Irnazaquin applied in legume crops has a long residual time in soil, which often impacts safety of the susceptible crops. To increase safety of imazaquin application, two composted litters, bovine manure （BM） and ch...Irnazaquin applied in legume crops has a long residual time in soil, which often impacts safety of the susceptible crops. To increase safety of imazaquin application, two composted litters, bovine manure （BM） and chicken manure （CM）, were used to determine their effects on imazaquin environmental behavior by incorporating each kind of manure into the tested sandy loam soil at 10% （w/w）. The degradation of imazaquin in BM- and CM-amended soil was about 2.4 and 1.5 times, respectively, faster than that in unamended soil. The half-lives of imazaquin in BM-amended soil varied between 6.7 and 15.4 d over the temperature range of 20 to 40℃, and the degradation rate constant （k） increased by a factor of about 1.5 for every 10℃ change. Higher mix ratio did not significantly increase the degradation, and the optimal active degradation of imazaquin was observed approximately at the mix ratio of 10：1 of soil to BM. The different moisture levels had negligible effect on imazaquin degradation. In both unamended and BM-amended treatments, two metabolites were observed at 5, 10 and 30 d after treatment. One metabolite at retention time （RT） of 8.4 rain was identified as 2-（4- hydroxyl-5-oxo-2-imidazolin-2-yl） quinoline acid, originating from the loss of isopropyl group and hydroxylation at the 4-position of imidazolinone ring. The other at RT of 12.9 rain was identified as quinoline-2,3-dicarboxylic anhydride, resulting from detachment of imidazolinone ring and the forming of dicarboxylic anhydride. This finding suggested that the addition of farm litters into soil might be a good management option since it can not only increase soil fertility but also contribute to increase safety of imazaquin application to the following susceptible crops.展开更多
In a bid to make slow release formulations of imazaquin, the herbicide was encapsulated in starch and chitosan beads reinforced with alginate. The beads were characterized using SEM, DSC and FTIR. Two types of formula...In a bid to make slow release formulations of imazaquin, the herbicide was encapsulated in starch and chitosan beads reinforced with alginate. The beads were characterized using SEM, DSC and FTIR. Two types of formulations were made by extrusion into 0.25 M calcium chloride solution: chitosan/alginate (LNCI) and starch/alginate (LNSI) beads, and the third was by gelatinization of starch at 75?C (LNSI2). Findings showed highly porous spherical beads, the starch/alginate beads bigger and less porous than the chitosan/alginate beads with diameters of 2.53 ± 0.01 and 2.31 ± 0.01 mm;porosity of 57.58% ± 0.2% and 81.28% ± 0.2% and swelling of 34.91% ± 0.2% and 80.35% ± 0.2%, respectively. FTIR revealed a reduction in intensity of the carboxylate peaks of alginate and the peak at 1058 cm?1, present in the FTIR of the matrices, is shifted to lower wave-numbers in the formulations, signifying interactions between the formulation components that make for good slow release. The DSC thermograms of all formulations showed evidence of interaction of imazaquin carboxylate group with the N-atoms of the macromolecules, which is indicative of reduced crystallinity of imazaquin.展开更多
The Egyptian broomrape (Orobanche aegyptiaca Pers.) is an obligate holoparasitic weed that causes severe damage to many important vegetable and field crops. In this investigation, three herbicides;chlorsulfuron, trias...The Egyptian broomrape (Orobanche aegyptiaca Pers.) is an obligate holoparasitic weed that causes severe damage to many important vegetable and field crops. In this investigation, three herbicides;chlorsulfuron, triasulfuron and imazaquin were tested to evaluate their efficiency in controlling the tomato broomrape. The herbicides significantly reduced the broomrape parasitizing tomato plants growing in pots, irrigated open field and under greenhouse conditions as foliar spray at the concentrations (0.5 - 10 μg·ml-1) without visible injury effect on the plants. In the pot experiments, triasulfuron increased the dead spikes from 77% to 84%;chlorsulfuron from 51% to 84% and imazaquin from 52% to 84% at the concentrations (0.5 - 5 μg·ml-1) compared with the control. In the irrigated open field experiment, the herbicides were less efficient in controlling the broomrape. The dead spikes increased from 10.5% to 29.1% at the concentrations (1 - 5 μg·ml-1) compared with the control. In the greenhouse experiment, the herbicides were more effective than open field and the dead spikes were increased from 30 to 68% at the concentrations 5 and 10 μg·ml-1. In conclusion, the foliar application of herbicides were able to increase the broomrape dead spikes attached to the tomato plants at the concentrations (3 - 5 μg·ml-1) without visible negative effect on tomato plants.展开更多
基金Project supported by the Natural Science Foundation of Hubei Province(No.2006ABA182).
