Material and fabrication factors governing rice seedling growth in seed rope direct seeding systems

Direct seeding of rice (DSR) offers significant advantages over transplanting, including water savings and reduced labour requirements. As a form of DSR, seed rope direct seeding of rice (SRDSR) retains these benefits while additional features such as a controllable and consistent hill spacing, a clustered seed distribution per hill, and operational convenience. The objectives of this research were to investigate the effects of seed rope materials and twisting number on rice seedling growth. The experiments were conducted under various seed rope treatments, namely, direct seeding (CK), polylactic nonwoven fabric (NR), and wrinkled paper (WR), with gradients of twisting numbers of 10, 15, 20, 25 and 30. The results revealed that there were no significant differences in the emergence rate, seeding height, or root parameters among the NR, WR-10 and CK treatments. The growth indicators of rice in the NR groups did not show significant fluctuations with increasing twisting number, whereas the WR treatments resulted in a decreasing trend. With respect to the same twisting number, the NR treatments performed better than the WR treatments. In addition, SRDSR increases the seeds' resistance to environmental temperature and humidity stress. This study elucidated the mechanistic effects of seed rope treatments on seedling growth through a comprehensive analysis of the physical-mechanical properties and microstructure of the encapsulation materials, thereby providing a theoretical foundation for the advancement of seed rope-based seeding technology.