中国土壤和植物养分管理现状与改进策略

针对当前我国农业生产面临增肥不增产、土壤养分过量累积、化肥施用过量和养分利用效率下降等重大问题,本文综述了中国土壤养分与植物营养状况的历史演变和研究进展,提出中国植物营养科学研究应在跟踪国际科学前沿的同时,紧密结合中国农业生产实际,通过大幅度提高养分效率和作物产量为农业可持续发展做出应有的贡献。     

中国土壤和植物养分管理现状与改进策略

针对当前我国农业生产面临增肥不增产、土壤养分过量累积、化肥施用过量和养分利用效率下降等重大问题, 本文综述了中国土壤养分与植物营养状况的历史演变和研究进展, 提出中国植物营养科学研究应在跟踪国际科学前沿的同时, 紧密结合中国农业生产实际, 通过大幅度提高养分效率和作物产量为农业可持续发展做出应有的贡献。     

植物与土壤微生物在调控生态系统养分循环中的作用

陆地生态系统的地上、地下是相互联系的。植物与土壤微生物作为陆地生态系统中的重要组成部分, 它们之间的相互作用是生态系统地上、地下结合的重要纽带。该文首先介绍了植物在养分循环中对营养元素的吸收、积累和归还等作用, 阐述了土壤微生物对养分有效性及土壤质量具有重要的作用。其次, 重点综述了植物与土壤微生物之间相互依存、相互竞争的关系。植物通过其凋落物与分泌物为土壤微生物提供营养, 土壤微生物作为分解者提供植物可吸收的营养元素, 比如共生体菌根真菌即可使植物根与土壤真菌达到互惠。然而, 植物的养分吸收与微生物的养分固持同时存在, 因而两者之间存在对养分的竞争。通过植物多样性对土壤微生物多样性的影响分析, 以及土壤微生物直接或间接作用于植物多样性和生产力的分析, 探讨了植物物种多样性与土壤微生物多样性之间的内在联系。针对当前植物与土壤微生物对养分循环的调控机制的争论, 提出植物凋落物是调节植物与土壤微生物养分循环的良好媒介, 植物与土壤微生物的共同作用对维持整个生态系统的稳定性具有重要意义。也指出了目前在陆地生态系统地上、地下研究中存在的不足和亟待解决的问题。     

伊贝根际微生物

<正>土壤微生物是土壤中最活跃的因子,一方面是土壤天然有机体的转化者,另一方面是土壤养分的源和库,与植物营养和土壤肥力密切相关,在土壤物质和能量循环转化过程中起着重要作用。在植物的整个生长期间,根系进行着活跃的代谢作用,向根外不断分泌有机物质,这些分泌物是根际微生物的重要营养和能量来源,其成分和数量影响着根际微生物的种类和繁殖。根际微生物的数量、活性和群落结构及其变化直接影响到植物吸收水分和养分。因此,植物、土壤和微生物之间存在着相互依赖、相互作用的复杂的三边关系[1-2]。     

长期施肥对农牧交错带栗钙土土壤理化性质及生物学特性的影响

探究干旱栗钙土土壤长期施肥的施肥效应，揭示不同施肥模式下土壤理化性质及微生物特性的演变特征，为内蒙古农牧交错地区农田合理培肥和科学评估施肥效果提供依据。依托内蒙古武川旱作试验站的长期轮作定位施肥试验(2004—2019年),分析了不同施肥处理对农牧交错带栗钙土耕层土壤理化性质和生物学特性的影响。结果表明：长期有机肥配施化肥和单施有机肥可显著降低土壤容重，增大土壤孔隙度，而不平衡施肥(如NP、NK、PK、N处理)和不施肥处理土壤容重有增加趋势；与不施肥处理相比，不同施肥方式土壤有机碳、全氮、碱解氮、有效磷和速效钾含量均有所提高，土壤养分均表现为有机肥配施化肥>有机肥施用>化肥平衡施用>化肥不平衡施用>不施肥；在土壤微生物方面，有机肥配施化肥土壤细菌数量显著提高108.36%～118.92%,真菌数量提高27.68%～50.46%,放线菌数量提高35.43%～40.25%;长期施用有机肥和平衡施用化肥能改善土壤结构，提高土壤养分和微生物数量，尤以有机肥与化肥两者配施联用效果最好。以合理氮、磷、钾多元素配比施用对农牧交错带干旱栗钙土土壤质量有明显改善，不平衡施肥土壤性...     

