Pesticides and Fertilizers: Friends or Enemies? A Comprehensive Analysis of the Pros and Cons
Pests and soil fertility are two external factors affecting crop yields. The use of pesticides effectively prevents, destroys and controls “pests”; the use of chemical fertilizers, especially nitrogen fertilizers, has improved soil fertility and was one of the main reasons for the surge in Asian grain yields during the Green Revolution.
In 2010, global pesticide sales were expected to exceed 40 billion US dollars, with herbicides holding the largest market share. In addition, between 1961 and 2002, world mineral fertilizer production increased by nearly 350%. Over the past 40 years, the use of inorganic fertilizers has brought about approximately 40% of the recorded increase in grain production.
⟦NL> The enemy
In 2011, toxic algal blooms caused by fertilizer runoff covered one third of Lake Erie in North America.
Due to the overuse of pesticides and chemical fertilizers, we face a series of the most serious environmental pollution problems, including acidification of soil and water, pollution of surface and groundwater resources, and continuously increasing greenhouse gas emissions. Usually, in fact, less than 1% of applied pesticides can enter the target pests, while the remainder causes air, soil and water pollution. At present in China, the nitrogen uptake efficiency of rice, wheat and maize is only about 26% to 28%, while the uptake rate of vegetable crops is less than 20%, with the remainder entirely lost to the environment.
Over-reliance on pesticides not only damages the balance of the ecosystem but also exacerbates the vicious cycle of pest resistance. This in turn leads to further increased investment in pesticide development and utilization, yet crop losses caused by pests have barely improved and are currently basically comparable to those of 50 years ago, estimated at around 30% to 40%. The resulting consequence is an increase in the number of pest outbreaks caused by improper pesticide use.
In addition, the problem of pesticide residues in food is also cause for concern.
The way forward
On a farm in Pennsylvania, USA, chicken manure is used as fertilizer. Mobile chicken coops carry the chickens to every corner of the farm, which prevents the manure from seeping into the nearby Chesapeake Bay.
The current challenge is to abandon existing unsustainable production methods, shift to land-nourishing production methods, and use ecosystem approaches to solve pest problems, providing a solid foundation for the sustainable intensification of crop production. This is also exactly the direction of FAO's efforts.