秸秆添加对土壤微生物–根系形态介导的番茄磷吸收的影响

  【目的】  研究了添加秸秆后土壤微生物(包括解磷微生物)丰度、磷有效性的动态变化,以及作物根系的生长发育特征对作物磷吸收的影响。  【方法】  以番茄 (Solanum lycopersicum)为供试作物进行田间试验,设置添加秸秆和不添加秸秆对照两个处理,在番茄移栽后第15、30及45 天,测定了番茄地上部生物量、磷含量和根系形态,同时测定了土壤微生物数量(细菌、真菌、解磷微生物)、微生物生物量磷和速效磷含量,分析了微生物?根系–作物磷吸收的关系。  【结果】  添加秸秆提高了成熟期番茄的地上部生物量,显著提高了叶片和地上部的磷吸收量,地上部(叶+茎+果实)总磷吸收量较不加秸秆番茄增加21.8%。与无秸秆对照处理相比,添加秸秆处理提高了土壤细菌以及具phoD,phoC和pqqC功能基因的解磷微生物丰度,增加了微生物量磷。添加秸秆处理降低了移栽后15 天番茄根系生物量和组织密度,增加了根系比根长,降低了移栽后15到30 天的番茄根系生长。番茄移栽后第30 天到45 天,土壤细菌、真菌丰度下降,微生物量磷降低,丰富的解磷微生物以及微生物量磷降低介导的磷活化,驱动番茄根系生长加快,比根长增加,根系直径降低。根系生长与土壤有效磷(Olsen-P)相关性显著。  【结论】  添加秸秆初期微生物增生导致番茄根系生长缓慢,后期微生物量磷的降低和解磷微生物对磷的活化促进细根的快速伸长。秸秆还田激发微生物量磷活化协同根系高效磷吸收特征,促进成熟期番茄地上部磷吸收的增加。     

根系互作对玉米大豆间作作物磷吸收的影响

【目的】间作作物的养分吸收与根系相互作用有着密切关系。研究玉米大豆间作后根系互作对磷含量、磷积累动态的影响,旨在为以玉米大豆为主的间作体系中磷的高效利用提供科学依据。【方法】本文通过盆栽试验,采用玉米和大豆根系无分隔(NB)、尼龙网分隔(MB)、塑料膜分隔(PB)3种分隔方式,研究了间作玉米(苗期、大喇叭口期、孕穗期、成熟期)和大豆(苗期、分枝期、鼓粒期、成熟期)在不同生育期对土壤中磷的吸收。【结果】与PB相比,MB处理的玉米茎中磷含量在孕穗期提高了16.8%(P0.05);叶中磷含量在苗期、大喇叭口期分别提高了6.6%、14.2%(P0.05);NB处理玉米茎中磷含量在大喇叭口期、孕穗期分别提高了25.4%、55.0%(P0.05);玉米叶中磷含量在大喇叭口期、成熟期分别提高了21.3%、22.2%(P0.05);与PB相比,NB处理大豆茎中磷含量在分枝期、成熟期分别提高了21.3%、24.7%(P0.05);叶中磷含量在分枝期提高了11.4%(P0.05),MB处理大豆叶中磷含量在分枝期提高了4.8%(P0.05)。与PB相比,NB处理玉米茎中磷积累量在大喇叭口期、孕穗期提高了24.6%、32.3%(P0.05),MB处理玉米茎中磷积累量在大喇叭口期提高了50.6%(P0.05),叶中磷积累量在苗期提高了33.6%(P0.05)。与PB相比,NB处理大豆茎中磷积累量在分枝期、鼓粒期分别提高了36.3%、51.8%(P0.05),叶中磷积累量在分枝期、成熟期分别提高了27.3%、110.6%(P0.05);MB处理大豆茎中磷积累量在鼓粒期提高了35.7%(P0.05)。【结论】根系互作系统中的玉米和大豆茎、叶中磷的累积量大于根系分离生长系统。因此,玉米大豆间作具有明显的磷吸收利用优势。     

