Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon(SOC)stabilization.However,the dynamics of soil aggregation and the straw-derived carbon(C...Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon(SOC)stabilization.However,the dynamics of soil aggregation and the straw-derived carbon(C)incorporation within aggregate fractions are not well understood.An experiment was established in 2004 to test the effects of two treatments,no-tillage with residue(NT)and conventional tillage without residue(CT),on the soil aggregate-size distribution and SOC stabilization in a continuous maize(Zea mays L.)cropping system located in the semiarid region of northern China.Soil samples were collected from the 0-10 cm layer in 2008,2010 and 2015,and were separated into four aggregate-size classes(〉2,0.25-2,0.053-0.25,and〈0.053 mm)by wet-sieving.In each year,NT soil had a higher proportion of macroaggregates(i.e.,〉2 and 0.25-2 mm)and associated SOC concentration compared with CT.Additionally,to compare straw-derived C incorporation within NT and CT aggregate fractions,^13C-labeled straw was incubated with intact NT and CT soils.After 90 days,the highest proportion of 13C-labeled straw-derived C was observed in the〉2 mm fraction,and this proportion was lower in NT than that in CT soil.Overall,we conclude that long-term continuous NT increased the proportion of macroaggregates and the C concentration within macroaggregates,and the physical protection provided by NT is beneficial for soil C sequestration in the continuous maize cropping system in semiarid regions of northern China.展开更多
A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nut...A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nutrients stratification and yields of rice and post-rice crops. After flooded paddy field (FPF) was practiced with RNT for a long time, soil profile changed from G to A-P-G, and horizon G was shifted to a deeper position in the profile. Also the proportion of macroaggregate (> 2 mm) increased, whereas the proportion of silt and clay (< 0.053 mm) decreased under RNT, indicating a better soil structure that will prevent erosion. RNT helped to control leaching and significantly improved total N, P, K and organic matter in soil. The highest crop yields were found under RNT system every year, and total crop yields were higher under conventional paddy-upland rotation tillage (CR) than under FPF, except in 2003 and 2006 when serious drought occurred. RNT was proven to be a better tillage method for lowland rice-based cropping system.展开更多
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
基金supported by the National Natural Science Foundation of China(31171512)the Central Publicinterest Scientific Institution Basal Research Fund,China(Y2017PT26)
文摘Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon(SOC)stabilization.However,the dynamics of soil aggregation and the straw-derived carbon(C)incorporation within aggregate fractions are not well understood.An experiment was established in 2004 to test the effects of two treatments,no-tillage with residue(NT)and conventional tillage without residue(CT),on the soil aggregate-size distribution and SOC stabilization in a continuous maize(Zea mays L.)cropping system located in the semiarid region of northern China.Soil samples were collected from the 0-10 cm layer in 2008,2010 and 2015,and were separated into four aggregate-size classes(〉2,0.25-2,0.053-0.25,and〈0.053 mm)by wet-sieving.In each year,NT soil had a higher proportion of macroaggregates(i.e.,〉2 and 0.25-2 mm)and associated SOC concentration compared with CT.Additionally,to compare straw-derived C incorporation within NT and CT aggregate fractions,^13C-labeled straw was incubated with intact NT and CT soils.After 90 days,the highest proportion of 13C-labeled straw-derived C was observed in the〉2 mm fraction,and this proportion was lower in NT than that in CT soil.Overall,we conclude that long-term continuous NT increased the proportion of macroaggregates and the C concentration within macroaggregates,and the physical protection provided by NT is beneficial for soil C sequestration in the continuous maize cropping system in semiarid regions of northern China.
基金Project supported by the National Natural Science Foundation of China (No.40501033)the National Key Technologies R&D Program for the 11th Five-Year Plan of China (No.2007BAD87B10)
文摘A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nutrients stratification and yields of rice and post-rice crops. After flooded paddy field (FPF) was practiced with RNT for a long time, soil profile changed from G to A-P-G, and horizon G was shifted to a deeper position in the profile. Also the proportion of macroaggregate (> 2 mm) increased, whereas the proportion of silt and clay (< 0.053 mm) decreased under RNT, indicating a better soil structure that will prevent erosion. RNT helped to control leaching and significantly improved total N, P, K and organic matter in soil. The highest crop yields were found under RNT system every year, and total crop yields were higher under conventional paddy-upland rotation tillage (CR) than under FPF, except in 2003 and 2006 when serious drought occurred. RNT was proven to be a better tillage method for lowland rice-based cropping system.
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.
