土壤—植物根际磷的生物有效性研究进展

探讨土壤－植物根际磷素养分状况及利用机理，提高土壤磷的生物有效性，使土壤中潜在的难溶性磷库活化，提高磷肥利用率，对促进农业生产的持续发展和陆地生态系统的良性循环具有重大的现实意义。文章从这一角度出发，论述了根际土壤中根际微生物，根际pH值，根系分泌物，菌根，根际土壤磷酸酶等各种因素对提高土壤磷素利用率的机理。     

解磷微生物对土壤磷资源利用影响的研究进展

我国磷肥的使用量正逐年递增,但由于施入土壤的磷素大多被固定,以无效态(难溶态)在土壤中积累,导致磷资源的利用率很低,如何提高土壤磷资源的利用率已成为近些年的研究热点。解磷微生物能够利用自身代谢产物或者通过与其他生物的协同作用,将土壤中难溶的磷酸盐转化为植物生长可利用磷,因此而备受关注。本文在介绍我国磷资源概况的基础上,综述了解磷微生物的生态分布、解磷能力、解磷机理,对土壤与植物磷素利用的影响,同时介绍了解磷微生物在环境污染物控制中的应用,旨在为解磷微生物在磷资源利用方面的研究提供理论支持。     

丛枝菌根真菌促进植物摄取土壤磷的作用机制

磷在土壤中易被固定沉淀,在植物磷利用率低的情况下,过度施肥会造成磷肥浪费,可能通过地表径流、地下水溶解等方式,造成水体富营养化产生面源污染,对人类生产生活造成较大影响。丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)和植物结合所形成的共生菌根可以显著增强植株对磷的吸收利用。通过AMF可以提高宿主植株对磷的吸收转运的特性,从AMF促进植株对磷元素的摄取机制、AMF促进植物磷摄取分子机理、AMF作用下根系分泌物对植株磷利用的影响与根际微生物对AMF磷元素利用的影响4个方面的研究进展进行分析总结。AMF可以通过改变宿主植株的根系形态和菌丝网络的形成,扩大植株对养分吸收范围;释放有机酸、磷酸酶和质子等根系分泌物改变土壤结构和理化性质,与根际微生物共同作用降解土壤中难溶性磷酸盐;诱导相关磷转运蛋白基因的特异性表达,提高植株对磷的转运能力而促进其吸收。     

菜地土壤解磷微生物特征及其在磷形态转化调控中的作用

目前蔬菜生产存在为追求高产而盲目"高磷投入"的现象,尽管持续高量的磷肥投入导致菜地土壤磷库储量较之粮田更加丰富,但土壤中的磷极易被固定形成无效态磷,导致菜地磷肥当季利用率低以及磷高积累带来的环境风险。而解磷微生物可以利用自身的代谢功能驱动土壤难溶性磷向有效磷的转化,从而直接影响土壤磷素周转及供磷水平。本文探讨了菜地土壤解磷微生物特征、根际磷素周转及其对蔬菜磷吸收利用的贡献、磷肥及碳源种类对解磷微生物的影响、解磷微生物在菜地面源污染防控中的作用及其今后高效应用研究方向,旨在为今后提高蔬菜磷肥利用率,以及充分利用菜地累积态磷,从而进一步降低环境风险提供参考。     

高投入蔬菜种植体系磷素高效利用的根际对话及效应研究进展

蔬菜种植体系是一种高投入体系,高量磷肥的投入会造成磷资源浪费和磷高积累带来的环境风险。通过根际调控增加磷有效性以及提高蔬菜对磷的吸收利用是菜地减磷增效行之有效的手段之一。基于该研究思路,综述了根际对话三大模块,植物-植物对话（蔬菜间套作根系互作）、植物-微生物对话（蔬菜根系与菌根真菌及根际促生菌互作）以及微生物-微生物对话（菜地解磷微生物与根际微生物互作）在促进蔬菜根系发育、活化土壤累积态磷从而增加蔬菜对磷的吸收利用方面的作用及其作用机制。同时阐述了人为调控不同模块,如利用解磷微生物菌肥提高蔬菜磷吸收利用,以及在缓解蔬菜连作障碍方面的应用效果及机理。最后探讨今后高投入体系根际对话的研究方向,旨在为推动高投入蔬菜种植体系磷肥管理的绿色和可持续发展提供理论依据。     

