Effects of weathering state of coarse‐soil fragments on tree‐seedling nutrient uptake

Fine earth accumulated within the weathering fissures of the coarse‐soil fraction (particles > 2 mm), so called “stone‐protected fine earth”, can provide a high short‐term nutrient release by cation exchange. It is thus hypothesized that unweathered gneiss particles cannot provide plants with exchangeable‐cation nutrients and that biological weathering is needed to include silicate‐bound nutrients into biochemical cycles. In a microcosm experiment, ectomycorrhizal Norway spruce (Picea abies) seedlings were grown on either weathered or unweathered paragneiss coarse‐soil fragments under natural hydraulic and climatic boundary conditions. A nutrient solution containing N, P, and K was added, however Mg and Ca could only be taken up from the coarse‐soil substrate. Solutes in drainage were analyzed during the experiment; plant nutrient uptake was determined after the experiment ended. Solute dynamics depended on the weathering state of the substrates: unweathered gneiss showed high initial Mg and Ca fluxes that diminished strongly afterwards, whereas weathered gneiss showed a much more gradual and sustainable release of these cations. Patterns in dissolved organic C and sulfate drainage indicated that the internal pores of weathered gneiss fragments contained organic material most likely as a result of living spaces from microorganisms. Plant biomass did not differ between treatments, however Mg content was higher in seedlings grown on weathered gneiss. Nutrient budgets demonstrated that the “stonesphere” of weathered gneiss can act as a quasi‐constant nutrient source whereas unweathered gneiss only provided high initial nutrients fluxes. In nutrient‐depleted, acidified fine‐earth environments, the coarse‐soil fraction may therefore act as a retreat for nutrient‐adsorbing tissues and as a buffer for nutrient shortages.     

Pore characteristics and hydraulic properties of a sandy loam supplied for a century with either animal manure or mineral fertilizers

Abstract Application of organic residues to soil is generally assumed to improve soil tilth. Only few studies have reported the long‐term effects on the more subtle aspects of soil porosity, and no reports have considered the potential effects of organic amendments on the pore system in the subsoil. We sampled undisturbed soil cores (100 cm³ and 6280 cm³) using metal cylinders in differently fertilized plots in the long‐term field experiment at Askov Experimental Station, Denmark. We selected the 0–60 cm soil layer of plots dressed for a century with either mineral fertilizers (labelled NPK) or animal manure (labelled AM) and unfertilized plots (UNF) as a reference. Both fertilization treatments were studied at two levels of nutrient application: ‘normal’ (labelled ‘1’) and 1.5 times ‘normal’ (labelled ‘1½’). Water retention, air permeability and air diffusivity were measured on the small cores, and we used the large cores for measuring near‐saturated and saturated hydraulic conductivity. In the plough layer, the AM and NPK soils displayed identical pore volumes in size fractions that were larger as well as smaller than 30 μm, while the UNF soil had a significantly smaller volume of pores < 30 μm. No clear trends were found in treatment effects on pore organization as calculated from air diffusivity and air permeability measurements. No significant differences in hydraulic conductivity were found in the plough layer. For the subsoil below ploughing depth, significantly larger macropore volumes and near‐saturated hydraulic conductivities were found for soil of plots receiving the larger (‘1½’) amount of nutrients compared with the ‘normally’ dressed soil. This effect was independent of fertilization system (AM or NPK). We attribute the larger volume of macropores to the improved root growth conditions in the soil with the higher nutrient level. We conclude that addition of animal manure at rates realistic in agriculture has only a modest effect on soil pore characteristics of the plough layer soil compared with the use of mineral fertilizers. For the subsoil below ploughing depth, a high level of nutrient application may increase soil macroporosity and near‐saturated hydraulic conductivity, but the origin of nutrients is of no significance.     

The optimal nutrition of maize in the hungarian national long‐term field experimental network

In Hungary, maize is grown on 1 million ha and occupies more than 20% of the arable land. The rich assortment of maize cultivars of different vegetation periods and different responses to nutritional effects, water supply etc. gives the growers the possibility to choose the cultivars suiting best the site characteristics (Jolânkai et al. 1999). Among the cereals maize has the highest genetical potential. To utilize its yield and quality potential, soil types of high nutrient content and regular nutrient supply are required (Gyõrffy, 1979). Both over‐ and under‐fertilization have an unfavourable effect on the yield and quality of maize (Debreczeni, 1985). Crops can be supplied with the appropriate nutrient amounts only with the knowledge of soil characteristics in the different agro‐ecological regions (nutrient content, water supply, soil compactness, pH, nutrient supplying capacity etc.). In Hungary, a network of long‐term field fertilization trials with uniform fertilizer treatments has been maintained at nine experimental sites representing different agro‐ecological regions of the country. This experimental network gives a basis to test the nutrient responses of our main crops and calibrate their optimal nutrient supply (Kismányoky, 1991).     

