Corn straw return to the field is a vital agronomic practice for increasing soil organic carbon(SOC)and its labile fractions,as well as soil aggregates and organic carbon(OC)associated with water-stable aggregates(WSA...Corn straw return to the field is a vital agronomic practice for increasing soil organic carbon(SOC)and its labile fractions,as well as soil aggregates and organic carbon(OC)associated with water-stable aggregates(WSA).Moreover,the labile SOC fractions play an important role in OC turnover and sequestration.The aims of this study were to determine how different corn straw returning modes affect the contents of labile SOC fractions and OC associated with WSA.Corn straw was returned in the following depths:(1)on undisturbed soil surface(NTS),(2)in the 0–10 cm soil depth(MTS),(3)in the 0–20 cm soil depth(CTS),and(4)no corn straw applied(CK).After five years(2014–2018),soil was sampled in the 0–20 and 20–40 cm depths to measure the water-extractable organic C(WEOC),permanganate oxidizable C(KMnO4-C),light fraction organic C(LFOC),and WSA fractions.The results showed that compared with CK,corn straw amended soils(NTS,MTS and CTS)increased SOC content by 11.55%–16.58%,WEOC by 41.38%–51.42%,KMnO4-C and LFOC by 29.84%–34.09%and 56.68%–65.36%in the 0–40 cm soil depth.The LFOC and KMnO4-C were proved to be the most sensitive fractions to different corn straw returning modes.Compared with CK,soils amended with corn straw increased mean weight diameter by 24.24%–40.48%in the 0–20 cm soil depth.The NTS and MTS preserved more than 60.00%of OC in macro-aggregates compared with CK.No significant difference was found in corn yield across all corn straw returning modes throughout the study period,indicating that adoption of NTS and MTS would increase SOC content and improve soil structure,and would not decline crop production.展开更多
通过对松嫩平原玉米田土壤CO2排放的连续观测,研究连作玉米田土壤CO2排放规律及与土壤温度、土壤水分的关系,并计算玉米田土壤碳平衡特征。结果表明,玉米田土壤CO2排放通量呈现明显季节性,6~8月土壤CO2排放量较大,而在4和11月维持较低...通过对松嫩平原玉米田土壤CO2排放的连续观测,研究连作玉米田土壤CO2排放规律及与土壤温度、土壤水分的关系,并计算玉米田土壤碳平衡特征。结果表明,玉米田土壤CO2排放通量呈现明显季节性,6~8月土壤CO2排放量较大,而在4和11月维持较低水平。秸秆还田处理（MTS）土壤CO2排放通量、最大通量和平均通量高于翻耕处理（CT）。土壤CO2排放通量与地温呈显著正相关,指数方程表征二者关系效果最佳,线性方程效果最低,除个别情况,深层土壤拟合效果高于浅层土壤;MTS处理的土壤CO2排放通量与土壤温度相关性高于CT处理。土壤CO2排放通量与12 cm深度土壤水分相关性不显著。通过对秸秆、根茬还田碳与土壤CO2排放碳的测算,MTS处理秸秆还田碳量较CO2排放碳量平均每年多2 744.6 kg C·hm-2,呈碳汇效应;CT处理秸秆还田碳量较CO2排放碳量平均每年少810.4 kg C·hm-2,呈碳源效应。展开更多
基金the National Natural Science Foundation of China(42077022)Key Research and Development Program of Jilin Province(20200402098NC).
文摘Corn straw return to the field is a vital agronomic practice for increasing soil organic carbon(SOC)and its labile fractions,as well as soil aggregates and organic carbon(OC)associated with water-stable aggregates(WSA).Moreover,the labile SOC fractions play an important role in OC turnover and sequestration.The aims of this study were to determine how different corn straw returning modes affect the contents of labile SOC fractions and OC associated with WSA.Corn straw was returned in the following depths:(1)on undisturbed soil surface(NTS),(2)in the 0–10 cm soil depth(MTS),(3)in the 0–20 cm soil depth(CTS),and(4)no corn straw applied(CK).After five years(2014–2018),soil was sampled in the 0–20 and 20–40 cm depths to measure the water-extractable organic C(WEOC),permanganate oxidizable C(KMnO4-C),light fraction organic C(LFOC),and WSA fractions.The results showed that compared with CK,corn straw amended soils(NTS,MTS and CTS)increased SOC content by 11.55%–16.58%,WEOC by 41.38%–51.42%,KMnO4-C and LFOC by 29.84%–34.09%and 56.68%–65.36%in the 0–40 cm soil depth.The LFOC and KMnO4-C were proved to be the most sensitive fractions to different corn straw returning modes.Compared with CK,soils amended with corn straw increased mean weight diameter by 24.24%–40.48%in the 0–20 cm soil depth.The NTS and MTS preserved more than 60.00%of OC in macro-aggregates compared with CK.No significant difference was found in corn yield across all corn straw returning modes throughout the study period,indicating that adoption of NTS and MTS would increase SOC content and improve soil structure,and would not decline crop production.
文摘通过对松嫩平原玉米田土壤CO2排放的连续观测,研究连作玉米田土壤CO2排放规律及与土壤温度、土壤水分的关系,并计算玉米田土壤碳平衡特征。结果表明,玉米田土壤CO2排放通量呈现明显季节性,6~8月土壤CO2排放量较大,而在4和11月维持较低水平。秸秆还田处理（MTS）土壤CO2排放通量、最大通量和平均通量高于翻耕处理（CT）。土壤CO2排放通量与地温呈显著正相关,指数方程表征二者关系效果最佳,线性方程效果最低,除个别情况,深层土壤拟合效果高于浅层土壤;MTS处理的土壤CO2排放通量与土壤温度相关性高于CT处理。土壤CO2排放通量与12 cm深度土壤水分相关性不显著。通过对秸秆、根茬还田碳与土壤CO2排放碳的测算,MTS处理秸秆还田碳量较CO2排放碳量平均每年多2 744.6 kg C·hm-2,呈碳汇效应;CT处理秸秆还田碳量较CO2排放碳量平均每年少810.4 kg C·hm-2,呈碳源效应。