磷同位素示踪技术在生态与资源环境科学研究中的新进展

同位素示踪技术广泛应用于土壤-植物-动物生产-环境系统中磷的活化、形态转化、吸收利用、迁移规律等方面的研究,极大地推动了生态、资源环境科学的发展。本文介绍了几种利用同位素示踪技术研究磷在土壤-植物-动物生产-环境系统中动态行为方法的进展,其中放射性同位素磷稀释技术已应用于盆栽和大田试验的研究,主要包括直接标记水溶性磷肥磷或土壤易交换性磷、间接标记难溶性磷和难溶性磷酸盐通过中子堆照活化3种方法。磷酸盐中氧稳定性同位素示踪技术是新近发展起来、并不断完善的方法,为磷从农田到水体环境迁移过程的定量研究提供了可能,但该技术在土壤-植物系统中的应用还存在一定的局限性,有待技术与理论上的进一步完善。核磁共振技术为生态系统中磷形态变化,尤其是有机磷形态的定性与定量研究提供新的研究手段。     

根际溶磷微生物促生机制研究进展

溶磷微生物是广泛存在于植株根际土壤中的一类重要功能微生物,它们可以溶解难溶性磷酸盐以释放出可溶性磷供植株吸收利用。溶磷微生物在促进植株生长方面发挥着重要作用,本文从矿质元素、激素、根系构型、光合作用、土壤肥力等方面综述了溶磷微生物对植株生长的促生机制,并提出了今后研究的发展方向。     

印度芥菜对土壤中难溶态镉、铅的吸收差异

通过根际袋法土培盆栽试验，研究了印度芥菜对石灰性土壤中难熔态Cd,Pb的吸收差异。试验结果表明，印度芥菜能吸收石灰性土壤中的难溶态Cd,Pb并对其有较高的忍耐性。印度芥菜吸收的Cd70%以上累只在地上部而吸收的Pb83%以以累积在根系；印度芥菜根际土壤中的DTPA提取态Cd显著高于非根际土壤，但根际与非根际土壤中的DTPA提取的Pb含量差异不显著。本试验条件下，印度芥菜对土壤Cd的净化率为0．83％－1．25％，对土壤Pb的净化率则只有0.04%-0.07%。     

辽宁省主要土壤的供磷特点及磷肥肥效

影响磷肥肥效的因素,其中最为重要的是土壤条件。施用磷肥效果的大小,既取决于土壤中可给态磷的含量,也决定于与磷肥相互作用的土壤性质,如引起难溶性磷酸盐的溶解,或可给态磷酸盐的固定等特点。     

土壤固定态P的微生物转化和利用研究

本文综述了土壤中固定态P的存在方式及其微生物的转化和利用 .着重阐述细菌和真菌对土壤难溶性磷酸盐的解磷作用及其机理 ;同时也对热带—亚热带地区以可变电荷矿物为主的红黄壤中专性吸附磷的微生物转化和利用研究作了概述     

溶磷细菌肥对石灰性土壤磷素转化的影响

通过室内模拟培养和大豆盆栽土培生物模拟试验，研究了磷细菌溶解磷酸钙的能力及在北方石灰性土壤上施用磷细菌肥对土壤磷素转化的影响。试验结果表明：磷细菌菌株具有较强溶解磷酸钙的能力，磷酸钙的溶出率从第1天的2．80％提高到第8天的22．00％。在贫速效磷和富难溶性磷土壤上施用溶磷细菌肥有利于土壤中难溶态的Ca10-P和缓效态Ca8-P含量下降，促使土壤中Ca2-P和Al-P的含量增加，从而使土壤中有效磷含量增加。而对于富速效磷的土壤，无论施菌肥与否对土壤中各种形杰的无机磷绢分基本没有影响．     

Höhe der Erhaltungsdüngung und Ausnutzung von Düngerphosphat vor dem Hintergrund der P-Alterung im Boden

