| The research site is located in Mohe County,Daxinganling area,Heilongjiang Province,and is the only continuous permafrost distribution area in China.This paper takes three kinds of permafrost with disturbance as the research object,and uses the method of indoor simulation freezing and thawing to measure the physical and chemical properties of soil in different depth,analyzes the differences of soil physical and chemical properties in permafrost area before and after freezing and thawing,and reveals the change of soil carbon,nitrogen and phosphorus in frozen soil and the reasons for the change.The main results are as follows.(1)In this study,Soil organic carbon content decreased with the increase of soil layer under different freeze-thaw treatments and before freeze-thaw.Under different freeze-thaw time,the maximum value of soil organic carbon content was 25.25 g·kg-1,and the minimum value was 18.87 g·kg-1.There was no significant difference in each soil layer(P>0.05).The maximum value of soil organic carbon content under human disturbance was 33.00 g·kg-1,and the minimum value was 21.33 g·kg-1.There was a significant difference between 0-20 cm and 40-60 cm(P<0.05).The maximum value of soil organic carbon content under severe human disturbance was 34.14 g·kg-1,and the minimum value was 23.46 g·kg-1.There was a significant difference between 0-20 cm and 20-40 cm(P<0.05).Under different freezing and thawing temperatures,the maximum value of soil organic carbon content was 28.60 g·kg-1,and the minimum value was 19.04 g·kg-1.There were significant differences in the contents of40-60 cm and 60-80 cm soil layers(P<0.05).The maximum value of soil organic carbon content under human disturbance was 33.52 g·kg-1,and the minimum value was 21.30g·kg-1\.There were significant differences in the contents of 0-20 cm and 20-40 cm soil layers,40-60 cm and 60-80 cm soil layers(P<0.05).The maximum value of soil organic carbon content under severe human disturbance was 35.90 g·kg-1,and the minimum value was 23.52 g·kg-1.There was a significant difference in soil content between 60-80 cm and above 80 cm(P<0.05).Under different water content conditions,the maximum value of soil organic carbon content was 30.39 g·kg-1,and the minimum value was 18.80 g·kg-1.There were significant differences in organic carbon content between 60-80 cm and above 80 cm soil layers(P<0.05).The maximum value of soil organic carbon content under human disturbance was 34.59 g·kg-1,and the minimum value was 21.43 g·kg-1.There was a significant difference in organic carbon content between 0-20 cm and 40-60 cm soil layers(P<0.05).36.10 g·kg-1and 23.50g·kg-1.There were significant differences in organic carbon content between 0-20 cm and 20-40 cm soil layers(P<0.05).(2)The soil total nitrogen content of different freeze-thaw treatments and before freeze-thaw decreased with the increase of soil layer.Under different freeze-thaw time,the maximum value of soil total nitrogen content was 1.560 g·kg-1,and the minimum value was 0.813 g·kg-1.There was no significant difference in total nitrogen content among the soil layers(P>0.05).The maximum and minimum of total nitrogen content were 1.810 g·kg-1and 1.173 g·kg-1.There was significant difference in total nitrogen content between 40-60 cm and 60-80 cm soil layers(P<0.05).The maximum and minimum contents of total nitrogen were 2.017 g·kg-1and 1.240 g·kg-1,respectively.There was significant difference in total nitrogen content between 20-40 cm and 40-60 cm soil layers(P<0.05).Under different freezing and thawing temperatures,the maximum and minimum of total nitrogen content were 1.700 g·kg-1and 0.790 g·kg-1.There was significant difference in total nitrogen content between 40-60 cm and 80 cm soil layers(P<0.05).The maximum and minimum contents of total nitrogen were1.807 g·kg-1and 1.087 g·kg-1.There was significant difference in total nitrogen content between 40-60 cm and 60-80 cm soil layers(P<0.05).The maximum and minimum contents of total nitrogen were 1.877 g·kg-1and 1.283 g·kg-1,respectively.There was significant difference in total nitrogen content between 40-60 cm and 60-80 cm soil layers(P<0.05).Under different water content treatments,the maximum value of soil total nitrogen content was 1.610 g·kg-1,and the minimum value was 0.530 g·kg-1.There was significant difference in total nitrogen content among different soil layers(P<0.05).The maximum and minimum of total nitrogen content were 1.820 g·kg-1and 1.135g·kg-1.There was significant difference in total nitrogen content among different soil layers(P<0.05).The maximum and minimum contents of total nitrogen were 1.885g·kg-1and 1.260 g·kg-1.There was no significant difference in total nitrogen content among the soil layers(P>0.05).