炕洞土是一种好肥料。土炕内的土坯一般砌成蜂窝式,烧炕时烟在炕内通过的时间较长,烟中的氮能很好地被炕土吸收,所以炕土含有较多的有效养分。据有关单位的化验,用了1年的炕,炕洞土含氮量0.22％,含磷酸0.24％;2～3年的炕洞土,含氮量0.35％,含磷酸0.71％。但也不是年代越多肥份越高。火炕 Kandong soil is a good fertilizer. Soil kang within the general build brick briquette, burning kang smoke in the kang within a long time, the smoke of nitrogen can be well absorbed by kang soil, kang soil contains more effective nutrients. According to the tests of the relevant units, with 1 year of kang, kong soil nitrogen content of 0.22%, containing 0.24% phosphoric acid; 2 ~ 3 years of kang soil, nitrogen content of 0.35%, 0.71% phosphoric acid. But not the more the higher the fertilizer. Ondol