Influence of deer exclusion on soil nutrients in oak forests of a central European low mountain range

High densities of red deer can have severe impacts on soil nutrient status by removing the ground vegetation and enhancing erosion of the fertile soil layers. We compared four fenced deer exclosures with adjacent unfenced sites to evaluate the effect of deer grazing and trampling on the soil nutrient status (C_org, N_t, PO₄³⁻, Ca²⁺, Mg²⁺, K⁺) in sloping oak forests of a central European low mountain range. The investigation was set up as a three‐factor randomized complete block design (RCBD) with the factors: ‘fencing’ (fenced/unfenced), ‘gradient’ (gentle/steep) and ‘aspect’ (windward/leeward). We hypothesized that exclusion of red deer by fencing would increase soil nutrient contents independent of slope gradient and aspect. Fencing increased the contents of C_org, N_t, Ca²⁺ and PO₄³⁻, but only at the windward sites. This effect was less pronounced at the gently sloping site than at the steep site, which exhibited the lowest contents of C_org, N_t and PO₄³⁻ of all sites. We did not find increased soil nutrients in the fenced exclosures at the leeward sites, neither at the steep nor at the gently sloping site. At both slope aspects nutrient contents (C_org, N_t, PO₄³⁻, K⁺) tended to be higher on the gentle than at the corresponding steep slopes. Our results suggest that red deer trampling and grazing enhance the loss of soil nutrients at predisposed sites such as windward locations with a high slope gradient. Only at such sites did the exclusion of red deer increase several soil nutrients. Copyright © 2005 John Wiley & Sons, Ltd.     

Short and long‐term distribution with depth of soil organic carbon and nutrients under traditional and conservation tillage in a Mediterranean environment (southwest Spain)

The impacts of tillage and cropping sequences on soil organic matter and nutrients have been frequently reported to affect the uppermost soil layers, but there is little published information concerning effects at greater depth. This article reports results on the distribution of soil organic carbon (SOC), active carbon (AC), N, Olsen‐P and extractable K within 100 cm in short (4 yr) and long (16 yr) term experiments under different tillage systems. Short (TT₄) and long (TT₁₆) traditional tillage are compared with conservation tillage, reduced (RT₁₆) and non‐tillage (NT₄). The results show more accumulation of SOC in the near‐surface under RT₁₆ and NT₄ in both experiments compared with traditional tillage. Moreover, greater C content occurs to 40 cm depth in the long‐term experiment. The results demonstrate the importance of time on C accumulation, not only in near‐surface layers but also at greater depths. Active C is an indicator of the increase in soil quality in the long‐term experiment. This trend is only apparent for the first 10 cm in the short‐term experiment. Patterns in N, Olsen‐P and extractable K are similar to that of SOC. However, only extractable K is significantly greater in soil under conservation tillage (RT₁₆ and NT₄) after short and long periods. Potassium availability is a good indicator of the changes caused by tillage. Our results indicate that studies of soils at depth could be very useful in long‐term experiments to demonstrate the effect of conservation tillage on C and nutrient distribution.     

Farmyard manure and chemical fertilizers as a source of nutrients for raspberry

Abstract

A long term field experiment was undertaken in four different sites in Québec for evaluating Newbury raspberry nutrient requirement. Addition of farmyard manure one year before the plot establishment at the rate of 70 tons/hectare, increased the fruit production by 20% over the check plot; its residual effect persists even four years after incorporation. Critical nutrient contents of leaves are shown, maximum yields of this cultivar depending on the plant age and the amount of N‐P‐K application are tabulated. These parameters, in combination with farmyard manure, further increased the fruit production up to 35% when ever soil moisture was well provided. A positive effect of P fertilizer on the fruit production was more pronounced than that of N‐fertilizer on this territory and the response to K fertilizer could be obtained where a farmyard manure was applied.     

Soil Characteristics and Mineral Nutrient in Wild Jatropha Population of India

Abstract

Mature leaves of naturally occurring Jatropha curcas plants and soils samples were collected from four different populations to determine the soil characteristics, soil‐available nutrients, and leaf nutrient contents. This study provides a reliable account of the endogenic concentrations of nutrients present in jatropha leaves. Soil manganese [diethylenetriamine pentaacetic acid (DTPA)‐Mn] was the only soil‐available nutrient significantly correlated with its content in the plant. Relationships between soil characteristics, available nutrient in soil, and their content in plant leaves were also attempted.     

