水保所知识产出(1956---)知识库

【 目的】研究不同施肥处理下土壤细菌群落的特征，为建立促进土壤生态系统稳定和健康的养分管理制
度提供依据。【 方法】陕西省杨凌示范区“国家黄土肥力与肥料效益监测基地”的 28 年长期定位试验始于
1990 年秋，种植制度为冬小麦–夏休闲，无灌溉。本研究选取定位试验中不施肥 (CK)、施用氮磷钾肥 (N、
P 2 O 5 、K 2 O 分别为 135、108、67.5 kg/hm 2 ，NPK) 和有机无机肥配施 (70% N 来自牛粪，MNPK) 3 个处理。于
2018 年 6 月小麦收获后采集 0—20 cm 耕层土样，测定养分含量、含水量、微生物量碳含量、微生物量氮含量
及目标土壤微生物。以 1% 琼脂糖凝胶电泳法检测土壤中 DNA，根据 97% 相似度对序列进行 OTU 聚类、α 多
样性分析 (包括 Shannon、ACE 和 Chao1 等指数)，使用 CANOCO 4.5 软件对土壤细菌门水平群落结构、细菌相
对丰度等与土壤理化性质进行冗余分析。【 结果】与 CK 相比，NPK 和 MNPK 处理显著提高了土壤有机碳、全
氮、微生物量碳、微生物量氮、硝态氮和铵态氮含量，显著降低了土壤 pH 值。不同处理细菌基因拷贝数为每
克干土 6.69 × 10 9 ～16.46 × 10 9 ，与 CK 相比，NPK 和 MNPK 处理细菌数量分别提高了 77% 和 146%。MNPK 处
理的土壤细菌 Shannon 多样性指数显著高于 CK 和 NPK 处理，而 Simpson 指数显著低于 CK 和 NPK 处理，
NPK 与 CK 处理间两个指数无显著差异。3 个处理的细菌丰富度指数 (Chao1 指数和 ACE 指数) 和均匀度指数均
没有显著差异。在门水平上，共获得 35 个细菌类群，其中，放线菌门 (Actinobacteria)、变形菌门
(Proteobacteria)、酸杆菌门 (Acidobacteria) 和绿弯菌门 (Chloroflexi) 为主要优势菌门 (相对丰度 > 10%)，占到全
部菌门的 80.1%～81.7%。与 CK 相比，MNPK 处理显著降低了放线菌门 (F = 5.845，P < 0.05) 的相对丰度，增
加了拟杆菌门 (F = 4.461，P < 0.05) 的相对丰度，3 个处理间其他菌门均无显著差异。冗余分析结果显示，
CK 与 NPK、MNPK 处理的土壤细菌群落结构具有明显差异，且 MNPK 处理对土壤细菌群落组成的影响更大。
土壤理化性质对细菌菌群影响表现为：土壤硝态氮 > 可溶性有机碳 > pH > 铵态氮 > 有机碳 > 土壤含水量，这些
理化因子均是影响微生物生长的关键因子。【 结论】关中土区旱作雨养条件下，化肥平衡施用和有机无机肥
配施均显著提高了土壤中细菌数量、多样性和丰富度，有机无机肥配施还改变了细菌群落结构，特别是降低了
放线菌门、增加了拟杆菌门的丰度，更有利于土壤生态系统的稳定和健康。

【Objectives】The fertility change in nutrient contents and microbial structure of farmland after long-
term fertilization was studied in this paper, which would provide theoretical base for reasonable fertilization
practice to maintain a stable and healthy soil ecosystem.【Methods】The investigated farmland was from a 28-
years’ long-term fertilization experiment in the “National Monitoring Base of Soil Fertility and Fertilizer
Efficiency on Loess Soil” in Yangling Demonstration Zone, Shaanxi Province, where the cropping system was
winter wheat-summer fallow and without irrigation. The soil samples were collected from three of the experiment
treatments, namely, no fertilization control (CK), pure chemical fertilizer (NPK,    N–P 2 O 5 –K 2 O＝135–108–67.5 kg/hm 2 )
and chemical fertilizer and manure combination (MNPK, 70% of N from cattle manure). After harvest of wheat,
soil samples of 0–20 cm in depth were collected. The soil nutrient contents, water content, microbial biomass C
and N contents were determined. The DNA of genome in soil samples were extracted and detected by 1%
agarose gel electrophoresis, and sequenced afterwards. The Shannon, ACE and Chao1 indices were
calculated.【Results】Compared with CK, the NPK and MNPK significantly increased soil organic carbon, total
nitrogen, microbial biomass carbon, microbial biomass nitrogen, nitrate nitrogen and ammonium nitrogen, while
significantly reduced soil pH. The copy number of bacterial genes were 6.69 × 10 9  – 16.46 × 10 9  per gram of dry
soil for the three treatments, and those in NPK and MNPK treatments were 77% and 146% significantly higher
than that in CK. The Shannon diversity index of soil bacteria of MNPK was significantly higher, while Simpson
index were significantly lower than those of CK and NPK treatments, and there was no significant difference
between NPK and CK. The bacterial richness index (Chao1 index and ACE index) and the uniformity index
were not significantly different among the 3 treatments. A total of 35 groups of bacteria were obtained at the
level of phylum, in which Actinobacteria, Proteobacteria, Acidobacteria and Chloroflexi were the main
dominant ones (relative abundance > 10%), and accounted for 80.1%–81.7% of the total bacteria phyla.
Compared with CK, MNPK significantly reduced the relative abundance of Actinomycetes (F = 5.845, P <
0.05) and increased that of Bacteroides (F = 4.461, P < 0.05). There was no significant difference for other phyla
of bacteria among the 3 treatments. The results of redundancy analysis showed that the soil bacterial community
structures were significantly different between no fertilization (CK) and fertilization (NPK and MNPK), and
MNPK had a greater impact than NPK on soil bacterial community composition. The importance of soil physical
and chemical properties affecting the bacterial communities was as follows: nitrate nitrogen > soluble organic
carbon > pH > ammonium nitrogen > organic carbon > soil water content.【Conclusions】In the rain-fed
farmland in Eum-orthic anthrosol area of Guanzhong, the bacteria population, diversity and richness are
significantly improved in soils under long-term balanced chemical fertilization and combination of organic and
inorganic fertilization. Combination of organic and inorganic fertilizers could increase the bacteria diversity that is
more efficient in increasing the abundance of Bacteroides and decreasing that of Actinomycetes, which represents
more stable and healthy in soil ecosystem.