbicida na manjim obiteljskim gospodarstvima i u ekološkom uzgoju kukuruza.
Several cover crops (CCs) exert allelopathic effects that suppress weed growth. The aim of the present study was to evaluate the effects of aqueous extracts containing different concentrations 0, ...0.5, 1, 2.5, 5, 7.5 and 10% (
/
) of Brassicaceae CCs (
and of the CCs
and
on germination and early growth of
L. The allelopathic effects were species and concentration-dependent.
, for example, caused the greatest potential to inhibit germination, shoot, radicle length and fresh seedling weight, whereas
and
inhibited germination and early growth of
only at concentrations ≥7.5%. In contrast, no inhibition was observed when aqueous extracts of
and
were added at any of tested concentration. Liquid chromatography-tandem mass spectrometry detected 15 phenolic compounds in Brassicaceae CCs with the highest content (µg/g) of vanillin (48.8), chlorogenic acid (1057), vanilic acid (79), caffeic acid (102.5) and syringic acid (27.3) in
. Our results suggest that
is the most allelopathic CCs and that the fruits of
are the plant organs richest in allelochemicals.
Rhizobia are an important component of sustainable agricultural production. In symbiosis with legumes, they provide adequate amounts of nitrogen for their growth and leave nitrogen in the soil for ...crops that follow in the rotation. One of the major threats to symbiotic nitrogen fixation are herbicides. The effect of herbicides on symbiotic nitrogen fixation can be positive or negative. The positive effect is manifested in the stimulation of growth and development of rhizobia. When symbiosis is negatively affected, the efficiency of nitrogen fixation is reduced, resulting in lower legume growth and yield. Herbicides can contact rhizobia immediately after application or, in the case of persistent herbicides, later in the growing season. Herbicides may affect the rhizobia, the host plant, or the establishment and development of the symbiosis. This paper reviews previous research on the effects of herbicides on rhizobia.
The phytotoxic effects of mesotrione residues on sugar beet (
Beta vulgaris
L.) were determined in two agricultural soils (humofluvisol and hipogley) in order to show the relevance of soil ...characterization in crop rotation practice. Soils were treated with mesotrione at seven rates that simulated the levels of mesotrione in soil considering its field half-life. The visual injury and reduction in fresh weight and total carotenoid content were determined during the three-week cultivation in plastic pots under controlled conditions. The Freundlich isotherm model was used to reach the adsorption parameters of mesotrione in both soils. Humofluvisol showed at least twice as less adsorption affinity for mesotrione as hipogley. The effective dose (ED
50
) of mesotrione for 50% reduction in sugar beet fresh weight content was 5.9 g a i ha
−1
in hipogley and 4.4 g a i ha
−1
in humofluvisol. The ED
50
for 50% reduction in total carotenoid content was 4.7 g a i ha
−1
in hipogley and 2.1 g a i ha
−1
in humofluvisol. The crop rotation has to be performed considering the soil characteristics due to its effect on the bioavailable amount of mesotrione residues in soil resulting in different levels of crop injury in two soils at the same rate.
Variations in soil pH have been shown to affect mesotrione adsorption, which in turn, may have an impact on crop susceptibility. Therefore, a greenhouse experiment was conducted to evaluate the ...effect of simulated mesotrione residues on pea crop grown in the typical agricultural soil (gleysol) of north-western Croatia. The soil pH was manipulated to obtain neutral (pH 7.0) and acidic (pH 5.0) values. Simulated mesotrione residues were 1.1, 2.3, 4.5, 9.0, 18, 36 and 72 g a.i. ha−1. Crop visual injuries as well as reductions in chlorophyll fluorescence and aboveground dry biomass were higher at pH 7.0 than at pH 5.0. With increasing mesotrione residues, the reductions in chlorophyll fluorescence ranged from 38.8% to 89.7% at pH 5.0 and from 63.7% to 99.3% at pH 7.0. Compared to chlorophyll fluorescence, the reductions in dry biomass were smaller and ranged from 49.2% to 96.8% at pH 7.0 and from 32.0% to 82.6% at pH 5.0 for the mesotrione residues from 1.1 to 72 g a.i. ha−1. These results indicate that soil pH is an important factor determining the susceptibility of pea crop to simulated mesotrione residues.
Huds. is an important pinoxaden-resistant grass weed in many countries of Europe. Recently, the low efficacy of pinoxaden was reported in winter cereals in Croatia, but a preliminary dose-response ...trial showed no herbicide resistance for the investigated weed population. Therefore, a two-year experiment was conducted under greenhouse conditions to determine the efficacy of various pinoxaden doses (20, 40 and 80 g a.i. ha
) on weed visual injuries and biomass reduction after herbicide application at different growth stages. As expected, the maximum weed biomass reduction (97.3%) was achieved by applying the highest dose (80 g a.i. ha
) at the earliest growth stage (ZCK 12-14). A pinoxaden dose of 20 g a.i. ha
resulted in satisfactory weed biomass reduction (88.9%) only when applied at ZCK 12-14. The recommended dose (40 g a.i. ha
) also provided sufficient weed control up to the growth stage ZCK 21-25. Slightly delayed (ZCK 31-32) application of the recommended dose brought about a low weed biomass reduction (60.1%). Double than the recommended dose also failed to provide satisfactory weed control at the advanced weed growth stages (ZCK 31-32 and ZCK 37-39). Thus, reported low efficacy of pinoxaden is most likely because of delayed herbicide application when
is overgrown.