紫茎泽兰(Ageratina adenophora)入侵对土壤微生物群落和理化性质的影响

外来入侵植物与入侵地土壤微生物群落的互作关系是影响外来植物入侵力和生态系统可入侵性的一个重要领域。因此,研究外来植物入侵对入侵地土壤微生物群落及其理化性质的影响不仅可以全面地评估入侵植物对生态系统的影响,而且对于探索外来植物入侵的土壤微生物学机制尤为重要。采用磷脂脂肪酸(PLFAs)和传统培养相结合的方法研究了外来入侵植物紫茎泽兰对入侵地土壤微生物群落结构的影响;同时研究了紫茎泽兰入侵对11种土壤理化因子的影响。结果表明紫茎泽兰入侵改变了土壤微生物群落结构,提高了土壤自生固氮菌、氨氧化细菌和真菌的数量;同时,显著地提高了土壤的有效磷、速效钾、硝态氮、氨态氮和土壤有机碳含量,降低了土壤总钾含量和pH值。土壤微生物不同生理类群的变化与土壤中植物可直接吸收利用养分的变化显著相关。紫茎泽兰在入侵地成功定殖后,可能通过改变土壤微生物群落结构,特别是增加了与土壤养分循环相关的微生物功能类群数量,进而提高了土壤可利用的养分水平,创造对自身生长有利的土壤环境。紫茎泽兰改变土壤微生物群落是其入侵的一部分,这种改变进而加速了土壤养分循环,可能增强了紫茎泽兰的养分吸收,进而促进其生长、竞争和扩张。     

黑土长期施肥及养分循环再利用的作物产量及土壤肥力质量变化Ⅲ.土壤养分收支

许了1985－1999年试验期间各模拟施肥模型的作物移出养分量和施肥输入养分量,结果表明,施用N肥可加剧土壤P收支赤字,而施用N,P肥则加剧土壤K收支赤字,实验展示了我国在20世纪70年代大面积贫P土壤和80年代大面积缺K土壤出现的原因,保持养分循环再利用可缓解土壤养分收支赤字,但不能满足丰产作物的养分需求,在保持养分循环利用基础上根据土壤肥力适当施用化肥,可满足丰产作物的养分需求和平衡土壤养分收支,不致发生大量过剩N进入环境。     

不同施肥制度对潮棕壤微生物量碳的影响

利用长期定位试验研究了下辽河平原地区不同施肥处理下潮棕壤微生物量碳的变化。结果表明:不施肥处理的微生物量碳含量最低,化肥均衡施用和施用循环肥均能显著提高土壤微生物量碳含量(P<0.05),以化肥N、P、K 循环猪圈肥处理效果最好;各处理的微生物量碳均呈现出春冬季较低,夏秋季较高的趋势;化肥均衡施用配合循环肥能显著提高土壤微生物量碳的周转强度,缩短周转时间(P<0.05),以化肥N、P、K 循环猪圈肥处理土壤微生物量碳的周转时间最短,1年可周转1.03次。     

养分管理对农田土壤微生物量的影响

土壤微生物与土壤质量、健康、植物的生产力和农业的可持续发展密切相关。任何对土壤中微生物的扰动都可能影响土壤的长期生产力,并可能产生严重后果。大量研究结果表明,肥料类型、施肥处理年限长短、施肥水平高低及施肥措施都会造成土壤成分的变化,进而影响土壤中微生物的生长以及繁殖。简要介绍了微生物量的几种测定方法,综述了各种养分管理措施对农田生态系统中土壤微生物量的影响,从而了解土壤微生物因人类对土壤的利用而发生的变化,以期为农业的可持续发展和生态环境的保护提供理论依据。     

施用生物质炭和羊粪对宿根连作茶园根际土壤微生物的影响

茶树长期宿根连作会导致土壤酸化严重、土壤营养不平衡、根际土壤微生态结构恶化.研究生物质炭、羊粪对宿根连作茶树生长以及土壤微生物群落结构和功能的影响,探讨其对宿根连作茶树土壤环境的调节效果,可为宿根连作茶园土壤微生态的改善提供理论依据.本研究以宿根连作20年的茶园土壤为对象,利用Biolog技术和磷脂脂肪酸(PLFA)方法,研究施用生物质炭(40 t·hm^-2)和羊粪替代部分化肥对连作茶树产量和品质、土壤化学性质、根际土壤微生物群落功能和结构的影响.结果表明:施用生物质炭、羊粪1年后酸化茶园土壤的p H和土壤养分显著提高,并提高了茶叶产量.与常规施肥相比,施用生物质炭、羊粪替代部分化肥处理显著提高了茶树根际土壤微生物的碳源代谢活性和微生物多样性,对胺类、碳水化合物和聚合物的相对利用有所增加.生物质炭和羊粪处理的根际土壤总PLFA含量分别比常规施肥处理提高了20.9%和47.5%,羊粪处理还显著降低了总饱和/总单一不饱和脂肪酸比例.生物质炭和羊粪可改善茶园土壤酸化状况和土壤肥力,对宿根连作茶树的生长具有促进作用,两种措施均不同程度地增加了土壤微生物的代谢活性和微生物量、提高了多样性指数、改善了微生物群落结构.施用生物质炭和羊粪可作为调节宿根连作茶园根际土壤微生态的有效措施.     