Phosphorus fertilizer rate to maintain the soil P status and the utilization of fertilizer P Once a soil has a P status adequate for optimum plant growth the aim of the farmer is to maintain it. Fertilizer phosphate, even water soluble, is utilized by crop plants generally by less than 20% only in the year of application. Furthermore, the solubility of residual P in soil decreases with time, a process known as “aging” of P. These observations have led to the widespread assumption, that fertilizer P is partly converted into a status unavailable to plants. This would mean that the amount of P necessary to maintain the soil P status has to be permanently higher than P removal of plants. The objective of this work was to test the validity of this conclusion. For this purpose long-term P fertilizer field and pot experiments were carried out on different soils. The results show that the soil test values, lactate (DL or CAL) and water extractable P, remained almost at the same level if fertilizer P was applied in amounts equal to those removed by the crop harvest products. A tendency of decreasing the soluble soil P level was only observed if the soluble soil P content was much higher than necessary for plants. However, the easily extractable P decreased or increased if P applications were less or higher than the amount of P removed by crops, respectively. Desorption studies have revealed that the amount of P desorbed within one week also remained constant if P application was equal to P removal. However, if P was applied in excess of plant removal this proportion was not fully desorbed within one week, whereas the plants were able to utilize it on the long run. We conclude that the “aging” of fertilizer P in soil does not result in a loss of P for crop plants. On the contrary, fertilizer P applied to the soil in a soluble form is fully utilized by the plants in extended periods of time. The rate of P application to maintain the P status of the soil is therefore equal to the quantity of P removed by the plant material.     

Enhanced plant growth by uniform placement of superphosphate with rock phosphate in acidic soils

Abstract

Partially acidulated rock phosphate or compacted soluble phosphate‐rock phosphate mixture has been suggested as an alternative phosphorus (P) source for plants in acidic soils. Interaction between the soluble and the insoluble fractions would be conducive to plant utilization of both P sources in the fertilizer material. Direct evidence supports the beneficial reactions between the two P sources, however, was still insufficient. A pot experiment was hence conducted to evaluate the possible interaction of ³²P‐labeled single superphosphate (SSP) and a less reactive rock phosphate (RP) from Jinxiang mine, China. In the experiment, SSP and RP were applied to two acidic red soils (typic Hapludults) in a manner that would favor or diminish their interaction either by distributing both P sources homogeneously within the whole volume of the pot soil (uniform placement) or by separating them vertically with each being applied to half of the soil volume (fraction placement). The reference treatments of SSP and RP were arranged in similar manners. Two successive harvests of ryegrass were made during a 2‐month period. Results indicated that uniform placement of SSP and RP significantly enhanced plant growth and P uptake, and that P recovery of SSP‐P in the higher P‐fixing soil was almost twice that of the fraction placement. The data of plant PdfL% (percentage of P derived from labeled‐P), which indicated that >80% of plant P was derived from SSP, however, failed to support the idea that soluble P had increased plant utilization of RP. Alternatively, it is considered that the low grade RP had increased plant utilization of both SSP‐P and soil‐P. Uniform placement of RP and SSP also strikingly improved plant calcium (Ca) and magnesium (Mg) nutrition. The phenomenon suggested that SSP‐RP mixture might be a good P source on similar acidic soils in subtropical China.     

土壤微生物在枸溶性和聚合态磷肥活化利用中的作用

[目的]如何实现磷肥高效利用是农业生产中亟待解决的重要问题.研究土壤微生物在磷肥形态转化与高效利用过程中的作用及机制,为理解作物-磷肥品种-土壤微生物匹配机制提供科学依据.[方法]盆栽试验选用褐土,速效磷为4.53 mg/kg,供试玉米品种为'郑单958'.试验土壤首先进行高温灭菌和不灭菌处理,然后分别施用磷酸一铵(M...     

Influence of vesicular-arbuscular mycorrhizae on phosphate fertilizer efficiency in two tropical acid soils planted with micropropagated oil palm (Elaeis guineensis jacq.)

