Low Soil Phosphorus Research Articles

Phosphorus Use Efficiency of Leafy Brassica sp. Grown in Three Contrasting Soils: Growth, Enzyme Activity and Phosphorus Fractionation

Plant adaptations to low soil phosphorus (P) availability have been intensively studied in Brassica sp. in an attempt to identify the mechanisms involved in P uptake and utilization. The present pot experiment was conducted to evaluate the relationships between plant shoot and root growth, P uptake and use efficiency parameters, and P fractions and enzyme activity, in two species grown in three soil types. The aim of this study was to determine whether adaptation mechanisms are soil-dependent. Two kale species were grown in soils typical for coastal Croatia (terra rossa, rendzina, and fluvisol) with low P availability. Plants grown in fluvisol had the highest shoot biomass and accumulated most P, whereas plants developed the longest roots in terra rossa. Phosphatase activity differed among soils. P use efficiency differed among soils and species. Genotype IJK 17 showed better adaptation to low P availability, which was related to better uptake efficiency. In general, soils differed in inorganic and organic P fractions in rhizosphere soil, but no difference between genotypes was found. The activities of alkaline phosphatase and phosphodiesterase were negatively correlated with most organic P fractions, suggesting their function in the mineralization of soil organic P. Kale species activate different mechanisms of P uptake and utilization when grown in contrasting soil types, suggesting that specific responses to the soil type were more important than the genotypic difference.

Diallel analysis of soybean (Glycine max L.) for biomass yield and root characteristics under low phosphorus soil conditions in Western Ethiopia.

Combining ability studies under low soil P conditions provides useful information on the inheritance of important traits to improve soybean for low P tolerance. The study aimed at determining the combining ability and gene actions of biomass yield and root traits in soybean under low phosphorus conditions. Nine parental genotypes and their 36 half diallel F2/F3 progenies were evaluated at two locations in Ethiopia on soils of low P availability. Highly significant (P<0.01) general combining ability (GCA) were found for all the traits and specific combining ability (SCA) for root dry weight and root fresh weight; while the SCA effects of all the rest of the traits were significant (P<0.05). The higher relative contributions of GCA over SCA revealed the preponderance of additive gene action in the inheritance of biomass yield, root dry weight, biomass dry weight, root volume, and root fresh weight with respective relative GCA:SCA contributions of (60.6, 39.4), (50.4, 49.6), (54.9, 45.1), (51.1, 48.9), and (52.1, 47.9); while the narrow-sense heritability was high (34.3%) only for biomass yield. Hardee-1 displayed significant (P<0.05) and positive GCA effects for most of the studied traits, and several crosses involving this parent showed superior performances. The traits i.e., biomass yield, biomass dry weight, root volume and root fresh weight showed highly (P<0.001) correlation with grain yield. Thus, breeding programs aiming to improve soybean for biomass yield and root traits under low-P condition can use Hardee-1 as a parent.

Responses of rubber tree seedlings (Hevea brasiliensis) to phosphorus deficient soils

ABSTRACT While the adaptation and responses of model plants to phosphorus (P) deficiency are well documented, those of the rubber tree remain unclear. Here, we investigated above‐ and below‐ground responses of rubber tree seedlings over the development of the first to third extension unit in a mesocosm system. Rubber tree seedlings were grown in high and low phosphorus soil for 7 months. Tissue nutrient contents, morphological, and physiological traits were quantified. We found that low P significantly reduced leaf P content, photosynthetic capabilities, and induced the accumulation of phenolic and flavonoid compounds, particularly in old leaves. Root traits were significantly affected by P stress early in their development. Root surface area and volume were increased through reduced lateral root branching and increased lateral root length. The alteration of root architectural traits took place prior to the reduction of P content in roots and leaves. Our findings provide new insights into rubber tree physiology and the effective fertilization management of rubber plantation in low P soils.

Global transcriptomic analysis reveals candidate genes associated with different phosphorus acquisition strategies among soybean varieties.

