不同比例蚓粪替代化肥对设施土壤活性碳氮含量的影响

  目的  土壤微生物量碳氮（MBC、MBN）和水溶性有机碳氮（WSOC、WSON）是土壤中活跃的碳氮组分，是衡量土壤碳氮周转与养分有效性的重要指标。探究不同比例蚓粪替代化肥条件下，设施土壤微生物量碳氮、水溶性有机碳氮含量变化特征，旨在为设施土壤合理施肥提升提供科学依据。  方法  依托温室内有机肥替代部分化肥长期定位试验，以黄瓜为供试材料，试验共设6个处理，分别为100%化肥（CF100）、75%化肥（CF75）、25%蚓粪替代化肥（VM25）、50%蚓粪替代化肥（VM50）、100%蚓粪替代化肥（VM100）、不施肥（CK）。  结果  0 ~ 10 cm土层土壤活性碳氮含量略高于10 ~ 20 cm土层，其在生育期内呈先增高后降低的变化趋势。其中VM50处理提升效果最显著，较CF100处理分别提高了66.46%（0 ~ 10 cm土层）、76.02%（10 ~ 20 cm土层）；在黄瓜盛果期各处理土壤WSOC含量相对较高，VM50处理土壤WSOC含量较CF100处理分别提高22.88%（0 ~ 10 cm土层）、18.84%（10 ~ 20 cm土层）；0 ~ 10 cm土层，与CF100相比，生育前期VM25处理对土壤MBN含量提升效果较好，生育后期VM50处理对土壤MBN含量提升效果较好。10 ~ 20 cm土层，在黄瓜初果期各处理土壤WSON含量相对较高，VM50处理土壤WSON含量较CF100处理分别提高50.90%（0 ~ 10 cm土层）、12.55%（10 ~ 20 cm土层）；3种比例蚓粪替代化肥显著提高0 ~ 10 cm土层 MBC、WSOC在总有机碳，MBN、WSON在全氮中的占比，VM25、VM50处理对反映土壤微生物群落的结构信息的土壤MBC/MBN降低效果较好，VM50处理对土壤WSOC/WSON降低效果较好。  结论  在设施栽培条件下，可以通过蚓粪适量施入的措施合理替代化肥，达到给作物持续供应养分的目的，为设施栽培中科学合理施肥提供科学依据。

Regulation of Activated Carbon and Nitrogen Contents in Greenhouse Soil by Different Proportions of Vermicompost Instead of Chemical Fertilizers

  Objective  In order to provide scientific basis for improving soil quality, the variation characteristics of soil microbial biomass carbon (MBC) and nitrogen (MBN), water-soluble organic carbon (WSOC) and nitrogen (WSON) in greenhouse soil were studied under different proportions of earthworm casts instead of chemical fertilizers.   Method  Based on the long-term located experiment of organic material replacing partial chemical fertilizer in greenhouse, the experiment consists of 6 treatments with cucumber as the tested material. They were 100% chemical fertilizer (CF100), 75% chemical fertilizer (CF75), 25% vermicompost substitute chemical fertilizer (VM25), 50% vermicompost substitute chemical fertilizer (VM50), 100% vermicompost substitute chemical fertilizer (VM100) and no fertilizer (CK).   Result  The results showed that the variation trend of soil active carbon and nitrogen in 10-20 cm soil layer was similar to that in 0-10 cm soil layer, but slightly lower than that in 0-10cm soil layer. Among the three ratios of vermicompost to chemical fertilizer, VM50 was the most effective. The contents of MBC in soil of VM50 treatment increased by 66.46% (0-10 cm soil layer) and 76.02% (10-20 cm soil layer) than those of CF100 treatment, and the content of MBC in soil of each treatment was relatively high in full fruit stage of cucumber compared with CF100 treatment. Soil WSOC contents in VM50 treatment increased by 22.88% (0-10 cm soil layer) and 18.84% (10-20 cm soil layer) , respectively. VM50 treatment had a better effect on increasing MBN content in soil at the later growth stage. In 10-20 cm soil layer, the soil WSON content in each treatment was relatively high at the initial fruit stage of cucumber, and the soil WSON contents in VM50 treatment were 50.90% (0-10 cm soil layer) and 12.55% (10-20 cm soil layer) higher than those in CF100 treatment, respectively. Three ratios of vermicompost instead of chemical fertilizer could increase soil C/N, VM25 and VM50 treatments had a better effect on MBC/MBN reduction, which reflected the structure information of soil microbial community, and VM50 treatments had a better effect on WSOC/WSON.   Conclusion  The earthworm casts were used as partial fertilizers in greenhouse soil, which would establish a theoretical foundation for scientific and rational fertilization in protected cultivation.