三种不同种植模式对土壤细菌群落多样性的影响

采用变性梯度凝胶电泳(DGGE )技术,研究了不同种植模式对土壤细菌群落多样性的影响。结果表明,不同种植模式下DGGE图谱条带的数量及亮度有较大区别,且有几条特征性条带发生了明显的变化。0—15 cm土层细菌群落的丰富度、多样性指数及均匀度指数均表现为:“菜稻菜模式”（RVCs） “休闲轮作模式”（FRCs） “蔬菜连作模式”（VCCs）;15—30 cm土层细菌群落的丰富度、多样性指数及均匀度指数均表现为:FRCs RVCs VCCs。UPGMC聚类分析表明,RVCs 处理的细菌群落结构相似性较低。主成分分析表明,对各主成分起分异作用的主要是 RVCs和FRCs;与主成分因子1 正相关程度较高的种植模式为:RVCs和VCCs,与主成分因子2 正相关程度较高的是 FRCs。可见,水稻土细菌群落多样性与种植模式密切相关,这些变化对土壤细菌群落有重要的调节作用。     

Changes in soil chemical characteristics with different tillage practices in a semi-arid environment

We examined the effects of various tillage intensities: no-tillage (NT), minimum tillage with chisel plow (MT), conventional tillage with mouldboard plow (CT), and zone-tillage subsoiling with a paraplow (ZT) applied in alternate years in rotation with NT, on the topsoil profile distribution (0–30 cm) of pH, soil organic carbon (SOC), organic N and available nutrients on a semi-arid soil from Central Spain. The equivalent depth approach was used to compare SOC, N and nutrient stocks in the various tillage treatments. Measurements made at the end of 5 years showed that in the 0–30 cm depth, SOC and N had increased under NT and ZT compared with MT and CT. Most dramatic changes occurred within the 0–5 cm depth where plots under NT and ZT had respectively 7.0 Mg ha⁻¹ and 6.2 Mg ha⁻¹ more SOC and 0.5 Mg ha⁻¹ and 0.3 Mg ha⁻¹ more N than under MT or CT. No-tillage and ZT plots, however, exhibited strong vertical gradients of SOC and N with concentrations decreasing from 0–5 to 20–30 cm. In the 0–20 cm layer, higher concentrations of P and K under NT and ZT than under MT or CT were also found. Soil pH under NT and ZT was 0.3 units lower than under MT or CT at a depth of 0–5 cm. This acidifying effect was restricted at the surface layer and in the 20–30 cm interval, pH values under NT and ZT were higher than in MT and CT plots. These results suggest that in the soil studied, ZT in rotation with NT maintain most advantages associated with NT, and present a definite potential for use as a partial-width rotational tillage practice.     

基于传统和高通量测序技术研究地膜对辣椒土壤特性及细菌多样性的影响

以不同种类地膜覆盖条件下辣椒菜园土壤为研究对象,运用传统和高通量测序技术,研究南方地区不同种类地膜覆盖对辣椒菜园土壤理化、生物学性状和细菌多样性的影响。结果表明：南方地区蔬菜生产中利用不同种类地膜,尤其以聚乙烯为原料的白色透明地膜、黑色地膜和银色地膜不仅有助于提高辣椒耕作层土壤温度与含水量,而且对减缓土壤pH的下降具有显著效果。此外,在细菌门分类水平上,不同种类地膜覆盖条件下土壤细菌的优势菌群表现为变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）、酸杆菌门（Acidobacteria）和芽单胞菌门（Gemmatimonadetes）细菌,其中以变形菌门（Proteobacteria）细菌的丰度最高;属分类水平上,不可培养细菌属、黄杆菌属（Flavobacterium）、溶杆菌属（Lysobacter）、芽孢杆菌属（Bacillus）、H16（Ralstonia eutropha）和鞘氨醇单胞菌属（Sphingomonas）细菌是南方地区不同种类地膜覆盖土壤中的优势菌属。此外,地膜覆盖不仅降低了土壤中对环境条件要求苛刻的不可培养细菌的丰度,而且有助于溶杆菌属和芽孢杆菌属等部分具有促生功能细菌的积聚。上述结果表明：南方地区蔬菜生产中利用地膜并没有导致菜园土壤质量劣化,而且有助于提高土壤肥力和保持土壤健康。     

