关键词: 水稻, 氮素, 绿色归一化植被指数, 决策

Abstract: The rational application of nitrogen fertilizer is the key to increasing rice yield and income. Improper application of nitrogen fertilizer will not only lead to excessive growth of rice plants at tillering stage, lodging at maturity, and reduced yield but also pollute farmland soil and surrounding environment and destroy soil nutrient structure. Therefore, a decisionmaking scheme of variable application of nitrogen fertilizer is proposed to apply nitrogen fertilizer accurately.The content of nitrogen in the soil was measured by UV spectrophotometry, and the content of nitrogen in the soil was analyzed. The SPAD value of rice leaves was measured to map the canopy nitrogen content, the canopy spectral image information was collected by UAV equipped spectral camera, the green normalized vegetation GNDVI index with the strongest correlation was selected, and its correlation model with SPAD was constructed. Then the rice canopy nitrogen content model was constructed, and the decisionmaking scheme of variable nitrogen application in rice was put forward. It was found that the decisionmaking scheme improved the nitrogen use efficiency, increased the rice yield by 7.2 t, and the economic benefit by 8.39%.

Key words: rice, nitrogen, green normalized vegetation index, policy decision