• ISSN 1008-505X
  • CN 11-3996/S
李增强, 张贤, 王建红, 曹凯, 徐昌旭, 曹卫东. 化肥减施对紫云英还田土壤活性有机碳和碳转化酶活性的影响[J]. 植物营养与肥料学报, 2019, 25(4): 525-534. DOI: 10.11674/zwyf.18121
引用本文: 李增强, 张贤, 王建红, 曹凯, 徐昌旭, 曹卫东. 化肥减施对紫云英还田土壤活性有机碳和碳转化酶活性的影响[J]. 植物营养与肥料学报, 2019, 25(4): 525-534. DOI: 10.11674/zwyf.18121
LI Zeng-qiang, ZHANG Xian, WANG Jian-hong, CAO Kai, XU Chang-xu, CAO Wei-dong. Effect of chemical fertilizer reduction with return of Chinese milk vetch (Astragalus sinicus L.) on soil labile organic carbon and carbon conversion enzyme activities[J]. Journal of Plant Nutrition and Fertilizers, 2019, 25(4): 525-534. DOI: 10.11674/zwyf.18121
Citation: LI Zeng-qiang, ZHANG Xian, WANG Jian-hong, CAO Kai, XU Chang-xu, CAO Wei-dong. Effect of chemical fertilizer reduction with return of Chinese milk vetch (Astragalus sinicus L.) on soil labile organic carbon and carbon conversion enzyme activities[J]. Journal of Plant Nutrition and Fertilizers, 2019, 25(4): 525-534. DOI: 10.11674/zwyf.18121

化肥减施对紫云英还田土壤活性有机碳和碳转化酶活性的影响

Effect of chemical fertilizer reduction with return of Chinese milk vetch (Astragalus sinicus L.) on soil labile organic carbon and carbon conversion enzyme activities

  • 摘要:
    目的 评价紫云英绿肥还田配施化肥对稻田土壤活性有机碳含量以及与碳转化相关酶活性的影响。
    方法 田间试验在浙江省金华市红壤黄筋泥土发育而成的水稻土上进行。供试紫云英 (Astragalus sinicus L.) 品种为‘宁波大桥’,每年4月在紫云英盛花期异地翻压。试验连续进行了6年,处理包括空白对照 (CK)、单施常规量化肥 (CF),单施紫云英 (MV),紫云英配合20%、40%、60%和80%的常规化肥量共7个处理。除空白和单施化肥处理外,其它处理均翻压45 t/hm2紫云英鲜草。N、P2O5、K2O化肥常规用量分别为210、56.3、112.5 kg/hm2。水稻收获后,采集0—20 cm表层土样,测定了土壤活性有机碳 (可溶性有机碳 (DOC)、热水提取态有机碳 (HEOC)、微生物生物量碳 (MBC)、颗粒有机碳 (POC)、易氧化有机碳 (ROC)) 和总有机碳 (TOC) 含量,以及碳转化酶 (纤维素酶、蔗糖酶、β-葡萄糖苷酶、酚氧化酶和过氧化物酶) 活性。
    结果 与CF相比,MV处理能够显著增加DOC、HEOC和ROC含量,对MBC和TOC含量无显著影响;显著增加纤维素酶、蔗糖酶和β-葡萄糖苷酶活性,对酚氧化酶和过氧化物酶活性无显著影响。四个紫云英配施化肥处理中,DOC和POC含量以MV + 60%CF处理最高,显著高于MV处理。随着配施化肥量的增加,土壤碳库管理指数随之增加。MV处理的纤维素酶、蔗糖酶、β-葡萄糖苷酶、酚氧化酶和过氧化物酶活性均显著低于其与化肥配合处理,上述五种酶活性均以MV + 60%CF处理最高。几何平均酶活性和总体酶活性均表现为MV < MV + 20%CF < MV + 40%CF、MV + 80%CF < MV + 60%CF处理 (P < 0.05)。通径分析表明纤维素酶活性对HEOC具有最大的直接正效应,蔗糖酶活性分别对DOC和MBC表现出最大的直接正效应,β-葡萄糖苷酶活性分别对POC和ROC表现出最大的直接正效应。酚氧化酶活性对DOC表现出最高的间接效应,β-葡萄糖苷酶活性则对HEOC具有最高的间接效应,过氧化物酶活性分别对MBC、POC和ROC表现出最大的间接效应。
    结论 紫云英还田量为45 t/hm2条件下,适当减少常规化肥用量能够显著增加土壤活性有机碳含量和碳转化酶活性,以配施60%的化肥用量效果最佳。土壤活性有机碳含量受纤维素酶、蔗糖酶和β-葡萄糖苷酶活性的直接影响,而受酚氧化酶和过氧化物酶活性的间接影响。

     

