长期施用生物炭对塿土土壤理化性质及微生物的影响

Long-term Effect of Application of Biochar on Physiochemical Properties and Microorganism of Loessial Soil

为了研究生物炭对土壤改良的影响是否具有长期效应,对施用不同量生物炭0kg/hm^2(CK),1 000kg/hm^2(T1),5 000kg/hm^2(T2),10 000kg/hm^2(T3)4a之后的塿土进行氮素和碳素质量分数测定和土壤氨氧化菌、反硝化细菌的定量分析。结果表明:与未添加生物炭的土壤(CK)相比,在冬前分蘖期和拔节期T2和T3处理下的氨氧化菌丰度显著高于CK;在冬前分蘖期、拔节期和成熟期生物炭处理下的反硝化细菌丰度显著高于CK。土壤铵态氮质量分数在分蘖前期、拔节期和成熟期的T3处理下显著高于CK;土壤硝态氮质量分数在拔节期和成熟期的T2和T3处理下分别显著高于CK;土壤碱解氮质量分数在越冬期和拔节期分别是CK和T3达到最高水平,且显著高于其他处理;土壤全氮质量分数在分蘖前期和开花期的T3和T1处理下达到最高水平,均显著高于CK;土壤有机碳质量分数在拔节期、开花期和成熟期的T3处理下达到最高水平,且显著高于CK,但CK和T1、T2之间无显著差异。可见,施用生物炭1 000kg/hm^2(T1)和5 000kg/hm^2(T2)4a之后,与CK相比土壤氮素和碳素的提高不明显;生物炭处理与CK相比,添加生物炭提高土壤中反硝化细菌丰度;施用生物炭10 000kg/hm^2(T3)显著提高土壤中氨氧化菌丰度。

In order to explore long-term effect of biochar on soil improvement,the field experiment was conducted with four biochar levels,including 0kg/hm^2（CK）,1 000kg/hm^2（T1）,5 000kg/hm^2（T2）,and 10 000kg/hm^2（T3）four years ago,nitrogen and carbon mass fraction of soil was measured,and the abundance of soil microorganism was analyzed with Real-time PCR of amoA and nirS gene.The results showed that the amoA gene abundance in T2 and T3were significantly higher than CK in early tilleringand jointing stage,and the nirS gene abundance of biochar treatments were significantly higher than CK inearly tillering,jointing stage and maturity.The soil nitrate nitrogen mass fraction in T2 and T3were significantly higher than CK in jointing stage and maturity,meanwhile the soil ammonium nitrogen mass fraction in T3 was significantly higher than CK inearly tillering,jointing and maturity.The soil available nitrogen mass fraction in CK and T3 was respectively the maxium mass fraction inearly tillering and jointing stage,while the soil total nitrogen mass fraction in T3 and T1was the maxiummass fraction in early tillering and flowering stage respectively and both were significantly higher than CK.The soil organic carbonmass fraction in T3 was the highest level in jointing,flowering stage and maturity,while there was no significance difference between CK,T1 and T2in soil organic matter mass fraction.We found that after application of 1 000kg/hm^2 and 5 000kg/hm^2 biochar four years,the improvenment of soil nitrogen and carbon was no longer remarkable.Application of biochar had a long-term improvement on amoA gene abundance after four years.Adding 10 000kg/hm^2（T3）biochar to soil after years improved the nirS gene abundance significantly.