Dear Florence, you are of the opinion that "priority should be given to crops which can limit GHG emissions". I agree in general but have also some comments:
1. Emissions from crops in developing countries are not very important, except insofar as they involve net deforestation. Emissions in modern mechanized agriculture are far more important, by way of the fuel used by agricultural machinery. Growing crops, in fact, sequesters carbon from the armosphere through photosynthesis. And on the whole, emissions from agriculture are a tiny fraction of all emissions, mostly originated in manufacturing, big cities, and some mining related activities such as the production of cement. In the poorest countries, reducing emissions is probably among lower priorities, after getting food, not being killed by violence, and other immediate threats to everyday life. Most of them live without electricity, and producing electricity for one or two billion people means burning a lot of fossil fuels and thus producing more emissions: not increasing emissions may condemn those billions of people to darkness for a very long time. Middle-income countries, chiefly in Asia like China, have also other priorities (getting developed) and will postpone serious reduction of their emissions till they are done.
2. Some modern forms of tillage and farming are far less deleterious, or directly beneficial, in terms of emissions, but not always palatable for people preocuppied by the environment or endeavouring to promote subsistence farming.
For instance, no-tillage or limited-tillage systems (like those widely practiced by modern extensive farmers in Brazil, Argentina and the US) greatly reduce the use of machinery and fuel, and also reduce soil erosion (because of less compactation of soils by heavy equipment). They reduce fossil fuel burning, and by planting the new crop on the bed created by the previous one, they keep the land under green cover most of the time, which reduces water and wind erosion.
For another and more controversial example: growing genetically modified crops reduces the use of fuel for herbicide application (one single pass is often enough, because the GM crop does not absorb the herbicide which in turn kills most of the weeds at once); besides, the most important GM crop, soybeans, is a legume, thus capturing and storing nitrogen (and not only carbon) in the soil, when the crop residues are remixed with topsoil in the no-tillage system. Now, those conservationist systems are all practiced by modern farming systems in places like the US or the Argentine plains, not in traditional peasant production systems in South Asia or Sub Saharan Africa (nor in Europe, where GM crops are a no-no). In fact, more emissions are customarily caused by small peasants clearing woodland by slash and burn than by modern farmers practicing no-tillage crops.
Warning: Food for thought may often be unpalatable, but it is always good for one's mind.
Dear Florence, you are of the opinion that "priority should be given to crops which can limit GHG emissions". I agree in general but have also some comments:
1. Emissions from crops in developing countries are not very important, except insofar as they involve net deforestation. Emissions in modern mechanized agriculture are far more important, by way of the fuel used by agricultural machinery. Growing crops, in fact, sequesters carbon from the armosphere through photosynthesis. And on the whole, emissions from agriculture are a tiny fraction of all emissions, mostly originated in manufacturing, big cities, and some mining related activities such as the production of cement. In the poorest countries, reducing emissions is probably among lower priorities, after getting food, not being killed by violence, and other immediate threats to everyday life. Most of them live without electricity, and producing electricity for one or two billion people means burning a lot of fossil fuels and thus producing more emissions: not increasing emissions may condemn those billions of people to darkness for a very long time. Middle-income countries, chiefly in Asia like China, have also other priorities (getting developed) and will postpone serious reduction of their emissions till they are done.
2. Some modern forms of tillage and farming are far less deleterious, or directly beneficial, in terms of emissions, but not always palatable for people preocuppied by the environment or endeavouring to promote subsistence farming.
For instance, no-tillage or limited-tillage systems (like those widely practiced by modern extensive farmers in Brazil, Argentina and the US) greatly reduce the use of machinery and fuel, and also reduce soil erosion (because of less compactation of soils by heavy equipment). They reduce fossil fuel burning, and by planting the new crop on the bed created by the previous one, they keep the land under green cover most of the time, which reduces water and wind erosion.
For another and more controversial example: growing genetically modified crops reduces the use of fuel for herbicide application (one single pass is often enough, because the GM crop does not absorb the herbicide which in turn kills most of the weeds at once); besides, the most important GM crop, soybeans, is a legume, thus capturing and storing nitrogen (and not only carbon) in the soil, when the crop residues are remixed with topsoil in the no-tillage system. Now, those conservationist systems are all practiced by modern farming systems in places like the US or the Argentine plains, not in traditional peasant production systems in South Asia or Sub Saharan Africa (nor in Europe, where GM crops are a no-no). In fact, more emissions are customarily caused by small peasants clearing woodland by slash and burn than by modern farmers practicing no-tillage crops.
Warning: Food for thought may often be unpalatable, but it is always good for one's mind.