生态环境学报2026，Vol.35Issue(1)：62-74,13.DOI:10.16258/j.cnki.1674-5906.2026.01.006
盐碱土有机态氮组分对秸秆及秸秆生物炭输入的响应机理
Response Mechanism of Organic Nitrogen Components in Saline-alkali Soil to the Input of Straw and Straw Biochar
摘要
Abstract
Nutrient degradation in saline-alkali soil in the Yellow River Delta,particularly the decline in nitrogen availability,has severely constrained the sustainable development in the regional agriculture.Organic nitrogen,the primary form of total nitrogen in soil,comprises components whose distribution and transformation(such as acidogenic ammonia nitrogen and amino acid nitrogen)directly impact the nitrogen supply capacity.Salt stress may further disrupt these cycles.Owing to its distinctive structural and functional properties,such as high adsorption capacity and carbon sequestration potential,biochar has been shown to enhance soil nitrogen activation by increasing the levels of acid-soluble ammonium and amino acid nitrogen.Returning straw to the field contributes to nitrogen retention and release by adding organic matter,stimulating enzyme activity,and improving the stability of aggregates.However,there is a lack of systematic research on the differences in the mechanisms of the two approaches in regulating the organic nitrogen components of saline-alkaline soil,particularly their effects on key enzymes of the nitrogen cycle,microbial processes,and the aggregate-nitrogen coupling relationship.This study focused on moderately saline-alkaline soils in the Yellow River Delta.By examining the effects of three treatments—no corn stalk return(control group,CK),direct corn stalk return(ST),and application of corn stalk-derived biochar(BI)—on soil organic nitrogen components,enzyme activities,microbial diversity,and soil aggregates,the objective was to assess their influence on soil nitrogen mineralization,enzymatic functions,and microbial diversity,thereby elucidating the mechanisms by which biochar and straw return improve saline-alkali soils.The results indicated that both ST and BI treatments significantly increased total total nitrogen(TN)and three forms of inorganic nitrogen.Notably,BI treatment resulted in significantly greater increases in TN,ammonium nitrogen,and fixed ammonium than the ST treatment(p<0.05).ST treatment,on the other hand,had a more pronounced effect on enhancing the total inorganic nitrogen and nitrate nitrogen content(p<0.05).Both treatments markedly improved the levels of organic nitrogen components in saline soil,with the BI treatment showing a more substantial effect(p<0.05).Compared to the control group,BI increased the acid-hydrolyzable total nitrogen(TAHN),non-acid-hydrolyzable nitrogen(NHN),acid-hydrolyzable ammonium nitrogen(ASN),amino acid nitrogen(AAN),amino sugar nitrogen(AMN),and hydrolyzable unknown nitrogen(HUN)by 38.86%,75.62%,35.05%,34.38%,39.61%,and 59.19%,respectively.Both ST and BI treatments significantly enhanced the activities of soil urease,protease,alkaline phosphatase,sucrase,and catalase,with the BI treatment showing a notably stronger effect(p<0.05),resulting in activity increases of 139%,104%,43.4%,50.2%,and 76.8%,respectively.BI treatment significantly increased soil microbial diversity(p<0.05),and the richness index,Simpson diversity index,and Shannon diversity index increased by 15.0%,9.57%,and 20.8%,respectively,compared with the ST treatment.BI had a more significant effect on increasing the acid-hydrolyzable nitrogen content of aggregates of the four particle sizes(p<0.05),especially in aggregates with particle sizes of 0.053-0.25 mm.Correlation analysis revealed that the organic nitrogen components in saline-alkali soil were significantly and positively associated with both soil enzyme and microbial activity.This suggests that straw and straw-derived biochar primarily modify the organic nitrogen profile by stimulating enzymatic processes and enhancing microbial function,thereby promoting the transformation and retention of nitrogen.TAHN,a relatively active component of the soil nitrogen pool,serves as a direct indicator of improved nitrogen supply potential resulting from soil amendment.The distribution of acid-hydrolyzable organic nitrogen components followed the order AAN>AMN>HUN>ASN,with AAN and AMN identified as the primary sources of mineralizable nitrogen.Biochar treatment increased the concentrations of AAN and ASN by 34.38%and 39.61%,respectively,indicating enhanced accumulation of active nitrogen owing to improved microbial nitrogen fixation capacity.In contrast,NHN exhibited minimal changes in response to the treatments,further supporting the conclusion that biochar and straw primarily enhance nitrogen availability by regulating the levels of active nitrogen components.Overall,returning straw biochar to the field had a more significant effect on increasing the total nitrogen in saline-alkali soil,whereas returning straw had a more significant effect on increasing nitrate-nitrogen.Both treatments significantly increased the organic nitrogen components in the soil,with the enhancement effect of biochar on TAHN,AMN,ASN,AAN,and HUN being more pronounced.Biochar had a more significant effect than straw return in increasing the nitrogen contribution rate of the large and medium aggregates.Biochar is conducive to retaining acid-hydrolyzable nitrogen content in the soil microaggregates of saline-alkali soils.Both straw and straw biochar return significantly increased the enzyme activity in saline-alkali soil;however,straw return had a more pronounced effect,especially on urease.Furthermore,the return of straw and straw biochar significantly enhanced microbial activity in saline-alkali soil,with straw biochar exhibiting a stronger effect.This suggests that straw application markedly enhances soil enzyme activity,facilitating nitrogen transformation.The microbial diversity index,along with the Simpson and Shannon indices,exhibited the greatest increase under biochar treatment,indicating that biochar improved the microbial habitat,boosted microbial abundance and activity,and consequently strengthened the soil's nitrogen mineralization and retention capacity.Owing to its porous structure and ability to stimulate microbial processes,biochar significantly improves nitrogen transformation in soil,alters the distribution of organic nitrogen fractions in saline-alkali soils,and contributes positively to nitrogen retention and stability.The organic nitrogen fractions in saline-alkali soil showed significant positive correlations with both soil enzymes and microbial activity,suggesting that straw and straw-derived biochar primarily influence organic nitrogen composition by enhancing these biological factors.In summary,both straw biochar and straw application offer distinct advantages in improving the nitrogen cycle in saline-alkali soils.Future studies should focus on developing an integrated application model that combines the strengths of both approaches to enhance soil fertility and ecological function more effectively,thereby providing a scientific foundation for the sustainable management of saline-alkali-affected lands.关键词
生物炭/秸秆/盐碱土/有机态氮组分/土壤酶活性/土壤微生物活性Key words
biochar/straw/saline-alkali soil/organic nitrogen components/soil enzyme activity/soil microbial diversity分类
农业科技引用本文复制引用
WANG Guolin,LIU Kaiying,SONG Ningning,LIU Jun,WANG Fangli,WANG Xuexia,ZONG Haiying,LI Shaojing..盐碱土有机态氮组分对秸秆及秸秆生物炭输入的响应机理[J].生态环境学报,2026,35(1):62-74,13.基金项目
山东省重点研发计划(乡村振兴科技创新提振行动计划)项目(2024TZXD077-04) （乡村振兴科技创新提振行动计划）
山东省生态农业产业技术体系(SDAIT-30-02) （SDAIT-30-02）
横向科研项目(横20240398 （）
横20250193) （）
区域农业绿色发展产教融合研究生联合培养示范基地(015/1121001) （015/1121001）
