Stability and applicability of the leaf value model for variable nitrogen application based on SPAD value in rice

Area of Science:

• Agricultural Science
• Agronomy
• Plant Nutrition

Background:

• Fertilization models are crucial for optimizing nutrient application in agriculture.
• Existing nitrogen (N) application models require validation for broader applicability.
• The leaf value model offers a non-destructive method for N fertilizer management in rice.

Purpose of the Study:

• To evaluate the stability and applicability of the leaf value model across different geographical areas and rice cultivars.
• To construct and refine the leaf value model using data from a new region and multiple cultivars.
• To assess the model's performance in predicting N requirements and target yields.

Main Methods:

• Experimental validation of the leaf value model in a new region (A2) with four rice cultivars.
• Comparison of N uptake and target yield data with a previous study area (A1).
• Statistical analysis of the relationship between SPAD values (leaf N indicators) and field N supply.

Main Results:

• The leaf value model demonstrated stability and applicability across different areas and cultivars.
• For 'Qyou6' cultivar in A2, apparent total N uptake increased by 12% compared to A1, with a slight change in target yield.
• Significant linear relationships were observed between SPAD-derived indexes and N supply, with high R2 values, indicating model reliability.

Conclusions:

• The leaf value model shows considerable stability and applicability for N fertilizer management in rice.
• The model can be reliably used for making timely and non-destructive N fertilizer decisions in rice planting.
• Further research can expand the model's utility across diverse rice-growing environments and genotypes.