    Abstract:
    Objectives To evaluate the effects of reduction of chemical fertilizer with return of Chinese milk vetch (Astragalus sinicus L. hereafter vetch) on paddy soil labile organic carbon content and C conversion enzyme.
    Methods Field experiments were carried on the paddy soil derived from quaternary red clay in Jinhua City, Zhejiang Province. Vetch cultivar Ningbodaqiao was used in this experiment. The vetch was incorporated into soil at flowering stage in April every year. The field experiments continued for six years and had seven treatments, i.e. CK (no fertilizer), CF (only application of chemical fertilizers), MV (vetch return without chemical fertilizers), MV + 20%CF (vetch return plus 20% chemical fertilizers), MV + 40%CF (vetch return plus 40% chemical fertilizers), MV + 60%CF (vetch return plus 60% chemical fertilizers), and MV + 80%CF (vetch return plus 80% chemical fertilizers). The amount of fresh vetch returned was 45 t/hm2. The amount of chemical fertilizer was 210 (N), 56.3 (P2O5) and 112.5 (K2O) kg/hm2 in the CF treatment. After the rice harvest, soil samples were collected in October, 2016. Contents of soil labile organic carbon, including dissolved organic carbon (DOC), hot-water extractable organic carbon (HEOC), microbial biomass carbon (MBC), particle organic carbon (POC), readily oxidizable organic carbon (ROC), and soil total organic carbon (TOC), and C-conversion enzyme (cellulase, invertase, β-glucosidase, phenol oxidase and peroxidase) activities were investigated.
    Results In comparison with CF treatment, MV treatment significantly increased the contents of DOC, HEOC and ROC, but had no effect on the contents of MBC and TOC. The contents of DOC, HEOC, MBC, ROC and TOC in CF and MV treatments were significantly lower than those in MV + 20%CF, MV + 40%CF, MV + 60%CF和MV + 80%CF treatments. With the increase of chemical fertilizers application rates, the contents of DOC, HEOC, MBC and ROC increased first and then decreased, with the highest contents in MV + 60%CF treatment, while TOC content showed little change. The content of POC in MV treatment was higher than that in CF treatment, but lower than that in MV + 60%CF treatment. MV treatment significantly increased the values of DOC/TOC and HEOC/TOC compared with CF treatment. The values of DOC/TOC and ROC/TOC in CF treatment were significantly lower than those in MV + 20%CF, MV + 40%CF, MV + 60%CF and MV + 80%CF treatments. The increase in chemical fertilizer application amount had no significant influence on the ratio of soil labile organic carbon to TOC. The carbon management index in CF treatment was significantly lower than that in MV, MV + 20%CF, MV + 40%CF, MV + 60%CF and MV + 80%CF treatments. The carbon management index tended to increase with the increase of chemical fertilizer application amount after vetch incorporation. Compared with CF treatment, MV treatment significantly increased the activities of cellulase, invertase and β-glucosidase but had little influences on the activities of phenol oxidase and peroxidase. The cellulase, invertase, β-glucosidase, phenol oxidase and peroxidase activities in both CF and MV treatment were significantly lower than those in MV + 20%CF, MV + 40%CF, MV + 60%CF and MV+80%CF treatments. With increase of chemical fertilizer application rates, the five enzyme activities increased first and then decreased, with the highest contents in MV+60%CF treatment. Geometric mean enzyme activity and total enzyme activity were significantly influenced by different fertilizer treatment in the order of CK < CF < MV < MV + 20%CF < MV + 40%CF and MV + 80%CF < MV + 60%CF (P < 0.05). MV treatment showed significantly higher relative activities of cellulase and invertase (the ratio of enzyme activities to microbial biomass carbon) compared with CF treatment. CF treatment had significantly lower relative activities of invertase and β-glucosidase but higher relative activity of peroxidase compared with MV + 20%CF, MV + 40%CF, MV + 60%CF and MV + 80%CF treatments. Path analysis showed that cellulase activity had the highest positive direct effect on HEOC content, invertase activity had the highest positive direct effect on DOC and MBC contents, and β-glucosidase activity had the highest positive direct effect on POC and ROC contents. Furthermore, phenol oxidase activity had the highest positive indirect effect on DOC content, β-glucosidase activity had the highest positive indirect effect on HEOC, and peroxidase activity had the highest positive indirect effect on MBC, POC and ROC.
    Conclusions Return of vetch along with chemical fertilizers could significantly increase soil labile organic carbon contents and C-cycling involved enzyme activities, with the best effects in the application of 60% chemical fertilizers treatment. Cellulase, invertase and β-glucosidase activities had direct positive effects on soil labile organic carbon contents. Phenol oxidase and peroxidase activities showed indirect effects on soil labile organic carbon contents.

     

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