长期不同植被覆盖和施肥管理对黑土活性有机碳的影响

【目的】阐明长期不同植被覆盖与施肥管理后,同一地块的黑土的总有机碳(TOC)、活性有机碳的变化。探讨黑土可持续利用的土地管理模式。【方法】第一个田间试验开始于1985年,研究不同植被覆盖(裸地、草地、耕地)下的黑土活性有机碳的含量和分布变化。第二个田间试验开始于1993年,研究了不同施肥处理(无肥对照(CK)、氮磷(NP)、氮磷配施有机肥(NPOM))对活性有机碳变化的影响。【结果】不同植被凋落物和根系分泌物及长期不同施肥管理均对黑土活性有机碳的形成产生明显的影响。与1985年相比,裸地TOC和全氮(TN)分别下降11.2%和15.3%,草地TOC和TN分别增长13.2%和5.8%,耕地TOC增长1.1%,而TN下降15.5%。与裸地相比,耕地和草地轻组有机氮分别增长13.9%和46.2%,轻组有机碳增长36.48%和62.0%。不同植被下热水浸提有机碳和高锰酸钾氧化碳总量的顺序为草地耕地裸地。在第二个试验中,施加有机肥能使TOC和TN分别增加了25.5%和18.6%。与对照相比,有机肥和氮磷肥的配施,使轻组有机氮分别增加了126.7%和12.17%,轻组有机碳增加了125.14%和17.14%。与对照和施氮磷肥相比,施加有机肥使颗粒有机氮分别增加了49.8%和23.2%,颗粒有机碳增加了6.5%和29.9%。高锰酸钾氧化有机碳和热水浸提有机碳含量的顺序为CKNPNPOM。【结论】草地与氮磷配施有机肥处理均有利于土壤TOC及活性有机碳的积累。

Changes of Black Soil Labile Organic Carbon Pool Under Different Vegetation and Fertilization Managements

【Objective】 An attempt was made in this paper to investigate the dynamics of total organic C (TOC), labile organic C (CLOC) in relation to the system productivity of different black under soil long-term management strategies. 【Method】 The first experiment was designed to study the effects of different chemical compositions and complexity of residues in three grass and crop treatments, including bare fallow, grass fallow, plantation with no fertilizer on the contents of labile organic carbon of the black soil. The long-term fertilization experiment including three treatments was designed, i.e., plantation with on fertilizer (CK), chemical NP, and organic manure plus chemical NP. 【Result】 The result indicated that different residues returned into the soil had remarkable influence on the black soil labile organic carbon formation. The TOC and TN under bare fallow declined by 11.2% and 15.3% compared with those in 1985. The TOC and TN in the grass fallow was 13.2% and 5.8% higher than those in 1985. The storages of soil TOC in the plantation increased by 1.1% and TN declined by 15.5%. In contrast with the bare fallow treatment, the soil covered with plantation and grass fallow, increased by 13.9%, and 46.2% of light fraction organic nitrate and 36.48% and 62.0% of light fraction organic carbon, respectively. The sequence in the amounts of hot-water organic carbon and readily oxidizable carbon in different vegetations was grass fallow＞plantation＞bare fallow. In the second experiment, application of manure increased the concentrations of TOC by 25.5% and of TN by 18.6%.Compared with the CK treatment, the application of manure, fertilizer NP, increased the light fraction organic nitrate by 126.7%, and 12.17% and light fraction organic carbon by 125.14% and 17.14%, respectively. Compared with the CK and NP treatments, the application of manure increased the particulate organic nitrogen by 49.8% and 23.2% and 6.5%, and particulate organic carbon by 29.9%, respectively. The decline sequence in the amounts of hot-water organic carbon and readily oxidizable carbon in soils under cropping was CK＜NP＜NPOM. 【Conclusion】Grass cover and NPOM treatments are beneficial to the soil organic carbon and labile organic carbon accumulation.