Characteristics Of Carbon Pools,Nitrogen Pools,Phosphorus,Potassium And Nitrogen Balance,Phosphorus Balance As Well As Potassium Balance In Soil Profile In Typical Spring Maize Planted Regions In Northeast China

In recent years,excessive utilization of land use and fertilization contributes to significant difference between soil Profile of soil carbon,soil nitrogen,soil phosphorus and soil potassium in northeast three provinces. The characteristics of carbon pools and nitrogen pools in 0-90 cm soil depth were elucidated to make clear the potential of carbon and nitrogen immobilization under the current farmers’ fertilizer practices in typical spring maize planted in northeast China. 17 sites in each province of Heilongjiang Jilin Liaoning, adding up to 51 sites were observed on farmer’s agricultural systems during the whole growth period of spring maize in the year of 2012, soil total carbon(TC), soil organic carbon(SOC), inorganic carbon(IC), particulate organic carbon(POC), microbial biomass carbon(SMBC), dissolved organic carbon(DOC), soil total nitrogen(TN), mineral nitrogen(NO3-N, NH4-N), particulate organic nitrogen(PON), microbial biomass nitrogen(SMBN),dissolved organic nitrogen(DON) in 0-30, 30-60, 60-90 cm soil depth and spring maize yield were determined, and nitrogen balance between before the maize was sown and after the maize was harvested was calculated. And also soil total phosphorus, available phosphorus, available potassium, slowly available potassium were calculated in0-30 cm soil depth. The results showed that:1.The TC stock,TN stock of 0-90 cm soil depth in Heilongjiang, Jilin and Liaoning were 5.7、4.3、3.6 t·ha-1,357.9、286.9、218.1 t·ha-1; the SOC stock and IC stock of 0-90 cm soil depth in Heilongjiang, Jilin and Liaoning were 5.1、4.0、3.0 t·ha-1, 0.6、 0.3、0.5 t·ha-1 in typical spring maize planted in northeast China, respectively; and the mean of SOC stock in each province were significant(p<0.05).2. In 0-30 cm soil depth, the mean of TC, SOC and TN concentration in each province was significant(p<0.05), In 30-60 cm or 60-90 cm soil depth, the mean of TC and SOC concentration in Heilongjiang was significantly(p<0.05)higher than that in Jilin and Liaoning. With soil depth increased, TC TN and SOC concentration in each depth were decreased.3. In soil active carbon and nitrogen pools field, In 0-30 soil depth, the difference of the mean of POC and PON concentration, POC/SOC, SMBC/SOC, DOC/SOC,PON/TN、SMBN/TN among Heilongjiang, Jilin and Liaoning provinces increased and SMBC and SMBN concentration were decreased as latitude decreased, the difference of the mean of SMBC, PON and SMBN concentration, POC/SOC, DOC/SOC or PON/TN concentration at each province were significant(p<0.05).4.In 30-60 cm soil depth, the mean of POC, POC/SOC、DOC/SOC among Heilongjiang, Jilin and Liaoning provinces increased with latitude decreased, and the difference of the mean of POC/SOC at each province reached significantly(p<0.05),but SMBC in Heilongjiang was significantly(p<0.05) higher than that in Jilin and Liaoning.In 60-90 cm soil depth, The mean of POC、POC/SOC、DOC/SOC、 SMBC/SOC in Heilongjiang were significantly lower than that in Jilin and Liaoning, but SMBC in Jilin was significantly higher than that in Liaoning. On the whole, total carbon, soil organic carbon, inorganic carbon and soil active carbon pools at each province decreased with the soil depth increased.5. In 0-30 soil depth, the difference of the mean of PON concentration, PON/TN, SMBN/TN among Heilongjiang, Jilin, and Liaoning provinces increased and SMBN concentration decreased as latitude decreased. In 30-60 cm soil depth, the mean of PON/TN among Heilongjiang, Jilin, and Liaoning provinces increased as latitude decreased, and the difference of the mean of PON/TN at each province was significant(p<0.05). In 60-90 cm soil depth, the mean of SMBN or SMBN/TN in Jilin province was significantly(p<0.05) higher than that in Heilongjiang and Liaoning provinces, and the mean of DON/TN in Heilongjiang was significantly(p<0.05) lower than that in Jilin or Liaoning provinces. On the whole, total nitrogen and soil active nitrogen pools at each province decreased as the soil depth increased.6. In 0-30 cm soil depth, the mean of AP concentration in Heilongjiang, Jilin, and Liaoning province was significant(p<0.05), and the mean of total P in Heilongjiang and Liaoning was significant(p<0.05). As to potassium, the mean of available K, slowly available K in Heilongjiang were significant to other two provinces(p<0.05).7. It was similar trend on the increased or decreased of soil active carbon pools and nitrogen pools among Heilongjiang, Jilin and Liaoning provinces. It was suggested that more attentions should be paid on the reasonable proportion of fertilizer application to improve the C and N availability of cropland soils and on the potential environmental impacts of this fertilization.