Fig 1.
Changes in temperature, hours of sunshine, and precipitation during the maize growth period in 2010, 2011, and 2012 at the Xinxiang experimental station.
Table 1.
Maize grain yield, ear numbers per ha, kernels per ear, 1000-kernel weight of maize, as an effect of different tillage practices and different planting density in 2010, 2011, and 2012.
Fig 2.
Effects of tillage management (SS, subsoiling; CK, no tillage) on maize dry matter in plots planted at density of 45000 plants ha-1, (LD), 67500 plants ha-1(MD), and 90000 plants ha-1 (HD) in each growth stage during 2010 (A), 2011 (D–F), and 2012 (G–I).
Vertical bars represent the standard deviations of the means. * P< 0.05; **P< 0.01.
Fig 3.
Dry matter accumulation pre- and post-anthesis in the control (no tillage, CK) and subsoiled (SS) crops from density of 45000 plants ha-1 (LD), 67500 plants ha-1(MD), and 90000 plants ha-1 (HD) in 2010 (A), 2011 (B) and 2012 (C).
Vertical columns and bars represent the means and standard errors of three replicates, respectively. Different letters on the graph indicate significant differences at P< 0.05.
Fig 4.
Grain-filling in crops from subsoiled (SS) and no-tilled (CK) plots planted at 45000 plants ha-1(LD, A), 67500 plants ha-1medium (MD, B), and 90000 plants ha-1(HD, C) during post-anthesis stage in 2012.
Vertical bars are the standard deviations of the means. *P<0.05; **P<0.01, ***P<0.001.
Table 2.
Grain filling rate parameters in subsoiled (SS) and non-tilled (CK) plots in 2012.
Fig 5.
Leaf area index dynamics during the maize growth season in subsoiled (SS) and non-tilled (CK) plots planted at density of 45000 plants ha-1 (LD), 67500 plants ha-1(MD), and 90000 plants ha-1 (HD) in 2011 (A–C, respectively) and 2012 (D–F, respectively).
Vertical bars are the standard deviations of the means. *P<0.05; **P<0.01.
Fig 6.
The net photosynthetic rate (Pn) of leaves post-anthesis in subsoiled (SS) and no-tilled (CK) plots planted at 45000 plants ha-1 (LD), 67500 plants ha-1 (MD), and 90000 plants ha-1 (HD) in 2011 (A–C, respectively) and 2012 (D–F, respectively).
Vertical bars are the standard deviations of the means. *P<0.05; **P<0.01.
Fig 7.
The Fv/Fm (A–C) and ΦPSII (D–F) of the post-anthesis leaves from maize planted in plots of 45000 plants ha-1 (LD, A and D), 67500 plants ha-1 (MD, B and E), and 90000 plants ha-1 (HD, C and F) densities managed by subsoiling (SS) or no tillage (CK) in 2012.
Vertical bars represent the standard deviations of the means. * P< 0.05; **P< 0.01.
Table 3.
Density of root dry weight (g m-3) at a soil depth of 0–50 cm soil depth during the anthesis stage of subsoiled (SS) vs. non-tilled (CK) plots in 2012.
Fig 8.
The amount of root bleeding sap determined in plants from plots planted at 45000 plants ha-1 (A), 67500 plants ha-1 (B), and 90000 plants ha-1 (C) at during post-anthesis under subsoiling (SS) and non-tillage (CK) conditions in 2012.
Vertical bars represent the standard deviations of the means. * P< 0.05; **P< 0.01.
Fig 9.
Soil bulk at depth intervals between 0 and 50 cm during the maize anthesis stage in plots managed by subsoiling (SS) or no tillage (CK) in 2012.
Error bars represent the standard error of the mean. Different letters above the error bars indicate significant differences at the P<0.05 level (ANOVA and Duncan’s multiple range test; n = 3).