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I guess it depends on your definition of technology. Those diesel engines you mention are certainly technology. All the fertilizers, pesticides, and even those "practices" you mention are technologies developed, often, in our universities. In the last 110 years we've gone from it taking 30% of the population to feed this country, to 2% feeding it 10 times over.
The modern American farmer is an incredible marvel of modern innovation.
This is the real technological innovation that has allowed the world's population to explode. Specifically the development of synthetic fertilizers in the late 1800's and early 1900's, most of which was done in Germany, the UK, and the Nordic countries, not the U.S.
We wouldn't have 7 billion people on the planet now if it weren't for chemical fertilizers, our population would be much lower and a lot more people would be concentrating their labors on food production to feed the population. Chemical fertilizers allowed a lot smaller number of people to produce enough food to feed the entire population, allowing the population numbers to grow and people to move off the farm & concentrate their labors on making other things, things and technologies that led to the world we have today. Without the development of fertilizer, technology wouldn't have been able to develop nearly as far as it has. Whether you view that as good or bad is debatable.
So if you really want to point to one development that contributed the most to the modern technological world we live in, that's the invention of chemical fertilizers.
http://en.wikipedia.org/wiki/History_of_fertilizer
