Originally Posted by mur'phon
While I'm all for improving eficency, not using fertilizer seems like a waste, since it is available, why not use it?
Straying from the subject, I'll just make a note here: The issue with fertilizers is how much should be used to make the most of the resource. If you increase the amount of water or fertilizer applied to a field, you increase crop yield at a diminishing rate. The idea would be to accept a reduced usage to make to most of the resource because don't forget that the majority of nitrates and fertilizers used are chemicals, not animal waste. By accepting a 10%-20% drop in crop yield, you might be able to extend supplies of these chemicals by decades where you will have an overall greater amount of food produced in the long run.
In agriculture, there will always be demand for livestock, but if we were to only use products that we would normally just throw away or are undesirable; that would be a means to utilize waste products for meat production. When I said 'most' farmland, I mean using much more of the land for human consumption. The potato has most of the nutrients we need to live, not to mention the highest calorie-land ratio of any food.
I simply would suggest that the ethanol production that we have in placed be abandoned and only used on a limited scale where the products used are not grown on prime farmland or with corn planted for that purpose. Only when something would otherwise be thrown away as waste should biomass be used for animal feed or ethanol production. With more food can come more to export or a greater population carrying capacity.
Also the issue of growth rate depends upon birth/death rates. When a population multiplies, it's because the death rate declines, but birth rate remains the same. Once there is an abundance of technology and people, then the birth rate falls. The problem after that comes from either an unbalanced population pyramid with fewer children to elderly, or highly variable birth rate that depends on the economy.
If we can prepare a plan where a state can sustain a population reduction, anticipating fewer children and more elderly, then great. However, Japan and Italy doesn't have such a plan; but they aren't even willing to accept foreign born children to take the place of the declining population of offspring. They need to increase the number of children they have, or they will suffer economic problems for a generation or more.