Soybean adapts to phosphorus-deficient soils through three important phosphorus acquisition strategies, namely altered root conformation, exudation of carboxylic acids, and symbiosis with clumping mycorrhizal fungi. However, the trade-offs and regulatory mechanisms of these three phosphorus acquisition strategies in soybean have not been researched. In this study, we investigated the responses of ten different soybean varieties to low soil phosphorus availability by determining biomass, phosphorus accumulation, root morphology, exudation, and mycorrhizal colonization rate. Furthermore, the molecular regulatory mechanisms underlying root phosphorus acquisition strategies were examined among varieties with different low-phosphorus tolerance using transcriptome sequencing and weighted gene co-expression network analysis. The results showed that two types of phosphorus acquisition strategies-"outsourcing" and "do-it-yourself"-were employed by soybean varieties under low phosphorus availability. The "do-it-yourself" varieties, represented by QD11, Zh30, and Sd, obtained sufficient phosphorus by increasing their root surface area and secreting carboxylic acids. In contrast, the "outsourcing" varieties, represented by Zh301, Zh13, and Hc6, used increased symbiosis with mycorrhizae to obtain phosphorus owing to their large root diameters. Transcriptome analysis showed that the direction of acetyl-CoA metabolism could be the dividing line between the two strategies of soybean selection. ERF1 and WRKY1 may be involved in the regulation of phosphorus acquisition strategies for soybeans grown under low P environments. These findings will enhance our understanding of phosphorus acquisition strategies in soybeans. In addition, they will facilitate the development of breeding strategies that are more flexible to accommodate a variety of production scenarios in agriculture under low phosphorus environments.

Phosphorus limitation of early growth differs between nitrogen-fixing and nonfixing dry tropical forest tree species.

Tropical forests are often characterized by low soil phosphorus (P) availability, suggesting that P limits plant performance. However, how seedlings from different functional types respond to soil P availability is poorly known but important for understanding and modeling forest dynamics under changing environmental conditions. We grew four nitrogen (N)-fixing Fabaceae and seven diverse non-N-fixing tropical dry forest tree species in a shade house under three P fertilization treatments and evaluated carbon (C) allocation responses, P demand, P-use, investment in P acquisition traits, and correlations among P acquisition traits. Nitrogen fixers grew larger with increasing P addition in contrast to non-N fixers, which showed fewer responses in C allocation and P use. Foliar P increased with P addition for both functional types, while P acquisition strategies did not vary among treatments but differed between functional types, with N fixers showing higher root phosphatase activity (RPA) than nonfixers. Growth responses suggest that N fixers are limited by P, but nonfixers may be limited by other resources. However, regardless of limitation, P acquisition traits such as mycorrhizal colonization and RPA were nonplastic across a steep P gradient. Differential limitation among plant functional types has implications for forest succession and earth system models.

No-till improves selected soil properties, phosphorous availability and utilization efficiency, and soybean yield on some smallholder farms in South Africa

Some of the limiting factors for smallholder farmer soybean production in South Africa are low native soil phosphorus (P) availability and poor utilization efficiency of added P. Phosphorus fertilization, use of improved or high yield potential cultivars and appropriate cropping systems could increase soybean yields. The objective of this study was to determine the effects of tillage, cultivar and P fertilization levels on P uptake and P use efficiency, as well as plant growth, yield, grain protein and oil content, in a soybean based cropping system. The study was conducted under dryland conditions at Sheepmoor, Mpumalanga. A field experiment was established in a randomized complete block design. Treatments were arranged in a 2 × 3 × 3 strip-split-plot structure. There were two tillage systems [no-till (NT) and conventional tillage (CT)], three cultivars (PAN 1614R, PAN 1521R, and PAN 1532R), and three phosphorus rates (0, 30, and 60 kg/ha). All treatment combinations were replicated three times. P uptake improved with P application, although there were no differences between 30 and 60 kg/ha whilst PFP was significantly higher at 30 kg/ha P. Yield was significantly higher at 30 kg/ha P application under NT and varied with cultivars. P application at 30 and 60 kg/ha significantly reduced oil content by 11.3 and 7.16%, respectively, but had inverse effects on protein content. The activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) also increased with P application. Improvement of soybean yield and its attributes, grain quality, P uptake, PFP, soil physicochemical and microbial properties emphasize the importance of fertilizer application, sustainable cropping systems coupled with careful cultivar selection. Therefore, in order to improve soil fertility and soybean yield under small farm conditions, the application of no-till and optimum application of fertilizers should be prioritized.