施磷影响番茄磷吸收的根系及微生物动态过程

探究不同供磷条件下蔬菜作物根系形态、根际生理属性和解磷微生物丰度的变化,有助于揭示蔬菜作物 高效利用磷的机制,为高投入蔬菜种植体系实现减磷增效提供理论基础。以番茄为供试作物进行田间试验,设 置 T0(不施化学磷肥)、T0.5P(施磷量 100 kg/hm²;减施化学磷肥 50%)、T0.8P(施磷量 160 kg/hm²;减施化学磷肥 20%)、TP(施磷量 200 kg/hm²;常规施磷)4 个处理,测定移栽后第 15、30 及 45 d 番茄地上部生物量和磷吸收 以及根系形态(根长密度、比根长)、根际生理属性(有机酸含量)和土壤解磷微生物(phoD、phoC 和 pqqC)基 因丰度,阐明降低磷肥施用量影响作物根系、微生物以及驱动番茄磷吸收的动态过程。与常规施肥相比,减施磷 肥 50%(施磷 100 kg/hm²)促进了移栽后 45 d 番茄根系比根长的增加,提高了移栽后 45 d 番茄根际有机酸的分泌, 同时刺激了移栽后 30 和 45 d 土壤编码 phoC 和 pqqC 基因解磷微生物的增生。解磷微生物 phoC 和 pqqC 基因丰度 与番茄根系比根长和根际有机酸的分泌呈显著正相关。减施磷肥 20%(施磷 160 kg/hm²)与常规施肥相比,对番 茄根系根长密度、比根长以及根际有机酸的分泌无显著影响,但显著促进了成熟期番茄地上部磷吸收。集约化蔬 菜种植体系具有较大的减施磷肥的空间,最大化发挥植物根系形态、生理可塑性以及协同解磷微生物活化磷的能 力是实现减磷增效的关键。     

施磷对棉花根系形态及其对磷吸收的影响

通过盆栽试验，研究了不同施磷量和相同磷量及不同磷量施在不同比例的土体中对棉花根系形态及其对磷素吸收的影响。结果表明，磷对棉花根系具有刺激作用，施磷后使棉花根系长度、根表面积和根密度增大，吸磷量增多，从而促进了棉花的生长。当磷肥施入部分土体时，其对棉花根系生长的促进作用可以用Y=X0.72来表示。     

不同磷形态对水稻根系细菌群落特征的影响

为了探索不同磷形态处理下土壤、水稻根际和根内环境中细菌群落组成、结构、多样性,从而挖掘不同磷形态下水稻根际中介导植物-微生物相互作用的细菌群落特征.以籼稻(kasalath)为试验材料,采集南京的低磷土壤进行为期8周的水稻盆栽试验,采用高通量测序方法(16S rDNA Illumina测序),并结合土壤有效磷浓度和水稻...     

砂培条件下两种磷效率棉花根系形态及根际特征差异

为对比两种磷效率棉花在两种磷水平(0.1和5 mmol/L)的根系形态和根际特征的差异。以磷高效型棉花ZM42和磷低效型棉花XLZ13为研究对象设计砂培花盆分层试验,测定生物量、吸磷量、根系形态数据、分层Olsen－P、 pH值和酸性磷酸酶。结果表明：在砂培条件下两种磷效率棉花生物量和磷素积累量随施磷量的增加均有不同程度增加; ZM42在两种磷处理的根部生物量、吸磷量以及根冠比都优于XLZ13。在两种磷处理下, ZM42根系中根径(0~0.4 mm)的细根长度较XLZ13长,细根在总根长中的比例较高。总根长中细根越多有利于促进植株对磷的吸收。生长介质中磷含量降低时,棉花根际pH值也随之降低,高效品种ZM42的根际pH值降低幅度显著高于XLZ13;两种磷效率棉花在两个时期的根际土壤磷酸酶活性均随着施磷量的减少而增加,磷高效棉花ZM42分泌的土壤磷酸酶活性均高于磷低效棉花XLZ13。由此可见,两种磷效率棉花在相同生长介质中根际机理存在差异,且在低磷胁迫下磷高效棉花根系形态特征改变是根际磷活化主要机理之一。     