Endophyte roles in nutrient acquisition,root system architecture development and oxidative stress tolerance

Plants associate with communities of microbes (bacteria and fungi) that play critical roles in plant development, nutrient acquisition and oxidative stress tolerance. The major share of plant microbiota is endophytes which inhabit plant tissues and help them in various capacities. In this article, we have reviewed what is presently known with regard to how endophytic microbes interact with plants to modulate root development, branching, root hair formation and their implications in overall plant development. Endophytic microbes link the interactions of plants, rhizospheric microbes and soil to promote nutrient solubilization and further vectoring these nutrients to the plant roots making the soil-plant-microbe continuum. Further, plant roots internalize microbes and oxidatively extract nutrients from microbes in the rhizophagy cycle. The oxidative interactions between endophytes and plants result in the acquisition of nutrients by plants and are also instrumental in oxidative stress tolerance of plants. It is evident that plants actively cultivate microbes internally, on surfaces and in soils to acquire nutrients, modulate development and improve health. Understanding this continuum could be of greater significance in connecting endophytes with the hidden half of the plant that can also be harnessed in applied terms to enhance nutrient acquisition through the development of favourable root system architecture for sustainable production under stress conditions.     

长期施肥黄土旱塬农田土壤-微生物-植物系统碳氮磷生态化学计量特征

探讨长期不同施肥制度对农田土壤、植物生态系统的碳(C)、氮(N)、磷(P)含量及其生态化学计量比的影响,可为揭示该系统能量平衡和养分循环,实现农业生态系统元素平衡及可持续发展提供参考意义。以位于黄土高原半干旱地区的长武国家黄土高原农业生态实验站长期施肥试验为研究对象,选取不施肥(CK)、单施氮肥(N)、单施磷肥(P)、施氮磷肥(NP)、单施有机肥(M)、氮肥配施有机肥(NM)、磷肥配施有机肥(PM)、氮磷肥配施有机肥(NPM)8个处理,分析了黄土旱塬典型农田土壤-微生物-植物生态系统中C、N、P含量及其生态化学计量变化规律。研究结果表明:1)长期单施有机肥和化肥配施有机肥处理可显著提高土壤和有机质C、N、P含量。2)氮、磷肥的输入显著降低了土壤和小麦C∶N、N∶P,施P显著降低了有机态C∶P和小麦C∶P;有机肥配施对微生物生物量和小麦C∶N∶P的影响更为明显。3)长期有机肥配施条件下土壤养分和小麦化学计量比存在较强的相关关系。微生物生物量碳与有机C、N、P呈显著正相关,土壤微生物生物量氮与土壤N、P总量呈显著正相关,微生物生物量磷与土壤C、N、P总量含量呈显著负相关;植株碳含量与微生物...     

Effects of labile soil carbon on nutrient partitioning between an arctic graminoid and microbes

We measured partitioning of N and P uptake between soil microorganisms and potted Festuca vivipara in soil from a subarctic heath in response to factorial addition of three levels of labile carbon (glucose) combined with two levels of inorganic N and P. The glucose was added to either non-sterilized or sterilized (autoclaved) soils in quantities which were within the range of reported, naturally occurring amounts of C released periodically from the plant canopy. The aims were, firstly, to examine whether the glucose stimulated microbial nutrient uptake to the extent of reducing plant nutrient uptake. This is expected in nutrient-deficient soils if microbes and plants compete for the same nutrients. Secondly, we wanted to test our earlier␣interpretation that growth reduction observed in graminoids after addition of leaf extracts could be caused directly by labile carbon addition, rather than by phytotoxins in the extracts. Addition of high amounts of N did not affect the microbial N pool, whereas high amounts of added P significantly increased the microbial P pool, indicating a luxury P uptake in the microbes. Both plant N and in particular P uptake increased strongly in response to soil sterilization and to addition of extra N or P. The increased␣uptake led to enhanced plant growth when both elements were applied in high amounts, but only led to increased tissue concentrations without growth responses when the nutrients were added separately. Glucose had strong and contrasting effects on plant and microbial N and P uptake. Microbial N and P uptake increased, soil inorganic N and P concentrations were reduced and plant N and P uptake declined when glucose was added. The responses were dose-dependent within the range of 0–450 μg C g⁻¹ soil added to the non-sterilized soil. The opposite responses of plants and microbes showed that plant acquisition of limiting nutrients is dependent on release of nutrients from the soil microbes, which is under strong regulation by the availability and microbial uptake of labile C. Hence, we conclude, firstly, that the microbial populations can compete efficiently with plants for nutrients to an extent of affecting plant growth when the microbial access to labile carbon is high in nutrient deficient soils. We also conclude that reduced growth of plants after addition of leaf extracts to soil can be caused by carbon-induced shifts in nutrient partitioning between plants and microbes, and not necessarily by phytotoxins added with the extracts as suggested by some experiments. Received: 15 February 1997 / Accepted: 12 July 1997     