Towards Sustainable Maize Production: Understanding the Morpho-Physiological, Genetics, and Molecular Mechanisms for Tolerance to Low Soil Nitrogen, Phosphorus, and Potassium

Maize is one of the globally most important cereal crops used for food, feed and fuel. It requires optimum soil nutrients such as Nitrogen (N), Phosphorus (P), and Potassium (K) for proper growth and development as well as for tolerance to biotic and other abiotic stresses. Yield potentials are not met under suboptimal soil fertility. One of the innovations that can reduce environmental impacts of continuous fertilization and lower the cost of maize production under low soil nutrient conditions is the development and use of tolerant cultivars. This paper provides spotlights on the following: (1) morphology and physiology of root and shoot systems; (2) genetics and genomics; and (3) transcriptome, proteome, and metabolome profiles, to elucidate maize tolerance to low amounts of soil nutrients, N, P, and K. Maize cultivars having deeper rooting structure, more lateral roots, dense roots, and high root exudates are more tolerant to N, P, and K limited conditions. Cultivars that are tolerant to N, P, and K stress (low) have high nutrient use efficiency, good photosynthetic and translocation activity that support high aboveground shoot weight under suboptimal N, P, and K conditions. Maize tolerance to N, P, and K stress (low) is quantitative, and mainly controlled by additive genes. Maize cultivar development and dissemination programs can exploit the mechanisms highlighted in this review.

Ionomic and metabolic responses of wheat seedlings to PEG-6000-simulated drought stress under two phosphorus levels.

BackgroundWheat (Triticum aestivum L.) is a major food crop worldwide. Low soil phosphorus content and drought are the main constraints on wheat production in Xinjiang, China.MethodsIn this study, the ionic and metabolic responses of one wheat variety (“Xindong20”) to drought stress simulated by using polyethylene glycol 6000 (PEG-6000) were investigated under low phosphorus (LP) and conventional phosphorus (CP) conditions by analysing wheat mineral elements and metabolites. Besides, due to xanthohumol was the metabolite with the most significant difference in expression detected in “Xindong 20”, two wheat variety “Xindong20 and Xindong 23” were selected to conduct the germination test simultaneously, to further verify the function of xanthohumol in wheat growth. Xanthohumol was mixed with PEG solution (20%) to prepare PEG solutions with different concentrations (0%, 0.1%, 0.5%, and 1%) of xanthohumol. Then wheat grains were soaked in the solutions for 20 hours, followed by a germination test. After 7 days, the indicators including shoot length, max root length, and root number were determined to identify whether the metabolite was beneficial to improve the drought tolerance of wheat.ResultsThe results showed that the root density and volume of wheat in LP treatment were higher than those in CP treatment. The roots underwent programmed cell death both in LP and CP treatments under PEG-6000-simulated drought stress, however, the DNA degradation in root cells in LP treatment was lower than that in CP treatment after rehydration for 3 d. Before drought stress, the malondialdehyde (MDA) content in shoot and the peroxidase (POD) activity in root in LP treatment were significantly higher than those in CP treatment, while the soluble sugar content and chlorophyll content in LP treatment were significantly lower than those in CP treatment. During drought stress, the POD activity maintained at a high level and the soluble sugar content gradually increased in LP treatment. After rehydration, the MDA content still maintained at a high level in LP treatment, the superoxide dismutase (SOD) activity increased, and the contents of soluble sugar and chlorophyll were significantly higher than those in CP treatment. The analysis of mineral elements and metabolites showed that the wheat in CP treatment was more sensitive to drought stress than that in LP treatment. Besides, the effect of drought stress was greater on shoot than on root in CP treatment, while it was opposite in LP treatment. The effect of drought stress on sugar metabolism gradually increased. Germination assays showed that 0.1% exogenous xanthohumol addition could significantly increase the shoot length of the two wheat varieties under drought stress.ConclusionAppropriate low phosphorus supply could increase antioxidant enzyme activity in wheat, and enhance sugar metabolism to regulate osmotic balance, as well as the accumulation of various organic acids to maintain the intracellular ion homeostasis. Therefore, compared to the conventional phosphorus supply level, appropriate low phosphorus supply can significantly improve the drought tolerance of wheat. Additionally, addition of 0.1% exogenous xanthohumol, an important differential expressed metabolite in drought-stressed wheat, could effectively promote wheat shoot growth under drought stress.

