Objective The absorption and distribution of nitrogen(N),phosphorus(P),and potassium(K) of Hedyotis diffusa was studied in field tests.Methods Through regular sampling,dry matter accumulation was studied,the contents of N,P,and K were analyzed by conventional methods.Results The uptake amount of N,P,and K by H.diffusa was lower at seedling stage,but increased rapidly at branching,blossoming,and fruiting stages,and the uptake amount of N and P decreased and K was negatively absorbed at mature stage.The uptake amount of N by H.diffusa was the highest,following was K2O,while P2O5 was the lowest.In the growing season of H.diffusa,the ratio of N,P2O5,and K2O was 1.00:0.14:0.54.N Mainly distributed in leaf at seedling,branching,and blossoming stages,while P2O5 and K2O mainly distributed in stem.The mineral nutrition mostly distributed in stem,flowers,and fruits at fruiting and mature stages,N and P2O5 mostly distributed in flowers and fruits,but K2O mainly accumulated in stem.Conclusion A little fertilizer should be applied at seedling stage,oppositly the use amount of fertilizer should be increased at branching,blossoming,and fruiting stages,particularly P and K at fruiting stage.

Objective: To establish a method to determine 5 hazardous elements in animal traditional Chinese medicines (TCM) by microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS).Methods: HNO 3-H 2 O 2 was used to decompose animal TCM, the working parameters of ICP-MS were optimized, and the matrix effect and the mass spectrum interferences were corrected by the in-line addition of Ge, In and Bi internal standard solution and the collided reaction cell technology (KED mode), respectively.Results: The detection limits of 5 hazardous elements were within the range of 0.04-0.52 μg·L-1 , the relative standard deviations (RSD) were within the range of 1.1%-4.8% , and the recoveries were within the range of 92.4%-110.0%.The method was applied to determine the 5 hazardous elements in 40 batches of animal TCM.The results indicated that some kinds of hazardous elements in animal TCM were high, and more attention should be paid to the problems in the production and use of animal TCM.Conclusion: The analysis method is simple, rapid and accurate, and suitable for the determination of hazardous elements in animal TCM.