• ISSN 1008-505X
  • CN 11-3996/S

长期施用不同改良剂及轮作对连作花生土壤有机氮组分及氮矿化的影响

Effects of long-term application of different amendments and crop rotation on organic nitrogen fractions and nitrogen mineralization in continuously cropped peanut soil

  • 摘要:
    目的 土壤改良剂可通过改善土壤微环境、调节微生物活动,影响土壤易矿化有机氮组分和矿化速率,为作物提供更充足的有效氮源,进而促进作物的健康生长。探究长期施用不同改良剂对连作土壤氮素有效性及作物生长的影响,以期提出适宜于连作经济作物种植的土壤管理措施。
    方法 沈阳农业大学国家花生产业技术体系土壤肥料基地长期定位试验始于2011年,包括4个处理:花生连作对照 (PC)、玉米−花生轮作 (MPR)、花生连作分别配合施用化学改良剂 (PCCA) 和生物改良剂 (PCBA)处理,各处理均基施 N 60 kg/hm2、P2O5 82.5 kg/hm2、K2O 112.5 kg/hm2。在2023 年花生苗期、开花下针期、结荚期及成熟期,采集土壤样品,进行氮矿化培养试验,同时测定土壤无机氮、有机氮组分、微生物量氮、固定态铵含量。成熟期取植物样品,测定养分含量、生物量及花生产量。
    结果 与 PC 相比,PCCA 处理提高了花生各生育时期土壤铵态氮或硝态氮含量,铵态氮增幅为高达198.71%,硝态氮增幅高达86.56%;PCCA和PCBA处理显著提高了培养 21天后土壤的净氮矿化速率,较PC处理分别增加43.77%和35.65%,且 PCCA 的增幅高于 PCBA。PCCA 和 MPR 处理对各生育期土壤有机氮组分含量的影响不尽相同,与 PC 相比,PCCA 处理各生育期土壤酸解铵态氮和酸解氨基酸态氮含量分别显著提升了 7.79%~29.32%和13.87%~19.02%,MPR 处理分别显著提高了 9.15%~32.16%和12.17%~22.00%;PCCA和 MPR 处理成熟期酸解氨基糖态氮含量分别提高 26.16%和 30.77%,成熟期酸解未知态氮含量分别提高 30.65%和37.84%,同时非酸解氮含量显著分别降低 15.50%和13.38%,MPR 处理各有机氮组分含量与 PCCA 处理相当。PCCA、PCBA 和 MPR 均显著提高了土壤微生物量氮及固定态铵含量,培养后 (培养21天) 微生物量氮较 PC 的增幅为 18.43%~22.28%;固定态铵的增幅为 11.58%~22.49%,PCCA 对固定态铵的提升效果与MPR相当。
    结论 在花生连作土壤上,施用化学改良剂或者轮作提升了土壤酸解铵态氮、酸解氨基酸态氮含量,提高了土壤氮矿化速率和矿化量,化学改良剂处理矿化形成的部分无机氮以固定态铵的形式在土壤中保存下来,提高了土壤氮素供应的稳定性,因而在提升花生荚果和茎叶中氮磷钾积累量方面获得了优于轮作的效果。生物改良剂对土壤有机氮组分特别是酸解有机氮组分无显著影响,但提升了花生苗期和开花下针期土壤中铵态氮和硝态氮含量,因而促进了花生早期的养分供给,也获得了显著的增产效果。因此,施用化学改良剂和生物改良剂均是替代轮作的有效措施。

     

    Abstract:
    Objectives Soil amendments are frequently employed to enhance the micro-environmental conditions and accelerate the mineralization rates of organic matter. By doing so, they furnish crops with an efficient nutrient supply and foster a conducive environment for healthy growth. In this study, we conducted a comparative analysis to assess the impact of the long-term application of soil amendments on soil nitrogen availability and crop growth within a continuously cropped system. The ultimate aim is to formulate appropriate soil management strategies tailored for economically significant continuous cropping systems.
    Methods A long-term experiment was carried out in the Base for Soil Fertilizer of National Peanut Industry Technology System of Shenyang Agricultural University since 2011. The four treatments were: peanut continuous cropping (PC), maize-peanut rotation (MPR), peanut continuous cropping applied with chemical amendments (PCCA) and bio-amendments (PCBA). All the treatments were basal applied with N 60 kg/hm2, P2O5 82.5 kg/hm2 and K2O 112.5 kg/hm2. Soil samples were collected during the seedling, flowering and needling, podding, and maturity stages of peanut in 2023 for nitrogen mineralization incubation tests, and the determination of soil inorganic N, organic nitrogen fractions, microbial biomass nitrogen (MBN), and fixed ammonium (FN). At maturity, plant samples were collected to determine nutrient content, biomass, and peanut yield.
    Results Compared with PC, PCCA treatment increased soil NH4+-N by up to 198.71% and NO3-N by up to 86.56% across all growth stages, PCCA and PCBA increased net nitrogen mineralization rate after 21 days of incubation by 43.77% and 35.65%, respectively, and the increase by PCCA was significantly higher than that by PCBA. The effects of PCCA and MPR on organic nitrogen fractions depended on the growth stages. Compared to PC, PCCA significantly increased soil acidolysed ammonium nitrogen and acidolysed amino acid nitrogen contents by 7.79%–29.32% and 13.87%–19.02%, respectively, and MPR increased these fractions by 9.15%–32.16% and 12.17%–22.00%, respectively. At maturity, PCCA and MPR significantly increased acidolysed amino sugar nitrogen by 26.16% and 30.77%, and acidolysed unknown nitrogen by 30.65% and 37.84%, respectively, but significantly reduced non-acidolysed nitrogen by 15.50% and 13.38%. The organic nitrogen fractions in MPR were comparable to those in PCCA. PCCA, PCBA, and MPR significantly increased soil MBN and FN by 18.43%–22.28% and 11.58%–22.49% after 21 days of incubation, respectively. PCCA had a similar pronounced effect on fixed ammonium relative to MPR.
    Conclusions In peanut continuous cropping soil, the application of chemical amendments or crop rotation increased the contents of soil acidolysed ammonium nitrogen and acidolysed amino acid nitrogen, as well as the rate and amount of soil nitrogen mineralization. In the chemical amendment-treated soil, a portion of the inorganic nitrogen formed through mineralization was preserved in the soil in the form of fixed ammonium, enhancing the stability of soil nitrogen supply. As a result, the amendment treatment achieved better effects than crop rotation in increasing the accumulation of N, P, and K in peanut pods and shoots. Bio-amendments had no significant impact on soil organic nitrogen fractions, especially acidolysed organic nitrogen fractions. However, it elevated the contents of ammonium nitrogen and nitrate nitrogen in soil during the peanut seedling stage and the pegging-flowering stage, thereby promoting nutrient supply in the early growth stages of peanuts and also resulting in a significant yield increase. Therefore, the application of chemical amendments and bio-amendments are effective measures to replace crop rotation.

     

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