Summary The influence of vesicular-arbuscular mycorrhizae on the efficiency of triple superphosphate and rock phosphate fertilizers was compared in two tropical, acid, P-fixing soils (Ivory Coast) in which the available P was labelled with ³²PO _inf4 ^sup3- . Both soils were planted with micropropagated oil palms. The growth reponses to the fertilizer applications were low unless accompanied by VAM inoculation, but both fertilizers were equally available to plants. Isotopic-dilution kinetics analyses indicated that the rock phosphate was solubilized in both soils and there was an enrichment of the labile pool of plant-available P, similar to that with superphosphate. The specific activity and the fraction of P derived from either fertilizer was similar in both mycorrhizal and non-mycorrhizal plants, showing that both absorbed P from the same labile pool of P in the fertilized soils. However, VAM inoculation increased the fertilizer utilization coefficient of plants 2.7- to 5.6-fold, depending on the soil and fertilizer. We conclude that VAM inoculation increases fertilizer efficiency, as much of rock phosphate as of superphosphate, for plants growing in acid, P-fixing soils, and the processes involved are not different for the two fertilizers.     

磷肥配施生物质改良剂对盐渍土改良与玉米增产的效应

以玉米为供试作物，通过田间试验设置无磷肥和生物质改良剂对照、单施不同量磷肥和磷肥配施生物质改良剂(微生物菌肥、生物质炭、腐殖酸和黄腐酸)处理，研究了磷肥配施生物质改良剂对盐渍化土壤的改良效应及对玉米的增产作用。结果表明：与对照处理相比，各处理的土壤容重和pH分别降低1.96%～14.38%和0.11%～1.98%，土壤有效磷含量增加33.71%～182.39%；施磷75 kg/hm²处理下的籽粒磷素积累量最高，施磷150 kg/hm²处理下的茎秆、叶片和植株的磷素积累量最显著；磷肥利用率、磷肥农学效率和磷肥偏生产力随施磷量增加呈下降趋势。与对照处理相比，各处理的玉米单株鲜重和干重分别增加6.52%～34.78%和11.54%～42.31%，百粒重和产量分别增加31.15%～40.52%和21.81%～60.02%。主成分分析表明，150 kg/hm²磷肥配施7 500 kg/hm²生物质炭处理的综合得分最高(分值为1.255 1)，该处理在土壤改良、磷肥利用与玉米增产等方面的综合效果最优。     

Ureolytic microorganisms and soil fertility: A review

Abstract

Soil microorganisms play an important role in increasing soil fertility and recycling of nutrients within the soil. Different microorganisms including filamentous fungi, yeasts, mycorrhiza, bacteria, cyanobacteria, and actinomycetes possess the urease enzymes. Urease plays a role in soil enrichment through degradation or hydrolysis of organic nitrogen (N). Urea is an important fertilizer and may enter the soil with the excretions of higher animals and through destruction of the nitrogenous bases contained in the nucleic acids of plant and animal tissues. These products increase soil fertility by an urease. Ureolytic production and activity, and fertility of soil are affected by chemical propertes of soil, environmental factors, sources of urea, and soil microorganism. Problems encountered in use of urea as a fertilizer result from its rapid hydrolysis to ammonium carbonate by soil urease activity and the concomitant rise in pH and accumulation of ammonium. These problems include damage to germinating seedlings and young plants and gaseous loss of urea N as ammonia. The technologies and management practices that can be used to improve urea efficiency and reduce losses include coating of granules, soil incorporation, and use of new slow‐release fertilizers by forming sparingly soluble urea‐aldehyde compounds as ureaforms, crotonylidene diurea, isobutylidene diurea or using natural N‐containing compounds such as composted sludges of municipal and animal wastes. The degradative process of the ureolytic microorganims on animal and plant organic N wastes could help to satisfy condition of eliminating excessive wastes and pollution and simultaneously supply plant with available N.     