Mechanisms of soil acidification reducing bacterial diversity

A central goal in soil microbial ecology research is to identify the biodiversity patterns and reveal the underlying mechanisms. Long-term soil acidification is known to reduce soil bacterial diversity, but the mechanisms responsible for this pattern have not been well explored. Soil acidification may reduce bacterial richness through ecological filtering (EF). In contrast, two types of processes may promote the maintenance of bacterial richness: species may adapt to the acidic pressure through evolution, and endemic species already adapted to the acidic pressure can colonize the acidified soils through dispersal. To identify the relative contribution of EF and evolution/dispersal (ED), we collected soils with a pH range of 4–7 from different ecosystems, conducted an acidification experiment with a similar pH range in a neutral soil, and proposed a conceptual framework that could distinguish the three potential types of mechanism (neither EF nor ED operate; EF operates alone; ED counteracts some effect of EF). We found that the entire bacterial domain was driven by the third type of mechanism, with ED counteracting about 42.4% (95% confidence interval: 32.7–50.4%) effect of EF. Meanwhile, different bacterial phyla/classes were governed by different types of mechanisms, and the dominant was the third type. Our results highlight the importance of both ecological and evolutionary mechanisms for regulating soil bacterial communities under environmental changes.     

马铃薯||玉米间作对土壤细菌多样性的影响

为探明连续马铃薯、玉米单作及间作种植对土壤细菌群落组成的影响,利用IonS5~(TM)XL高通量测序平台,分析了单作玉米(M)、单作马铃薯(P)、马铃薯||玉米间作(PM)下,土壤细菌群落组成以及多样性间的差异。结果表明:与单作相比,马铃薯||玉米间作土壤有机质含量显著升高(P0.05),但土壤全氮、碱解氮、全磷、速效钾、土壤pH等没有显著变化。所获得的56 787个土壤细菌可操作分类单元(OTUs)共分为46门、55纲、114目、208科、455属。土壤变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)和放线菌门(Actinobacteria)细菌占总相对丰度的57.68%～65.11%,为优势菌门;间作对土壤细菌群落多样性(香农指数、辛普森指数)、丰富度(ACE指数和Chao1指数)无显著影响,但改变了基于门、属水平上的细菌群落组成。与单作马铃薯相比,间作显著降低了土壤变形菌门(Proteobacteria)相对丰度(P=0.023),提高了浮霉菌门(Planctomycetes)的相对丰度(P=0.043)。在属水平上,相对丰度较低的芽单胞菌属(Gemmatimonas)、Candidatus Solibacter属更易受到种植方式的影响;间作提高了节杆菌属(Arthrobacter)、芽球菌属(Blastococcus)和芽孢杆菌属(Bacillus)的相对丰度。随细菌群落结构变化,细菌群落功能上出现差异,通过KEGG功能预测共得到7个一级功能层, 35个二级功能层,表现出功能上的丰富性,土壤细菌群落在代谢、遗传信息处理和细胞过程方面功能活跃。7个一级功能层中的代谢功能组在马铃薯||玉米间作与马铃薯单作间有显著差异。利用前向选择,经蒙特卡罗检验表明,连续马铃薯、玉米单作及间作栽培5年后的土壤各理化性状指标与土壤细菌群落组成、多样性间的相关性均不显著。连续马铃薯||玉米间作及单作5年条件下土壤细菌群落组成的变化是由马铃薯||玉米间作作物种间互利和竞争关系而驱动的。     

不同施肥处理对柳枝稷土壤理化性质及细菌多样性的影响

为研究优化施肥对柳枝稷土壤理化性质及细菌多样性结构和多样性的影响,以半干旱区种植3年的柳枝稷表层土壤为对象,采用高通量测序技术研究了不同施氮水平(0、60、120和240 kg·hm-2)对0～20 cm土层土壤理化性质、细菌多样性及其结构的影响,以盐碱荒地作为对照(CK).结果表明,总的来看,施氮可显著降低土壤pH值...     

