| 徐香茹,蔡岸冬,徐明岗,汪景宽,张文菊.长期施肥下水稻土有机碳固持形态与特征[J].农业环境科学学报,2015,34(4):753-760. |
| 长期施肥下水稻土有机碳固持形态与特征 |
| Characteristics of Organic Carbon Stabilization in Paddy Soil Under Long-term Different Fertilization |
| 投稿时间：2014-11-26 |
| DOI：10.11654/jaes.2015.04.021 |
| 中文关键词: 有机碳 组分 稳定机制 水稻土 土壤碳固定 |
| 英文关键词: soil organic carbon fractionation stabilization mechanism paddy soil carbon sequestration |
| 基金项目:国家自然科学基金面上项目(41371247);中央级公益性科研院所专项资金资助项目(IARRP-2014-28) |
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| 中文摘要: |
| 基于为期30年的红壤性水稻土长期定位试验,选用不施肥(CK)、化肥氮磷钾配施(NPK)、NPK配施低量有机肥(NPKM7/3)、NPK配施中量有机肥(NPKM5/5)、NPK配施高量有机肥(NPKM3/7)五个处理,通过物理-化学联合分组方法,分析土壤有机碳在不同施肥处理下的非保护、物理、化学、生化、物理-化学及物理-生化保护组分的碳含量特征及其与土壤总有机碳之间的关系,并探讨稻田土壤有机碳的固持机制。结果表明,除了非保护的轻组和微团聚体内闭蓄态的粘粉粒组分外,其他组分的质量比例在各施肥处理间均有显著性差异。有机无机配施(NPKM7/3、NPKM5/5、NPKM3/7)下,总有机碳含量(19.1~25.0 g·kg-1)、非保护的粗颗粒有机碳(cPOM)含量(8.41~12.7 g·kg-1)及物理保护的微团聚体有机碳(6.41~6.62 g·kg-1)含量均显著高于CK处理(P<0.05)。对化学、生化、物理-化学及物理-生化保护态的有机碳含量无显著性影响,表明非保护的cPOM及物理保护的微团聚体(μagg)对施肥的响应最敏感。相关分析表明,cPOM、物理保护的μagg及其闭蓄的细颗粒有机碳(iPOM)与土壤总有机碳含量之间呈显著正相关关系(P<0.05),相关方程的斜率表明有机碳变化引起了组分变化,其中:土壤总有机碳变化引起的cPOM变化率最高(50%);土壤总有机碳积累引起物理保护的μagg及其闭蓄的iPOM碳组分变化率为12%;生化保护的非酸解粘粒和物理-化学保护的酸解的粉粒虽与土壤总有机碳显著相关,其变化率仅为2%~3%;其他各保护机制下的组分与土壤总有机碳含量均无显著相关关系。这表明在现行种植和管理制度下,供试红壤性水稻土有机碳主要以cPOM及μagg有机碳的形式积累,土壤化学、生化、物理-化学及物理-生化保护碳组分可能已经达到平衡。 |
| 英文摘要: |
| Understanding the mechanisms of soil organic carbon(SOC) stabilization would help improve soil carbon sequestration in paddy soil. In this paper, we obtained paddy soils from a 30 year experimental field under five different fertilization, including no fertilizer(control), mineral nitrogen(N)-phosphorus(P)-potassium(K) fertilizers(NPK), 70% mineral N+30% organic N plus PK(NPKM7/3), 50% mineral N+50% organic N plus PK(NPKM5/5), and 30% mineral N+70% organic N plus PK(NPKM3/7). Organic N was provided from green manure and pig manure. The soils were subjected to separating unprotected, and physically, chemically, bio-chemically, physical-chemically, and physical-biochemically protected SOC fractions by a physical-chemical combined fractionation method. Except the unprotected light fraction and the occluded silt and clay-sized fraction, the mass proportion of all other SOC factions was significantly different between the treatments. Compared with non-fertilization(CK) treatment, chemical fertilizers mixed with organic manure(NPKM7/3、NPKM5/5 and NPKM3/7) significantly increased the content of total SOC(19.1~25.0 g·kg-1), unprotected coarse particulate organic carbon(cPOM)(8.41~12.7 g·kg-1), and physically protected aggregate(μagg) organic carbon(6.41~6.62 g·kg-1) in red paddy soil(P<0.05). There were no significant differences for the chemically, biochemically, physical-chemically and physical-biochemically protected fractions between the five treatments. These results indicated that the unprotected cPOM and the physically protected μagg fractions were the most sensitive ones in long-term fertilization. There was a linear positive correlation between total SOC and tcPOM, physically protected μagg, and occluded POM inside the μagg(iPOM) fraction(P<0.05), and their response efficiency to total SOC accumulation(the slope of the regression)was 0.5, 0.12, and 0.12 respectively. However, the response efficiency of non-hydrolysis clay and physic-chemically protected silt fraction to total SOC accumulation was only 0.02 to 0.03, even though they had significant responses. There was no significant relationship of the rest fractions with total SOC. Under the present cropping and management practices, cPOM and micro-aggregates were the main stabilization mechanisms for soil carbon sequestration. Soil physically, chemically, biological-chemically and physical-biochemically protected SOC fractions might have reached the maximum capacity in this paddy soil. |
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