Effects Of Application Organic-inorganic Compound Fertilizer From Cattle Manure On Soil Labile Organic Carbon Franctions

A field experiment was carried out to study the impact of organic-inorganic compound fertilizer based on animal manure on soil labile organic carbon fractions under different treatments including no fertilizer control (CK), chemical fertilizer (NPK), organic manure (OM) and three kinds of organic-inorganic compound fertilizer based on cattle manure. It mainly studied the dynamic change of permanganate oxidizable carbon (POXC), dissolved organic carbon (DOC) and water-soluble organic carbon (WSOC), and investigated the interrelation of soil liable organic carbon fractions and soil nutrients and crop yield. The main conclusions as follows:(1) In wheat-maize rotation, application of three kind organic-inorganic compound fertilizers can significantly improve POXC in0-40cm soil layer, but the POXC response changed with soil depth and N levels. Compared to CK, the POXC concentration of HCM in0～20cm soil layer and LCM in20-40cm soil layer increase29.90%and18.45%, respectively. The effect of organic-inorganic fertilizer on POXC of soil total organic carbon (TOC) changes with soil depth varies. The increased rate of POXC of TOC in0-20cm soil layer under CM was highest (18.64%), followed by HCM and LCM, while the increased rate (15.19%) of HCM was highest in20-40cm soil layer. Moreover, there was significant or highly significant positive correlation between POXC and available K in topsoil. And the relationship of POXC and total nitrogen (TN), available potassium (AP), available phosphorus (AP) and maize production reached highly significant level (P<0.01).(2) In wheat-maize rotation, Compared to before the test, the DOC concentration of different fertilize treatments in0-40cm soil layer decreased and the highest decline was CK (35.56%). The DOC of TOC also show reduction trend in total but existed some differences among treatments. DOC was5.13～12.35%in0-20cm soil layer and6.32～15.20%in20～40cm soil layer of TOC was higher than that of CK in the corn maturity, respectively. In addition, the relationship only between DOC and available K in topsoil showed a highly significant (P<0.01) and there was also a significant correlation between DOC and wheat yield at jointing stage and booting stage (P<0.05).(3) In wheat-maize crop rotation, different fertilization treatment increased WSOC of0～40cm soil layer in varying degrees. Compared to CK, the WSOC in0～20cm and0～40cm soil layer under three kinds of organic-inorganic compound fertilizer increased24.13～51.64%and1.05～17.41%, respectively, and the WSOC of HCM were the highest in different soil layers. Meanwhile, different fertilization treatment increased WSOC of TOC in0～40cm soil layer in varying degrees relative to the control, the POXC of TOC in0～20cm and20～40cm soil layer increased0.03～28.74%and2.46～17.09%, respectively. There was a highly significant correlation between WSOC and available potassium in topsoil, and available phosphorus in20～40cm soil layer (P<0.01). And the correlation between WSOC and wheat yield at jointing stage and booting stage reach a significant level (P <0.05).