• ISSN 1008-505X
  • CN 11-3996/S
崔继文, 徐新朋, 何萍, 周卫, 朱平. 氮素有机替代对东北黑土区土壤微生物碳磷资源限制的影响[J]. 植物营养与肥料学报, 2020, 26(11): 1953-1966. DOI: 10.11674/zwyf.20317
引用本文: 崔继文, 徐新朋, 何萍, 周卫, 朱平. 氮素有机替代对东北黑土区土壤微生物碳磷资源限制的影响[J]. 植物营养与肥料学报, 2020, 26(11): 1953-1966. DOI: 10.11674/zwyf.20317
CUI Ji-wen, XU Xin-peng, HE Ping, ZHOU Wei, ZHU Ping. Effect of organic nitrogen substitution on soil microbial resources limitation by carbon and phosphorus in black soil of Northeast China[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(11): 1953-1966. DOI: 10.11674/zwyf.20317
Citation: CUI Ji-wen, XU Xin-peng, HE Ping, ZHOU Wei, ZHU Ping. Effect of organic nitrogen substitution on soil microbial resources limitation by carbon and phosphorus in black soil of Northeast China[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(11): 1953-1966. DOI: 10.11674/zwyf.20317

氮素有机替代对东北黑土区土壤微生物碳磷资源限制的影响

Effect of organic nitrogen substitution on soil microbial resources limitation by carbon and phosphorus in black soil of Northeast China

  • 摘要:
    目的 土壤微生物数量和结构普遍受到碳 (C),氮 (N)、磷 (P)等养分有效性的影响,研究不同施肥措施对东北黑土区土壤理化性质、微生物量和酶活性的影响,深入了解土壤微生物养分资源限制状况及其变化规律,为提高土壤生物肥力提供理论依据。
    方法 试验设在黑龙江省哈尔滨市,土壤类型为黑土,种植制度为玉米单作。试验开始于2019年,共设9个处理:不施肥 (CK)、习惯施肥 (FP)、推荐施肥 (OPT)、推荐施肥不施氮 (–N);有机氮替代推荐施氮量的10% (M1)、20% (M2)、30% (M3)、40% (M4) 和50% (M5)。玉米收获后,采集0—20 cm土壤样品,测定土壤含水量、pH、有机质、全氮、速效磷、速效钾、可溶性有机碳、可溶性有机氮、微生物量碳、微生物量氮和4种土壤酶 (酸性磷酸酶、β-D-葡萄糖苷酶、L-亮氨酸氨基肽酶、β-N-乙酰氨基葡萄糖苷酶) 活性。
    结果 与OPT处理相比,有机氮替代化肥氮处理提高了土壤速效养分含量 (可溶性有机碳、有效磷、速效钾) 和微生物量 (微生物量碳、微生物量氮),其中可溶性有机碳、有效磷和速效钾的含量随替代比例的增加分别增加了15.5%~46.6%、1.4%~18.5%和2.4%~18.8%;MBC和MBN的含量随有机替代比例的增加分别增加了1.4%~19.9%和0.04%~22.7%。PCA分析显示出CK、化肥处理 (FP、OPT、–N) 和有机氮替代化肥氮处理 (M1、M2、M3、M4、M5) 下的土壤酶活性具有显著差异;RDA分析进一步表明有效磷 (F = 14.1,P = 0.002) 是影响酶活性变化的主要理化因子,解释了不同处理间酶活性差异的36.1%。酶化学计量散点图显示出试验点的土壤微生物均受到磷的限制,FP处理下的土壤微生物还受到碳的限制。此外,与CK相比,有机氮替代化肥氮显著提高了β-D-葡萄糖苷酶与酸性磷酸酶的比值,但是矢量角度在不同有机替代处理间并无显著差异。
    结论 在本试验区中,未施肥处理下土壤微生物受到碳和磷的共同限制,习惯施肥和优化施肥均会加剧微生物的碳限制。有机氮替代化肥氮可以显著提高土壤的养分含量与生物肥力,解除土壤微生物的碳限制,并显著减轻土壤微生物的磷限制。但是磷限制的减轻效果并未随有机氮替代化肥氮比例的增加而显著增加,考虑到有机肥养分释放较为缓慢,具体的有机替代比例还需开展长期试验。

     

    Abstract:
    Objectives Soil microorganisms are generally limited by the availability of carbon (C), nitrogen (N) and phosphorus (P). Studying the effects of different fertilization methods on soil physico-chemical properties, soil microbial biomass, and enzyme activities will improve our understanding on the roles of soil nutrients and microbes, and provide theoretical basis for improving soil fertility.
    Methods An experiment was conducted on a black soil in Heilongjiang Province. Maize crop was cultivated in 2019 planting season with 9 different treatments viz: no fertilizer (CK), Farmers’practice (FP); optimum nutrient treatment (OPT); N-omission based on OPT treatment (–N); and organic nitrogen (horse manure) substituted for chemical nitrogen fertilizer by 10% (M1); 20% (M2); 30% (M3); 40% (M4) and 50% (M5). After the maize harvest, soil samples were collected at 0–20 cm depth to determine soil moisture, pH, organic carbon, total nitrogen, available phosphorus, available potassium, soluble carbon (DOC), and soluble nitrogen, microbial biomass carbon, microbial biomass nitrogen, and soil enzyme activities (acid phosphatase, β-D-glucosidase, L-leucine aminopeptidase, β-N-acetylglucosaminidase).
    Results Compared with OPT treatment, the contents of available nutrients (soluble organic carbon; available phosphorus; available potassium) significantly increased by 15.5%–46.6%, 1.4%–18.5% and 2.4%–18.8% respectively, and microbial biomass (microbial biomass carbon; microbial biomass nitrogen) increased by 1.4%–19.9% and 0.04%–22.7% respectively with the increase of organic substitution ratio in organic nitrogen substitution treatments. PCA analysis showed that there were significant differences in enzyme activities among CK, FP, OPT, –N and chemical nitrogen substituted with organic nitrogen (M1–M5). RDA analysis further showed that DOC (F = 23.8, P = 0.002) was the main factor affecting the change of enzyme activities by explaining 48.8% of the difference among different treatments. The scatter plot of enzyme stoichiometry showed that the soil microorganisms in the test site were limited by P, and the soil microorganisms under FP treatment were also limited by C. Compared with CK, organic fertilizer substitution significantly improved the BG/AP ratio, but there was no significant difference between different substitution ratios.
    Conclusions In this study area, the soil microorganism is limited by both Cand Punderno fertilization condition. Both conventional fertilization and optimized fertilization aggravated the carbon limitation of soil microorganism. The substitution of organic fertilizer for chemical nitrogen fertilizer significantly improved the soil nutrients and biological fertility, and significantly reduce the C and P limitations of soil microorganisms. However, the reduction effect of phosphorus limitation did not increase with the increase in the proportion of organic fertilizer replacing chemical nitrogen fertilizer. Considering the slow release of nutrients inorganic fertilizer, the specific proportion of organic fertilizer substitution still needs to be observed through long-term experiments.

     

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