世界上共有三大片黑土,其一分布在乌克兰,其二分布在美国密西西比河流域,其三就分布在我国的黑龙江和吉林两省境内,东北黑土区的开垦历史已有300年之久。黑土开垦后,黑土的肥力性状发生了变化,有部分土壤向着不断培肥熟化的方向发展,但大量的、比较普遍的则是土壤的自然肥力呈 There are three major types of black soil in the world, one in Ukraine and the second in the Mississippi River basin in the United States. The third one is distributed in the two provinces of Heilongjiang and Jilin in China. The history of reclamation in the northeastern black soil area has been 300 years. After the reclamation of black soil, the fertility traits of black soil changed, and some of the soil developed towards the direction of continuous fertilization and maturation. However, a large amount of soil fertility was generally found