Nutritional imbalance in agricultural development

The growth of crops consumes nutrients such as nitrogen and phosphorus in agricultural soils, and in addition to ensuring agricultural production, nutrients need to be continuously supplemented. Farmland fertilization is the main way to supply nutrients to crops, but this approach doubles the amount of nitrogen and phosphorus that enters the Earth's biosphere. Although this investment can maintain the global crop production to meet the needs of population growth, and can accelerate the development of rural economy. However, agricultural fertilizer pollution has caused us to pay a heavy environmental cost, including the decline of water quality, the eutrophication of marine ecosystems, the threat of photochemical smog, and the global warming effect caused by carbon dioxide.

We can find solutions to agricultural imbalances through analysis of different agricultural systems. Here are three examples: the low-investment corn farming system in western Kenya, the high-yield wheat and corn cropping system in North China, and the corn-soybean circulating crop system in the Midwestern United States. Unlike the rest of the world, maize production in sub-Saharan Africa has not increased significantly for many years, and 250 million people are chronically deficient. Agricultural nutrient inputs in most areas do not satisfy the replenishment of nutrient losses in the soil. For example, in 90 small farms in the Siaya area of ​​Kenya, the input of nitrogen fertilizer in fertilizers is lower than the amount needed to grow crops, and the maintenance of this system relies on the continuous extraction of nutrients from the soil, so that these once fertile soils are now Barren.

In contrast, China's agricultural output has grown rapidly since 1975, and many regions have doubled their food production per unit area. In order to ensure food security, China's policy-oriented role in the use of chemical fertilizers is the main factor driving the increase in grain production. In many areas, the amount of fertilizer input far exceeds that of the United States and Northern Europe, resulting in excessive fertilizer loss to the environment and affecting water. And the quality of the air.

Since the 1940s, the increase in nitrogen and phosphorus fertilizers in the Mississippi Basin has also led to an increase in food production. From 1970 to 1995, the amount of fertilizer applied was much higher than the demand for crops, and it also caused eutrophication of freshwater and coastal waters of the Gulf of Mexico.

In contrast, the input of chemical fertilizers in the North China Plain is significantly excessive. In fact, if the use of nitrogen fertilizer is halved, it will not affect the yield and quality of food. Fertilizer use is also excessive in the intensive wheat farming system in Mexico. In these areas, reducing the amount of fertilizer input is beneficial to the agricultural economy and the environment. However, these measures alone do not prevent environmental damage, which is similar to the environmental damage caused by the loss of agricultural nutrients in the Mississippi Basin and Northern Europe. These agricultural systems also require further measures for environmental issues, and some potential and effective programs and practices have been applied. Some of these measures (such as determining more appropriate fertilization time and location, replanting livestock feed crops, and protecting and restoring riparian vegetation belts) can now be implemented. Of course, more effective agricultural measures are needed.

The agricultural system should also pay attention to soil quality and fertility while increasing food production. Once food production meets the requirements, more emphasis is placed on other aspects of the agricultural system, such as water and air impacts, impacts on biodiversity, and impacts on human life and health, as well as ecological and agronomic processes.

The restriction on the regulation of crop nutrients in the agricultural system is the lack of detailed farmland fertilization budgets that quantify the various inputs and pathways of nutrients. China and the European Union have joined an integrated biogeochemical research project that will submit policy-related information on nutritional balance and its impact, while many countries such as the United States and Canada do not participate in the project.

The agricultural system is not only one of the two in terms of insufficient production and excess nutrients. However, the agricultural sector in most countries lacks effective assessments of the results of appropriate changes in agricultural production methods and does not implement incentives for adopting nutrient-based production methods and practices. If these measures are not taken, it is difficult to maintain and develop a modern agricultural system without jeopardizing human health and the ecological environment.