Turning the Table: Plants Consume Microbes as a Source of Nutrients

Interactions between plants and microbes in soil, the final frontier of ecology, determine the availability of nutrients to plants and thereby primary production of terrestrial ecosystems. Nutrient cycling in soils is considered a battle between autotrophs and heterotrophs in which the latter usually outcompete the former, although recent studies have questioned the unconditional reign of microbes on nutrient cycles and the plants'' dependence on microbes for breakdown of organic matter. Here we present evidence indicative of a more active role of plants in nutrient cycling than currently considered. Using fluorescent-labeled non-pathogenic and non-symbiotic strains of a bacterium and a fungus (Escherichia coli and Saccharomyces cerevisiae, respectively), we demonstrate that microbes enter root cells and are subsequently digested to release nitrogen that is used in shoots. Extensive modifications of root cell walls, as substantiated by cell wall outgrowth and induction of genes encoding cell wall synthesizing, loosening and degrading enzymes, may facilitate the uptake of microbes into root cells. Our study provides further evidence that the autotrophy of plants has a heterotrophic constituent which could explain the presence of root-inhabiting microbes of unknown ecological function. Our discovery has implications for soil ecology and applications including future sustainable agriculture with efficient nutrient cycles.     

Herbivorous insect decreases plant nutrient uptake: the role of soil nutrient availability and association of below‐ground symbionts

1. Plants take nutrients from the rhizosphere via two pathways: (i) by absorbing soil nutrients directly via their roots and (ii) indirectly via symbiotic associations with nutrient‐providing microbes. Herbivorous insects can alter these pathways by herbivory, adding their excrement to the soil, and affecting plant–microbe associations. 2. Little is known, however, about the effects of herbivorous insects on plant nutrient uptake. Greenhouse experiments with soybean, aphids, and rhizobia were carried out to examine the effects of aphids on plant nutrient uptake. 3. First, the inorganic soil nitrogen and the sugar in aphid honeydew between aphid‐infected and ‐free plants were compared. It was found that aphid honeydew added 41 g m^?2 of sugar to the soil, and that aphids decreased the inorganic soil nitrogen by 86%. This decrease may have been caused by microbial immobilisation of soil nitrogen followed by increased microbial abundance as a result of aphid honeydew. 4. Second, nitrogen forms in xylem sap between aphid‐infected and ‐free plants were compared to examine nitrogen uptake. Aphids decreased the nitrogen uptake via both pathways, and strength of the impact on direct uptake via plant roots was greater than indirect uptake via rhizobia. The reduced nitrogen uptake by the direct pathway was as a result of microbial immobilisation, and that by the indirect pathway was probably because of the interaction of microbial immobilisation and carbon stress, which was caused by aphid infection. 5. The present results demonstrate that herbivorous insects can negatively influence the two pathways of plant nutrient uptake and alter their relative importance.     

Improving crop nutrient efficiency through root architecture modifications

Improving crop nutrient ef ficiency becomes an essential consideration for environmentally friendly and sustainable agriculture. Plant growth and development is dependent on 17 essential nutrient elements,among them,nitrogen(N) and phosphorus(P) are the two most important mineral nutrients. Hence it is not surprising that low N and/or low P availability in soils severely constrains crop growth and productivity,and thereby have become high priority targets for improving nutrient ef ficiency in crops. Root exploration largely determines the ability of plants to acquire mineral nutrients from soils. Therefore,root architecture,the 3-dimensional con figuration of the plant's root system in the soil,is of great importance for improving crop nutrient ef ficiency. Furthermore,the symbiotic associations between host plants and arbuscular mycorrhiza fungi/rhizobial bacteria,are additional important strategies to enhance nutrient acquisition. In this review,we summarize the recent advances in the current understanding of crop species control of root architecture alterations in response to nutrient availability and root/microbe symbioses,through gene or QTL regulation,which results in enhanced nutrient acquisition.