植物根系和根际微生物对氮的竞争

植物根系可促进土壤中有机碳和氮的矿化^[1-3]。     

不同磷供应水平下小麦根系形态及根际过程的变化特征

以石麦15和衡观35两个品种小麦为试验材料,应用根袋栽培方式,研究了不同施磷量对小麦根系形态和根际特征的影响。结果表明,与施磷量P2O5 0.1 g/kg相比,高量供磷（P2O5 0.3 g/kg）条件下石麦15地上部生物量和磷累积量增加幅度大于衡观35;但不施磷处理衡观35地上部生物量降低幅度小于石麦15,磷含量和累积量高于石麦15,衡观35耐低磷能力较强。土壤供磷不足时,衡观35总根长中直径0.16 mm细根所占比例高于石麦15,根系平均直径较小;而高磷供应下,石麦15根系中直径0.16 mm细根长度较长,在总根长中所占比例较高。总根长和直径0.16 mm的细根长度与植株地上部磷累积量之间呈显著正相关关系。总根长越长尤其是细根越多,有利于促进植株对磷的吸收。与非根际土壤相比,高磷供应下根际土壤有机磷含量增加,微生物量磷含量降低;而供磷不足时根际土壤碱性磷酸酶活性较高,有机磷含量较低。与施磷量P2O5 0.1 g/kg相比,高量供磷下根际土壤pH值升高、碱性磷酸酶活性下降,不施磷处理根际土壤pH值降低。本研究表明,供磷不足时,小麦根系形态和根际过程均发生适应性变化,而高量供磷条件下,小麦植株根系形态的改变因品种而异。     

不同磷形态对两种磷效率小麦根系指标与根际特征差异的影响

磷高效基因型小麦的筛选,对于高效合理地利用生物有效性低的土壤磷源有着极其重要的意义.本文以典型的磷高效型小麦小偃54和磷低效型小麦京411为研究对象,采用石英砂砾培养的方式种植40d,通过测定小麦的生物量、含磷量、根系形态、根系酸化能力和酸性磷酸酶活性,探索了两种磷效率小麦根系形态和生理特征对两种不同无机磷源磷酸铁(FePO4)和有机磷源植酸钠(Na-Phytate)的响应.结果表明:施用FePO4时,与京411相比磷高效型小麦小偃54表现出根长显著伸长、pH值显著降低和根系吸收质子显著减少的适应性反应,根系生物量和根冠比显著低于京411,小偃54的根系生物量仅为京411的83％,并且在此施肥条件下,两种小麦的地上生物量低于无磷处理.小偃54的磷高效性在施用Na-Phytate时可以得到体现.施用Na-Phytate会导致小偃54的根长伸长、根尖数增加与单位根鲜重酸性磷酸酶的分泌量增加.两种小麦苗龄为40d时对Na-Phytate的利用效率显著高于FePO4,其表现为小偃54在Na-Phytate处理下的地上生物量和含磷量为FePO4处理的148％和336％,京411的地上生物量和含磷量为FePO4处理的146％和391％.FePO4与Na-Phytate混施时两种小麦的生物量和含磷量并未比单施Na-Phytate高,由上述结果可知两种小麦对介质中不同磷源的利用机制不同.     

