Table 1.
Composition and structural properties of rice starch under different straw returning.
| Seasons | Early rice | Late rice | |||||
|---|---|---|---|---|---|---|---|
| Treatments | CK | SBR | SR | CK | SBR | SR | |
| Amylose content (%) | 14.39ab | 13.69b | 15.10a | 16.24a | 15.95a | 15.66a | |
| Protein content (%) | 7.99a | 8.69a | 6.58b | 7.14c | 8.94a | 8.17b | |
| Amylopectin chain length distribution (%) | DP ≤ 12 | 26.49a | 26.59a | 26.01b | 30.84a | 29.83b | 28.46c |
| DP13-24 | 50.34a | 47.48b | 48.16b | 46.72a | 45.54b | 45.80b | |
| DP 25–36 | 11.06c | 13.46a | 12.7b | 13.81a | 13.52a | 13.59a | |
| DP ≥ 37 | 12.11b | 12.47b | 13.13a | 8.63c | 11.11b | 12.15a | |
| α-1,6 linkage (%) | 2.55b | 1.23c | 3.79a | 2.37c | 3.14b | 4.11a | |
| α-1,4 linkage (%) | 97.45b | 98.77a | 96.21c | 97.63a | 96.86ab | 95.89b | |
| Degree of branching (%) | 2.55b | 1.23c | 3.79a | 2.37c | 3.14b | 4.11a | |
| Relative of crystallinity (%) | 27.16 | 29.05 | 33.13 | 39.1 | 37.29 | 44.29 | |
| Volume percentage (%) |
d < 10 μm | 69.56b | 71.23b | 73.76a | 88.91b | 88.58b | 89.32a |
| d > 10 μm | 30.44a | 28.77a | 26.24b | 11.09a | 11.12a | 10.68b | |
| Surface area percentage (%) |
d < 10 μm | 91.98a | 92.11a | 90.64b | 93.33a | 93.36a | 91.55b |
| d > 10 μm | 8.02b | 7.89b | 9.36a | 6.67b | 6.64b | 8.55a | |
| Number percentage (%) |
d < 10 μm | 99.77a | 99.79a | 99.76a | 99.68a | 99.02b | 99.76a |
| d > 10 μm | 0.23a | 0.21a | 0.24a | 0.32b | 0.98a | 0.24b | |
| Average diameter (μm) | 4.5a | 4.6a | 4.0b | 4.9a | 4.7a | 4.2b | |
Different lowercase indicates significant differences in different values at p < 0.05 in the same column and the same rice season.
CK, straw removed with chemical fertilizers application; SBR, straw burning returning; SR, straw returning in situ.
DP, Degree of polymerization; d, diameter.