Activation Technology For Humic Acid From Leonardite And Its Effects On Growth Of Ryegrass

Humic acid(Humic)can be divided into mineral source humic acid and biological source humic acid.The humic acid in this experiment is derived from mineral source humic acid.Leonardite contains huge molecular humic acid,which is poor solubility and litttle active functional groups,so that playing role of small.Therefore,in order to improve the activity of humic acid,this paper explored the best activation technology by the comparison of several method.Analyzing and evaluating the activation products,and the effect of humic acid in agriculture is discussed,including the effect of humic acid on orchard soil microbial and effect on ryegrass growth,the effect of humic acid on soil phosphorus availability and its improvement effects on saline alkali soil.To provide a theoretical basis for the future of activation technology for humic acid from Leonardite and mass production and Application.The main results were as follows:1.The roller mill dissolved humic acid potassium with hydroxide activation to improve the solubility,the optimum conditions were the quality of potassium hydroxide accounted for10% of leonardite,the rotation rate is 50r/min,the grinding time is 60 min.Under these conditions,the water solubility of humic acid was 31.4%,pH was 7.52,the electric conductivity was 865μS/cm,and the water solubility was higher than that of the non activated treatment,which was about 174.7%.2.Humic acid could improve the soil microbial community structure.In the pot experiment,2500 g orchard soil was added with 50 g humic acid,the number of soil actinomycetes by culturing for 95 days reached to 35,627,000 per gram of soil,but CK was only about 4502 per gram of soil.3.Humic acid significantly increased the physiological activity of ryegrass,and soluble fulvic acid significantly increased the activity of SOD and nitrate reductase.However,humic acid significantly increased root activity and enhanced root growth.Humic acid from leonardite could ensure adequate soil carbon pool resources,and sustain rapid growth of ryegrass.Ryegrass’ cumulative biomass of HS5 when the 51 day of growth was higher thanthat of CK 145 g.4.Monoammonium dihydrogen phosphate and activated leonardite were mixed according to the ratio of 1: 0,1: 0.1,1:1 and 1:5 respectively.The mixture of phosphate and activated leonardite was incubated in the same cinnamon soil with same quantity at room temperature under three soil relative moisture contents of 50%,75% and 100%,respectively.The available phosphate in the incubation mixtures was determined according to different sample collecting time.The results revealed that the phosphorus fertilizer was invalid in the soil in a short period incubation time,and the available phosphorus content in the soil was rapidly decreased after 7 to 14 days incubation.The decrease rate of available phosphate under relative moisture contents of 50%,75% and 100% reached 30%,21% and 13%,respectively.Many literatures reported that the humic acid can reduce the soil of phosphorus fixation in soil.Compared to those treatments with none activated leonardite,the activated leonardite treatments had enhanced the available phosphorus content significantly in the soil.Among the activated leonardite treatments,the highest available phosphorus content was fond in the treatment with the 1:5 ratio of P2O5 and AHA,followed by the treatment with 1:1 ratio of P2O5 and AHA.5.In the experiment of high saline alkali soil,with the increase of humic acid,the total salt content of soil reduced significantly.2500 g saline-alkali soil was added with 400 g humic acid,the total salt content of soil was decreased than CK by 23.5%.However,different humic acid added,the pH value of saline alkali soil had not significant difference.6.With humic acid adsorption characteristics of soil exchangeable ions,total salt decreased with the addition of humic acid has reached extremely significant level for polynomial(P),and the related equation is y=-4×10-6x2+ 0.0032x+0.1596,where y is the total salt decreased(g/ kg)and x is the amount of humic acid(g/ pot),namely in the test of humic acid dosage range,the total salt of Dongying saline alkali soil decreases significantly with increasing amount of humic acid.