根系互作对谷子和花生间作体系根际微生物碳代谢的影响

间作系统因其产量优势及生态功能在全世界都广泛应用,尤其是禾本科与豆科作物的优势组合,但该间作体系中作物根系互作对碳代谢特性的影响尚不明确。通过2年田间试验结合盆栽模拟根系分隔（根系无互作;根系部分互作;根系完全互作）方法,采用Biolog技术研究了不同种植模式对谷子和花生籽粒产量、土地生产力及土壤微生物碳源利用特征的影响。2017～2018年田间试验结果表明,2种间作模式下土地当量比（LER）均大于1,尤其是谷子-花生2∶2模式LER于2018年达到1.36,表明禾本科作物谷子与豆科作物花生体系是具有产量优势的间作系统。室内盆栽研究结果表明,间作模式下谷子的生物量与产量分别增加了49.0%和92.6%,花生则增加了11.1%和44.6%,谷子与花生的收获指数（HI）也显著增加。与完全分隔无根系互作相比,根系互作促进了根际微生物碳源利用效率,谷子与花生根际微生物对31种碳源平均利用率分别增加了19.6%和72.2%。土壤微生物对6大碳源种类的平均利用以糖类和氨基酸类为主,对酚酸类利用率最低。主成分分析结果表明,间作与部分间作花生对根际土壤碳源利用率显著高于谷子与花生单作,而单作花生对碳源...     

Effects of vertical distribution of soil inorganic nitrogen on root growth and subsequent nitrogen uptake by field vegetable crops

Information is needed about root growth and N uptake of crops under different soil conditions to increase nitrogen use efficiency in horticultural production. The purpose of this study was to investigate if differences in vertical distribution of soil nitrogen (N_inorg) affected root growth and N uptake of a variety of horticultural crops. Two field experiments were performed each over 2 years with shallow or deep placement of soil N_inorg obtained by management of cover crops. Vegetable crops of leek, potato, Chinese cabbage, beetroot, summer squash and white cabbage reached root depths of 0.5, 0.7, 1.3, 1.9, 1.9 and more than 2.4 m, respectively, at harvest, and showed rates of root depth penetration from 0.2 to 1.5 mm day^?1 °C^?1. Shallow placement of soil N_inorg resulted in greater N uptake in the shallow‐rooted leek and potato. Deep placement of soil N_inorg resulted in greater rates of root depth penetration in the deep‐rooted Chinese cabbage, summer squash and white cabbage, which increased their depth by 0.2–0.4 m. The root frequency was decreased in shallow soil layers (white cabbage) and increased in deep soil layers (Chinese cabbage, summer squash and white cabbage). The influence of vertical distribution of soil N_inorg on root distribution and capacity for depletion of soil N_inorg was much less than the effect of inherent differences between species. Thus, knowledge about differences in root growth between species should be used when designing crop rotations with high N use efficiency.     

Subsoil strength and yield of vegetable crops

Abstract. In a field experiment over two years, broad beans ( Vicia faba ), cabbage ( Brassica oleracea var. capitata ), leeks ( Allium porrum ) and red beet ( Beta vulgaris var. esculenta ) were grown on a sandy clay loam soil in which a range of bulk densities and penetration resistances had been established by (1) thorough loosening to 0.9 m by trenching, (2) artificially compacting with tractor wheelings or (3) leaving unloosened.
Loosening the soil substantially increased, and compacting it decreased, yields of all four crops. The mean penetration resistance of the subsoil at field capacity correlated negatively with dry matter production. The relationship was broadly similar for all crops and years, showing a decrease in dry matter production of about 1 t ha^-1 per 0.5 MPa increase in resistance over the range examined.     

Effects of cover crops sown in autumn on N and P leaching

A field experiment with separately tile-drained plots was used to study the ability of oilseed radish (Rhaphanus sativus L.), as a cover crop sown after harvest of a main crop of cereals or peas, to reduce nitrogen (N) and phosphorus (P) leaching losses from a clay loam in southern Sweden over 6 years. In addition to oilseed radish in pure stand, two cover crop mixtures (hairy vetch (Vicia villosa) and rye (Secale cereale) for 3 years and oilseed radish in mixture with buckwheat (Fagopyrum esculentum) for 2 years) were tested. The cover crop plots (three replicates per treatment) were compared with unplanted plots as a control. Plots cropped with oilseed radish during autumn (August–November) had significantly smaller yearly mean N concentration in drainage water over 5 of 6 years compared with unplanted controls. Mineral N content in the soil profile in autumn was significantly less in oilseed radish plots than for control plots in all years. The cover crop mixtures of hairy vetch and rye or buckwheat and oilseed radish also showed the potential to reduce soil mineral N in autumn and N concentration in drainage water, compared with unplanted controls. The cover crops had no impact on P leaching. In conclusion, oilseed radish has the ability to reduce leaching losses of N, without increasing the risk of P leaching.     

