Study On The Effect Of Biochar Combined With Biogas Slurry On Horizontal Infiltration Characteristics And Physical And Chemical Properties Of Soil

Biogas slurry is the residue produced by anaerobic fermentation of organic matter such as human and animal manure and crop straws.It is a high-quality organic fertilizer with comprehensive nutrients and fast and effective fertilization.Biochar is a class of highly aromatic refractory solid materials produced by high-temperature pyrolysis carbonization of crop straw under oxygen-limited conditions.It has high carbon content and is not easy to be degraded by microorganisms.It is an ideal material for increasing soil carbon pool,reducing atmospheric CO₂ concentration,and mitigating global warming.In this paper,horizontal infiltration and indoor one-dimensional adsorption experiments are used to study the effects of different biogas slurry ratios,biochar mixed amount,biochar mixed thickness,and soil bulk density on soil total nitrogen,organic matter,and physicochemical properties and other effects.The purpose is to increase the retention of nutrients in the biogas slurry in the soil and improve the utilization efficiency of the biogas slurry.The main conclusions are as follows:?1?In the horizontal infiltration test,the moving speed of the wet front,the cumulative infiltration amount,and the soil water diffusivity all decreased gradually with the increase of the biogas slurry ratio,soil bulk density,and biochar mixing.It is shown that the parameters of soil water transport observed in the experiment are affected by the combined effects of biogas slurry ratio,soil bulk density and biochar mixed amount.?2?Under different treatment conditions,the changes in the conductivity of the exudate showed a gradual increase with time and gradually flattened,but there were still some differences in the changes in the conductivity of the exudate in each group.When the biogas slurry ratio is 1:8,the mixed amount and thickness of biochar have a certain effect on the conductivity of exudate but have no regular effect.When the biogas slurry ratio is 1:6,The amount of carbon blending and the thickness of blending have no obvious regular effect on the conductivity of exudate,but when the ratio of biogas slurry is 1:8,the conductivity value gradually begins to show as the thickness and blending of biochar.When the amount of biogas slurry is 1:4,the conductivity of exudate is affected by the amount and thickness of biochar.The above test results show that when the biogas slurry ratio is constant,the key factor affecting the conductivity of the exudate may be the amount and thickness of biochar in the soil,and the influence of the amount of biochar is relatively large.?3?With the same soil bulk density and biogas slurry ratio,as the amount of biochar application increases,the total nitrogen content of the soil exudate gradually decreases,that is,the application of biochar can increase the total nitrogen content of the soil within a certain range.As the application rate increased,the soil bulk density gradually decreased,and the soil>0.25mm water-stable aggregates and the total soil porosity gradually increased;when the biogas slurry ratio was different,as the biogas slurry ratio decreased,the soil bulk density gradually increased.The content of water-stable aggregates and the total porosity of soil increased gradually when the soil was more than 0.25mm.With the increase of the amount of biochar application,the pH value of the soil gradually increased,but the increase trend of the soil pH value was not significant.When the biogas slurry ratio is different,as the biogas slurry ratio decreases,the overall soil pH value gradually increases but the trend is not significant.?4?When the amount and thickness of biochar are constant,the soil organic matter content will decrease as the soil bulk density gradually increases;when the soil bulk density is constant,the soil organic matter content will increase with the increase of biochar mixture amount,of which biochar.When the blending amount is 2.0%,it has the greatest effect on the soil organic matter content,which has nothing to do with the thickness of the biochar blending;when the soil bulk density is constant,the soil organic matter content gradually increases with the increase of the biochar blending thickness,and the biochar blending thickness is 20cm,it has the greatest effect on soil organic matter content,and has nothing to do with the amount of biochar.?5?When the amount and thickness of biochar are constant,the total nitrogen content of the soil will increase as the soil bulk density gradually increases;when the soil bulk density is constant,the total nitrogen content of the soil will increase with the increase of the biochar content.When the carbon content is 2.0%,the total nitrogen content of the soil will have the greatest effect.When the soil bulk density is constant,the soil total nitrogen content will gradually increase with the increase of the biochar mixing thickness,but there is no obvious regular influence trend,which may be affected by soil texture and mixed amount of biochar.