Effects Of Organic Matter Addition On Cinnamon Soil Organic Carbon Fractions,Water Holding And Compression Characteristics

Decline in soil fertility,shallow plough layer and water retention characteristic shortage have been the actual problems that restricted the local production in the west region of Liaoning Province.An indoor incubation and field experiments were conducted to study the effect of addition type of organic matter(corn stalks-JG,biochar-BR,commercial organic fertilizers-OR,and biochar made by stalks-JBR)and different fertilization mode(MT-no-tilled plots,deep incorporation of stalks-ST,organic fertilizer-OM,and CK)on the organic carbon factions,water retention,compression characteristics.Effects of different fertilization modes on the soil carbon sequestration,water holding capacity,and reduction of soil compaction were discussed to provide data support and theory basis for enhancing soil yield and increasing efficiency of dry land production in Northeast of China.The main conclusions are as follows.1.Effects of organic matter additions on soil organic carbon fraction,water retention,and soil compression characteristics.(1)The effects of different incubation time on the soil organic carbon(SOC)and activity organic matter(AOM)showed that particulate organic carbon(POC),dissolved organic carbon(DOC)and easily oxidized organic carbon(EOC)have a very significantly increasing trend with the incubation time,and a significant opposite trend was observed for microbial biomass carbon(MBC)and mineral combined organic carbon(MOC)except that there is no significant differences between T6 and T10 for SOC.The effect of the type and ratio of organic matter addition to SOC and AOC in T6 and T10 indicated that there were significant or extremely significant differences for soil carbon fraction except for the single effect of addition ratio on EOC in T6 stage.Except for MBC of T10,SOC and AOC showed that 3% addition were higher than 1% addition.Single effects of addition type had different influences on SOC and AOC.The interaction effect of addition type and ratio had no significant differences with SOC,MOC of T6 and MBC of T10,then other fractions reached significant or extremely significant differences.(2)The single and interaction effects of addition type and ratio on the soil-water characteristic curve and water parameter showed that soil moisture of 3% addition were higher than 1% addition except high suction treatment of JBR under the same water suction.Effects of addition ratio to the soil-water characteristic curve.The single and interaction effect of matters type and addition proportion all had significant difference with soil moisture content(saturation moisture content,field capacity,and wilting moisture content)and soil physical index.Increasing organic matters were benefit for enhancing soil water capacity and JG had the best treatment effect.(3)Under the external pressure,the addition type and ratio of organic matter affect the shape of the soil compression curve,compression characteristics and the initial void ratio of the soil.Under different soil water suction,the single and interaction effects of addition type and ratio on soil compaction parameters are different,which maximum curvature and pre consolidation pressure value of 3% adding are higher than 1% adding,while reducing soil initial porosity ratio,compression index and rebound index.Increasing the proportion of organic materials are beneficial to enhancing the pressure resistance of soil.2.Effects of fertilization modes on soil active organic carbon fractions,water holding capacity and compression characteristics(1)The effects of Fertilizer Cultivation on SOC and AOC in different soil layers were different for soil depths,and all 0-10 cm contents were significantly or very significant.The changes of SOC and AOC(POC,MBC,DOC and EOC)in soil profiles were very different.MT treatment effectively increased the contents of SOC,POC and MOC in the plough layer,while ST treatment could increase the MBC and DOC contents in the plough layer.(2)Compared with CK treatment,MT,OM and ST treatments can significantly improve water holding capacity and field capacity.The interaction of fertilization modes and soil depths had significant effects on soil moisture constants and S index.(3)Fertilization modes and soil moisture content all significantly affect the pre consolidation pressure of soil.The interaction effect of fertilization modes and soil moisture content on soil compressibility index is very significant.In summary,improving soil organic carbon and mineral bound organic carbon content are beneficial to increasing field capacity,saturated water content and wilting point content,which is beneficial to reduce the risk of soil compaction.Therefore,considering the local conditions,selecting suitable organic material type to fertilize the soil or using no tillage(MT)fertilization can increase soil organic carbon content,improve soil water holding and compressive properties.