The subtle relationship between Spad value and nitrogen

The subtle relationship between Spad value and nitrogen

As we all know, the pad value represents the relative amount of chlorophyll in plants, or the "greenness" of plants. The light absorption rate of the leaves for different wavelengths is different. In the blue region of 400-500 nm and the red region of 600-700 nm, the absorption of the blade reaches a maximum value. Spad values ​​result from this. Based on this absorption characteristic, the SPAD502 chlorophyll meter measures the absorptivity of the leaves in the red and near-infrared regions, from which the spad value is calculated. It is a numerical representation of the corresponding parameters of the current chlorophyll content in the leaves.

Since we already know how the paddle values ​​in plant leaves are calculated, how do we understand the subtle relationship between Spad values ​​and nitrogen? Nitrogen is one of the most demanding elements in phytonutrients. Its application amount directly affects the normal growth and development of plants. So, if the plant lacks nitrogen, how do we know it? In fact, the sap value of plants determined by chlorophyll meter has a certain proportional relationship with nitrogen.

According to the figure, we can actually conclude that the chlorophyll content (indicated by the SPAD value) increases in proportion to the nitrogen content in the leaves (an important nutrient component). The curve also seems to indicate that the padding value is directly proportional to the nitrogen content, the nitrogen content increases with the increase in the padd value, and the increase in nitrogen indicates that the plants are getting healthier.

Because of the subtle relationship between the plant's padding value and nitrogen, for growers, if we know the demand for nitrogen, we can control the supply of nitrogen fertilizer. In this way, the padding value makes a great contribution to the amount of nitrogen fertilizer. According to statistics, the Spad value can help reduce the nitrogen fertilizer use by 10% under the premise of ensuring that the crop yield does not decrease. It also reduces the crop disease and environmental pollution that may be caused by excessive use of nitrogen fertilizer. With the continuous deepening of people's awareness of environmental protection, the pollution of nitrogen fertilizers to the environment is being understood and put into practice by more and more people. We are obligated to make a contribution to environmental protection, and the value of the chlorophyll meter will be a good choice.