Effects Of Activated Humic Acid Application On Wheat-Maize Growth,Soil Fertility And Soil CO₂ Flux

Humic acid fertilizer is a new type of organic fertilizer,which plays a role in promoting crop growth and yield,adjusting soil organic carbon and nitrogen mineralization process and soil nutrient balance.This present research studied on the characteristics of CO₂ flux with continuous observation,soil fertility and wheat-maize biological characteristics and yield in the wheat-maize farmland ecosystem of cinnamon soil,aimed to elucidate the influence of the activation and dosage of humic acid on the biological characteristics of wheat-maize,soil fertility and CO₂ flux.The main results were as follows:?1?The application of humic acid promoted the growth of wheat-maize,increased crop yield and above-ground biomass,and the difference was significant with different fertilization treatments.Maize yield was lower with alkali activated humic acid treatment AHA1 than that with oxygen activated humic acid treatment OHA1 increase,and the medium dosage has the opposite trend.AHA1 treatment of wheat-maize yield were higher compared with other treatments,for wheat and maize yield was the most obvious effect.It can be seen that the application of humic acid has a significant effect on wheat-maize yield in the cinnamon soil.According to the multiple linear stepwise regression analysis,it was concluded that CEC had direct effects on the aboveground biomass of wheat-maize,and to some extent,determined the aboveground biomass of wheat-maize.?2?Compared with Blank treatment,the soil bulk density of humic acid was decreased,and in the wheat season and maize season,AHA3 treatment and OHA1 treatment were lowest,reduced by 15.42% and 11.84%.In addition to AHA2 treatment,humic acid treatment significantly increased the content of large aggregates?> 0.25 mm?and average weight diameter?MWD?in the soil.Compared with Blank treatment,humic acid treatment made soil moisture,soil porosity?soil saturated water content,capillary water content,FMC,TP,capillary porosity and aeration porosity?and soil nutrient status?pH,EC,OM,TN,IN and CEC?improving.Compared with Blank treatment,soil moisture and porosity were obviously increased with AHA3 treatment in wheat season,and OHA1 and OHA2 were better in maize season.Compared with Blank treatment,soil total nitrogen content was the highest with OHA1,increased by 20.61% in wheat season,and AHA2 was the most significantest,increased by 28.57% in maize season.Compared with Blank treatment,soil organic matter with OHA3 treatment was significantly increased by 16% and 13.70% in wheat-maize season.Through principal component analysis with eight physical factors and five chemical factors,soil fertility OHA1> OHA2> OHA3> AHA1> AHA3> AHA2> Blank> CK.The comprehensive score of the two principal components is clustered,and the fertility level of the cinnamon soil in Tai'an can be first class?OHA1,OHA2?> second class?OHA3,AHA1,AHA3?> third class?AHA2?> fourth class?Blank?> fifth class?CK?.?3?Compared with CK,there was no significantly in soil CO₂ flux in Blank,the average of soil CO₂ flux in humic acid treatment was significantly increased by 13.23%-21.88% in the maize season,it can be seen that the application of humic acid can obviously increase the rate of CO₂ emission from soil.Compared with CK and Blank,the soil CO₂ accumulation flux with humic acid treatment in wheat-maize season was significantly increased,which were lower with OHA1 and OHA3 than others humic acid treatment.According to the regression analysis by multiple linear stepwise,it was concluded that soil ammonium content had a direct effect on the soil CO₂ accumulation flux of wheat-maize.Based on the above results,the application of humic acid has a significant effect in improving the soil structure and soil chemical properties in the wheat-maize continuous cropping system in the cinnamon soil.Application of humic acid can significantly improve soil fertility levels,with the decrease of the amount of oxygen activated humic acid.Soil fertility of alkali activation treatment was lower than that of oxygen activation treatment.Compared with CK,Blank increased soil fertility.Humic acid treatment were positive to crop yield.The results provide scientific basis and data support for the promotion of activated humic acid fertilizers,the improvement of soil productivity in the cinnamon soil and the protection of the ecological environment.