不同氮肥处理对污染红壤中铜有效性的影响

通过室内培养试验,发现不同氮肥处理对污染红壤中铜有效性有显著影响。在培养前期(0~15 d),施用尿素显著降低了红壤水溶态铜和有效态铜含量,而施用硫酸铵和硝酸钙则显著提高了水溶态铜含量,且硝酸钙的作用显著大于硫酸铵,但这两种氮肥对红壤有效态铜含量影响较小;培养60 d后,尿素对该红壤两种形态铜的抑制效应逐渐转为正效应,且硫酸铵的促进作用更为显著;硝酸钙对红壤两种形态铜的促进作用不如尿素。氮肥的施用量对两种形态铜也具有显著影响。同一施氮水平下,水溶态铜含量和有效态铜含量在不同氮肥处理间均达显著差异(硫酸铵>尿素>硝酸钙)。不同氮肥影响红壤铜有效性的主要机制是土壤pH的变化,红壤水溶态铜和有效态铜含量均与pH呈极显著负相关。     

不同施肥模式对茶园红黄壤细菌群落基因多样性的影响

运用温度梯度凝胶电泳技术研究不同培肥措施下闽东地区红黄壤茶园定位实验地的土壤细菌群落基因多样性。结果表明,不同培肥措施对细菌丰富度和多样性都有明显的影响,其中单施无机肥降低了土壤细菌群落结构多样性,不利于保持茶园土壤生态系统的稳定性,而"无机肥+有机肥+豆科绿肥"综合培肥模式对土壤微生物丰富度和基因多样性提高幅度最大。聚类分析表明,不施肥与单施无机肥的细菌群落结构最为相近,而"无机肥+有机肥+豆科绿肥"和"无机肥+豆科绿肥"培肥模式的细菌群落结构与其它施肥处理间的差异性较大,其中"无机肥+有机肥+豆科绿肥"尤为显著,说明套种豆科绿肥对微生物群落结构有显著影响。"无机肥+有机肥+豆科绿肥"培肥模式的茶叶产量和茶叶营养物质累积量最大,这进一步佐证了此培肥模式能促进茶园生态系统生产力。     

均腐土不同亚纲典型土系土壤细菌群落多样性研究

为研究中国土壤系统分类(CST)体系下均腐土不同亚纲土壤细菌群落结构的多样性,以 4个干润均腐土[富牧西系(DFm)、春雷南系(DCl)、保国系(DBg)、明水系(DMs)]和 4个湿润均腐土[大西江系(MDx)、新发北系(MXf)、卫星农场系(MWx)、裴德系(MPd)]的腐殖质层(Ah层)为研究对象,采用高通量测序技术研究细菌群落多样性,分析细菌群落结构与环境因子间的关系,以探讨影响均腐土不同亚纲群落结构的主要环境因子。结果表明:均腐土 8个土系样品共获得 1 674 634条基因序列,Shannon指数和 Chao1指数表现为:干润均腐土 >湿润均腐土。均腐土 8个土系细菌群落主要包括 10个门类,其中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)为富牧西系、春雷南系、保国系、大西江系、新发北系、卫星农场系、裴德系优势菌门,明水系以绿湾菌门(Chloroflexi)、变形菌门(Proteobacteria)、放线菌门(Actinobacteria)为优势菌门;属水平上,均腐土各土系的群落差异较大。样品热图分析将 8个土系细菌群落聚为 2类,其中干润均腐土聚为一类,湿润均腐土聚为一类。pH、交换性 Ca、CEC、交换性 Mg、SOC和 TP是影响均腐土细菌群落结构发生变化的主要因子( P<0.05)。此外,RDA分析发现,土壤 pH为影响均腐土细菌群落结构的主导因子,而 pH、交换性 Ca、CEC为驱动干润均腐土细菌群落结构发生变化的主要影响因素,交换性 Mg、SOC、TP为驱动湿润均腐土细菌群落发生变化的主要影响因素。     

