Preliminary Results on the Application of Phosphorus and Silicon to Improve the Post-Transplantation Growth of High-Density Nursery Seedlings

Abstract

Transplanting high-density nursery (HDN) seedlings reduces seedling raising costs by increasing the sowing density compared to regular seedlings and shortens the seedling growth period. However, there is a concern that the poor early growth of HDN seedlings hinders rice production in cold regions, such as northern Japan. This study conducted a growth comparison test using a combination of phosphorus (P) and silicon (Si), which stabilizes early rice growth. The results showed that the application of P or Si alone increased the shoot dry weight at the heading stage. The application of 60 mg kg−1 or more P fertilizer increased the HDN shoot dry weight, while 2 g kg−1 Si was effective in increasing the shoot dry weight. However, the joint application of P and Si did not increase plant height or stem number or synergistically increase the shoot dry weight compared to the application of P or Si alone. As the P concentration in the soil increased owing to the P treatment, Si suppressed the excessive uptake of inorganic P and maintained its concentration at an appropriate level. The application of P and Si is important to increase the shoot dry weight of rice. In addition, Si may play a role in regulating the appropriate level of P uptake by HDN. The application of P and Si stabilized the initial growth of the HDN.