How do soil P tests, plant yield and P acquisition by Lotus tenuis plants reflect the availability of added P from different phosphate sources

A szabadföldi trágyázási (tartam)kísérletek eredményeit talaj-, illetve diagnosztikai célú növényvizsgálatok segítségével tudjuk kiterjeszteni, általánosítani – figyelembe véve természetesen a kiterjesztés korlátait is. Célszerűnek láttuk ezen túl a talaj könnyen oldható tápelem-, közöttük P-tartalmát is meghatározni a hazánkban hivatalosan elfogadott AL- (ammónium-laktátos) módszer mellett az Európai Unióban és Észak-Amerikában alkalmazott P-tesztekkel is (CaCl2-, H2O-, Olsen-, Bray1-, LE-, Mehlich3- stb.) a hazai OMTK kísérletek talajmintáiban. A kísérleti helyek talajtulajdonságaiban megnyilvánuló jelentős különbségek lehetőséget adnak rá, hogy a talaj P-teszteket – és a növényi P-felvételt – jellegzetes hazai talajokon, sokszor szélsőséges talajparaméterek mellett vizsgáljuk. Az egyes P-szintek között a 28 év átlagában mintegy évi 50 kg P2O5·ha-1volt a különbség. A P0-szinten mért P-tartalmak jól jelezték az egyes kísérleti helyek talajának eltérő P-ellátottságát, illetve, közvetve, fizikai féleségében, pH és mészállapotában meglévő különbségeket. A P2-szinten – a hazai talajokra, P-igényes növényekre a hazai szabadföldi P-trágyázási tartamkísérleti adatbázisban talált összefüggésekre alapozott – új AL-P határértékek szerint csupán a bicsérdi csernozjom barna erdőtalajon nem javult a P-ellátottság legalább a „jó” szintig. Vizsgálataink megerősítették az AL-módszer függőségét a CaCO3-tartalomtól: a Mehlich3 módszerrel való összefüggésben a karbonátmentes és a karbonátos talajok csoportja erőteljesen elkülönült egymástól. Az AL-P korrekció elvégzése, azaz az AL-P értékeknek egy standard talajtulajdonság-sorra való konvertálása (KA: 36; pH(KCl): 6,8; CaCO3: 0,1%) látványosan csökkentette az AL-módszernek a talaj CaCO3-tartalmától való függőségét. Az AL-P és Olsen-P, valamint a korrigált AL-P és Olsen-P tartalmak összehasonlításában ugynakkor ugyanez az összefüggés nem volt állapítható, ami arra utal, hogy az Olsen módszer bizonyos fokig szintén pH- és mészállapot függő. Kísérleti eredményeink megerősítették a Sarkadi-féle AL-P korrekciós modell helytálló voltát. Fenti megállapításunkat ugyanakkor a növényi P-tartalmakkal való összefüggéseknek is igazolniuk kell. Szükséges tehát a talajvizsgálati eredményeknek a diagnosztikai célú növényvizsgálatokkal, valamint a terméseredményekkel való összevetése. A tartamkísérletek talajai lehetőséget nyújtanak a környezetvédelmi célú P-vizsgálatok értékelésére, a talaj P-feltöltöttsége környezeti kockázatának becslésére. Ezekkel a kérdésekkel a cikksorozat további részeiben kívánunk foglalkozni.

Download Full-text

Richness of Rhizosphere Organisms Affects Plant P Nutrition According to P Source and Mobility

Agriculture ◽

10.3390/agriculture11020157 ◽

2021 ◽

Vol 11 (2) ◽

pp. 157

Author(s):

Jean Trap ◽

Patricia Mahafaka Ranoarisoa ◽

Usman Irshad ◽

Claude Plassard

Keyword(s):

