深松施肥对黑土活性有机碳氮组分及酶活性的影响

Effects of Subsoiling Combined with Fertilization on the Fractions of Soil Active Organic Carbon and Soil Active Nitrogen,and Enzyme Activities in Black Soil in Northeast China

探究不同深松施肥措施对黑土活性有机碳氮组分及酶活性的影响对黑土有机质保育有重要意义。于东北黑土典型地区—黑龙江省绥化市试验点开展为期2年春玉米种植试验,共设5个处理:免耕+单施化肥(T1)、深松25 cm+单施化肥(T2)、深松25 cm+化肥有机肥配施(T3)、深松35 cm+单施化肥(T4)和深松35 cm+化肥有机肥配施(T5)处理,分析黑土活性有机碳氮组分和相关土壤酶活性的变化。结果表明:深松、施肥及其交互作用均显著影响土壤活性有机碳氮组分,对颗粒有机碳和颗粒有机氮影响最显著(P<0.001)。相对T1处理,单纯改变深松深度(T2和T4处理)会显著降低土壤活性有机碳氮组分,尤其颗粒有机碳和颗粒有机氮下降幅度最大;深松+化肥有机肥配施则可以显著增加土壤活性有机碳氮组分含量,与施化肥的T2处理相比,T3处理土壤有机碳、易氧化有机碳、颗粒有机碳和颗粒有机氮含量分别增加8.37%、35.10%、46.64%和42.39%(P<0.05);深松能够提高土壤碳氮稳定性,相比T1免耕处理,深松25cm和深松35 cm土壤微生物生物量碳/有机碳、颗粒有机碳/有机碳比例均显著降低(P<0.05),深松35 cm下土壤颗粒有机氮/总氮比例也显著降低(P<0.05)。深松对土壤乙酰基β-葡萄糖胺酶、纤维素酶、β-葡萄糖苷酶和木聚糖酶活性均没有显著影响,而增施有机肥(T3相对T2处理)显著提高了土壤纤维素酶活性。综合而言,深松25 cm+化肥有机肥配施措施能够保持土壤活性有机碳氮组分含量,是该地区黑土地保育和有机质提升的推荐技术。

【Objective】It is of great scientific significance to explore effects of the practice of subsoiling coupled with fertilization on the fractions of activated organic carbon and nitrogen,and enzyme activities in black soil.【Method】Based on a 2-year field experiment in Qinggang County,Heilongjiang Province,a black soil region typical of Northeast China,variations of the soil were analyzed in fractions of dissolved organic carbon(DOC),microbial biomass carbon(MBC),microbial biomass nitrogen(MBN),particulate organic carbon(POC),particulate organic nitrogen(PON),and readily oxidizable organic carbon(ROC),and in activity of N-acetylglucosaminnidase(NAG),Cellobiohydrolase(CBH),β-glucosidase(BG)andβ-xylosidase(BXYL)with treatment in the experiment,which consisted of five treatments,including no-till+chemical fertilizer(T1),subsoiling 25 cm(in depth)+chemical fertilizer(T2),subsoiling 25 cm+chemical fertilizer+organic manure(T3),subsoiling 35 cm+chemical fertilizer(T4),sub-soiling 35 cm+chemical fertilizer+organic manure(T5).【Result】Results showed that both subsoiling and fertilization and their interactions significantly affected the contents of soil activated carbon and nitrogen,particularly of POC and PON;Subsoiling(T2 and T4)significantly reduced the contents of soil activated organic carbon and nitrogen components with varying degree relative to depth of subsoiling,T2 was significantly lower than T1(P<0.05)in POC and PON content;T3 and T5 significantly increased the contents of soil activated organic carbon and nitrogen.T3 was 8.37%,46.64%,35.10%and 42.39%(P<0.05)higher than T2 in content of SOC,POC,ROC and PON.Besides,subsoiling improved stability of the soil activated organic carbon and nitrogen components.Compared with T1,subsoiling treatments significantly reduced the ratios of MBC/SOC and POC/SOC in the soil(P<0.05),and subsoiling 35 cm in depth significantly decreased the ratio of PON/TN(P<0.05);T2 and T4 did not differed much from T1 in enzyme activity,whereas T3 significantly increased CBH activity relative to T2.【Conclusion】To sum up,subsoiling 25 cm in depth combined with application of chemical fertilizer and organic manure can maintain the content of activated organic carbon and nitrogen components in the soil,hence it is recommended to be extrapolate as an effective farming technique to build up black soil farmland and to increase organic matter content in the soil of this area.