不同施肥模式下黄泥田水稻土团聚体稳定性及有机碳矿化特征

Characteristics of aggregate stability and organic carbon mineralization of paddy soil in yellow mud field under different fertilization modes

依托长期定位施肥(2011—2018年)试验,采用团聚体湿筛及室内培养碱液吸收法,研究了不同施肥模式对黄泥田土壤团聚体稳定性及有机碳矿化的影响。结果表明:(1)有机物料投入下的两种施肥模式(CM:控释BB肥配施牛粪,RS:化肥配施秸秆)较单施化肥(NPK)模式显著提高了黄泥田土壤团聚体的稳定性,并显著提高了土壤有机碳含量(22%—33%);(2)与NPK处理相比,RS与CM处理使土壤有机碳矿化速率分别提高了18%和23%,有机碳累积矿化量分别提高了18%和24%,有机碳潜在矿化量分别提高了16%和33%,土壤有机碳累积矿化率分别降低了5.2%和4.1%;(3)大团聚体(>2.00 mm)有机碳含量最高,微团聚体(<0.25 mm)有机碳含量最低;(4)矿化前期各团聚体有机碳矿化速率呈大团聚体>中团聚体>微团聚体的特征,而在矿化后期呈现相反的变化特征。黄泥田土壤有机碳的矿化累积与团聚稳定性呈显著正相关关系,不同粒径团聚体有机碳固持能力也呈大团聚体>中团聚体>微团聚体的特征。长期有机培肥(RS与CM)可以提高黄泥田水稻土团聚体的稳定性及潜在有机碳矿化量与有机碳周转速率,提高土壤有机碳固持能力,其中一次性基施控释BB肥配施牛粪的施肥模式最有利于黄泥田良好土壤团聚体结构的形成与有机碳的累积。

Relying on the long-term positioning fertilization experiment(2011—2018),the effects of different fertilization modes on soil aggregate stability and organic carbon mineralization in yellow mud field were studied by using aggregate wet screening and indoor culture lye absorption method.The results showed that:(1)compared with single application of chemical fertilizer(NPK),the two organic fertilization mode(CM:controlledrelease BB fertilizer combined with cow manure,RS:chemical fertilizer combined with straw)significantly improved the stability of soil aggregates and the soil organic carbon content(22%—33%);(2)Compared with NPK treatment,RS treatment and CM treatment increased the mineralization rate of soil organic carbon by 18%and 23%,the cumulative mineralization of organic carbon by 18%and 24%,the potential mineralization of organic carbon by 16%and 33%,and reduced the cumulative mineralization rate of soil organic carbon by 5.2%and 4.1%,respectively;(3)The organic carbon content in large aggregates(>2.00 mm)was the highest and that in micro aggregates(<0.25 mm)was the lowest;(4)In the early stage of mineralization,the organic carbon mineralization rate of each aggregate showed the characteristics of large aggregate>medium aggregate>micro aggregate,while in the later stage of mineralization,it showed the opposite characteristics.There was a significant positive correlation between mineralization and accumulation of soil organic carbon and agglomeration stability in yellow mud field.The retention capacity of organic carbon of aggregates with different particle sizes also showed the characteristics of large aggregates>medium aggregates>micro aggregates.Long term organic fertilization(RS and CM)could improve the stability of paddy soil aggregates,potential organic carbon mineralization and organic carbon turnover rate in yellow mud field,and improve the retention capacity of soil organic carbon.Among them,the fertilization mode of one-time base application of controlled release BB fertilizer combined with cow dung was the most conducive to the formation of good soil aggregate structure and the accumulation of organic carbon in yellow mud field.