Careful Consideration ◽

Soil Conditions ◽

Organic P ◽

P Nutrition ◽

Soil P ◽

P Acquisition ◽

Complex Interactions ◽

Experimental Trials ◽

The Relationship

Plants evolve complex interactions with diverse soil mutualist organisms to enhance P mobilization from the soil. These strategies are particularly important when P is poorly available. It is still unclear how the soil P source (e.g., mineral P versus recalcitrant organic P) and its mobility in the soil (high or low) affect soil mutualist biological (ectomycorrhizal fungi, bacteria and bacterial-feeding nematodes) richness—plant P acquisition relationships. Using a set of six microcosm experiments conducted in growth chamber across contrasting P situations, we tested the hypothesis that the relationship between the increasing addition of soil mutualist organisms in the rhizosphere of the plant and plant P acquisition depends on P source and mobility. The highest correlation (R2 = 0.70) between plant P acquisition with soil rhizosphere biological richness was found in a high P-sorbing soil amended with an organic P source. In the five other situations, the relationships became significant either in soil conditions, with or without mineral P addition, or when the P source was supplied as organic P in the absence of soil, although with a low correlation coefficient (0.09 < R2 < 0.15). We thus encourage the systematic and careful consideration of the form and mobility of P in the experimental trials that aim to assess the role of biological complexity on plant P nutrition.

Download Full-text

A comparison of some surface soil phosphorus tests that could be used to assess P export potential

Soil Research ◽

10.1071/sr06142 ◽

2007 ◽

Vol 45 (5) ◽

pp. 397 ◽

Cited By ~ 11

Author(s):

David Nash ◽

Murray Hannah ◽

Kirsten Barlow ◽

Fiona Robertson ◽

Nicole Mathers ◽

...

Keyword(s):

Organic P ◽

Soil Tests ◽

Soil P ◽

Olsen P ◽

P Sorption ◽

P Loss ◽

Extractable P ◽

Soil P Tests ◽

Total P ◽

Water Extractable

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.

Download Full-text

Root exudation index: screening organic acid exudation and phosphorus acquisition efficiency in soybean genotypes

Crop and Pasture Science ◽

10.1071/cp15329 ◽

2016 ◽

Vol 67 (10) ◽

pp. 1096 ◽

Cited By ~ 20

Author(s):

Vengavasi Krishnapriya ◽

Renu Pandey

Keyword(s):

Molecular Weight ◽

Root Exudation ◽

Growth And Yield ◽

Yield Potential ◽

Secretory Proteins ◽

P Availability ◽

Screening Process ◽

Soil P ◽

P Acquisition ◽

Soybean Genotypes

High-molecular-weight secretory proteins and low-molecular-weight exudates (carboxylates, phenols, free amino acids and sugars) released from roots of soybean (Glycine max (L.) Merr.) differentially influence genotypic phosphorus (P) acquisition efficiency (PAE). We hypothesised that genotypes with higher root exudation potential would exhibit enhanced P acquisition, and screened 116 diverse soybean genotypes by labelling shoots with 14CO2. A root exudation index (REI) derived from total 14C in the root exudate at sufficient (250 μm) and low (4 μm) P levels was used to classify genotypes for PAE. Genotypes with REI >2.25 exhibited significantly higher exudation at low than at sufficient P, which in turn increased PAE. Under low P availability, efficient genotypes exude a greater quantity of organic compounds into the rhizosphere. This increases P availability to meet the crop requirement, enabling the crop to produce consistent biomass and seed yield with reduced fertiliser addition. Such maintenance of growth and yield potential by mining the inherent soil P is a favourable trait in genotypes, reducing dependence on P fertilisers. Measuring REI at seedling stage to select P-efficient plants accelerates the screening process by accommodating large numbers of genotypes.

Download Full-text

Novel approaches to improving growth of pasture legumes at low phosphorus levels

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.2014.76.2952 ◽

2014 ◽

Vol 76 ◽

pp. 197-202

Author(s):

S.N. Nichols ◽

J.R. Crush

Keyword(s):

White Clover ◽

Root Length ◽

Specific Root Length ◽

Root Traits ◽

Dry Weight ◽

Root Weight ◽

Soil P ◽

P Acquisition ◽

Shoot Dry Weight ◽

Use Efficiency

Abstract Strategies to reduce the economic and environmental costs of phosphate (P) fertiliser use in mixed pastures through plant breeding are focussed on inefficiencies in the legume component. One approach is breeding within white clover for root systems with improved P acquisition properties. Selection for root length per unit root weight (specific root length, SRL) showed that higher SRL plants could retain more biomass in the above ground fraction with decreasing soil P, whereas plants with lower SRL diverted more biomass to roots. Back cross 1 (BC1) generation interspecific hybrids between white clover and a wild relative, Trifolium uniflorum L., may possess additional root traits influencing P acquisition. In glasshouse experiments, some T. repens × T. uniflorum hybrids, back-crossed to white clover, also exhibited higher shoot dry weight than their white clover cultivar parents at low nutrient supply levels and low to intermediate soil Olsen P. This, combined with low internal P concentrations, suggests some BC1 hybrids may be more tolerant of low soil P than white clover. Differences in both P acquisition ability and internal P use efficiency may contribute to the observed yield differences. There are good prospects for delivery of new-generation clover cultivars with improved phosphate use efficiency to New Zealand farmers. Keywords: phosphorus, white clover, Trifolium uniflorum, interspecific