文摘Irnazaquin applied in legume crops has a long residual time in soil, which often impacts safety of the susceptible crops. To increase safety of imazaquin application, two composted litters, bovine manure （BM） and chicken manure （CM）, were used to determine their effects on imazaquin environmental behavior by incorporating each kind of manure into the tested sandy loam soil at 10% （w/w）. The degradation of imazaquin in BM- and CM-amended soil was about 2.4 and 1.5 times, respectively, faster than that in unamended soil. The half-lives of imazaquin in BM-amended soil varied between 6.7 and 15.4 d over the temperature range of 20 to 40℃, and the degradation rate constant （k） increased by a factor of about 1.5 for every 10℃ change. Higher mix ratio did not significantly increase the degradation, and the optimal active degradation of imazaquin was observed approximately at the mix ratio of 10：1 of soil to BM. The different moisture levels had negligible effect on imazaquin degradation. In both unamended and BM-amended treatments, two metabolites were observed at 5, 10 and 30 d after treatment. One metabolite at retention time （RT） of 8.4 rain was identified as 2-（4- hydroxyl-5-oxo-2-imidazolin-2-yl） quinoline acid, originating from the loss of isopropyl group and hydroxylation at the 4-position of imidazolinone ring. The other at RT of 12.9 rain was identified as quinoline-2,3-dicarboxylic anhydride, resulting from detachment of imidazolinone ring and the forming of dicarboxylic anhydride. This finding suggested that the addition of farm litters into soil might be a good management option since it can not only increase soil fertility but also contribute to increase safety of imazaquin application to the following susceptible crops.
文摘In a bid to make slow release formulations of imazaquin, the herbicide was encapsulated in starch and chitosan beads reinforced with alginate. The beads were characterized using SEM, DSC and FTIR. Two types of formulations were made by extrusion into 0.25 M calcium chloride solution: chitosan/alginate (LNCI) and starch/alginate (LNSI) beads, and the third was by gelatinization of starch at 75?C (LNSI2). Findings showed highly porous spherical beads, the starch/alginate beads bigger and less porous than the chitosan/alginate beads with diameters of 2.53 ± 0.01 and 2.31 ± 0.01 mm;porosity of 57.58% ± 0.2% and 81.28% ± 0.2% and swelling of 34.91% ± 0.2% and 80.35% ± 0.2%, respectively. FTIR revealed a reduction in intensity of the carboxylate peaks of alginate and the peak at 1058 cm?1, present in the FTIR of the matrices, is shifted to lower wave-numbers in the formulations, signifying interactions between the formulation components that make for good slow release. The DSC thermograms of all formulations showed evidence of interaction of imazaquin carboxylate group with the N-atoms of the macromolecules, which is indicative of reduced crystallinity of imazaquin.
文摘The Egyptian broomrape (Orobanche aegyptiaca Pers.) is an obligate holoparasitic weed that causes severe damage to many important vegetable and field crops. In this investigation, three herbicides;chlorsulfuron, triasulfuron and imazaquin were tested to evaluate their efficiency in controlling the tomato broomrape. The herbicides significantly reduced the broomrape parasitizing tomato plants growing in pots, irrigated open field and under greenhouse conditions as foliar spray at the concentrations (0.5 - 10 μg·ml-1) without visible injury effect on the plants. In the pot experiments, triasulfuron increased the dead spikes from 77% to 84%;chlorsulfuron from 51% to 84% and imazaquin from 52% to 84% at the concentrations (0.5 - 5 μg·ml-1) compared with the control. In the irrigated open field experiment, the herbicides were less efficient in controlling the broomrape. The dead spikes increased from 10.5% to 29.1% at the concentrations (1 - 5 μg·ml-1) compared with the control. In the greenhouse experiment, the herbicides were more effective than open field and the dead spikes were increased from 30 to 68% at the concentrations 5 and 10 μg·ml-1. In conclusion, the foliar application of herbicides were able to increase the broomrape dead spikes attached to the tomato plants at the concentrations (3 - 5 μg·ml-1) without visible negative effect on tomato plants.
