Effect of rice-fish-chicken ridge cultivation on stem lodging resistance, panicle traits, and yield of rice

Based on previous studies of ridge cultivation, rice-fish co-culture, and rice-chicken co-culture, we proposed an integrated technology of ridge cultivation of rice combined with fish and chicken co-culture (RFC), and observed its' obvious yield and economic benefits. The objective of this study was to determine the effects of RFC on stem lodging resistance, panicle traits, and grain yield in rice. Field experiments were conducted in 2018 and 2019 to compare the stem lodging resistance characteristics, panicle traits, and rice yield when grown under conventional ridge cultivation (CK), ridge cultivation of rice-fish co-culture (RF), ridge cultivation of rice-chicken co-culture (RC), and RFC. The results showed that the height, fresh weight, gravity center height, and internode length of rice plants differed among the treatments in both years, but the differences were not significant. RFC and RC had higher internode outer diameters and wall thicknesses, panicle lengths, and panicle fresh weights than CK, but the differences were not significant. RFC and RC produced similar rice yields as CK. RF had a lower internode outer diameter and wall thickness, panicle length, and panicle fresh weight than CK, but the differences were not significant except for the panicle fresh weight in 2019 (P < 0.05). RF produced a significantly higher grain yield than CK in both years (P < 0.05), with an average increase of 29.98%. RFC and RC had higher average stem-breaking resistances than CK by 19.69% and 8.10% in 2018 and 2019, respectively. In particular, the difference in stem-breaking resistance between RFC and CK was significant for the fourth and fifth internodes (P < 0.05). RF had a smaller stem cross-section modulus and lower stem-breaking resistance than CK, but the differences were not significant. RFC and RC had lower average maximum bending stress by 17.85% and 15.08%, respectively, and a lower average lodging index by 4.35% and 4.26%, respectively, than CK in 2018 and 2019, respectively, but the differences were not significant. RF had a higher average internode lodging index than CK by 11.47%, and the differences were significant for the third internode in 2018 and the second to the fifth internodes in 2019. In conclusion, RFC and RC increased the panicle length and panicle fresh weight of rice plants, stabilized the rice yield, increased the stem internode diameter and wall thickness, enhanced the stem-breaking resistance and cross-section modulus, and reduced the stem maximum bending stress and lodging index. Our study suggests that RFC and RC are preferable for developing strong stems and improving rice lodging resistance.