Response of the bacterial diversity and soil enzyme activity in particle-size fractions of Mollisol after different fertilization in a long-term experiment

Particle-size soils were fractionated for evaluating changes in the composition of bacterial community and enzyme activity in response to 13 years of fertilization. This study focused on Mollisol and its particle-size fractions of 200–2,000 μm (coarse sand sized), 63 to 200 μm (fine sand sized), 2 to 63 μm (silt sized), and 0.1 to 2 to μm (clay-sized). Long-term chemical fertilization lowered the pH of all particle fractions, whereas organic fertilizer application mitigated soil acidification. Nutrient concentrations depended on both fertilizer treatment and particle fractions and enzymes were unevenly active throughout the soil. Generally, the highest enzyme activities were observed in the silt and clay fractions of control soil and the soil treated with chemical fertilizer (N, P, and K (NPK)) and in the sand-sized fraction of soil treated with manure and chemical fertilizer (MNPK). Except for acid phosphomonoesterase, the other tested enzyme activities in coarse-sized fractions of MNPK soil were significantly higher than those of the control and NPK soils. Fertilization and soil fraction interactively (p?<?0.05) affected the enzyme activity. Denaturing gradient gel electrophoresis analysis showed that the bacterial community structure significantly differed in different particle sizes with a higher bacterial diversity in small-sized than in coarse-sized fractions. Dominant bands were excised and sequenced. We have found the following bacterial groups: Actinobacteria, γ-proteobacteria, and Acidobacteria. In addition, enrichment of organic matter in coarser fractions was related to greater bacterial diversity than any other treatment. Principal component analysis showed a smaller variability among fractions of the organic amended treatment. Redundancy analysis showed that the tested properties significantly affected the composition of bacterial community with the exception of C/N and available P. No significant correlation between enzyme activity and bacterial community composition was detected, whereas positive correlations between other soil properties and enzyme activities were observed to various extents. Probably, enzyme activities might be affected by specific functional bacterial communities rather than by the overall bacterial community. We concluded that the long-term application of organic manures contributed to the increase of soil organic matter content of particles higher than 200 mm, with higher bacterial diversity and increases in most of the enzyme activities.     

Microarray analysis of bacterial diversity and distribution in aggregates from a desert agricultural soil

Previous research has shown that soil structure can influence the distribution of bacteria in aggregates and, thereby, influence microbiological processes and diversity at small spatial scales. Here, we studied the microbial community structure of inner and outer fractions of microaggregates of a desert agricultural soil from the Imperial Valley of Southern California. To study the distribution of soil bacteria, 1,536 clones were identified using phylogenetic taxon probes to classify arrays of 16S rRNA genes. Among the predominant taxonomic groups were the α-Proteobacteria, Planctomycetes, and Acidobacteria. When compared across all phyla, the taxonomic compositions and distributions of bacterial taxa associated with the inner and outer fractions were nearly identical. Our results suggest that the ephemeral nature of soil aggregates in desert agricultural soils may reduce differences in the spatial distribution of bacterial populations as compared to that which occur in soils with more stable aggregates.     

Metabolism and persistence of atrazine in several field soils with different atrazine application histories