Intercropping legumes and cereals increases resource use efficiency and crop productivity in low phosphorus soils under semi-arid Mediterranean conditions

ABSTRACT Intercropping ensures multiple benefits like enhancement of yield, environmental security, production sustainability, and greater ecosystem services. In order to better understand how mixed crop cultures mitigate stressful conditions, this study aims to highlight the beneficial effect of the intercropping legume–cereal in enhancing nutrient uptake for plant growth and productivity in low phosphorus (P) soils. To address this question, faba bean (Vicia faba L. cv. Sidi Aich) and barley (Hordeum vulgare L. cv. Rihane 3) were grown as sole- and inter-crops over two growing seasons in 2017 and 2018 in a northern Algerian agro-ecosystem with a semiarid Mediterranean climate. The results showed that the plant growth and nodulation were significantly increased by 18% and 32%, respectively, for intercropping than for sole cropping and so more in 2018 compared to 2017. Moreover, grain yield and resource use efficiency (N and P) were significantly improved, as indicated by higher land equivalent ratio (LER > 1) in intercropping over sole cropping treatments. Also, the P and N concentrations measured in the rhizosphere were increased compared to bulk soil and even more so in the rhizosphere of intercropped species over two seasons. Our findings suggest that intercropping cereals with legumes may achieve high crop productivity and land use efficiency at reduced input levels.

Heat Stress Tolerance: A Prerequisite for the Selection of Drought- and Low Phosphorus-Tolerant Common Beans for Equatorial Tropical Regions Such as Ghana

Forty common bean accessions of multiple genetic background trait attribution regarding drought tolerance were selected based on mean yield performance from an earlier field test evaluation conducted using augmented RCBD. The various bean genotypes were further evaluated with phosphorus and water treatment interactions at two different levels for each factor. The experiment was conducted in a 2 × 2 × 40 factorial using RCBD with three replications under screen-house conditions at the CSIR-Crops Research Institute, Kumasi-Ghana. The objective was to select drought- and low phosphorus-tolerant common bean genotypes; which are suitable for tropical climatic conditions. The results showed that common bean with drought and heat trait tolerance survived, developed flowers and podded with seeds to physiological maturity, whilst genotypes with no heat trait tolerance had impaired reproductive structural development and growth disruption; thus, flowers could not develop into pods with seeds. This reproductive developmental anomaly was due to prevailing average daytime and nighttime high temperatures of 35.45 °C and 29.95 °C, respectively, recorded during the growth period, which reduced pollen fertility. Among the 478 experimental bean plants (two plants were missing) analyzed, 141 (29.5%) did not flower, 168 (35.18%) had their pods dropped whilst 99 (20.7%) podded with seeds to achieve physiological maturity. The podded-seed bean genotypes were of the SEF-line pedigrees, which were shown to be heat and drought-tolerant. Meanwhile, bean accessions with SMC, SMN and SMR code prefixes did not pod into seed despite possessing drought-tolerant traits. The effects of interactions between phosphorus and water treatments on the root characteristics of drought-tolerant common bean were as follows: root length, root surface area, average root diameter and root volume growth extensions doubled dimensionally under optimum conditions (P2W2) compared to stressed conditions (P1W1). The results from the present study identified four SEF-bean genotypes, namely, SEF15, SEF 47, SEF 60 and SEF 62, as superior yield performers, even under low soil phosphorus and in extreme high temperature conditions. Therefore, breeding for the selection of drought- and low-P-tolerant common bean for tropical agro-ecological environments must also consider concomitant heat stress tolerance.

Aluminum phosphate sludge as a phosphorus source for maize production under low soil phosphorus availability.

