What is the distinction between “modern science” and “science”? Are you claiming that the development of the Haber-Bosch process and other fertilizers, pesticides, insecticides, and fungicides did not increase yields?
What is “improve farming”? It does not seem to be a small feat to go from feeding 1.5B people to 8B people in 100 years, at far more calories per person.
Granted, the long term effects very well may have destroyed biodiversity and insects, but the immediate problem at the time was hunger and malnutrition. Although, one can make the case that the loss in biodiversity and insects is inevitable with excess human population, in which case the development of technologies increasing yield would be responsible for leading to the possibility of excess humans existing.