To assess the potential occurrence of accelerated herbicide degradation in soils, the mineralization and persistence of (14)C-labeled and nonlabeled atrazine was evaluated over 3 months in two soils from Belgium (BS, atrazine-treated 1973-2008; BC, nontreated) and two soils from Germany (CK, atrazine-treated 1986-1989; CM, nontreated). Prior to the experiment, accelerated solvent extraction of bulk field soils revealed atrazine (8.3 and 15.2 μg kg(-1)) in BS and CK soils and a number of metabolites directly after field sampling, even in BC and CM soils without previous atrazine treatment, by means of LC-MS/MS analyses. For atrazine degradation studies, all soils were incubated under different moisture conditions (50% maximum soil water-holding capacity (WHC(max))/slurried conditions). At the end of the incubation, the (14)C-atrazine mineralization was high in BS soil (81 and 83%) and also unexpectedly high in BC soil (40 and 81%), at 50% WHC(max) and slurried conditions, respectively. In CK soil, the (14)C-atrazine mineralization was higher (10 and 6%) than in CM soil (4.7 and 2.7%), but was not stimulated by slurried conditions. The results revealed that atrazine application history dramatically influences its degradation and mineralization. For the incubation period, the amount of extractable atrazine, composed of residues from freshly applied atrazine and residues from former field applications, remained significantly greater (statistical significance = 99.5 and 99.95%) for BS and CK soils, respectively, than the amount of extractable atrazine in the bulk field soils. This suggests that (i) mostly freshly applied atrazine is accessible for a complex microbial community, (ii) the applied atrazine is not completely mineralized and remains extractable even in adapted soils, and (iii) the microbial atrazine-mineralizing capacity strongly depends on atrazine application history and appears to be conserved on long time scales after the last application.     

改良剂施用对重金属污染土壤溶液化学性质及豇豆生理特性的影响研究

本文研究了在不同生长时期凹凸棒土、硅藻土、泥炭、腐植酸对土壤重金属的钝化及豇豆生理特性的影响。结果表明:由于土壤的缓冲性,4种改良剂对土壤溶液pH影响较小;泥炭、腐植酸对Zn、Cu的钝化效果比凹凸棒土、硅藻土好,但4种改良剂对土壤溶液Pb和Cd浓度影响不明显;腐植酸、凹凸棒土均在不同程度上提高了豇豆叶片超氧化物歧化酶、过氧化物酶的活性,其中腐植酸的作用最为明显。除泥炭外,3种改良剂均使豇豆叶片的丙二醛、脯氨酸含量降低。受叶片衰老的影响,成熟期各改良剂对豇豆生理特性的作用不如苗期明显;冗余分析表明:4种改良剂对重金属的钝化效果依次为腐植酸、泥炭、凹凸棒土、硅藻土。本次试验结果说明有机物料腐植酸、泥炭可作为缓解豇豆重金属Zn、Cu胁迫的改良剂。     

长期施肥对黄棕壤细菌多样性的影响

[目的]基于武汉黄棕壤长期定位试验(1981—2016年),探究不同施肥措施下土壤肥力演变和土壤微生物多样性变化,为黄棕壤培肥以及农业绿色可持续发展提供依据.[方法]本研究采用Illumina MiSeq高通量测序技术和偏最小二乘路径模型(PLS-PM)综合分析了不施肥(CK)、氮磷钾(NPK)、常量有机肥(OM)、氮...     

Bias in bacterial diversity as a result of Nycodenz extraction from bulk soil

Nycodenz density centrifugation (NDC) is an isolation method that allows extraction of both culturable and unculturable bacterial cells from soil, to be used in further downstream analysis; however, to date there has been a lack of information concerning the efficiency of this method. The aim of this study was therefore to investigate the overall efficiency of NDC extractions from soil and to identify sampling bias, if any.Bacterial cells were extracted from three soil plots from the Danish CRUCIAL field trial using an already established NDC protocol. To evaluate all aspects of the NDC procedure, DNA was extracted directly from soil, from NDC-extracted cells, and from the soil pellets left after NDC. Bacterial diversity was assessed by PCR amplification of the V4-V6 regions of the 16S rRNA from the extracted DNA followed by sample-tagged amplicon-pyrosequencing using the 454 Genome Sequencer FLX system. Sequences were processed and analyzed using the Ribosomal Database Project’s (RDP) Pyrosequencing Pipeline tools.In this study, we show that extraction of bacteria from soil using NDC can result in significant biases in the form of either over- or underrepresentation of specific bacterial phyla commonly found in soil. Furthermore, rarefaction analysis, analysis of similarity, multidimensional scaling plots and analysis of variance showed that the diversity in the NDC-extracted sample was reduced significantly compared to both the original soil sample and the remaining NDC-pellet. To further study the soil diversity a mathematical model was employed to estimate how many sequences would be required in order to find 95% of all operational taxonomic units (OTUs) in the soil. The model estimated that the soil contains approximately 29,400 OTUs and that just 351,500 sequences are needed to cover 95% of the bacterial biodiversity, the equivalent of one full standard GS FLX run.     

