CAJ | 학술논문

为揭示土壤结构改良剂聚丙烯酰胺（Polyacrylamide，PAM）在不同湿润速度下对土壤入渗的影响机制，通过土槽入渗试验，研究混施干粉PAM（0、22.5、45 kg·hm-2）的砂壤土在不同湿润速度（2.5 mm·min-1和6.25 mm·min-1）下土壤入渗参数的变化，通过测定非毛管孔隙率、导气率和团聚体含量来描述土壤结构特征。结果表明：湿润速度显著影响土壤累计入渗量和稳定入渗率，高速湿润条件下的累计入渗量和稳定入渗率比低速度湿润条件分别降低了23.75%和26.70%。在同一湿润速度下，PAM在不同阶段对土壤入渗的影响截然相反：湿润阶段，在PAM作用下土壤累计入渗量、土壤非毛管孔隙率和导气率等均有不同程度降低，且PAM用量越大降低幅度越大，此时正处在逐渐水解过程中的PAM分子长链堵塞了土壤孔隙，抑制了土壤水流运动；连续流阶段，PAM能够提高土壤稳定入渗率、土壤非毛管孔隙率和导气率，且PAM用量越大提高幅度越大，此时PAM分子已经完全水解，发挥了稳定土壤结构的作用，增加了土壤结构中水稳性团聚体含量，从而促进水流入渗。研究不同湿润速度下PAM水解过程对砂壤土入渗性能的影响，可以为PAM在改良土壤结构方面更广泛的应用提供理论依据。
위게시토양결구개량제취병희선알（Polyacrylamide，PAM）재불동습윤속도하대토양입삼적영향궤제，통과토조입삼시험，연구혼시간분PAM（0、22.5、45 kg·hm-2）적사양토재불동습윤속도（2.5 mm·min-1화6.25 mm·min-1）하토양입삼삼수적변화，통과측정비모관공극솔、도기솔화단취체함량래묘술토양결구특정。결과표명：습윤속도현저영향토양루계입삼량화은정입삼솔，고속습윤조건하적루계입삼량화은정입삼솔비저속도습윤조건분별강저료23.75%화26.70%。재동일습윤속도하，PAM재불동계단대토양입삼적영향절연상반：습윤계단，재PAM작용하토양루계입삼량、토양비모관공극솔화도기솔등균유불동정도강저，차PAM용량월대강저폭도월대，차시정처재축점수해과정중적PAM분자장련도새료토양공극，억제료토양수류운동；련속류계단，PAM능구제고토양은정입삼솔、토양비모관공극솔화도기솔，차PAM용량월대제고폭도월대，차시PAM분자이경완전수해，발휘료은정토양결구적작용，증가료토양결구중수은성단취체함량，종이촉진수류입삼。연구불동습윤속도하PAM수해과정대사양토입삼성능적영향，가이위PAM재개량토양결구방면경엄범적응용제공이론의거。
In order to reveal the influence of polyacrylamide(PAM)on soil infiltration under different wetting rates, 3 PAM amounts(0 kg· hm-2, 22.5 kg·hm-2 and 45 kg·hm-2)and 2 water inflow rates(2.5 mm·min-1 and 6.25 mm·min-1)were used in soil box to study the variation of soil infiltration parameters and to characterize soil structures by measuring capillary porosity, gas conductivity and aggregate content. Cu-mulative infiltration amount and stable infiltration rate were significantly influenced by wetting rates,and they were respectively 23.75%and 26.70%lower under high wetting rate than under low wetting rate. Under the same wetting rate, PAM had two quite different effects on soil infiltration over wetting course. At wetting phase, PAM was hydrolyzing and its long-chain molecules clogged soil pores and thus inhibited soil water movement, resulting in decreases in the cumulative soil infiltration, soil non-capillary porosity and conductivity gas rate, with more reduction at higher PAM rate. At continuous flow phase, PAM was completely hydrolyzed and it thus increased soil structure stability and water-stable aggregates, thereby improving soil infiltration rate, soil non-capillary porosity and conductivity gas rate in a dose-effect manner. These results would provide theoretical evidence for PAM application to improvement of soil structure.