Effects of different tillage methods with organic materials application on main soil properties

Aiming at explaining the effect of different tillage on soil properties at early maize growth in black soil region of northeast China,we conducted three tillage methods including no-tillage (NT),shallow tillage (ST) and deep tillage (DT),with different fertilization including no fertilization (CK),manure (M) and maize straw (S),to investigate their effects on emergence rate,soil temperature and soil other properties at maize jointing stage in 2016-2017.The results showed that the soil temperature declined with soil depth under three tillage methods.The ST treatment significantly increased soil temperature at 10 cm depth and the DT treatment significantly increased soil temperature at 20 cm depth with 16%,but had no effect on soil temperature at 25 cm depth.The emergence rate of NT treatment was only 40%,while that of the ST and DT treatments were both 70%.At maize jointing stage,organic fertilizer and straw application in 0-20 cm or 20-40 cm soil layer significantly increased available phosphorus (Av-P) content with DT treatment.Compared with CK,Av-P content in DTM and DTS treatments increased by 30.3%~40.9% and 58.9%~86.1%,respectively;there was no significant effects on the contents of alkaline-hydrochloric nitrogen (Av-N) and available potassium(Av-K).All treatments with the application of organic materials in short time showed no significant increase in SOC content; but light fraction(LF) SOC contents in 0-20 cm or 20-40 cm soil depth were increased.The three tillage methods were with little effect on the soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN),while straw returning and manure affected SMBC from -3.9%~288.6% and SMBN from -30.3%~124.4%,respectively.Obvious positive effect was found in 20-40 cm soil depth than in 0-20 cm soil depth.All treatments increased the content of Av-P,SOC and LF in 0-20 cm and 20-40cm soil depth,and straw incorporation was with a significant effect in improving soil LF,SMBC and SMBN.All sensitive indices were significantly affected by the interaction between organic materials and tillage methods.