Evaluation of Agronomic and Environmental Soil P Test Methods in a Network of Hungarian Long‐Term Field Trials

Abstract

Winter wheat shoot weight and phosphorus (P) concentrations, corn leaf weight and P concentrations, and soil AL, Olsen, H₂O, Bray 1, Pi (Fe-oxide impregnated paper strip) and AERM (anion exchange resin membrane) contents were determined in a network of uniform Hungarian national long‐term field trials. P application had a significant effect on soil P test values at different P levels and sites. The relationship between the different soil P test methods was studied separately for different soil groups (all, acid, and calcareous soils). Corn leaf weight was influenced by the sites much more than by soil P supply level, whereas corn leaf P percentage was influenced by both sites and P levels. For winter wheat, both sites and soil P levels had a positive effect on wheat shoot weight. Wheat shoot P percentage was influenced by the soil P supply much more than by the sites. Correlation between corn leaf P percentage and the Pi or AERM extractable P and between wheat shoot P percentage and the Pi and AERM P values was logarithmic.     

The long‐term fertilization experiments in Halle (Saale), Germany — Introduction and survey

Six of originally eight long‐term trials in Halle (Saale), Germany, are still continuing. Five are situated at Julius‐Kühn‐Feld, an experimental station launched by Julius Kühn in Halle in 1866. Apart from the Eternal Rye trial established in 1878, those are phosphorus, potassium, lime, and organic fertilization long‐term trials, all being launched by Karl Schmalfuß in 1949. Other long‐term trials have been terminated, but data are available on the effects of nitrogen fertilization and the physiological reaction of fertilizers. Another long‐term trial in Halle (Adam‐Kuckhoff‐Straße 17b) investigates the influence of fertilization on soil formation from loess. Up to now, the major results are as follows: 1. Changes in soil‐ecological properties due to fertilization and rotation were only evident after 30 years, and new steady states sometimes took 70 years to occur. 2. In the long term, the C‐ and N‐contents of the soil largely depend on the amount of hardly decomposable organic matter applied with organic fertilization. High mineral‐N doses, with consequent high crop and root residues, increased the humus content of the soil. 3. Mineral fertilization can replace organic fertilization in terms of sustainable yield capacity provided equal nutrient amounts were applied. 4. The high P‐supply ability of the soil in Halle could not be explained by traditional soil analysis methods of calculating plant‐available P. With some restrictions, the same is valid for K. 5. At the experimental site, soluble salts (nitrate, sulphate) accumulated in the subsoil. 6. A regular lime demand of central German chernozems could be proved, especially in case of low soil organic matter (SOM) and physiologically acid fertilization.     

Effects of climate factors and soil properties on soil nutrients and elemental stoichiometry across the Huang–Huai–Hai River Basin,China

Purpose

Soil nutrients, elemental stoichiometry, and their associated environmental control play important roles in nutrient cycling. The objectives of this study were (1) to investigate soil nutrients and elemental stoichiometry, especially potassium and its associative elemental stoichiometry with other nutrients under different land uses in terrestrial ecosystems; (2) to discuss the impacts of climate factors, soil texture, and soil physicochemical properties; and (3) to identify the key factors on soil nutrient levels and elemental stoichiometry.

Materials and methods

Soil data, including pH, bulk density (BD), cation exchange capacity (CEC), volumetric water content (VMC), clay, silt and sand contents, total carbon (TC), nitrogen (TN), phosphorous (TP) and potassium (TK), available nitrogen (AN), phosphorus (AP), potassium (AK), and soil organic matter (SOM) under different land-use types, were collected, and their elemental stoichiometry ratios were calculated. Climate data including temperature, precipitation, relative humidity, wind speed, and evapotranspiration were collected. The least significant difference test and one-way analysis of variance were applied to investigate the variability of soil nutrients and elemental stoichiometry among land-use types; the ordinary least squares method and the general linear model were used to illustrate the correlations between soil nutrients, elemental stoichiometry, and soil properties or climate factors and to identify the key influencing factors.

Results and discussion

Woodlands had the highest SOM, TN, AN, and AK contents, followed by grasslands, croplands, and shrublands, while the TP and TK contents only varied slightly among land-use types. SOM, TN, AN, N/P, and N/K were strongly negatively correlated to soil pH (p <?0.05) and were strongly positively correlated to soil CEC (p <?0.05). For soil texture, only C/N was moderately negatively correlated to silt content but moderately positively correlated to sand content (p <?0.05). For climate factors, SOM, TN, AN, N/P, and N/K were significantly negatively correlated to evapotranspiration and temperature (p <?0.05), and the correlations were usually moderate. Soil pH explained most of the total variation in soil nutrients, and climate factors explained 5.64–28.16% of soil nutrients and elemental stoichiometry (except for AP (0.0%) and TK (68.35%)).

