Ecoenzymatic stoichiometry reveals phosphorus addition alleviates microbial nutrient limitation and promotes soil carbon sequestration in agricultural ecosystems

Purpose

Variation in soil microbial metabolism remains highly uncertain in predicting soil carbon (C) sequestration, and is particularly and poorly understood in agroecosystem with high soil phosphorus (P) variability.

Materials and methods

This study quantified metabolic limitation of microbes and their association with carbon use efficiency (CUE) via extracellular enzymatic stoichiometry and biogeochemical equilibrium models in field experiment employing five inorganic P gradients (0, 75, 150, 225, and 300 kg P ha^?1) in farmland used to grow peas.

Results and discussion

Results showed P fertilization significantly increased soil Olsen-P and NO₃^?-N contents, and enzyme activities (β-1,4-glucosidase and β-D-cellobiosidase) were significantly affected by P fertilization. It indicated that P fertilization significantly decreased microbial P limitation due to the increase of soil available P. Interestingly, P application also significantly decreased microbial nitrogen (N) limitation, a phenomenon primarily attributable to increasing NO₃^?-N content via increasing biological N fixation within the pea field. Furthermore, P fertilization increased microbial CUE because the reduction in microbial N and P limitation leads to higher C allocation to microbial growth. Partial least squares path modeling (PLS-PM) further revealed that the reduction of microbial metabolic limitation is conducive to soil C sequestration.

Conclusions

Our study revealed that P application in agroecosystem can alleviate not only microbial P limitation but also N limitation, which further reduces soil C loss via increasing microbial CUE. This study provides important insight into better understanding the mechanisms whereby fertilization mediates soil C cycling driven by microbial metabolism in agricultural ecosystems.

     

Spatial variability of chemical attributes of the soil,plant and yield in a pear orchard

For fruiting trees, fertilization is usually recommended based on the analyses of soil and leaves, adopting a standard value for the whole orchard. This management can lead to undesirable imbalances to the plants and local agroecosystem. Thus, this trial aimed at mapping the spatial variability of properties of soil, plant and yield in a commercial area of pears production and investigating the yield response to a distinguished fertilization. The trial was carried out in Nova Laranjeiras, Paraná, where 36 trees were selected to receive conventional fertilization (CF) and other 36 trees received a site-specific fertilization (SSF). All variables (chemical and physical attributes of soil, leaf tissue, and yield) showed some spatial dependence. For all years, yield variability was considered very high. The yield of SSF system was slightly higher (2,625 kg ha^?1) and took up a larger area (59%) when compared to SF system (2,548 kg ha^?1 at 41% area).     

Effect of Soil Fertilizer,Foliar Fertilizer,and Growth Regulator Application on Milk Thistle Development,Seed Yield,and Silymarin Content

Abstract

An important consideration for milk thistle (Silybum marianum L.) cultivation is regulating development to lengthen the reproductive stage and increase seed yield with high silymarin content. The treatment of milk thistle with foliar fertilizers and growth regulators—thidiazuron (Dropp^®), 2,3,5‐triiodobenzoic acid (Tiba^®), mepiquat chloride (Pix^®), and prohexadione‐Ca (Regalis^®)—resulted in an increase in the proportion of mature flower heads. Highest seed yield was observed in plants treated with Pix^® and mineral soil fertilization, whereas in plants treated with foliar fertilizers, highest yields were observed with Pix^® and Regalis^®. The highest content of silymarin was found in plants treated with Dropp^® and foliar fertilizer. Generally, treatment of milk thistle with plant‐growth regulators in combination with soil or foliar mineral fertilizers increased the total amount of silymarin by increasing seed yield per hectare.     

