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粮田改为菜田后,土壤碳氮状况和水热条件发生了变化,菜田土壤的碳氮比(C/N)和碳氮含量可能发生显著变化。为此,本文通过收集中国主要蔬菜产区的土壤碳、氮数据和与之对应的粮田土壤碳、氮数据,进行了对比分析,得出以下结论:菜田土壤的C/N比出现了极显著的下降,比粮田下降了1.7个单位,粮田土壤的C/N比平均稳定在10.3左右,而菜田土壤的C/N比却下降到8.6,下降幅度达到17%。菜田土壤全氮含量显著高于粮田土壤,二者平均相差0.330 g/kg,有机质含量与粮田没有显著差异。菜田土壤C/N比下降主要发生在2种情景下:土壤全氮和有机质都在增加;有机质下降全氮增加。91%的菜田土壤全氮在增加,9%的在下降。52%的菜田土壤有机质在增加,48%的有机质在下降。
After changing the grain fields into vegetable fields, soil carbon and nitrogen conditions and hydrothermal conditions have changed. C / N and carbon and nitrogen contents of vegetable soils may change significantly. In this paper, the data of soil carbon and nitrogen in the main vegetable producing areas in China were collected and compared with the corresponding data of soil carbon and nitrogen in grain fields. The conclusions are as follows: The C / N ratio of vegetable soils appeared The extremely significant decrease was 1.7 units lower than that of grain fields. The average C / N ratio of soil in grain fields was about 10.3. However, the C / N ratio of vegetable soils decreased to 8.6%, with a decrease of 17%. The soil total nitrogen content in vegetable fields was significantly higher than that in grain fields, with an average difference of 0.330 g / kg between the two. There was no significant difference in organic matter content between the soil and grain fields. Soil C / N ratio in vegetable field decreased mainly in two kinds of scenarios: soil total nitrogen and organic matter were all increased; organic matter decreased total nitrogen increased. Soil nitrogen in 91% of the vegetable fields increased while 9% was declining. 52% of the vegetable soil organic matter is increasing, 48% of the organic matter is declining.