有机肥与无机肥配合施用对蔬菜作物N肥流向的影响

通过¹⁵N标记示踪试驻,研究了常规施肥和不同种植方式露地栽培黄瓜、番茄、花椰菜、大白菜、菜豆的N肥利用率及其流向．有机肥与无机肥配合施用对N肥流向的影响。结果表明,5种蔬菜露地栽培N肥利用率平均为28．63％,土壤N素残留率为39．07％,N素亏损率41.25%。有机肥与无机肥配合施用,当年蔬菜作物无机N肥吸收减少,但土壤N素残留率增加,N素亏损率下降。     

Variation of glucosinolates in vegetable crops of Brassica oleracea

Glucosinolates were evaluated in 5 groups and 65 accessions of Brassica oleracea (50 broccoli, 4 Brussels sprouts, 6 cabbage, 3 cauliflower, and 2 kale) grown under uniform cultural conditions. Glucosinolates and their concentrations varied among the different groups and within each group. The predominant glucosinolates in broccoli were 4-methylsulfinylbutyl glucosinolate (glucoraphanin), 3-butenyl glucosinolate (gluconapin), and 3-indolylmethyl glucosinoate (glucobrassicin). Glucoraphanin concentration in broccoli ranged from 0.8 micromol g(-1) DW in EV6-1 to 21.7 micromol g(-1) DW in Brigadier. Concentrations of the other glucosinolates in broccoli varied similarly over a wide range. In Brussels sprouts, cabbage, cauliflower, and kale, the predominant glucosinolates were sinigrin (8.9, 7.8, 9.3, and 10.4 micromol g(-1) DW, respectively) and glucobrassicin (3.2, 0.9, 1.3, and 1.2 micromol g(-1) DW, respectively). Brussels sprouts also had significant amounts of gluconapin (6.9 micromol g(-1) DW). Wide variations in glucosinolate content among genotypes suggest differences in their health-promoting properties and the opportunity for enhancement of their levels through genetic manipulation.     

施用钾肥对叶菜产量和品质的影响

Over a period of two years, field experiments were conducted on four silty loam soils grown with foliar vegetable crops including Chinese cabbage (Brassica pekinensis Rupr., cv.Lu-Bai 3), autumn greens (B. chinensis L., cv.Piao-Geng-Bai), winter greens (B. var.rosularis Tsen et Lee, cv.You-Dong-Er), and summer greens (B. chinensis L., cv.Zao-Shu 5), respectively. Each experiment included one CK treatment without K, N and P fertilizers applied, and four treatments with from low to high doses, 0~300 kg hm^-2 for Chinese cabbage, 0~150 kg hm^-2 for autumn and winter greens and 0~180 kg hm^-2 for summer greens, of K fertilizers in the form of sulfate of potash (SOP) applied together with N and P fertilizers. One treatment of K fertilizer in the form of muriate of potash (MOP) applied at high levels (150 or 180 kg hm^-2) together with N and P fertilizers was included in the experiments of autumn, winter and summer greens, respectively, in order to compare the effects of SOP and MOP. The market yields of the tested crops increased significantly with the increasing rate of K application. The crops supplied with K fertilizers yielded more stably as the CV% of their yields decreased with the rate of K application. K fertilization increased not only K contents but also the amounts of N, P and K absorbed in shoots of autumn, winter and summer greens, which were statistically significantly correlated to their yields. It can also be found that potassium improved the quality of the foliar vegetable crops as their dry mater contents were generally increased and Vc contents obviously increased and nitrate contents markedly decreased. As compared to MOP, SOP was more effective on the yields and quality of autumn, winter and summer greens at the high levels of fertilization.     