Effect of seed size and phosphorus fertilization on growth of selected legumes

Abstract

A screenhouse experiment was conducted to assess the effects of seed size and phosphorus (P) fertilization on growth of 12 herbaceous and shrub legumes [Arachis hypogaea, Cajanus cajan, Centrosema pascuorum, Centrosema brasilianum, Crotolaria ochroleuca, Glycine max, Lablab purpureus, Mucuna cochinchinensis, Mucuna pruriens var. utilis (black seed), Mucunapruriens (white seed), Pueraria phaseoloides and Vigna unguiculata] grown on a P‐deficient Plinthustalf. Species with large seed size showed higher biomass accumulation, nodulation and higher plant nutrient element content. However, response to P fertilization was higher in small size seeded species. Plant top dry weight was highly correlated with seed weight and seed nutrient element contents. Although P application significantly increased nitrogen (N), P, potassium (K), calcium (Ca), and magnesium (Mg) contents of plant tops, high rate of P fertilization appeared not to be beneficial to the early growth of the species tested on this P‐deficient soil. The use of large seed size with high seed nutrient element contents is highly recommended for fast establish ment of fallow legume species intended for use in production systems on P‐deficient soils.     

Influence of phosphorus application on yield,yield components,and quality of linseed

Abstract

Soil fertility depletion coupled with improper fertilization is one of the major constraints limiting linseed production in Ethiopia. Experiment was conducted in 2014/2015 on Nitisol in southeastern Ethiopian highlands to study the effect of phosphorus (P) fertilizer rate on yield, yield components, and oil content of linseed. It comprised of six levels of P fertilizer (0, 5, 10, 15, 20, and 25?kg?P?ha^?1) arranged in randomized complete block design with three replications. Results revealed that P fertilization brought significant effect on biomass yield, harvest index, plant height, number of capsules per plant, and kernel size. However, it didn’t significantly increase seed yield and oil content on linseed. Considering its influence on increasing biomass yield and improving yield components, application of 5?kg?P?ha^?1 has been recommended for replenishing the extracted P, maintaining soil fertility and improving linseed production on Nitisols of southeastern Ethiopian highlands and other similar agro-ecologies.     

Effect of seed phosphorus concentration on nodulation and growth of three common bean cultivars

Abstract

An experiment was conducted in the greenhouse to evaluate the effects of seed phosphorus (P) concentration on growth, nodulation, and nitrogen (N) and P accumulation of three common bean (Phaseolus vulgaris L.) cultivars. Seeds were produced under low or high soil P levels, and soaked, or not, in 200 mM KH₂PO₄ solution. The experiment had a 3×3×2×2 factorial block design: three cultivars (ICA Col 10103, Carioca and Honduras 35), three levels of applied P (15, 30 and 45 mg P kg^?1 soil), two native seed P concentrations, and two seed soaking treatments. Plants were harvested at flowering. Soaked seeds increased the number, dry mass and P content of nodules, but did not affect plant growth. Plants originated from seeds with high native P concentration presented higher shoot dry mass and nodule number and mass at every soil P level, and were less responsive to increased soil P supply, than plants from low seed P. In plants from seeds with high P, soil P levels did not alter significantly root dry mass, while in plants from seeds with low P bean cultivars expressed wider differences in root dry mass. The genotypic variability of nodulation was influenced by soil P levels and seed P concentration. Both higher soil or seed P supply enhanced N and P accumulation in shoots. These results indicate that a high seed P concentration produces plants less dependent on soil P supply, and can enhance nodulation and N₂ fixation of common bean. Seed P supply affected the cultivar performance, and should be considered in evaluation of bean genotypes.     

Fertilizer combinations benefit diameter growth of plantation black walnut

The diameter at breast height (dbh) growth of black walnut (Juglans nigra L.) trees in an 18‐year‐old plantation was measured over 4 years to determine the effect of nitrogen (N) and potassium (K) fertilization separately, in combination, and with and without phosphorus (P), broadcast annually at two rates. Trees in treatments containing N had significantly better dbh growth than trees in other treatments. However, doubling the application rate of 310 kg ha^‐1 of N and P and 490 kg ha^‐1 of K had no significant effect on dbh growth. There was a positive significant correlation for leaf N and dbh growth. The significant negative correlation between leaf P and dbh growth suggests that soil P concentrations may be less than the amount needed for accelerated dbh growth.     