Download Full-text

Trade-Offs in Phosphorus Acquisition Strategies of Five Common Tree Species in a Tropical Forest of Puerto Rico

Frontiers in Forests and Global Change ◽

10.3389/ffgc.2021.698191 ◽

2021 ◽

Vol 4 ◽

Author(s):

Daniela Yaffar ◽

Camille E. Defrenne ◽

Kristine G. Cabugao ◽

Stephanie N. Kivlin ◽

Joanne Childs ◽

...

Keyword(s):

Phosphatase Activity ◽

Tree Species ◽

Fine Root ◽

Root Traits ◽

Root Trait ◽

Soil P ◽

P Acquisition ◽

Trade Offs ◽

Acquisition Strategies ◽

Common Tree

Tree species that are successful in tropical lowlands have different acquisition strategies to overcome soil phosphorus (P) limitations. Some of these strategies belowground include adjustments in fine-root traits, such as morphology, architecture, association with arbuscular mycorrhizal fungi, and phosphatase activity. Trade-offs among P-acquisition strategies are expected because of their respective carbon cost. However, empirical evidence remains scarce which hinders our understanding of soil P-acquisition processes in tropical forests. Here, we measured seven fine-root functional traits related to P acquisition of five common tree species in three sites of the Luquillo Experimental Forest in Puerto Rico. We then described species-specific P-acquisition strategies and explored the changes in fine-root trait expression from 6 months before to 6 months after two consecutive hurricanes, Irma and María, passed over the island. We found that variations in root trait expression were driven mainly by the large interspecific differences across the three selected sites. In addition, we revealed a trade-off between highly colonized fine roots with high phosphatase activity and fine roots that have a high degree of branching. Furthermore, the former strategy was adopted by pioneer species (Spathodea campanulata and Cecropia schreberiana), whereas the latter was adopted by non-pioneer species (mostly Dacryodes excelsa and Prestoea montana). Additionally, we found that root trait expression did not change comparing 6 months before and after the hurricanes, with the exception of root phosphatase activity. Altogether, our results suggest a combination of structural and physiological root traits for soil P acquisition in P-poor tropical soils by common tropical tree species, and show stability on most of the root trait expression after hurricane disturbances.

Download Full-text

The Non-Simultaneous Enhancement of Phosphorus Acquisition and Mobilization Respond to Enhanced Arbuscular Mycorrhization on Maize (Zea mays L.)

Microorganisms ◽

10.3390/microorganisms7120651 ◽

2019 ◽

Vol 7 (12) ◽

pp. 651 ◽

Cited By ~ 1

Author(s):

Junli Hu ◽

Xiangchao Cui ◽

Junhua Wang ◽

Xiangui Lin

Keyword(s):

Zea Mays ◽

Zea Mays L ◽

Plant Biomass ◽

Mycorrhizal Colonization ◽

Shoot Biomass ◽

Growth Stages ◽

Alkaline Soil ◽

Soil P ◽

P Acquisition ◽

P Mobilization

Arbuscular mycorrhizal (AM) fungi can ameliorate not only plant phosphorus (P) nutrition but also soil P mobilization, while P mobilization occurs secondarily and may in turn limit P acquisition at certain crop growth stages. It can be termed as the “mycorrhiza-inducible P limitation”, which has so far largely escaped study. A pot experiment was conducted to test the dynamic P acquisition of maize (Zea mays L.) at the vegetative growth stage and P mobilization in the soil in response to AM fungal inoculation in an unsterilized arable alkaline soil. The experiment included two fertilization levels and two AM inoculation levels, i.e., nitrogen (N), P, and potassium (K) fertilization (NPK) and non-fertilization (control), as well as Funneliformis mosseae inoculation (+M) and non-inoculation (–M). Regardless of fertilization, +M increased mycorrhizal colonization and plant biomass at weeks 4 and 8 but increased tissue P concentration only at week 4 compared with those of –M. In addition, the plant P acquisition and shoot biomass in the control+M treatment at weeks 4 and 8 were close to and much lower than those of NPK–M, respectively. Furthermore, the increase in soil P mobilization potential, which was achieved by the accelerated soil alkaline phosphatase activity and the decreased soil pH, was lower than the increase in root P-acquiring efficiency, which was achieved by the enhanced mycorrhization and ZEAma;Pht1;6 (a mycorrhiza- inducible Pi transporter in maize root) expression. Regardless of fertilization, +M thus significantly decreased soil available P concentrations compared with those in the –M treatments. Therefore, there was a large, real gap between soil P mobilization and root P acquisition in response to enhanced root mycorrhizal colonization, substantially limiting plant P acquisition and growth.

