• ISSN 1008-505X
  • CN 11-3996/S
李文军, 黄庆海, 李大明, 柳开楼, 叶会财, 肖国滨, 张文菊, 徐明岗. 长期施肥红壤性稻田和旱地土壤有机碳积累差异[J]. 植物营养与肥料学报, 2021, 27(3): 544-552. DOI: 10.11674/zwyf.20313
引用本文: 李文军, 黄庆海, 李大明, 柳开楼, 叶会财, 肖国滨, 张文菊, 徐明岗. 长期施肥红壤性稻田和旱地土壤有机碳积累差异[J]. 植物营养与肥料学报, 2021, 27(3): 544-552. DOI: 10.11674/zwyf.20313
LI Wen-jun, HUANG Qing-hai, LI Da-ming, LIU Kai-lou, YE Hui-cai, XIAO Guo-bin, ZHANG Wen-ju, XU Ming-gang. Differences in organic carbon accumulation between reddish paddy and upland soils under long-term fertilization[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(3): 544-552. DOI: 10.11674/zwyf.20313
Citation: LI Wen-jun, HUANG Qing-hai, LI Da-ming, LIU Kai-lou, YE Hui-cai, XIAO Guo-bin, ZHANG Wen-ju, XU Ming-gang. Differences in organic carbon accumulation between reddish paddy and upland soils under long-term fertilization[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(3): 544-552. DOI: 10.11674/zwyf.20313

长期施肥红壤性稻田和旱地土壤有机碳积累差异

Differences in organic carbon accumulation between reddish paddy and upland soils under long-term fertilization

  • 摘要:
    目的 提高土壤有机碳水平对提升农田生产力有重要意义。基于长期定位施肥试验,比较施肥影响下相同成土母质发育的红壤性稻田和旱地土壤的总有机碳 (TOC) 及其组分的积累差异,以深入理解红壤有机碳的固持及稳定机制。
    方法 稻田和旱地长期施肥试验分别始于1981和1986年,包含CK (不施肥对照)、NPK (施氮磷钾化肥) 和NPKM (有机无机肥配施) 3个处理,在2017年晚稻和晚玉米收获后,采集两个试验上述处理的耕层 (0—20 cm) 土样,通过硫酸水解法分离土壤活性与惰性有机碳,测定并计算土壤中TOC及其组分的含量及储量,并利用Jenny模型拟合试验期间耕层土壤TOC含量的变化动态,估算土壤固碳潜力。
    结果 与CK相比,长期施肥可提高稻田和旱地土壤各有机碳组分的含量,且NPKM处理的效果优于NPK处理。相比于稻田土壤,施肥对旱地土壤各有机碳组分含量的提升更加明显。NPK和NPKM处理下,旱地土壤活性有机碳组分Ⅰ、活性有机碳组分Ⅱ、惰性有机碳含量的增幅分别是稻田土壤的2.7、2.7、5.8倍和2.0、1.4和2.5倍。不论施肥与否,稻田土壤TOC的固存量和固存潜力均显著高于旱地土壤。施肥促进土壤固碳,在稻田和旱地土壤上,NPKM处理的TOC固存量分别是NPK处理的1.7和25.5倍,TOC固存潜力则分别是NPK处理的1.4和5.8倍。长期不同施肥均显著提高稻田和旱地土壤年均碳投入量,线性拟合方程表明,随碳投入量增加,土壤活性有机碳储量的累积对稻田、旱地土壤TOC储量累积的贡献率分别达64.7%、44.6%。不同处理间稻田与旱地土壤活性有机碳 (包括活性有机碳组分Ⅰ与活性有机碳组分Ⅱ) 含量的差异可解释其TOC含量差异的52.9%~60.0%。
    结论 与施氮磷钾化肥相比,有机无机肥配施可更好的促进土壤固碳,且在旱地土壤上的促进作用比在稻田土壤上更为明显。与稻田土壤相比,旱地土壤各有机碳组分含量的变化对长期施肥的响应更敏感,且在施氮磷钾化肥条件下表现更为明显。红壤性稻田和旱地土壤TOC积累的主要贡献组分分别为活性有机碳和惰性有机碳。红壤植稻虽有利于有机碳固持,但红壤性稻田土壤的活性碳占比较高,可能易因不当管理而发生损失。

     

    Abstract:
    Objectives Increasing soil organic carbon level is of great significance for improving farmland productivity. The accumulation characteristics of organic carbon were studied under long-term different fertilization modes in a reddish paddy soil and an upland red soil that both developed from the same parent material, which would provide scientific basis for further understanding the underlying mechanism of organic carbon sequestration and stabilization in fertilized red soils.
    Methods The study included two long-term fertilization experiments, one was in paddy field and started in 1981, and the other was in adjacent upland field and started in 1986. Surface soil samples (0‒20 cm) were collected after harvest of late rice and maize in November 2017 in the three treatments of CK (no fertilizer), NPK (chemical N, P, K fertilizers) and NPKM (chemical NPK fertilizers plus organic manure) of both the experiments. The contents and storages of TOC and H2SO4-hydrolyzed labile and recalcitrant organic carbon in soils were measured. In addition, soil TOC sequestration potential was computed by fitting the dynamics of TOC content using Jenny model.
    Results Fertilization increased the contents of all organic carbon fractions in soils, and NPKM treatment increased more than NPK did. The content increase range of all the organic carbon fractions in the upland soil was significantly higher than that in the paddy soil. Under NPK treatment, the increase ranges of labile organic carbon fraction Ⅰ (LOCF-Ⅰ), labile organic carbon fraction Ⅱ (LOCF-Ⅱ) and recalcitrant organic carbon (ROC) in upland soil were 2.7 times, 2.7 times and 5.8 times of those in paddy soil, respectively, while under NPKM treatment, the increase ranges of LOCF-Ⅰ, LOCF-Ⅱ and ROC in upland soil were 2.0 times, 1.4 times and 2.5 times of those in paddy soil, respectively. No matter fertilization or not, the TOC sequestration amount and potential in paddy soils were significantly higher than those in upland soils. NPKM treatment presented better effect for promoting TOC sequestration as compared with NPK treatment. The soil TOC sequestration amount and potential under NPKM treatment were 1.7 times and 1.4 times of those under NPK treatment in paddy field, and were 25.5 times and 5.8 times in upland field. Long-term fertilization significantly increased exogenous carbon input in both paddy and upland fields, and the increase of labile organic carbon storage contributed 64.7% of TOC storage in paddy soil and 44.6% in upland soil, respectively. The contents of LOCF-Ⅰ, LOCF-Ⅱ and ROC in the paddy soil were all significantly higher than those in the upland soil, regardless of fertilization regimes. The difference in total labile organic carbon (summing LOCF-Ⅰ and LOCF-Ⅱ) content between the paddy and the upland soil could explain 52.9%‒60.0% of the difference in TOC content.
    Conclusions Manure amendments combined with chemical NPK fertilizers significantly promote organic carbon sequestration in red soils as compared with chemical NPK fertilizers application alone, which is more pronounced in upland system. Compared with paddy soil, the change of content of each organic carbon fraction in upland soil was more sensitive to fertilizations, which is more obvious under the condition of chemical NPK fertilizers application. The main contributors of TOC accumulation in paddy and upland red soil are soil labile and recalcitrant organic carbon, respectively. Though reddish paddy soil is beneficial for TOC sequestration as compared with upland red soil, the proportions of labile fractions in its TOC is relatively higher, and thus is vulnerable to loss due to improper agricultural management.

     

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