培肥措施对复垦土壤轻重组有机碳氮的影响

为揭示复垦土壤轻重组分有机碳氮随复垦年限和培肥措施变化的特征,采用密度分组方法研究了不施肥(CK)、单施化肥(CF)、单施有机肥(M)、有机无机配施(MCF)和生物有机肥与化肥配施(MCFB)5种培肥措施下复垦4,8年土壤轻重组分碳氮含量及碳氮比变化规律。结果表明:复垦土壤总有机碳氮与轻重组有机碳氮含量变化趋势总体均表现为随复垦年限的增加而显著提高。经过8年复垦,不同处理间,单施有机肥对总有机碳(TOC)、总有机氮(TON)、轻组有机碳(LFOC)、重组有机碳(HFOC)与轻组有机氮(LFON)、重组有机氮(HFON)的提高效果总体优于其他处理,与生土相比,增加幅度分别为148.10%,68.09%,163.68%,129.51%,35.00%,92.59%。土壤轻组组分C/N重组组分C/N,土壤轻组组分C/N总体表现为随复垦年限增加而提高,以单施化肥最高,达25.48;重组C/N表现为随复垦年限增加而降低,以单施化肥最低,为6.44。施肥对土壤碳氮库管理指数影响显著,各施肥处理均以生物有机肥与化肥配施处理效果最好。综合来看,在等量养分投入的情况下,单施有机肥更有利于采煤塌陷区复垦土壤总有机碳氮库及轻重组有机碳的积累,单施化肥更大程度促进了轻组组分有机碳和重组组分有机氮的提升幅度。

Effects of Fertilization on Light and Heavy Fractions Organic Nitrogen in Reclaimed Soil

In order to reveal the changing characteristics of soil organic carbon and nitrogen of light and heavy fractions in reclaimed soil as affected by different reclamation years and fertilization measures, the variation of carbon and nitrogen contents and C/N ratio of light and heavy fractions were studied under five fertilization modes by the density fractionation (no-fertilizer control, CK; single fertilizer, CF; single organic manure, M; fertilizer combined organic manure, MCF; and biological organic fertilizer and chemical fertilizer mixed fertilizer, MCFB). The results showed that TOC (total organic carbon), TON (total organic nitrogen), carbon and nitrogen of light fraction and heavy fraction all increased with the increasing ages. Single organic manure showed significant increase in TOC, TON, LFOC, HFOC, LFON and HFON compared with other treatments after 8 years of reclamation, and the corresponding contents were 148.10%,68.09%,163.68%,129.51%, 35.00% and 92.59% higher than those of raw soil, respectively. The sequence of C/N was Light Fraction C/N > Heavy Fraction C/N. The light fraction C/N in all treatments increased with the increasing reclamation ages, being the highest (25.48) in CF, and the heavy fraction C/N in all treatments decreased with increasing time, being the lowest (6.44) in CF. Fertilization measures had a significant effect on the management index of soil C and N stocks. Treatments of MCFB could improve CMI and NMI more effectively than other treatments. On the whole, under same nutrient inputs condition, single organic manure was more conducive to the accumulation of soil total organic carbon and nitrogen pools and carbon and nitrogen contents of light and heavy fractions in the reclaimed soil of coal mining subsidence areas. Single fertilizer promoted the increases of light fraction organic carbon and heavy fraction organic nitrogen to a greater extent.