CAJ | 학술논문

土壤微生物量和呼吸对秸秆还田后的分解转化及碳固存效果有着显著的响应。为了探明在还田条件下，不同类型秸秆及其碳氮含量对土壤微生物量和呼吸的影响，研究将玉米和大豆不同植株部位秸秆与耕层黑土混合，置于25℃恒温条件下培养61 d。在第61 d测定土壤的微生物量碳（ MBC）、微生物量氮（ MBN）、矿质态氮和微生物呼吸速率，并分析比较它们在不同处理中的差异及其与秸秆C、 N含量之间的相互关系。结果显示，不同类型秸秆添加下的土壤MBC大小表现为：大豆根＞玉米茎下部＞大豆茎＞玉米叶＞玉米茎顶部＞玉米根＞大豆叶，土壤MBN的大小表现为：玉米茎下部＞玉米叶＞大豆根＞玉米根＞玉米茎顶部＞大豆茎＞大豆叶。除大豆叶外，其它处理的土壤MBC/MBN均显著小于空白处理。秸秆含碳量与MBC、 MBN、 MBC/MBN、微生物呼吸速率、呼吸熵之间均有显著的相关关系，而秸秆含碳量与土壤矿质氮含量之间有极显著的负相关关系。土壤MBC、微生物呼吸速率、微生物呼吸熵均与秸秆含氮量呈明显负相关关系。不同秸秆添加下的微生物呼吸速率和呼吸熵的大小表现基本一致，且呼吸速率、呼吸熵两者之间具有极显著的相关关系。大豆茎、大豆叶的呼吸速率和呼吸熵显著大于玉米秸秆2倍左右。研究说明秸秆还田促进了细菌、放线菌等C/N较低的微生物生长繁殖，含氮量高的秸秆不利于还田后期微生物生物量、微生物呼吸速率及活性的保持，土壤微生物活性比微生物量对秸秆分解、微生物呼吸速率的影响更大。图1，表3，参33。
토양미생물량화호흡대갈간환전후적분해전화급탄고존효과유착현저적향응。위료탐명재환전조건하，불동류형갈간급기탄담함량대토양미생물량화호흡적영향，연구장옥미화대두불동식주부위갈간여경층흑토혼합，치우25℃항온조건하배양61 d。재제61 d측정토양적미생물량탄（ MBC）、미생물량담（ MBN）、광질태담화미생물호흡속솔，병분석비교타문재불동처리중적차이급기여갈간C、 N함량지간적상호관계。결과현시，불동류형갈간첨가하적토양MBC대소표현위：대두근＞옥미경하부＞대두경＞옥미협＞옥미경정부＞옥미근＞대두협，토양MBN적대소표현위：옥미경하부＞옥미협＞대두근＞옥미근＞옥미경정부＞대두경＞대두협。제대두협외，기타처리적토양MBC/MBN균현저소우공백처리。갈간함탄량여MBC、 MBN、 MBC/MBN、미생물호흡속솔、호흡적지간균유현저적상관관계，이갈간함탄량여토양광질담함량지간유겁현저적부상관관계。토양MBC、미생물호흡속솔、미생물호흡적균여갈간함담량정명현부상관관계。불동갈간첨가하적미생물호흡속솔화호흡적적대소표현기본일치，차호흡속솔、호흡적량자지간구유겁현저적상관관계。대두경、대두협적호흡속솔화호흡적현저대우옥미갈간2배좌우。연구설명갈간환전촉진료세균、방선균등C/N교저적미생물생장번식，함담량고적갈간불리우환전후기미생물생물량、미생물호흡속솔급활성적보지，토양미생물활성비미생물량대갈간분해、미생물호흡속솔적영향경대。도1，표3，삼33。
Soil microbial biomass play an important role in the decomposition and transformation of residues returned to soil .In order to evaluate the effects of residue types and its carbon and nitrogen concentration on soil microbial biomass and respiration in black soil , different parts of corn and soybean straws were mixed separately with soil , and then incubated for 61 d at 25℃.The microbial biomass carbon (MBC) and nitrogen (MBN), mineral N and soil microbial respiration were measured after incubation , then the relationship between soil microbial biomass (MBC, MBN), respiration and C, N concentrations of different crop residue parts were analyzed .The results showed that the MBC under soybean roots treatments were highest , followed by bottom corn stover , soybean stalk , corn leaves , up corn stover, corn roots, the lowest were under soybean leaves .The MBN of different treatment in a descending order as: bottom corn stover, corn leaves, soybean roots, corn roots, up corn stover, soybean stalk, soybean leaves.Except for soybean leaves , the MBC/MBN of soil amended with residues were lower than blank control significantly .There were significant correlation between the carbon concentration of residues and MBC , MBN, MBC/MBN, microbial respiration rate and microbial metabolic quotient .MBC, mi-crobial respiration rate and microbial metabolic quotient were negative related to the nitrogen concentration of residues .Moreover , a highly significant negative correlation was found between carbon concentration of residues and mineral nitrogen concentration of soil . Soil microbial respiration rate and microbial metabolic quotient among different controls were similar .A significant positive correlation was found between microbial respiration rate and microbial metabolic quotient .Those results suggested that straw amendments promote the growth and reproduction of the microbes with lower C /N, such as bacteria and actinomycetes , residues with higher nitrogen concen-tration lead to lower microbial biomass , respiration and metabolic activity at later stage of incubation , the microbial metabolic activity is a more important factor than the soil microbial biomass in residues decomposition and microbial respiration .