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作 者 ：杨瑞吉^1,2;马海灵²;杨祁峰³;牛俊义²

期 刊 ：应用生态学报 2007年 18卷 01期 页码：113-117

关键词：油菜；

摘 要 ：通过田间小区试验，研究了不同油菜种植密度与施氮肥对麦茬复种饲料油菜耕层土壤(0～5 cm)微生物活性的影响.结果表明，复种油菜能显著或极显著性提高耕层土壤微生物量碳(C_mic)、土壤微生物量氮(N_mic)、土壤细菌数(SBN)、土壤真菌数(SFN)和土壤放线菌数(SAN)，而显著降低土壤微生物量碳/氮比(C_mic/N_mic).随油菜种植密度的提高，耕层C_mic、C_mic/N_mic、SBN呈逐渐增加态势，而N_mic、SAN呈降低趋势.随着施氮肥梯度增加，耕层SFN显著提高，C_mic和N_mic呈先降低后增加再降低趋势，以1 000 kg·hm^-2施肥处理最高.SFN和收获期SAN为先降低后升高，苗期SAN则为先升高后降低.相同处理油菜收获期各土壤微生物活性指标均高于苗期，而600 kg·hm^-2苗期SAN则相反.SBN和SAN与C_mic、N_mic呈正相关，与C_mic/N_mic呈负相关，SFN与C_mic、N_mic及C_mic/N_mic之间均无明显相关性.

Abstract:A field experiment was conducted to study the effects of planting density and nitrogen
application rate on the topsoil (0-15 cm) microbial activity under wheat/forage rape multiple
cropping. The results showed that multiple-cropping forage rape with wheat could significantly increase
soil microbial biomass C (C_mic), soil microbial biomass N (N_mic), soil bacteria number (SBN),
soil fungi number (SFN) and soil actinomyces number (SAN), but decrease soil microbial biomass
C/N (C_mic/N_mic). The C_mic/N_mic and SBN increased with increasing planting density of forage rape,
while N_mic and SAN were in adverse. SFN increased significantly with increasing nitrogen application
rate, but C_mic and N_mic decreased first, increased then, and decreased again, with the highest
in treatment 1 000 kg·hm^-2 N. Also with increasing nitrogen application rate, the SFN and SAN
during harvest stage of forage rape decreased first and increased then, while the SAN during seedling
stage increased first and decreased then. Soil microbial activities at rape harvest stage were all
higher than those at seedling stage, except for SAN in treatment 600 kg·hm^-2 N. SBN and SAN
were positively correlated with C_mic and N_mic, but negatively correlated with C_mic/N_mic. No significant
correlation was observed between SFN and C_mic, and SMBN and C_mic/N_mic.

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