I have read about places like India improving their crop yield by 500% over the last 40 years. What all technologies allow that kind of improvement aside from just tilling more land? The only ones I know of are
Fertilizer
Genetic engineering to increase photosynthesis efficiency
Genetic engineering to increase resistance to pests
Better irrigation
Beyond that I don’t know
Good old-fashioned plant breeding: look for plants that have higher yield, collect seed from them, and grow those out for the next cropping season. This technique has been used to improve crops since the dawn of agriculture.
There’s also the use of pesticides, so that locusts or rats don’t eat half your crop.
Don’t minimize the effects of fertilizer and water, they’re probably 90% of the solution.
In addition to better plant breeding there are a couple of other things:
Crop rotation (planting the same crop every year can “wear out” the soil faster.)
Improved soil stewardship (minimizing tillage and reducing erosion.)
Integrated pest management (not just pesticides and genetic engineering, but developing insect-resistant breeds, using beneficial insects to prey on the parasites, planting “border” crops to provide a habitat for pests, so they stay out of the feed crops, etc.)
Thier per arce output 40 years ago probably wasn’t that great to begin with compared to most western style farms, so a 500% increase could mean that they just caught up. Controlling floodwaters alone could have accounted for much of the increase.
This is a huge topic and something that can’t really be summed in a few lines. Some of the other major poimts:
Selection of appropriate crops. It might seem basic, but a lot of parts of India 40 years ago were still trying to grow dry land rice because that was the only tropical crop they had access to. Movement to sorghum or corn for those areas can increase production many thousnads of times.
Simply knowing what’s going on. Fertiliser, pesticides and so forth are wonderful things, but they aren’t magic bullets. Soil analyses, studies of the lifecycle of pests and so forth allow those things to be fine tuned so they have the rwuired effect. The same goes for almost any other managment tool.
Transport and storagee. It might seem trivial but it wasn’t that long ago that a famine in one prart of India could be occuring at exactly the same time as pople were throwing food into the river to clean out the silos soomewhere else inthe country. A lcack of transport and storage is one of the major causes of loss of productive capacity.
Education. Probably the single most important factor. Edcuating farmers, managers, businessmen and politicians alike on how to maximise producton is essential. Without a knowledge of HOW to do these things there’s no way that they will get done even if the knowledge and technology exist.
Land conversion. Cutting down forests, cultivating grazing land and so forth.
Considering that India started from a low base this isn’t surprising. For example this site shows thecorn yield in indiana from 1925 to 2004. Other sites indicate that Iowa had about the same progress. I used Indiana because none of the Iowa sites had such a succinct presentation.
Notice that in the last 40 years Indiana has had about a 185% increase in yields. And Indiana farmers used the best current practices during that period while I suspect that many farmers in India 40 years ago were still using outmoded methods. The use of modern methods, hybrid crops and the like can easily account for the greater gain for India as compared with Indiana.