JIA-2019-11

2609 CHEN Xu et al. Journal of Integrative Agriculture 2019, 18(11): 2605–2618 The abundances of the individual PLFAs were the highest at day 3 during the incubation and then began to decrease, except for actinomycetic PLFAs that were higher at day 15 regardless of the substrate addition (Appendix C). All PLFA Table 1 Effect of macroaggregate reduction on soil organic carbon (SOC) and mass of water-stable aggregate (WSA) before incubation 1) IAD RAD >2 mm 0.25–2 mm 0.053–0.25 mm 0.053 mm >2 mm 0.25–2 mm 0.053–0.25 mm 0.053 mm WSA (g 100 g –1 soil) Bare fallow 0 15.16±1.09 c 46.63±0.75 a 37.85±1.05 a 0 7.96±0.84 c 45.06±1.03 a 46.98±1.21 a Farmland 6.34±1.14 b 25.56±1.34 b 38.08±0.41 b 30.02±0.91 b 0 19.85±1.22 b 43.32±1.32 a 36.84±1.06 b Grassland 23.51±0.95 a 51.42±0.98 a 15.02±1.24 c 10.05±0.55 c 0 48.94±1.41 a 26.03±1.12 b 25.03±0.74 c SOC (g kg –1 ) Bare fallow 0 5.08±0.44 c 14.49±1.01 a 7.48±0.93 a 0 2.61±0.36 c 14.03±0.84 b 9.29±1.04 a Farmland 2.30±0.14 b 9.60±0.27 b 13.31±0.07 b 6.57±0.35 a 0 7.47±0.66 b 15.6±0.58 a 8.42±0.62 b Grassland 10.28±0.29 a 27.83±1.34 a 9.32±0.26 c 3.14±0.21 b 0 21.64±0.92 a 10.96±0.54 c 6.04±0.43 c N (g kg –1 ) Bare fallow 0 0.36±0.010 c 1.07±0.001 a 0.66±0.074 a 0 0.19±0.006 c 1.02±0.019 a 0.76±0.008 a Farmland 0.16±0.002 b 0.66±0.007 b 0.94±0.010 b 0.64±0.010 a 0 0.48±0.002 b 1.09±0.008 a 0.71±0.012 a Grassland 0.75±0.021 a 2.05±0.074 a 0.69±0.009 c 0.28±0.011 b 0 1.85±0.031 a 0.91±0.022 b 0.58±0.015 b C:N Bare fallow 14 14 11 14 14 12 Farmland 14 15 14 10 16 14 12 Grassland 13 14 13 11 12 12 10 1) IAD, intact aggregate distribution; RAD, reduced aggregate distribution. Data are mean±SE ( n =3). Different lowercase letters indicate significant differences ( P <0.05) among soil managements. 0 10 20 30 40 50 60 0 50 100 150 200 250 300 350 400 450 0 10 20 30 40 50 60 0 50 100 150 200 250 300 350 400 450 0 10 20 30 40 50 60 0 50 100 150 200 250 300 350 400 450 0 10 20 30 40 50 60 0 50 100 150 200 250 300 350 400 450 NS NS NS NS NS NS NS * * * * GL-IAD GL-RAD FL-IAD FL-RAD BF-IAD BF-RAD Total PLFAs (nmol g –1 ) CK * NS NS NS NS NS NS NS * * * * * Inorganic N NS NS NS NS NS NS NS NS * * * * Glucose NS NS NS NS NS NS NS NS * * * * Alanine Incubation time (day) Fig. 1 Dynamics of total phospholipid fatty acid abundance during the incubation. Treatments include intact aggregate distribution (IAD) and reduced aggregate distribution (RAD) for grassland (GL), farmland (FL) and bare fallow (BF). The asterisks and NS indicate significant ( P <0.05) and non-significant ( P >0.05) differences between IAD and RAD for a specific land use, respectively. Means ( n =3) and standard errors are shown.