不同深度土壤控水对稻田土壤微生物区系及细菌群落多样性的影响

为研究不同深度土壤控水对壤土稻田土壤水势、微生物区系和细菌群落多样性的影响,通过土培池栽试验,在水稻生育后期设置土壤深度0~5 cm（S05）、0~10 cm（S10）和0~15 cm（S15）控水处理,以保持水层为对照,分析了不同深度控水处理下5 cm、10 cm、15 cm深土壤水势与土壤微生物区系、细菌群落多样性的变化。结果表明：土壤5 cm、10 cm、15 cm深度的水势随着控水深度增加而降低,S05控水处理主要影响上层（5 cm）土壤水势,S10控水处理影响上、中层（10 cm）土壤水势,S15控水处理土壤水势随土层深度的增加而升高。花后8 d和32 d,S05控水处理上层土壤细菌数量显著高于S10、S15控水处理;花后16~24 d,S05控水处理中层、下层（15 cm）土壤细菌数量均显著高于S15控水处理;土壤水势与水稻生育后期中、下层土壤细菌数量呈极显著正相关关系。S05控水处理10 cm、15 cm土层的细菌丰富度Chao指数均显著高于S15控水处理及CK。3个控水处理中,5 cm土层细菌的多样性Shannon指数以S05控水处理最低。优势细菌菌群分析发现,优势群落主要为变形菌门、绿弯菌门、酸杆菌门、拟杆菌门,四者总相对丰度在80%以上;S15控水处理中层土壤变形菌门相对丰度低于S05和S10控水处理。3个控水处理土壤样品中优势纲（相对丰度大于2%）达15个,主要包括α-变形菌纲、β-变形菌纲、δ-变形菌纲、厌氧绳菌纲等,这4个纲的总相对丰度在47%以上,其中厌氧绳菌纲相对丰度最高;上层土壤中S05控水处理的β-变形菌纲相对丰度显著低于S10和S15控水处理。因此,不同深度土壤控水对壤土土壤水势、细菌数量存在影响,改变了细菌的多样性及丰富度,对土壤细菌优势菌种类无显著影响。     

Energy use efficiency of deficit-irrigated silage maize in different soil tillage practices on a high plain with a semi-arid climate

ABSTRACT

Energy requirement increases rapidly in agriculture due to the increase in mechanization. The aim of the present study is to evaluate the energy use efficiency of silage maize under three different tillage practices (conventional, reduced, no-tillage) combined with four different irrigation levels (full and three deficit irrigations). The no-tillage and reduced tillage practices provided savings in input energy at the rate of 17.4 and 9.1%, respectively compared to the conventional tillage. The highest silage yields in all irrigation levels were obtained in the no-tillage practice. Therefore, in full and deficit irrigated silage maize, the highest energy ratio, energy productivity and net energy and the lowest specific energy values were manifested in the no-tillage practice. Energy rates in the no-tillage practice were higher by 34.2 and 22.9% than the conventional and the reduced tillage practices, respectively. Moreover, the direct and non-renewable energy requirements were the lowest in the no-tillage practice. In conclusion, the fully-irrigated no-tillage practice can be recommended to obtain the highest energy use ratio and productivity. However, no-tillage irrigated with up to 50% less water amount could be a better alternative for areas with a water shortage by improving the energy use ratio with better water and fuel savings.     

