Seed Priming and Foliar Application with Nitrogen and Zinc Improve Seedling Growth, Yield, and Zinc Accumulation in Rice
Patcharin Tuiwong, Sithisavet Lordkaew, Jeeraporn Veeradittakit, Sansanee Jamjod, Chanakan Prom‐u‐thai
Abstract
Improving grain yield and zinc (Zn) concentration yields a double benefit for farmers and consumers, especially when accomplished through the common practice of nitrogen (N) and Zn application. The objective of this study was to evaluate responses of a modern improved rice variety (SPT1) to Zn and N fertilizer management of seed germination, seedling growth, yield, and grain Zn accumulation. A preliminary laboratory study was conducted by priming seeds with variation of N and Zn solutions, consisting of (1) 0% urea + 0% ZnSO4 (N0Zn0), (2) 0% urea + 0.07% ZnSO4 (N0Zn+), (3) 0.05% urea + 0.07% ZnSO4 (N0.05Zn+), (4) 0.10% urea + 0.07% ZnSO4 (N0.10Zn+), (5) 0.15% urea + 0.07% ZnSO4 (N0.15Zn+), (6) 0.20% urea + 0.07% ZnSO4 (N0.20Zn+), and (7) 0.25% urea + 0.07% ZnSO4 (N0.25Zn+). Priming seeds with N0.15Zn+ led to a higher germination rate and growth performance. Seedling Zn concentration increased linearly along with the dry weights of root and coleoptile during germination. A second experiment in the field included priming the seed with (1) 0% urea + 0% ZnSO4 (N0Zn0), (2) 0.15% urea + 0% ZnSO4 (N+Zn0), (3) 0% urea + 0.07% ZnSO4 (N0Zn+), and (4) 0.15% urea + 0.07% ZnSO4 (N+Zn+); this experiment showed that simultaneous priming of seeds with 0.15% urea and 0.07% ZnSO4 (N+Zn+) resulted in the highest coleoptile length and seedling dry weight. The highest seedling Zn concentration was observed when priming seeds with N0Zn+ followed by N+Zn+, but the effect disappeared at the later growth stages. A third experiment in the field was conducted by foliar application with four different treatments of (1) 0% urea + 0% ZnSO4 (N0Zn0), (2) 1% urea + 0.5% ZnSO4 (N+Zn0), (3) 0% urea + 0.5% ZnSO4 (N0Zn+), and (4) 1% urea + 0.5% ZnSO4 (N+Zn+). The highest grain yield increases were achieved by foliar application of N+Zn0 (28.5%) and foliar application of N+Zn+ (32.5%), as compared with the control (N0Zn0). Grain Zn concentration was the highest under foliar application of N+Zn+, with a 37.9% increase compared with N0Zn0. This study confirmed that seedling growth performance can be enhanced by initially priming seeds with N and Zn solution, while grain yield and Zn concentration can be improved by foliar application of N and Zn fertilizer. The information would be useful for the appropriate combined application of Zn and N fertilizers in the practical field to improve grain yield and Zn accumulation as well as Zn nutrition among humans with rice-based diets. The result should be extended to a wider range of rice varieties under suitable management of N and Zn fertilizer.