湘北红壤丘岗稻田土壤有机碳、养分及微生物生物量空间变异

通过对湘北典型红壤丘岗254个稻田耕层样(01～8.cm)进行分析,比较了微地形对稻田土壤有机碳、氮、磷和微生物生物量的影响。结果表明,丘岗底部稻田土壤有机碳、全氮、微生物生物量碳、微生物生物量氮、可溶性氮含量分别比丘岗中下部稻田高14.6%1、3.6%、24.6%、20.4%和95.8%,丘岗中下部稻田土壤Olsen-P含量比丘岗底部稻田高33.3%,差异均达极显著水平(P0.01)。不同部位稻田土壤全磷、微生物生物量磷含量和有效磷库(微生物生物量磷与Olsen-P之和)含量差异不显著。此外,丘岗底部稻田土壤碳磷比、微生物生物量碳磷比和微生物商比丘岗中下部稻田高12.7%,28.5%,8.2%,其差异达显著(P0.05)或极显著(P0.01)水平。但微生物生物量氮/全氮、微生物生物量磷/全磷、土壤碳氮比和微生物生物量碳氮比差异不显著。

Spatial variation in organic carbon, nutrients and microbial biomass contents of paddy soils in hilly red soil region

The contents of soil organic C(SOC),total N(TN),total P(TP),dissoluble N(D_N),Olsen-P,and microbial biomass C,N,P(B_C,B_N,B_P) of 254 paddy soils(0—18 cm) in hilly red soil region of subtropical zone of China were studied.The results showed that the contents of SOC,TN,B_C,B_N and DON of paddy soils at bottom of hills were 14.6%,13.6%,24.6%,20.4% and 95.8% higher than that of paddy soils at foothill,respectively.The Olsen-P contents of paddy soils at foothill were 33.3% higher than that at bottom of hills.However,the differences in TP,B_P and available P(the sum of B_P and OlsenP) contents were not significant between various positions.In addition,the ratios of soil C/N,B_C/B_P and B_C/SOC of paddy soils at bottom of hills were 12.7%,28.5% and 8.2% higher than that at foothill,respectively,but the differences in ratios of soil C/N,B_C/B_N,B_N/TN and B_P/TP were not significant statistically between various positions.