The carbon content of plants accounts for about 45% of their body weight, which is the proportion of dry weight. When plants have vitality, the carbon content accounts for 18%.
 
China's agriculture has gone through thousands of years of development history, roughly divided by fertilization types, with the 1980s as the boundary. Before the 1980s, the planting industry mainly used organic fertilizers, producing sweet fruits and rice, with few pests and easy control; Since the 1980s, chemical fertilizers have gradually become the mainstay, and agricultural products have become less flavorful and difficult to swallow, with frequent outbreaks of pests and diseases that are difficult to control. The reason for this is obviously related to the changes in the proportion of plant nutrients caused by the type of fertilization.

The essential nutrient content of fresh plants is 70% oxygen, 18% carbon, 10% hydrogen, 0.3% nitrogen, 0.07% phosphorus, 0.3% potassium, 0.3% calcium, 0.05% magnesium, and 0.03% sulfur. Other trace elements such as iron, manganese, zinc, copper, boron, molybdenum, and chlorine are in the tens of thousands to tens of millions of parts. 

From the perspective of the six elements with high plant content, the ratio of CHO/NPK should be controlled at 98/0.67. When organic fertilizer is mainly used in production, the above element ratio can be achieved, and the plant grows well with high total sugar content and good taste. Conversely, when NPK fertilizer is mainly used, the synthesis of carbohydrates in the plant is reduced, growth is poor, total sugar content in the product is low, and the taste is poor. At the same time, the cell wall (membrane) is poorly developed and susceptible to diseases.

A few suggestions:
1. Changing the previous view that plant C and O mainly come from CO2 in the air, Pan Ruichi's new edition of "Plant Physiology" tells us that only 30% of plant C and O come from CO2 in the air, and the remaining 70% should come from the soil.
Soil minerals do not supply carbon and oxygen, and the carbon and oxygen supplied by soil can only come from CO2 released by microbial decomposition of organic matter, water-soluble CO2, water-soluble organic acids, etc.
2. The view that changing the role of soil organic matter in the past is to improve the soil, and establishing the view that one of the functions of soil organic matter is to provide essential nutrients such as carbon and oxygen for plants. If the soil organic matter content is high or sufficient organic fertilizer is applied, plants will have abundant carbohydrates, good growth, strong disease resistance, and good product quality. On the contrary, it is bad.
3. Changing the previous view that "the increase in agricultural production in China for decades mainly relied on chemical fertilizers". Applying chemical fertilizers to supplement nutrient elements can have a certain increase in yield, but the greater increase in yield of chemical fertilizers lies in their acceleration of the decomposition of soil organic matter, which has accumulated in the soil for thousands of years, into the release of various organic nutrients. According to the microbial C/N ratio of 20-25/1, applying 100 pounds of urea will decompose and release 1500-2000 pounds of soil organic matter for fertilizer supply. Therefore, organic fertilizers should be the main source of production, with chemical fertilizers as a supplement.
4. To change the current view of "emphasizing NPK fertilizer and ignoring CHO fertilizer" in production, CHO should be included in the management of soil nutrients. From the perspective of nutrient movement trajectory, irrigation is not only the application of H fertilizer, but also the application of organic fertilizer is the application of C fertilizer and oxygen fertilizer (about 30% of C and O in plant dry matter come from the air, and 70% come from the soil).
5. Given the important roles of carbon and oxygen in organic composition and organisms, it is recommended that the country establish a "Plant Carbon and Oxygen Nutrition Research Laboratory or Institute" to take the lead in conducting research on plant carbon and oxygen nutrition in China.

Professor Wang Zhimin
2024.8.31