Download Full-text

Does the enhanced P acquisition by maize following legumes in a rotation result from improved soil P availability?

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2007.04.026 ◽

2007 ◽

Vol 39 (10) ◽

pp. 2555-2566 ◽

Cited By ~ 25

Author(s):

Pieter Pypers ◽

Michael Huybrighs ◽

Jan Diels ◽

Robert Abaidoo ◽

Erik Smolders ◽

...

Keyword(s):

P Availability ◽

Soil P ◽

Soil P Availability ◽

P Acquisition

Download Full-text

Changes in soil - plant P under heterogeneous P supply influence C allocation between the shoot and roots

Functional Plant Biology ◽

10.1071/fp08259 ◽

2009 ◽

Vol 36 (9) ◽

pp. 826 ◽

Cited By ~ 2

Author(s):

Qifu Ma ◽

Zed Rengel ◽

Jairo Palta

Keyword(s):

Root System ◽

Triticum Aestivum L ◽

Soil P ◽

P Acquisition ◽

Soil Zone ◽

Growth Difference ◽

Split Root ◽

Split Root System ◽

Lower Ratio ◽

P Supply

Wheat plants (Triticum aestivum L.) were subjected to varying phosphorus (P) supply and canopy 13CO2 feeding to uncouple the plant and soil factors regulating carbon (C) allocation between the shoot and roots and in the P-enriched v. P-deficient soil zone. In a split-root system, transferring from 200/200 µM P (high/high) to high/nil P or nil/nil P for 7 days was associated with 18–30% increase in the ratio of root-to-total 13C, whereas 8–12% more 13C was retained in the shoot of plants grown under continuous high/high P. Although the C signal between the shoot and roots weakened at day 12, it closely correlated with root P acquisition at both days. In a non-split-root system, plants supplied with 200 μm P (high) for 7 and 12 days had a lower ratio of root-to-total 13C than plants with continuous 20 μm P (low). Preferential C allocation and increased P acquisition occurred before any measurable growth difference. Shoot P status had a greater influence than soil P supply on plant C allocation, and rapid C signalling between the shoot and roots might serve as an important component of plant response to heterogeneous P conditions.

Download Full-text

Delivering improved phosphorus acquisition by root systems in pasture and arable crops

Understanding and improving crop root function - Burleigh Dodds Series in Agricultural Science ◽

10.19103/as.2020.0075.26 ◽

2021 ◽

pp. 589-648

Author(s):

Richard J. Simpson ◽

◽

Rebecca E. Haling ◽

Phillip Graham ◽

◽

...

Keyword(s):

Root Systems ◽

P Efficiency ◽

Arable Crops ◽

Soil P ◽

P Acquisition ◽

Pasture Legumes ◽

P Balance ◽

Low Efficiency ◽

Effective Use

Improving low efficiency of phosphorus (P) use in agriculture is an imperative because P is one of the key nutrients underpinning sustainable intensification of food production and the rock-phosphate reserves, from which P fertilisers are made, are finite. This paper describes key soil, root and microbial processes that influence P acquisition with a focus on factors that can be managed to ensure optimal use of fertiliser, and development of root systems for improved P acquisition. A case study describes grasslands in southern Australia where the P-balance efficiency of production is very low, mainly because soils are P deficient and moderately to highly P-sorbing. Use of soluble P fertiliser, P-banding and soil testing to guide soil P management ensures effective use of P fertiliser. Progress towards improved P efficiency using pasture legumes with high P-acquisition efficiency is outlined. Development of a ‘whole-of-system’ understanding for effective P acquisition by roots is highlighted.

Download Full-text