According to this overview article on foodsource.org, 87% of global soy production is processed into soybean oil (19%) and soy meal or ‘cake’. Of this, 99% is used as animal feed for (factory) livestock farming. About a fifth of Soybean oil production is used as biofuel, the rest is for human consumption f.i. cooking oils.
Land use change towards soy farms usually takes place in two steps: “A common pattern, however, is that land is first cleared for cattle ranching and shortly afterwards sold or rented out at a higher price for more lucrative soy production.” And acts as a positive feedback to more land use change (i.e. deforestation): “Soy expansion, accordingly, may indirectly bring about land use change by ‘pushing’ cattle ranching into frontier areas. The arrival of a high-value crop such as soy can also drive up local land prices and thereby incentivise the clearing of surrounding land.“
Quote: “Initiatives to reduce deforestation, such as certification schemes and the Amazon Soy Moratorium, have been embraced by the European pig and poultry industry. However, while these are important first steps, they have not yet led to the decoupling of soy production from land use change in South America. Globally, only 0.2-6% of the soy production volume is covered by some form of certification.”
Soybean oil and soy meal are a combined business model, the article states. Oil revenue is about twice as high per unit of soy as meal.The [FAO] holds that diets should shift to more plant based diets [source]. So if demand for soy meal as cattle feed drops, what about about demand for soybean oil for human consumption? It could be replaced by rapeseed oil, which yields about three times the amount of oil per unit of land.
Soybean oil is also used as a biodiesel. I have no sources comparing energy densities of soybean with alternative vegetable oils. There are concerns about mass production of biofuels as a threat to food security, land use change (more forest clearing) and the actual impact on reducing GHG emissions.