BackgroundWith increasing food demand as a consequence of the growing world population, there is a corresponding demand for additional sources of phosphorus (P). Alum-phosphate (Al-P) sludge is a by-product of wastewater treatment and can be a good source of P. In this study, the response of maize (Zea mays L.) to Al-P sludge was tested. Maize was chosen as the test crop due to its prevalent use as human and animal food and as a source of biofuel. The objective of the study was to investigate Al-P sludge as a source of P compared to a commercial fertilizer (monoammonium phosphate, MAP).MethodsA growth chamber assay was conducted over four cropping cycles (45 d each). The application rate was 9.7, 19.4, 29.1 and 38.8 mg P kg−1 dry soil. Amendments were applied once at the start of the first cropping cycle. Plants were harvested after each cycle and pots were re-seeded. Dry matter yield (DMY), total P uptake, Al-P uptake, soil total P and Olsen-P concentrations, pH, and EC were measured.ResultsDMY was significantly greater in pots amended with Al-P sludge than in pots treated with MAP. There was a significant rate × cropping cycle interaction effect on DMY with the differences among rates in cycle 1 different from those in cycle 4. Phosphorus uptake depended on cropping cycle, P source and P application rate. With sludge uptake higher than MAP in all cycles, the highest P uptake was observed at the highest application rate except for cycle 2 where this was observed at the rate of 29.1 mg kg−1. For MAP, phosphorus recovery efficiency (PRE) at the highest rate was significantly greater than that at the lowest rate whereas PRE in cycle 1 was significantly higher than that in cycle 4. In the first two cycles, aluminum uptake was negligible in both MAP and Al-P sludge treatments; however, in cycles 3 and 4, there was significantly more Al in maize from sludge amended pots. Our results show that Al-P sludge was as effective as MAP in supplying enough P for biomass yield. We, therefore, conclude that Al-P sludge could be an alternative source of P, especially for growing maize as feedstock for bioenergy.

How do tropical tree species maintain high growth rates on low-phosphorus soils?

How do tropical tree species maintain high growth rates on low-phosphorus soils?

Direct evidence for phosphorus limitation on Amazon forest productivity.

The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change.

Foliar phosphorus allocation and photosynthesis reveal plants' adaptative strategies to phosphorus limitation in tropical forests at different successional stages

High atmospheric nitrogen (N) deposition and low soil phosphorus (P) availability occur simultaneously in tropical areas, and thus tropical plants need to adapt nutrient-use strategies to maintain growth and survival. Therefore, identifying the adaptative strategies of tropical plants at different successional stages under low soil P availability is indispensable. Here, we separately investigated foliar traits, photosynthetic characteristics, and P fractions of 8 species in the primary and secondary tropical forests after 10 years of N and P fertilization. P addition increased foliar P concentrations and deceased N:P ratio in the primary forest and secondary forest. The foliar photosynthetic rates did not significantly respond to nutrient additions, and the foliar photosynthetic P-use efficiency (PPUE) reduced under the P addition in the primary forest. In contrast, the foliar photosynthetic rates and photosynthetic nitrogen (N)-use efficiency (PNUE) were enhanced with nutrient additions in the secondary forest. The allocations of foliar nucleic acid P and residual P were reduced by P addition in the primary forest, whereas the allocation of metabolic P was enhanced and the allocation of residual P was reduced by P addition in the secondary forest. Additionally, a higher proportion of structural P was found in the primary forest, and a higher proportion of metabolic P was observed in the secondary forest. Interesting, structural equation model analysis revealed that the plants decreased the allocation of foliar nucleic acid P and increased the allocation of structural P in the primary forest, thereby reducing photosynthetic rates. Whereas the plants enhanced photosynthetic rates by promoting PPUE and the allocation of foliar metabolic P in the secondary forest.Our findings highlighted tropical plants at different successional stages can reasonably allocate foliar P to regulate photosynthetic rates and acclimate to low P environments.

Effects of Phosphorus Fertilizer on Agronomic, Grain Yield and Other Physiological Traits of Some Selected Legume Crops