Comparison of soil fungal/bacterial ratios in a pH gradient using physiological and PLFA-based techniques

We have compared the total microbial biomass and the fungal/bacterial ratio estimated using substrate-induced respiration (SIR) in combination with the selective inhibition technique and using the phospholipid fatty acid (PLFA) technique in a pH gradient (3.0-7.2) consisting of 53 mature broad-leaved forest soils. A fungal/bacterial biomass index using the PLFA technique was calculated using the PLFA 18:2ω6,9 as an indicator of fungal biomass and the sum of 13 bacterial specific PLFAs as indicator of the bacterial biomass. Good linear correlation (p<0.001) was found between the total microbial biomass estimated with SIR and total PLFAs (totPLFA), indicating that 1 mg biomass-C was equivalent to 130 nmol totPLFA. Both biomass estimates were positively correlated to soil pH. The fungal/bacterial ratio measured using the selective inhibition technique decreased significantly with increasing pH from about 9 at pH 3 to approximately 2 at pH 7, while the fungal/bacterial biomass index using PLFA measurements tended to increase slightly with increasing soil pH. Good correlation between the soil content of ergosterol and of the PLFA 18:2ω6,9 indicated that the lack of congruency between the two methods in estimating fungal/bacterial ratios was not due to PLFA 18:2ω6,9-related non-fungal structures to any significant degree. Several PLFAs were strongly correlated to soil pH (R² values >0.8); for example the PLFAs 16:1ω5 and 16:1ω7c increased with increasing soil pH, while i16:0 and cy19:0 decreased. A principal component analysis of the total PLFA pattern gave a first component that was strongly correlated to soil pH (R²=0.85, p<0.001) indicating that the microbial community composition in these beech/beech-oak forest soils was to a large extent determined by soil pH.     

不同年代冬小麦品种的产量和磷生理效率对土壤肥力水平的响应

【目的】 本研究利用长期施肥定位试验构建的不同土壤肥力梯度,探索陕西关中地区小麦品种演替过程中产量、产量构成因素以及磷生理效率的变化,以期了解品种演替对土壤肥力水平以及磷效率的响应,为今后品种选育提供参考。 【方法】 长期试验包括 7 个处理,分别为不施肥处理 (CK)、单施两个水平有机肥处理 (M1 和 M2)、两个水平有机肥与两个水平无机肥配施处理 (M1N1P1、M1N2P2、M2N1P1、M2N2P2)。小麦品种为小偃 6 号 (80 年代)、小偃 22 (90 年代末) 以及西农 979 (当前品种)。 【结果】 小麦品种演替过程中单产水平逐步提高,同时小麦产量随着土壤肥力水平提高呈显著增加趋势;品种更替的增产效应主要反映在高肥力土壤上 (有机无机配施的 4 个处理),而在低肥力 (CK、M1、M2) 土壤上品种更替产量差异不显著。小麦品种演替过程中,在低肥力情况下穗数表现为 90 年代末的小偃 22 低于 80 年代的小偃 6 号,而当前品种西农 979 又高于小偃 6 号的趋势;但在高肥力情况下随品种演替穗数基本呈现为增加的趋势。在低肥力情况下随品种演替穗粒数的变化不一致,而在高肥力情况下穗粒数随品种演替基本呈增加的趋势。随着品种演替,无论在高肥力还是低肥力情况下,千粒重均呈逐渐增加的趋势。三个品种的穗数、穗粒数以及千粒重均随土壤肥力水平提高以及养分投入增加而呈增加的趋势。随着品种更替,无论高肥力还是低肥力土壤 100 kg 小麦需磷量均呈下降趋势,具体为小偃 6 号 > 西农 979 > 小偃 22 号;不过低肥力土壤的 100 kg 需磷量高于高肥力土壤。随品种的演替,无论高肥力土壤还是低肥力土壤磷生理效率均呈现升高的趋势,但是高肥力土壤的磷生理效率高于低肥力土壤。 【结论】 陕西关中地区随品种更替小麦单产逐渐提高,其中西农 979 单产的提升是由于穗数和千粒重的提高,而小偃 22 号单产的提升则由于穗粒数和千粒重的提高。品种更替在低肥力土壤上并没有表现出产量及磷效率的优势,在高肥力土壤上表现出产量及磷效率的协同提高。因此,品种更替对土壤肥力水平的要求更高,土壤培肥以及定向育种的有机结合是实现陕西关中小麦高产高效、可持续发展的有效方略。