Kvržične bakterije važan su dio održive poljoprivredne proizvodnje. Uspostavom simbiotskog odnosa, osiguravaju leguminozama, kao i kulturama koje slijede u plodoredu, dostatne količine dušika za rast ...i razvoj. Jednu od najvećih prijetnji uspješnog uspostavljanja simbiotskog odnosa predstavljaju herbicidi. Učinak herbicida na simbiotsku fiksaciju dušika može biti pozitivan ili negativan. Pozitivan učinak očituje se u poticanju rasta i razvoja kvržičnih bakterija. U slučaju negativnog djelovanja herbicida na simbiozu, fiksacija dušika biti će reducirana što će rezultirati reduciranim rastom i prinosom leguminoza. Herbicidi mogu doći u kontakt s kvržičnim bakterijama odmah nakon primjene ili u slučaju perzistentnih herbicida, kasnije u vegetaciji. Herbicidi mogu utjecati na same kvržične bakterije, biljku domaćina ili na uspostavu i odvijanje simbioze. U radu je dan pregled dosadašnjih istraživanja utjecaja herbicida na kvržične bakterije.
Rhizobia are an important component of sustainable agricultural production. In symbiosis with legumes, they provide adequate amounts of nitrogen for their growth and leave nitrogen in the soil for ...crops that follow in the rotation. One of the major threats to symbiotic nitrogen fixation are herbicides. The effect of herbicides on symbiotic nitrogen fixation can be positive or negative. The positive effect is manifested in the stimulation of growth and development of rhizobia. When symbiosis is negatively affected, the efficiency of nitrogen fixation is reduced, resulting in lower legume growth and yield. Herbicides can contact rhizobia immediately after application or, in the case of persistent herbicides, later in the growing season. Herbicides may affect the rhizobia, the host plant, or the establishment and development of the symbiosis. This paper reviews previous research on the effects of herbicides on rhizobia.
Herbicide residues can potentially injure sensitive crops grown in rotation. Thus, the objective of this study was to evaluate the sensitivity of six replacement crops to mesotrione residues 1 yr ...after herbicide application. In field bioassay, mesotrione was applied at recommended (144 g ai ha.sup.-1), twofold (288 g ai ha.sup.-1), and fourfold (576 g ai ha.sup.-1) rates at two soil types (Gleysol and Fluvisol). In field and laboratory bioassays, mesotrione residual activity was followed for a 21-d period using various measurements of phytotoxicity. No visible injuries to mesotrione residues were observed on oat (Avena sativa L.), rapeseed (Brassica napus L.), soybean (Glycine max L. Merr.) and sunflower (Helianthus annuus L.) in the field bioassay. Although mesotrione residues were not detected by HPLC-UV/DAD analysis, field bioassays indicated their presence due to visible injuries on field pea (Pisum sativum L.) grown in Gleysol soil with twofold and fourfold herbicide treatments. In contrast to other test crop responses, sugar beet exhibited visible injuries in both soils, and consequently, was subjected to laboratory bioassay. With increasing mesotrione rates, the reductions in sugar beet (Beta vulgaris L. var. saccharifera Alef.) fresh weight and total carotenoids content ranged from 6.2% to 18.7% and from 4.1% to 19.4% in Gleysol, and from 1.1% to 7.7% and from 0% to 11.9% in Fluvisol, respectively. Since herbicide residues could not often be detected by instrumental analysis, the bioassays seem to be a reliable tool for crop safety assessment. Key words: Field pea, Fluvisol, Gleysol, phytotoxicity, sugar beet.
Zatravljivanje vinograda sastavni je dio sustava održavanja tla u vinogradu. Zatravljivanje vinograda i korištenje pokrovnih usjeva općenito je prepoznato kao multifunkcionalna mogućnost održive ...poljoprivrede. Brojne su prednosti zatravljivanja golog tla. Osim smanjenja zakorovljenosti i potrebe za većom primjenom herbicida, treba istaknuti prednost održavanja i povećanja plodnosti tla, smanjenje erozije, gospodarenje vodom u tlu, smanjenje ispiranja i spiranja gnojiva i pesticida, očuvanje okoliša i bioraznolikosti. Iako se čini jednostavnom, uspostava zatravljivljena nasada zahtijeva dosta znanja. Zbog smanjenja negativnog učinka zatravljivanja treba pomno odabrati vrste za zatravljivanje, odnosno treba poznavati njihove prednosti i nedostatke.
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