Phosphorous is another nutrient that is critically important for legumes and the clover plants that are fixing nitrogen, but all plants need phosphorous as they do nitrogen. Legumes need a higher level of P fertility than the neighbouring grass plants. Phosphorus is vital for plant growth, and is a component of the nucleic acid structure of plants and bio-membranes. Therefore, it is important in cell division and tissue development. It is also involved in the energy metabolism of cells and is required for the biosynthesis of primary and secondary metabolites in plants. Legume crops requires less nitrogen but application of phosphorus and potassium plays a vital role in getting high yield per unit area. The application of phosphorus increases dry matter at harvest, number of pods plant -1 , seeds pod -1 , 1000 grain weight, seed yield and total biomass of mung bean. The experimental results of different authors stated that the highest number of pod plant -1 and grain yield of soyabean were obtained from maximum level of phosphorus as compared to other treatments. common bean crop dependent on nitrogen fixation needs more inorganic phosphorus than the same crop provided with mineral nitrogen. Common beans are therefore especially susceptible to low soil phosphorus when accompanied by low soil. Phosphorus also plays an important role in biological nitrogen fixation, for the symbiotic fixation of nitrogen to occur, the roots have to interact with compatible rhizobia in the soil and factors that affect root growth or the activity of the host plant would affect nodulation. however, the rate of phosphorus is varied from place to place, or it’s governed by the amount of P status in the soil. Since, legume crops demanding more P than other nutrient, we have to apply it obtained best grain yield. Keywords: Bacteria, Dry matter, Grain yield, Legume and Nodule DOI: 10.7176/JBAH/12-12-01 Publication date: June 30 th 2022

Linking soil phosphorus with forest litterfall resistance and resilience to cyclone disturbance: A pantropical meta-analysis.

While tropical cyclone regimes are shifting with climate change, the mechanisms underpinning the resistance (ability to withstand disturbance-induced change) and resilience (capacity to return to pre-disturbance reference) of tropical forest litterfall to cyclones remain largely unexplored pantropically. Single-site studies in Australia and Hawaii suggest that litterfall on low-phosphorus (P) soils is more resistant and less resilient to cyclones. We conducted a meta-analysis to investigate the pantropical importance of total soil P in mediating forest litterfall resistance and resilience to 22 tropical cyclones. We evaluated cyclone-induced and post-cyclone litterfall mass (g/m2 /day), and P and nitrogen (N) fluxes (mg/m2 /day) and concentrations (mg/g), all indicators of ecosystem function and essential for nutrient cycling. Across 73 case studies in Australia, Guadeloupe, Hawaii, Mexico, Puerto Rico, and Taiwan, total litterfall mass flux increased from ~2.5 ± 0.3 to 22.5 ± 3 g/m2 /day due to cyclones, with large variation among studies. Litterfall P and N fluxes post-cyclone represented ~5% and 10% of the average annual fluxes, respectively. Post-cyclone leaf litterfall N and P concentrations were 21.6 ± 1.2% and 58.6 ± 2.3% higher than pre-cyclone means. Mixed-effects models determined that soil P negatively moderated the pantropical litterfall resistance to cyclones, with a 100 mg P/kg increase in soil P corresponding to a 32% to 38% decrease in resistance. Based on 33% of the resistance case studies, total litterfall mass flux reached pre-disturbance levels within one-year post-disturbance. A GAMM indicated that soil P, gale wind duration and time post-cyclone jointly moderate the short-term resilience of total litterfall, with the nature of the relationship between resilience and soil P contingent on time and wind duration. Across pantropical forests observed to date, our results indicate that litterfall resistance and resilience in the face of intensifying cyclones will be partially determined by total soil P.

Phosphate fertilization in ‘sabiá’ (Mimosa caesalpiniifolia Benth.) implantation in crop-forest system in semiarid region

The use of fertilizers can increase the production of Forest species, which can be used for the extraction of wood in monocultures or in agroforestry systems. Thus, the objective was to evaluate the application of phosphorus doses in the implantation of Mimosa caesalpiniaefolia in a degraded area. The experimental design was a randomized complete block design with four blocks, with treatments at the following doses: 0, 12.5, 25.0, 50.0 and 100.0 g plant-1 of P2O5 (source: triple superphosphate), whose quantities used were folded the following year and applied in the projection of the crown. The variables measured were biometric attributes (height, stem diameter in base and in breast height), biomass, nutrient accumulation (whole plant) and soil fertility. There was an increase in height and diameter of the plant, biomass, accumulation of phosphorus in the plant and increase of phosphorus concentrations in the soil. The application of 29 g of P2O5 in the pit and after implantation, it is recommended to apply 47 g of P2O5 per plant in the projection of saplings seedlings in low phosphorus soils, after first year.

