Improve the soil

In these days, I am just interested in how to improve the soil. I think I almost get it, as I have spent lots of time and money. According to the calculation, I spent over JPY200,000 on 500 square meter land for 2 years. Then I learned that we should better choose the bark compost, self made nitrogen fertilizer, actinomycetes. And I wanna try the compost made from bamboo chips.