| In order to understand the residual digestion and adsorption of Trinexapac-ethyl and its metabolites Trinexapac in farmland after the application of anti-diester and its related preparations in farmland,this paper was analyzed by HPLC-UV,Residue analyswas and detection methods of Trinexapac-ethyl and its metabolites Trinexapac in field soils were analyzed and established.The Trinexapac-ethyl and its metabolites Trinexapac were studied systematically by batch balance method and indoor simulation technique.And the effects of adding biochar,chitosan and?-cyclodextrin,clay minerals and chemical fertilizers on the adsorption of Trinexapac-ethyl and their metabolites in two typical farmland soils in Hunan were studied.The main conclusions are as follows:1.The residual Trinexapac-ethyl and its metabolites in the farmland soils can be extracted with acidic acetonitrile.The extract was purified by Florwasil dispersive solid phase extraction and then analyzed by HPLC-UV.2.The Trinexapac and its metabolites were degradated at 20?under constant temperature and dark culture conditions,and the half-life was less than 9.5 days,indicating that it was susceptible to degradation and it will not form residual pollution.3.The adsorption process of Trinexapac-ethyl and Trinexapac in two kinds of farmland soils can be roughly divided into two stages.First,the rapid adsorption stage?about 12 hours,adding YKC and DKC may bring forward to within 2-10h?,the second was the adsorption equilibrium stage?after 12 h?.But in order to operate conveniently and make sure the accuracy and consistency of the results,the adsorption equilibrium time unified for 24h.4.The addition of chitosan can increase the adsorption capacity of Trinexapac-ethyl and its metabolites Trinexapac in two typical farmland soils in Hunan,and the increase rate was between 14.17%to 23.49%.The addition of?-cyclodextrin can obviously increase the adsorption capacity of Trinexapac-ethyl and its metabolites Trinexapac in alluvial soil.The increase rate of Trinexapac-ethyl and Trinexapac in the alluvial soil was between 29.55%to43.81%.However,thwas increase was very small in the Quaternary red soil,and the increase rate was only between 0.25%to 1.53%.The effect of pH on the adsorption of Trinexapac-ethyl and Trinexapac in Quaternary red soil was the highest under acidic conditions after adding chitosan or?-cyclodextrin.The adsorption capacity decreases with the increase of pH,and their adsorption in alluvial soil was the highest at p H=7.However,it decreased in acidic or alkaline conditions.5.The addition of YKC and DKC could significantly increase the adsorption capacity and adsorption rate of Trinexapac-ethyl and Trinexapac in the two farmland soils,while the effect of MCC and JGC was not that obvious.For the Quaternary red soil,the addition of YKC and DKC could increase the adsorption and adsorption rate of Trinexapac to a certain extent,while the effect of MCC and JGC was not that obvious,even before the adsorption time was less than 10 hours.The addition of YKC could significantly increase the adsorption and adsorption rate of Trinexapac,and the effect of DKC was very small,while MCC and JGC could significantly reduce the adsorption and adsorption rate of Trinexapac.6.Whether added four kinds of bio-carbon or not,the adsorption kinetics of Trinexapac-ethyl and Trinexapac in two kinds of farmland soils can be described by pseudo-second order kinetic equation.The isothermal adsorption curve can be consistent with Freundlich and Linear equation.7.After adding clay minerals,the adsorption capacity and adsorption rate of Trinexapac-ethyl in the two kinds of soils were increased,there is a big difference among increase rates,The adsorption capacity and adsorption rate of Trinexapac in the two tested farmland soils decreased by adding kaolinite,while the others increased and the increase was small.After adding clay minerals,the isothermal adsorption process of Trinexapac-ethyl and Trinexapac in two tested farmland soils conforms to Freundlich and Linear equations,but does not accord with Langmuir equation;And the adsorption capacity of Trinexapac-ethyl and Trinexapac were accurately reflected by adsorption constants Kd and LgKf.8.The application of chemical fertilizers can change the adsorption capacity of Trinexapac-ethyl and Trinexapac in two kinds of farmland soils tested to a certain extent.For the Quaternary red soil,the application of urea and ammonium chloride can increase the adsorption capacity of Trinexapac-ethyl and Trinexapac,the rate of increase was between4.38%and 12.19%,the application of the remaining four chemical fertilizers,can reduce the adsorption capacity,the rate of reduction was between 1.77%to 38.75%;and for the alluvial soil,the situation was much more complex,after the application of six chemical fertilizers,the adsorption amount of Trinexapac-ethyl and Trinexapac increased,the increase or decrease range of Trinexapac-ethyl within 30%,while the range of increase or decrease in Trinexapac was much wilder,such as the application of urea,ammonium chloride,KH2PO4can significantly increase its adsorption in the alluvial soil,the rate of increase was between72.03%to 190.72%,the application of superphosphate and KH2PO4 can significantly reduce the adsorption of Trinexapac,the rate of decrease was between 47.39%to 62.81%,and the application of KCl decrease adsorption by 1.63%with minimal impact. |
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