Effect of seed phosphorus and soil phosphorus applications on early growth of rice (Oryza sativa L.) cv. IR66

Abstract

The vigour and size of rice seedlings in the nursery are generally correlated with final grain yield. The present study examined the possibility that increasing seed phosphorus (P) concentration would stimulate early growth of rice seedlings and therefore would have the potential to increase rice yield. Rice seeds with a uniform size and three levels of P concentration (0.115, 0.173, and 0.240% on a dry weight basis) were sown in pots on a P deficient soil with three levels of P supply (0, 7.75, and 38.8 mg P kg^?1 soil) to investigate their effect on root and shoot dry weight and P accumulation at three harvest times, 10, 20, and 30 d after sowing (DAS). The effect of seed P concentration on plant growth was greatest at a low soil P concentration and it was less pronounced with increasing soil P concentration and with time at all levels of soil P. At 10 DAS, shoot dry weight was 15% higher at a high seed P concentration (0.240%) (p < O.O1) than at a low seed P concentration (0.115%) at each level of soil P supply whereas at subsequent harvests (20 and 30 DAS) the effect of seed P concentration was observed only when the soil P supply was deficient. In contrast with its effects on shoot dry weight, high seed P concentration increased root dry weight only at the latest harvest (30 DAS). The fact that high seed P increased P concentrations in shoot tips, and in roots at 10 DAS suggests that improved P nutrition of seedlings in the first 10 DAS may be the mechanism by which high seed P concentration stimulates early growth, especially in soils with low P concentration. Sowing rice seed with high P concentration may be beneficial for increasing farmer's rice yields, in P deficient soil, and requires further field investigations.     

Interaction Between Phosphorus Nutrition and Drought on Grain Yield,and Assimilation of Phosphorus and Nitrogen in Two Soybean Cultivars Differing in Protein Concentration in Grains

ABSTRACT

Drought affects many physiological and biochemical processes and thus reduces plant growth. Phosphorus (P) fertilization improves tolerance to drought stress in many plants. A greenhouse experiment examined the interactive effects of P nutrition and drought stress on P accumulation and translocation, yield, and protein concentration in grains of two cultivars of soybean [Glycine max (L.) Merr.]. Plants of cultivars ‘Heisheng 101’ (high protein in grains) and ‘Dongnong 464’ (low protein) were grown in a P-deficient soil supplied with 0–30 mg P kg^?1 soil. Drought stress was imposed at the initial flowering (R1) or the podding (R4) stage. Drought stress limited P accumulation and reduced P translocation to the seed. The addition of P enhanced the concentration and accumulation of nitrogen (N) and P in shoots and seeds of both cultivars. Drought stress decreased shoot biomass, grain yield, and P accumulation; the decrease was greater in ‘Dongnong 46’ than ‘Heisheng 101,’ and even more so if drought stress was imposed at R4 than at R1. In contrast, drought stress increased the concentration of N in shoot and protein in grains. The addition of P alleviated the effect of drought stress on plant growth, P accumulation, and grain yield in both cultivars but to a greater extent in ‘Dongnong 46’. The results suggest that application of P fertilizers could mitigate drought stress at the reproductive stage, resulting in less yield penalty and improvement of grain quality of soybean grown in P-deficient soils.     