High pressure liquid chromatographic determination of methomyl and oxamyl on vegetable crops

A reverse phase high pressure liquid chromatographic method is presented for the separation and determination of residues of the carbamates oxamyl and methomyl on vegetables. A liquid-liquid extraction and cleanup procedure is applied to the vegetable extract. Samples are eluted from a muBondapak C18 column and quantitated by ultraviolet absorbance at 240 nm. Recovery data for vegetable samples spiked at 2 ppm are presented.     

几种蔬菜对硝态氮、铵态氮的相对吸收能力

采用溶液培养方法探讨了莴笋、菠菜、小白菜和大青菜 4种蔬菜作物对硝、铵态氮的相对吸收能力以及这两种氮源对它们生长发育的影响。结果表明 ,单独供给NO3-N ,4种作物均生长发育良好 ;供给NO3--N +NH4+-N(NO3-∶NH4+=1∶1) ,生长量均有所下降 ,而单独供给NH4+-N时 ,生长量则大幅度下降。莴笋单独供给NO3--N时 ,其吸氮量显著高于供给NO3--N +NH4+-N的处理 ,大青菜、菠菜供给NO3--N +NH4+-N与单独供给NO3--N相比吸氮量大体相当 ;小白菜同时供应NO3--N +NH4+N时吸氮量最高 ,供给NO3--N时次之 ,供给NH4+-N时显著降低。供给NH4+-N时 4种作物吸氮量均比其它氮源显著降低。 4种作物对NO3--N与NH4+-N的吸收具有明显的偏向性。供给等氮量铵、硝态氮 (NO3--N +NH4+-N处理 )时 ,菠菜、小白菜吸收的NO3-N显著多于NH4+-N ,表现出喜硝性 ,莴笋则与此相反 ,表现出喜铵性 ;而大青菜对两种形态氮素的吸收量相差不多 ,表现出兼性吸收的特点。但上述偏向性具有阶段特点 ,即喜硝作物可能在某一阶段表现出喜铵性状     

长期施肥和秸秆还田对设施蔬菜土壤有机碳的影响

为了明确施肥和秸秆还田等措施对华北地区设施蔬菜土壤有机碳的影响,该研究以寿光设施蔬菜生产为对象,进行了连续11 a的长期定位试验,设置了对照（CK）、有机肥+秸秆还田（MS）、有机肥+优化氮肥（N1M）、有机肥+常规氮肥（N2M）、有机肥+优化氮肥+秸秆还田（N1MS）、有机肥+常规氮肥+秸秆还田（N2MS）6个处理,通过测定分析土壤有机碳含量、储量、有机物料碳转化效率、固碳速率等,探讨不同施肥和秸秆还田措施下土壤有机碳的变化规律。结果表明,施加有机肥+优化氮肥条件下,N1MS处理可以提高＞30～60 cm土壤有机碳含量,比N1M处理显著提高了40.5%（P＜0.05）,而施加有机肥+常规氮肥条件下,施加秸秆的增碳效果不明显;N2M显著增加表层（0～30 cm）土壤有机碳含量（P＜0.05）,比N1M处理提升47.0%;在有机肥+秸秆还田条件下,0～30 cm土层土壤有机碳随着施氮量的增加而增加,增加量大小顺序为N2MS（106.5%）＞N1MS（64.2%）＞MS（39.9%）;N2MS的土壤固碳速率在0～30和0～90 cm土层分别为1.85和3.74 t/(hm2?a)。因此,只考虑表层（0～30 cm）土壤固碳是远远不够的,应重视设施蔬菜等集约农业生产方式的深层土壤固碳。施用氮肥有利于提高有机物料转换为土壤有机碳的效率,且随着氮肥量的增加,有机物料的碳转化效率明显提高。设施蔬菜生产中,由于有机肥投入水平较高,秸秆还田转化为土壤有机碳的效率反而降低,秸秆还田和氮肥之间并未显现出对土壤有机碳的正交互作用,应进一步优化肥料和秸秆投入方式和水平,在维持蔬菜高产的前提下提高资源利用效率。