(3)The content of ammonium nitrogen and nitrate nitrogen in soil before different freeze-thawing treatment and freeze-thaw decreased with the increase of soil layer.The maximum value of interference ammonium nitrogen content was 1.223 mg·kg-1for different freeze-thawing time,0.713 mg·kg-1for the relative no one,and there was no significant difference in the content of ammonium nitrogen in each soil layer(P>0.05).The maximum value of nitrate nitrogen content was 0.133 mg·kg-1,and the minimum value was 0.014 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum content of artificial interference ammonium nitrogen is 1.653 mg·kg-1;the minimum value is 1.257 mg·kg-1,and the content of ammonium nitrogen in soil layer with 0-20 cm and 20-40 cm is significantly different(P<0.05).The maximum value of nitrate nitrogen content was 0.176 mg·kg-1,and the minimum value was 0.039 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum value of the content of ammonium nitrogen in severe artificial interference was 1.840 mg·kg-1;the minimum value was 1.287 mg·kg-1,respectively;there was no significant difference in the content of ammonium nitrogen in each soil layer(P>0.05).The maximum value of nitrate nitrogen content was 0.197 mg·kg-1,and the minimum value was 0.057 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum value of interference ammonium nitrogen content was 1.723 mg·kg-1,the minimum value was 0.936 mg·kg-1,and there was no significant difference in the content of ammonium nitrogen in each soil layer(P>0.05).The maximum value of nitrate nitrogen content was 0.127 mg·kg-1,and the minimum value was 0.011 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum content of artificial interference ammonium nitrogen was 1.820mg·kg-1;the minimum value was 1.073 mg·kg-1;there was no significant difference in the content of ammonium nitrogen in each soil layer(P>0.05).The maximum value of nitrate nitrogen content was 0.170 mg·kg-1,and the minimum value was 0.038 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum value of the content of ammonium nitrogen in severe artificial interference was 2.047 mg·kg-1;the minimum value was 1.220 mg·kg-1;there was no significant difference in the content of ammonium nitrogen in each soil layer(P>0.05).The maximum value of nitrate nitrogen content was 0.213 mg·kg-1,and the minimum value was 0.073 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum value of interference ammonium nitrogen content was 1.815 mg·kg-1for different water content treatments,and the minimum value was 1.005 mg·kg-1,and the content of ammonium nitrogen in 20-40 cm and 40-60 cm soil layer was significantly different(P<0.05).The maximum value of nitrate nitrogen content was 0.145 mg·kg-1,and the minimum value was 0.025 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum content of artificial interference ammonium nitrogen is 1.980 mg·kg-1;the minimum value is 1.090 mg·kg-1,and the content of ammonium nitrogen in 60-80cm and 80 cm soil layer is significantly different(P<0.05).The maximum value of nitrate nitrogen content was 0.170 mg·kg-1,and the minimum value was 0.040 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).The maximum value of the ammonium nitrogen content of severe artificial interference was 2.175 mg·kg-1;the minimum value was 1.300 mg·kg-1,and the content of ammonium nitrogen in 60-80 cm and 80 cm soil layer was significantly different(P<0.05).The maximum value of nitrate nitrogen content was 0.185 mg·kg-1,and the minimum value was 0.045 mg·kg-1.There was no significant difference in nitrate nitrogen content in each soil layer(P>0.05).(4)In this study,the total phosphorus content of soil before and after different freezing and thawing was decreased with the increase of soil layer,.The maximum phosphorus content of the soil was 0.898 mg·kg-1and the minimum value was 0.643mg·kg-1.There was no significant difference in total phosphorus content in each soil layer(P>0.05).The maximum of total phosphorus content in soil disturbed by human being is 1.001 mg·kg-1,and the minimum value is 0.675 mg·kg-1.The total phosphorus content of 0-20 cm and 20-40 cm soil layers was significantly different(P<0.05).The maximum total phosphorus content of soil with severe artificial disturbance was1.222 mg·kg-1,and the minimum value was 0.696 mg·kg-1.There was no significant difference in total phosphorus content in each soil layer(P>0.05).The maximum phosphorus content of soil was 1.041 mg·kg-1 and the minimum value was 0.604mg·kg-1.There was no significant difference in total phosphorus content in each soil layer(P>0.05).The maximum of total phosphorus content in soil disturbed by human being is 1.088 mg·kg-1,and the minimum value is 0.673 mg·kg-1.The total phosphorus content of 20-40 cm and 40-60 cm soil layers was significantly different(P<0.05).The maximum total phosphorus content of soil with severe artificial disturbance was1.284 mg·kg-1,and the minimum value was 0.733 mg·kg-1.There was no significant difference in total phosphorus content in each soil layer(P>0.05).The maximum phosphorus content of soil was 1.805 mg·kg-1and 0.826 mg·kg-1.The total phosphorus content of 40-60 cm and 60-80 cm soil layers was significantly different(P<0.05).The maximum of total phosphorus content in soil disturbed by human being is 1.890mg·kg-1,and the minimum value is 0.960 mg·kg-1.The total phosphorus content of soil layer was significantly different from that of 80 cm(P<0.05).The maximum of total phosphorus content in soil with severe artificial disturbance was 1.960 mg·kg-1,and the minimum value was 1.075 mg·kg-1.There was no significant difference in total phosphorus content in each soil layer(P>0.05). |
PDF Full Text Request