Response of Mature Phosphorus-Deficient Apple Trees to Phosphorus Fertilization and Liming

ABSTRACT

The aim of the study was to examine response of mature phosphorus (P) deficient apple (Malus domestica Borkh.) trees to phosphorus fertilization and liming. The experiment was carried out during 2003–2005 in a commercial orchard in Central Poland on ‘Jonagold’ apple trees/M.26 planted in 1996 on a coarse-textured soil with low both pH (4.6) and organic matter (1.2%). Calcium-lactate soluble phosphorus concentration in the soil was within an optimal range despite appearance of leaf phosphorus deficiency symptoms. Soil and foliar applications of phosphorus, and soil liming were applied. Soil phosphorus fertilization was made in the first year of the experimental at a rate of 100 kg P per ha as triple superphosphate. Foliar sprays of a soluble compound containing organic phosphorus were performed 5 times per season at 2-week intervals, starting 4 weeks after full bloom. Soil liming was applied in the fall 2002 at a rate of 1100 kg Ca ha^?1 as hydrated lime. Additional combination as soil phosphorus fertilization plus liming was also applied. Plots unsupplied with phosphorus and lime served as a control. The results showed that liming and liming plus soil P application increased soil pH, and phosphatase activity in the soil, and improved phosphorus nutrition, tree vigor, yield, fruit color, and firmness after storage; effect of these treatments was not found only in the first year of the study. In all years foliar phosphorus sprays improved phosphorus nutrition of apple trees, and fruit color and firmness after storage. In 2 out of 3 years foliar phosphorus application increased yield. The vegetative and reproductive responses of ‘Jonagold’ apple trees did not depend on soil phosphorus fertilization. It was concluded that maintaining an optimal pH of soils for apple trees limits the incidence of orchard phosphorus deficiency and that foliar phosphorus sprays should be applied in phosphorus-deficient apple orchards to improve yield, and fruit appearance and storability.     

Response of phosphorus fractions to land-use change followed by long-term fertilization in a sub-alpine humid soil of Qinghai–Tibet plateau

Purpose

Identification of phosphorus (P) species is essential to understand the transformation and availability of P in soil. However, P species as affected by land use change along with fertilization has received little attention in a sub-alpine humid soil of Tibet plateau.

Materials and methods

In this study, we investigated the changes in P species using Hedley sequential fractionation and liquid-state ³¹P-NMR spectroscopy in soils under meadow (M) and under cropland with (CF) or without (CNF) long-term fertilization for 26 years in a sub-alpine cold-humid region in Qinghai–Tibet plateau.

Results and discussion

Land-use change and long-term fertilization affected the status and fractions of P. A strong mineralization of organic P (OP) was induced by losing protection of soil organic matter (SOM) and Fe and Al oxides during land-use change and resulted in an increase of orthophosphate (from 56.49 mg kg^?1 in M soils to 130.07 mg kg^?1 in CNF soils) and great decreases of orthophosphate diesters (diester-P, from 23.35 mg kg^?1 in M soils to 10.68 mg kg^?1 in CNF soils) and monoesters (from 336.04 mg kg^?1 in M soils to 73.26 mg kg^?1 in CNF soils). Long-term fertilization boosted P supply but failed to reclaim soil diester-P (from 10.68 mg kg^?1 in CNF soils to 7.79 mg kg^?1 in CF soils). This may be due to the fragile protection from the combination of SOM with diester-P when long-term fertilization had only improved SOM in a slight extent.

Conclusions

These results suggest that SOM plays an important role in the soil P cycling and prevents OP mineralization and losses from soil. It is recommended that optimization of soil nutrient management integrated with SOM was required to improve the P use efficiency for the development of sustainable agriculture.

