The Study Of Farmland Soil C:N:P Stoichiometry Characteristics In China

In order to ensure the increase of grain production,the use of chemical fertilizers in China continues to grow at a rapid rate.The irrational use of chemical fertilizers causes serious pollution to the environment.Regulating the soil nutrient activity is one of the effective ways to solve this contradiction.Therefore,we need to understand the proportion of current soil nutrients in our country.This paper uses the method of mate analysis to analyze the data of “Soil Testing and Formula Fertilization Soil Basic Nutrient Dataset” and the National Scientific Fertilizer Net and “Soil Fertility Evolution in China”.The results are as follows:The farmland soil C/P varied from 89.04 to 3503.48 with a coefficient of variation of 0.5.The average of the seven regions was 623.52,736.13,895.95,899.58,1068.64,616.66,889.88,with the southwest region being significantly higher than the other regions,the minimum value was distributed in the northwest region.Soil N/P ranged from 6.06 to 291.23,and the coefficient of variation was 0.5,the average values in the seven regions were 62.63,67.85,88.96,88.34,103.52,59.46,and 87.24.The pattern of N/P is similar to C/P.Soil C/N ranged from 1.13 to 87.70 with a coefficient of variation of 0.4.The average values for North China,North-east China,East China,South China,North-west China,North-west China and Central China were 10.20,11.27,9.96,10.82,10.62,10.44,10.63,respectively.There was no significant difference between these regions.Based on the data of “Soil Fertility Evolution in China”,27 long-term location experiment data were analyzed.It is found that the C/N ratio is the lowest in alkaline soil,C/P(P represents available phosphorus)is the lowest in neutral soil,N/P distribution is similar to C/P,while N/TP(TP represents total phosphorus)is the highest in neutral soil.In neutral soil,the two treatments of N and NP are compared with CK treatment.C/N will increase significantly,and there is no significant difference between acid soil and alkaline soil,C/P ratio and N/P ratio are consistent in the three soils,and the ratio will be significantly reduced as long as the application of phosphate fertilizer.Under the long-term fertilization treatment,the C:N:P stoichiometry characteristic change pattern is as follows: The C:N ratio under CK treatment and chemical fertilizer treatment was not significantly different between 1979-1999(initial test period)and 2000-2012(after long-term fertilization),at NPKM the C:N ratio increased significantly between 2000 and 2012 with both NPKS treatments.The C/P ratio decreased significantly from 2000 to 2012 at NPK,NPKM,and PK treatments,and there was no significant C/P ratio under CK,NP,and NPKS treatments.There was no significant difference in the C/TP ratio under the long-term application of P,and the N:P ratio and the N/TP ratio were similar under the long-term treatment with P,and they were significantly lower in the later period.Studied the changes between different treatments found that the C/N ratio of chemical fertilizers containing N for a long period of time did not change significantly compared with CK treatment,but the C/N ratio was significantly increased when application N fertilizer and inorganic fertilizer(NM,NPM).C/P,N/P,C/TP,and N/TP were significantly lower in fertilizer treatments with P element compared to CK.The C/P ratio decreased significantly under the combined application of chemical fertilizer and inorganic fertilizer(NPKM),but there was no significant change for C/TP ratio.