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Impact of tillage systems on maize emergence
129-136Views:386In Europe, there has been a significant change in the way tillage is approached in recent years. This change is due to a growing awareness among farmers, politicians and society as a whole that soil is not a renewable resource in itself. From an agricultural point of view, the greatest impact on soil condition can be achieved through the use of the applied tillage systems. My research takes this approach as a basis when examining the different tillage systems and their impact on the environment. In this context, conventional and a variety of no-tillage systems are examined in this paper. As a next step, it is examined how the environmental conditions created by the different tillage systems influence the emergence of maize hybrids. The analyses are carried out in a multi-factorial, long-term tillage field experiment. The same batch of the same hybrid seed was sown in several crop years, and the effects of environmental conditions on the emergence process were examined. Environmental effects and emergence-related uptake were measured in the examined plots. Measurements of environmental effects included air temperature, precipitation, soil temperature measured at seeding depth, as well as % cover of stem residue on the surface in the treated plots. The first emergence time measurements of the sown crop in the plots of each treatment were compared and relationships between these factors were investigated.
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Sensitivity of maize to herbicides in experiments in Martonvásár in 2015
47-52Views:369The phytotoxic effect of herbicides applied post-emergence was investigated in a herbicide sensitivity experiment set up on parental maize genotypes in Martonvásár. A total of 48 Martonvásár inbred lines and 12 single line crosses were included in small-plot experiments set up in two replications. Ten herbicides were applied at the normal authorised rate and at twice this quantity. Compounds intended for pre-emergence application were applied when maize was in the 3–4-leaf stage and post-emergence herbicides in the 7–8-leaf stage of development. The extent of phytotoxicity was scored two weeks after treatment. Some of the herbicides tested are not authorised for use in seed production fields, but it is important to know how the parental genotypes respond to all types of herbicides. Phytotoxic symptoms of varying intensity were only observed on a third of the 60 parental genotypes examined; the majority of the lines exhibited no reaction to any of the herbicides. Averaged over the 60 genotypes the level of phytotoxic damage was less than 10% for the single dose. When the double dose was applied somewhat more severe damage was induced by products containing Mesotrione + Nicosulfuron or Foramsulfuron + Isoxadifen-ethyl, but this was still below 15%. The herbicide dose had a three times stronger influence on the intensity of the symptoms than the type of herbicide. With the exception of Topramezone, there was a significant difference between the effects of the normal and double doses. The greatest dose effect differences, in decreasing order, were observed for Mesotrione + Nicosulfuron, Foramsulfuron + Isoxadifen-ethyl. Nicosulfuron and Mesotrione + Terbutylazine. The Mesotrione + Terbutylazine active ingredient combination only caused mild (<10%) symptoms on a total of 11 genotypes, while the Mesotrione + Nicosulfuron combination induced more severe phytotoxic symptoms on 26 lines. When Nicosulfuron was applied alone it caused milder symptoms on fewer genotypes than in combination with Mesotrione. Among compounds of the sulphonyl-urea type, the least severe symptoms on the fewest genotypes were recorded in the case of Prosulfuron.
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Changes in the herbicide tolerance of maize genotypes in wet and dry years
124-127Views:231The tolerance of 15 inbred maize lines grown on chernozem soil with forest residues in Martonvásár was tested against herbicides applied post-emergence in two dry, warm years (2003 and 2011) and in two cool, wet years (2004 and 2010). The herbicides mesotrione + terbutylazine, nicosulfuron and dicamba were applied to maize inbred lines in the 7–8-leaf stage at the maximum dose authorised for practical use and at double this rate. The plants were scored for the intensity of visible phytotoxic symptoms 14 days after treatment.
The level of phytotoxicity observed in dry, warm years was 5.14%, averaged over the lines, herbicides and rates. The intensity of visible symptoms was almost 2.5 times as great in cool, wet years (12.76 %).
Averaged over the four years, the lines and the rates, the least damage was caused by dicamba (5.77 %), followed by mesotrione + terbutylazine (7.23 %). The most severe symptoms were induced by nicosulfuron (16.17 %). This could be attributed to the fact that some of the inbred lines were extremely sensitive to herbicides, especially those of the sulfonylurea type.
A difference of more than 1.5 times was observed between the two doses, but the correlation between the concentration and the severity of the visual symptoms was not strictly linear. Compared to the normal dose (100 %) the double rate resulted in a 162.5% increase in symptom severity. In most cases plants treated with the normal dose were symptom-free or only exhibited a low level of phytotoxicity.