     

Phosphorus source effects on alfalfa yield,total nitrogen content,and soil test phosphorus

Abstract

Recent studies showing a lack of response by alfalfa (Medicago sativa L.) to phosphorus (P) fertilization have raised concerns about the efficacy of commonly used P fertilizer materials in the southwestern United States. Studies were conducted between 1982 and 1985 in southeastern New Mexico to evaluate (i) alfalfa yield response to different P sources, (ii) the effect of P fertilizer source on forage total nitrogen (N) content and leafiness, and (iii) the effect of P fertilizer source on soil test P. Nine P sources were applied annually from 1982 through 1984 at a rate of 58 kg P/ha. Alfalfa was grown during 1985 without fertilization to examine the residual effect of P sources. Triple superphosphate (TSP) and monoammonium phosphate (MAP) gave the highest alfalfa forage yields over the 3‐year application period, but no residual fertilizer effects were observed when fertilization was discontinued. Fertilization did not affect forage leafiness. Except for a small N response in forage total N content in 1984, neither P nor concomitant applied N had a significant effect on forage N content over the 3‐year period. Phosphorus fertilization significantly increased average soil test P for the 3‐year period, but there were no significant differences between treatments. Currently used P materials (TSP and MAP) still appear to be the most efficacious for alfalfa production.     

Influence of P,Zn and Fe fertilization upon yield and protein quality of Sanilac Navy bean seed

Abstract

Treatments of P, Zn and Fe fertilizers were added to a Zn deficient Wisner silty clay loam soil. Sanilac bean plants were grown as the Zn responsive test crop and tissue samples were taken 5 weeks after planting for early growth and Zn uptake responses. At maturity, yield data were obtained and composite samples of beans were taken for determination of protein quality as evaluated by percentage of N, percentage of crude protein and relative contents of essential amino acids. A growth and Zn uptake response was obtained to ZnSO₄, ZnNTA and FeNTA fertilization at both P levels, while a yield response to the same treatments was obtained only at high soil P (448 kg/ha) levels. The percentage N, percentage crude protein and relative contents of essential amino acids did not change as a result of P, Zn or Fe fertilization even when yields were tripled due to Zn fertilization.     

EFFECTS OF CARBONIZED CHICKEN MANURE ON THE GROWTH,NODULATION, YIELD,NITROGEN AND PHOSPHORUS CONTENTS OF FOUR GRAIN LEGUMES

The effects of carbonized chicken manure (CCM) on the growth, nodulation, yield, nitrogen (N) and phosphorus (P) contents of four grain legumes (soybean, cowpea, common bean and adzuki bean) were evaluated in a greenhouse experiment. Carbonized chicken manure produced from chicken manure dried in a furnace at 450°C was used in this experiment. The manure was incorporated into the sandy loam soil of each grain legume at two rates (0 kg N ha^?1 and 100 kg N ha^?1) three weeks before sowing. Growth, nodulation and total biomass N and P were evaluated at peak flowering stage of growth. The CCM showed positive effects on nodule number and weight of soybean and cowpea while it depressed nodule number in adzuki bean. Biomass total N content of soybean and cowpea increased with CCM supply while it decreased in adzuki bean. Biomass and seed total P content of soybean, cowpea and adzuki bean all increased in response to CCM application. Soybean and cowpea seed yields increased by 27% and 43% respectively in response to CCM supply. There was a strong positive correlation between seed P content and seed yield of soybean which indicates the importance of elemental P to soybean seed yield. No such phenomenon was observed in adzuki bean. A strong positive correlation was also observed between seed total N content and seed yield of the grain legumes. The results indicate that although common bean had the highest biomass total P content at peak flowering stage both vegetative and reproductive growth were poor due to the unsuitably high day/night temperatures in the greenhouse. Application of CCM slightly depressed yield of adzuki bean due to the reduction in the number of pods per pot and the 100 seed weight. This study shows that CCM is a good source of N and P for the growth, nodulation and yield of some grain legumes particularly soybean and cowpea.     

