Japan
The Japanese agricultural sector accounts for about 1.4% of the total country's GDP. Only 12% of Japan's land is suitable for cultivation. Due to this lack of arable land, a system of terraces is used to farm in small areas. This results in one of the world's highest levels of crop yields per unit area, with an overall agricultural self-sufficiency rate of about 50% on fewer than cultivated.
Afforestation in Japan
One study examining the soil of various Japanese conifer plantations found that the plantations had a higher concentration of soil organic carbon than wild, natural forests in Japan. Soil carbon is associated with the amount of nutrients that a soil sample can hold. When areas undergo deforestation a lot of the soil organic carbon is exposed and vulnerable to degradation. This results in a loss of nutrients in deforested areas. It would be expected that plantations would have a much smaller amount of organic carbon in the soil because the soil was exposed and experienced a nutrient loss; however, it was found that conifer plantations in Japan actually had more soil carbon than wild forests in the area. It was determined that the heavy litter from newer conifer plantations resulted in an abundance of soil carbon. It was also noted that there was less soil carbon found in plantations that had undergone soil scarification prior to being planted. This was determined to be because soil scarification brought up and exposed more soil organic carbon and more was lost to degradation; however there was still a high concentration of soil carbon in those plantations as well.