Corn biomass,uptake and fractionation of soil phosphorus in five soils amended with organic wastes as P fertilizers

Abstract

Sustainable food production includes mitigating environmental pollution and avoiding unnecessary use of non-renewable mineral phosphate resources. Efficient phosphorus (P) utilization from organic wastes is crucial for alternative P sources to be adopted as fertilizers. There must be predictable plant responses in terms of P uptake and plant growth. An 18-week pot experiment was conducted to assess corn (Zea mays L.) plant growth, P uptake, soil test P and P fractionation in response to application of organic P fertilizer versus inorganic P fertilizer in five soils. Fertilizers were applied at a single P rate using: mono-ammonium phosphate, anaerobically digested dairy manure, composted chicken manure, vegetable compost and a no-P control. Five soils used varied in soil texture and pH. Corn biomass and tissue P concentrations were different among P fertilizers in two soils (Warden and Quincy), with greater shoot biomass for composted chicken manure and higher tissue P concentration for MAP. Plant dry biomass ranged from highest to lowest with fertilizer treatment as follows: composted chicken manure?>?AD dairy?=?MAP?=?no-P control?=?vegetable compost. Soil test P was higher in soils with any P fertilizer treatment versus the no-P control. The loosely bound and soluble P (2.7?mg P kg^?1) accounted for the smallest pool of inorganic P fractions, followed by iron bound P (13.7?mg P kg^?1), aluminum bound P (43.4?mg P kg^?1) and reductant soluble P (67.9?mg P kg^?1) while calcium bound P (584.6?mg P kg^?1) represented the largest pool of inorganic P.     

A 15N tracing technique-based analysis of the fate of fertilizer N: a 4-year case study in eastern China

The fate of fertilizer N applied with different irrigation amounts in tobacco fields was quantitatively studied by applying ¹⁵N double-labelled NH₄NO₃ in lysimeters. The ¹⁵N (fertilizer N originating from the fertilizer applied in 2011) in tobacco plants, ¹⁵N in soils and ¹⁵N loss were observed continuously from 2011 to 2014. The results showed that 21.6% of ¹⁵N was utilized by tobacco plants, 72.1% remained in the 0–60 cm soil layer and 6.3% was lost from the soil–plant system after the first season’s harvest (2011) of flue-cured tobacco. During the four seasons from 2011 to 2014, cumulative utilization of ¹⁵N by tobacco plants was 34.3%, while 54.2% remained in the 0–60 cm soil layer, and 11.5% was lost via mechanisms such as leaching and volatilization. The fate of ¹⁵N in terms of accumulation in plants and soils or losses from the soil–plant system from 2012 to 2014 was greatly affected by the fertilizer and irrigation management strategies in 2011. The results of this investigation suggest that the major amount of fertilizer N applied during the first season remains available in the soil for utilization by tobacco plants after 4 years.     

改性磷矿粉在石灰性土壤上的生物有效性及其机理研究

为缓解磷资源危机,充分利用不适于化学加工的磷矿资源,对磷矿采用活化技术开发利用,由此生产的改性磷肥已被证明在酸性土壤上有很高的生物有效性,但在石灰性土壤上的研究还比较少。本文选择4种不同产地(云南昆明、四川德阳、四川绵竹和贵州开阳)的磷矿粉,分别用有机活化剂和无机活化剂进行活化处理,制备改性磷矿粉,并就其在石灰性土壤对苗期春小麦的生物有效性进行了盆栽试验。结果表明,4种磷矿粉经活化处理后有效磷和水溶性磷含量均明显增加,无机活化剂提高了有效磷的含量,而有机活化剂对水溶性磷的提高幅度较大。改性磷矿粉处理均不同程度提高了石灰性土壤上春小麦的生物量干重、植株吸磷量和磷利用效率,有机活化剂处理制备的改性磷矿粉对春小麦生长的促进作用更为明显。运用红外光谱谱学技术对4种磷矿粉及相应的8种改性磷矿粉结构分析结果表明,磷矿粉经改性后其结构发生了明显变化,H2PO4和HPO42的特征谱带明显增加,增加的程度因磷矿粉的产地和活化剂种类不同而有差异。对磷矿粉化学成分分析结果表明,不同产地的磷矿粉其磷以及钙、铁、铝、镁等化学成分的含量差异较大,活化剂对磷矿粉的活化效果与磷矿粉本身的氧化物含量有关。在本试验条件下,磷矿粉Ⅲ(四川绵竹)的活化效果相对最好,与其氧化镁含量最高、总氧化物含量最低有关。不同类型活化剂对磷矿粉的活化效果不同,红外光谱分析结果表明,无机活化剂活化效果较好,而土培试验结果表明有机活化剂的活化效果较好,这一结果有待进一步的研究。