Vegetative and Reproductive Responses of Apple Trees to Zinc Fertilization under Conditions of Acid Coarse-Textured Soil

ABSTRACT

The aim of this study was to examine response of apple (Malus domestica Borkh.) trees to zinc (Zn) fertilization under conditions of acid coarse-textured soil with low 1M hydrochloric acid (HCl)-soluble Zn level. The experiment was carried out during 2004-2005 at a commercial orchard in Central Poland on mature ‘Jonagold’ apple trees/M.26 EMLA, planted at a spacing of 4 × 2.5 m. The trees were sprayed with Zn: (i) prebloom, at the stage of silver tip, and tight cluster at a rate of 140 and 100 g ha^{? 1}, respectively, (ii) postbloom, at the stage of petal fall, and 2 weeks later at a rate of 80 g ha^{? 1} in each spray treatment, and (iii) postharvest, 4–5 weeks before the natural leaf fall at a rate of 500 g ha^{? 1}. Other trees were supplied with Zn to soil at a rate of 3 kg ha^{? 1}. In all the studied treatments, Zn was used as ethylenediaminetetraacetic acid (EDTA). Trees unsupplied with Zn served as the control. Tree vigor, fruit set, yield and fruit quality at harvest (mean fruit weight, firmness, color, russeting, soluble solids concentration, and acidity) were not influenced by Zn fertilization. Postharvest Zn sprays slightly damaged leaf tissues but did not cause defoliation. Soil Zn application raised Zn concentrations in flowers, and leaves 28, 56, and 84 days after petal fall. Pre- and postbloom Zn sprays increased Zn status in flowers and leaves 28 days after flowering, respectively. The obtained results indicate that Zn fertilization of ‘Jonagold’ apple trees with Zn status in mid-summer leaves and flowers of 17 mg kg^{? 1} and 27 mg kg^{? 1}, respectively, is not successful in improving vigor and tree yield.     

Comparative response of corn and soybean to seed‐placed phosphorus over a range of soil test phosphorus

Abstract

The responses of corn and soybean to seed‐placed fertilizer were compared over NaHCO₃‐extractable soil phosphorus (P) levels ranging from 3 to 35 ppm in a two‐year experiment. Early season corn and soybean shoot‐P concentrations were increased with increasing soil test P and were increased with seed‐placed P regardless of soil test P, although the increases were greater for corn than soybean. Corn grain yield increased with increasing soil test P to a plateau level and increased with seed‐placed P regardless of soil test P. A side‐band (5 cm × 5 cm) application of 39 kg P ha^‐1 at a low soil test P increased yield more (P<0.15) than application of 7 kg P ha^‐1 with the seed. A side‐band application of 9 kg P ha^‐1 at a medium soil P test did not increase yield. Soybean yield was increased with increasing soil test P one year out of two, but did not respond to seed‐placed P in either year. The yield response of corn was attributed to the increased P concentration prior to the 6‐leaf stage.     

Long-Term Fertilization Effects on Rice Productivity and Nutrient Efficiency in Korean Paddy

ABSTRACT

Long-term fertilization tests evaluated rice (Oryza sativa) productivity in relation to application of nitrogen (N)-phosphorus (P)-potassium (K) (120-34.9-66.7 kg ha^{? 1}, respectively) during 1967–1972 and N-P-K (150-43.7-83.3 kg ha^{? 1}, respectively) during 1973–2000. The comparison treatments (NP, PK, and NK) and the control (not fertilized) were selected for calculating nutrient efficiency. Rice grain yield increased at a 17.78 kg ha^{? 1} yr^{? 1} in the control, mainly due to development of improved cultivars. Phosphorus management was found to be important for indigenous fertility and rice productivity in this paddy soil. Yield increased significantly with P fertilization. Without N fertilization (PK), rice productivity increased 56.85 kg ha^{? 1} yr^{? 1} from 62% of NPK at the initial stage to 74% after passing 34 years, which might be affected by increasing biological N fixation with P accumulation in soil. In NK treatment, rice yield increased at a relatively low rate (37.82 kg hr^{? 1} yr^{? 1}) from the same rice productivity with that of NPK in 1967 to 91% after 34 years. In comparison, yield increased at a high rate (62.82 kg hr^{? 1} yr^{? 1}) without K fertilization (NP) from ca. 90% of NPK and might exceed the yield of NPK after 64 years of long-term fertilization. Therefore, K fertilization level might be readjusted after long-term fertilizing in paddy soil.     

