添加秸秆和磷素对土壤微生物群落的影响

为了探讨添加小麦秸秆和磷素对低磷土壤微生物数量和群落结构的影响,设置2个梯度的小麦秸秆添加量(N₀和N₁分别为0和2.08 g·kg^-1)和4个施磷水平(P₀、P₁、P₂和P₃分别为0、100、200和400 mg·kg^-1)组合处理,采用磷脂脂肪酸(PLFA)法测定土壤微生物生物量.结果表明: 添加秸秆配合施入磷素对微生物总生物量、细菌生物量、真菌生物量和真菌/细菌(F/B)比值具有显著的促进作用,微生物总生物量、细菌生物量、真菌生物量和F/B均为N₁P₁>N₁P₀>N₁P₂>N₁P₃>N₀P₁>N₀P₂>N₀P₃.在相同磷素水平下,添加秸秆处理的各指标均显著高于未添加秸秆处理;在添加相同秸秆量条件下,施磷处理的各指标随磷素施入量先增加后降低,以P₁水平组合最优,其次是P₀,最后是P₂和P₃.

Effect of adding different amounts of wheat straw and phosphorus on soil microorganism community.

A pot experiment was conducted to study the effects of adding different amounts of wheat straw (0 g·kg^-1, N₀; 2.08 g·kg^-1, N₁) and phosphorus (0 mg·kg^-1, P₀; 100 mg·kg^-1, P₁; 200 mg·kg^-1, P₂; 400 mg·kg^-1, P₃) on microorganism community in a soil of low-phosphorus. Adding straw and phosphorus had significant effects on the soil microbial total biomass (MTB), bacterial biomass (MB), fungal biomass (FB), and fungi to bacteria ratio (F/B), which all decreased in order of N₁P₁>N₁P₀>N₁P₂>N₁P₃> N₀P₁> N₀P₂>N₀P₃. MTB, MB, FB and F/B ratio of the wheat straw addition treatments were all significantly higher than in the non-straw addition treatments under the same level of phosphorus addition. As for the same wheat straw addition, MTB, MB, FB and F/B ratio increased firstly and then decreased with increasing the level of phosphorus addition, and the combinations of P₁ level were optimal.