Effects Of Litter Input On Soil Carbon And Nitrogen And Nitrogen Net Mineralization In Two Forests

Carbon and nitrogen are important element of material on the earth.Forest in the global carbon and nitrogen cycle occupies an important position.The soil is the basis of forest.Researching the process of forest soil carbon and nitrogen is good for us to understand the cycle of carbon and nitrogen in ecological system.The experiment determined the content of carbon and nitrogen in C.camphora-P.massoniana and Pinus massoniana. At the same time,used litter-fall addition and removal litter were applied to control the input of soil carbon to explore relationship between the ground soil carbon input and the soil nitrogen mineralization. The results are as follows:(1) The month of the highest soil carbon content in Mixed forest is different.The month of the highest content of the SOC in double litter (DL) and control (CK) is August, while that in remove litter (RL) is June. The month of the highest content of the SOC in DL and RL in Pinus massoniana is March, while that in CK is October.The content of organic carbon in DL is higher than that of CK. The increased content of organic carbon between DL and CK in mixed forest is October (18.15g·kg-1)> March(14.95g·kg-1)> June (22.25g·kg-1)> August (10.54g·kg-1). The content of organic carbon in RL is less than that of CK. The reduced content of organic carbon between RL and CK in mixed forest is August (9.32g·kg-1)>March (5.54g·kg-1)>October (-0.07g·kg-1)>June (-7.83g·kg-1). The increased content of organic carbon between DL and CK in Pinus massoniana. is March (10.59g·kg-1)> October (6.68g·kg-1)>June (5.93g·kg-1)>August (5.26g·kg-1).Thereduced content of organic carbon between RL and CK in mixed forest is October (8.05g·kg-1)>June (5.06g·kg-1)>August (3.80g·kg-1)> March (1.99g·kg-1).(2) The content of total nitrogen in DL is higher than that of CK. The increased content of total nitrogen between DL and CK in mixed forest is October (1.10g·kg-1)> August (0.79g·kg-1)>June (0.66g·kg-1)> March (0.57g·kg-1). The content of total nitrogen in RL is less than that of CK. The reduced content of total nitrogen between RL and CK in mixed forest is August (0.54g·kg-1)>March (0.46g·kg-1)>October (-0.08g·kg-1)>June (-0.48g·kg-1). The increased content of total nitrogen between DL and CK in Pinus massoniana. is March (0.48g·kg-1)>June (0.38g·kg-1) > October (0.06g·kg-1)>August (0.04g·kg-1). The reduced content of total nitrogen between RL and CK in mixed forest is October (0.36g·kg-1)>August (0.27g·kg-1)>June (0.10g·kg-1)>March (0.09g·kg-1)(3) DL in mixed forest increased the N mineralization rate significantly in March and August, other months had no significant effect. RL reduced significantly nitrogen mineralization rate in March, other months had no significant effect. DL in Pinus massoniana (except March) significantly increased the N mineralization. RL significantly reduce nitrogen mineralization rate in June, other months had no significant effect. The N mineralization rate in DL is more than that of CK. The increased N mineralization rate between DL and CK in mixed forest is March (0.56mg·kg-1·d1-)>August (0.32mg·kg-1·d-1)>October (0.12mg·kg-1·d-1)>June (-0.05mg·kg-1·d-1).The N mineralization rate in RL is less than that of CK. The reduced N mineralization rate between RL and CK in mixed forest is March (0.41mg·kg-1·d-1)>August (0.04mg·kg-1·d-1)>October (0.01mg·kg-1·d-1)>June (-0.01mg·kg-1·d-1) The increased N mineralization rate between DL and CK in Pinus massoniana. is October (0.45mg·kg-1·d-1)>August (0.21mg·kg-1·d-1)>March (-0.18mg·kg-1·d-1)>June (-0.23mg·kg-1·d-1). The reduced content of total nitrogen between RL and CK in mixed forest is June (0.55mg·kg-1·d-1)> October (0.24mg·kg-1·d-1)> March (0.16mg·kg-1·d-1)> August (-0.20mg·kg-1·d-1)...