Optimizing Phosphorus and Potassium Fertilizer Recommendations using Spatial Uncertainty Assessments

Abstract

Variable‐rate nutrient management relies on soil fertility maps, yet the associated uncertainty is typically ignored in developing recommendations. In this article, ordinary kriging (OK) and several alternatives that rely on local estimates of uncertainty derived via probability kriging (PK) are evaluated for developing phosphorus (P) and potassium (K) fertilizer recommendations, using soil data collected at two different intensities. A decision support framework that incorporates economic and agronomic criteria to derive block‐average optimal quantile estimates (Opt Q) maximized net return for an 8‐year fertilization program. The economic results show an increase of $7.31 ha^?1 and $1.04 ha^?1 for P and K fertilization, respectively, using Opt Q rather than OK with the 0.2‐ha sampling grid and $14.79 ha^?1 and $8.93 ha^?1 for P and K fertilization, respectively, using the 0.5‐ha sampling grid. These results illustrate the importance of accounting for estimation uncertainty in developing variable‐rate fertilizer recommendations.     

The Effect of Humic Substances and Phosphate Fertilizer on Growth and Nutrient Uptake of the Potato

ABSTRACT

The use of applied phosphorus (P) and the uptake of nutrients from the soil by plants can be improved when the fertilizer is combined with the application of humic substances (HS). However, these beneficial effects are inconsistent and can depend on the type of soil. This study was performed to evaluate the effects of the application of HS (0, 1.25, and 7.50 mL pot^–1), as Humic HF®, and fertilizer-P (10, 50, 100, and 200 mg P dm^–3), as triple superphosphate, on root morphological characteristics, dry matter accumulation, nutrient uptake, and tuber yield of potatoes grown in sandy and clayey soils. Only under low P supply in the sandy soil did the supply of HS, at the rate of 1.25 mL pot^–1, increase the plant growth, yield of tubers, and uptake of macronutrients by the plants, without affecting the efficiency of the P fertilization. In the clayey soil, which had a higher organic matter content, the application of HS did not affect plant growth, tuber yield or nutrient uptake. In both soils, P fertilization increased plant growth, tuber yield, and nutrient uptake. The combined application of HS and P increased the root length of potatoes in sandy soil.     

Effects of long-term contrasting lime and phosphorus applications on barley grain yield,root growth and abundance of mycorrhiza

Lime and phosphorus (P) applications are common agricultural management practices. Our aim was to quantify the effects of long-term application practices on root growth and abundance of arbuscular mycorrhizal fungi (AMF) under field conditions. We assessed the effects of lime and P fertilizer applications on barley yield, root growth and AMF abundance in 2016. Treatments were no, low, medium and high liming rate corresponding to application of 0, 4, 8 and 12 Mg lime ha⁻¹ every 5–9 years since 1942 combined with no or yearly application of 15.6 kg P ha⁻¹ since 1944. At harvest, grain yield, root intensity (core-break) and AMF abundance at different soil depths were estimated. Root development was monitored during early growth with minirhizotrons in treatments receiving low, medium and high liming rates and P fertilization. A quadratic model relating grain yield to liming rate estimated yields to peak at 6.4 Mg lime ha⁻¹ with yields of 4.2 and 3.2 Mg grain ha⁻¹ with and without P fertilization, respectively. Low and medium liming rates resulted in greater AMF abundance, especially in the no P treatments. During early growth in P-fertilized treatments, 77% and 65% more roots developed in the soil profile when treated with medium and high liming rate, respectively, compared to low liming rate. We conclude that long-term application of lime in soils receiving yearly P fertilization improved conditions for root growth in soil layers below 30 cm, but at the high liming rate, this did not translate into higher yield.