Effects of mycorrhizae, plants, and soils on phosphorus leaching and plant uptake: Lessons learned from a mesocosm study

Societal Impact StatementWorldwide, farmers struggle to find the most efficacious practices which balance crop fertility needs and water quality protection. Through a greenhouse experiment, we investigated how soil status (high vs. low phosphorus [P] concentration), mycorrhizae (inoculated vs. not), and plant species (dogwood vs. willow) affected P plant uptake and leaching. We found mycorrhizae did not affect uptake or leaching, more P was leached from high than low P soil, dogwood uptook yet leached more P, and above ground biomass at the end of summer contained more P than roots. This study provides insights to be considered by researchers and practitioners who implement best management practices for water quality.Summary This research examined the effects of mycorrhizal inoculation in high and low phosphorus saturation soils on phosphorus uptake by Cornus sericea and Salix niger. The aim was to identify practices that improved water quality functions of riparian buffers to protect surface waters impacted by eutrophication. A mesocosm experiment arranged as a random block design was conducted with mycorrhizal presence, soil phosphorus saturation status, and plant species as factors. Leachate, plant uptake, and soil phosphorus were measured to assess the effects. Greater leachate and uptake of phosphorus were detected for C. sericea than for S. niger. Mycorrhizae had no effects on leaching nor on uptake of phosphorus in this experiment. High phosphorus saturated soils had greater leaching and uptake than the low phosphorus soils. Above ground biomass contained more phosphorus than below ground biomass in both species at time of harvest. Estimations of phosphorus removal through coppicing suggest a very slow removal rate in biodiverse multi‐functional riparian buffers. Our results suggest that cyclical coppicing can be an improvement to Best Management Practices. Diverse riparian buffers are limited in the amount of phosphorus that they can store and mitigate, even with coppicing. The emphasis therefore should be on agricultural best management practices that reduce phosphorus export from upland fields. Further studies in phosphorus accumulating plant species with appropriate mycorrhizal symbionts are needed.

Remarkable effects of microbial factors on soil phosphorus bioavailability: A country-scale study.

Low soil phosphorus (P) bioavailability causes the widespread occurrence of P-limited terrestrial ecosystems around the globe. Exploring the factors influencing soil P bioavailability at large spatial scales is critical for managing these ecosystems. However, previous studies have mostly focused on abiotic factors. In this study, we explored the effects of microbial factors on soil P bioavailability of terrestrial ecosystems using a country-scale sampling effort. Our results showed that soil microbial biomass carbon (MBC) and acid phosphatase were important predictors of soil P bioavailability of agro- and natural ecosystems across China although they appeared less important than total soil P. The two microbial factors had a positive effect on soil P bioavailability of both ecosystem types and were able to mediate the effects of several abiotic factors (e.g., mean annual temperature). Meanwhile, we revealed that soil phytase could affect soil P bioavailability at the country scale via ways similar to those of soil MBC and acid phosphatase, a pattern being more pronounced in agroecosystems than in natural ecosystems. Moreover, we obtained evidence for the positive effects of microbial genes encoding these enzymes on soil P bioavailability at the country scale although their effect sizes varied between the two ecosystem types. Taken together, this study demonstrated the remarkable effects of microbial factors on soil P bioavailability at a large spatial scale, highlighting the importance to consider microbial factors in managing the widespread P-limited terrestrial ecosystems.

Antagonistic effect of copper and zinc in fertilization of spring wheat under low soil phosphorus conditions

Sound micronutrient management requires an understanding of nutrient interactions and transformation processes in soil–plant systems which can regulate bioavailability and plant uptake. A series of studies were conducted under controlled environment and field conditions to evaluate wheat response to Cu and Zn fertilization on P-deficient soils from western Canada. The grain and straw yields of wheat were reduced in two (Waskada and Tisdale) of three soils used in the controlled environment study, while yield was not affected at the Echo field site in 2016 when both Cu and Zn sulfate fertilizer were applied at 5 kg·ha–1 rates. Zinc concentration in soil and plant tissues was increased to apparent toxic levels with fertilizer addition in Waskada soils. An imbalance in tissue P:Zn concentration related to micronutrient fertilization was observed in Waskada and Tisdale soils. The availability of Cu and Zn in post-harvest soils was increased with increasing rate of these fertilizers' addition. Chemical and spectroscopic speciation using sequential extraction and X-ray absorption near edge structure, respectively, revealed that Cu and Zn were mostly speciated as carbonate phases, and complexation of these elements with carbonate and phyllosilicate minerals is likely the process controlling bioavailability in the soils.