Conclusions

The results suggest that climate factors and soil properties both affect soil nutrients and elemental stoichiometry, and soil properties generally contribute more than climate factors to soil nutrient levels. The findings will help to improve our knowledge of nutrient flux responses to climate change while also assisting in developing management measures related to soil nutrients under conditions of climate change.

     

K‐Fertilization under different Agroecological conditions studied with maize

In Hungary the AL‐method using ammonium lactate acetic acid as extradants has been widely used for serial analysis of soil potassium and phosphorous available to plants in the last 30 y. Because of the considerable increase of the price of fertilizers and decline of the economic situation, there is a pressing need for cost‐effective fertilizer use. Recently this highlighted the importance of nutrient recommendations based on soil analyses. Small plot long‐term field fertilization experiments are the best means to quantify the efFect or the efficiency of K‐fertilization. Long‐term data sets can reveal on which soil type which crop responds most favourably to the different fertilizer doses and nutrient ratios under different, long‐term balanced soil nutrient levels. Since the experimental data of the National Long‐Term Field Trials reflect the agro‐ecological conditions of nine experimental sites representing different soil types of Hungary, these experiments provide excellent opportunity to study this topic. The trials were set up in 1967 with 20 fertilization treatments including three increasing N‐and P‐levels each, two K‐levels and their different combinations. From the experimental data of great number only those of four sites will be shown. Winter wheat, maize, and pea have been grown as test plants. In the experiment selected for presentation, maize had statistically proved responses to K‐fertilization. The efficiency of K‐fertilizer on different soil types shows, however, significant differences, which can not be completely explained with the results of K‐analysis gained with the AL‐method.     

Evaluation of soil health in organic vs. conventional farming of basmati rice in North India

Conventional agricultural practices that use excessive chemical fertilizers and pesticides come at a great price with respect to soil health, a key component to achieve agricultural sustainability. Organic farming could serve as an alternative agricultural system and solve the problems associated with the usage of agro‐chemicals by sustainable use of soil resources. A study was carried out to evaluate the impact of organic vs . conventional cultivations of basmati rice on soil health during Kharif (rainy) season of 2011 at Kaithal district of Haryana, India, under farmers' participatory mode. Long‐term application of organic residues in certified organic farms was found to improve physical, chemical, and biological indicators of soil health. Greater organic matter buildup as indicated by higher soil organic carbon content in organic fields was critical to increase soil aggregate stability by increasing water holding capacity and reducing bulk density. Proper supplementation of nutrients (both major and micro nutrients) through organic residue addition favored biologically available nutrients in organic systems. Further, the prevalence of organic substrates stimulated soil microorganisms to produce enzymes responsible for the conversion of unavailable nutrients to plant available forms. Most importantly, a closer look at the relationship between physicochemical and biological indicators of soil health evidenced the significance of organic matter to enzyme activities suggesting enhanced nutrient cycling in systems receiving organic amendments. Enzyme activities were very sensitive to short‐term (one growing season) effects of organic vs . conventional nutrient management. Soil chemical indicators (organic matter and nutrient contents) were also changed in the short‐term, but the response was secondary to the biochemical indicators. Taken together, this study indicates that organic farming practices foster biotic and abiotic interactions in the soil which may facilitate in moving towards a sustainable food future.     

Biochar‐Based Fertilization with Liquid Nutrient Enrichment: 21 Field Trials Covering 13 Crop Species in Nepal

Biochar produced in cost‐efficient flame curtain kilns (Kon‐Tiki) was nutrient enriched either with cow urine or with dissolved mineral (NPK) fertilizer to produce biochar‐based fertilizers containing between 60–100 kg N, 5–60 kg P₂O₅ and 60–100 kg K₂O, respectively, per ton of biochar. In 21 field trials, nutrient‐enriched biochars were applied at rates of 0·5–2 t ha⁻¹ into the root zone of 13 different crops. Treatments combining biochar, compost and organic or chemical fertilizer were evaluated; control treatments contained same amounts of nutrients but without biochar. All nutrient‐enriched biochar substrates improved yields compared with their respective no‐biochar controls. Biochar enriched with dissolved NPK produced on average 20% ± 5·1% (N  = 4 trials) higher yields than standard NPK fertilization without biochar. Cow urine‐enriched biochar blended with compost resulted on average in 123% ± 76·7% (N  = 13 trials) higher yields compared with the organic farmer practice with cow urine‐blended compost and outcompeted NPK‐enriched biochar (same nutrient dose) by 103% ± 12·4% (N  = 4 trials) respectively. Thus, the results of 21 field trials robustly revealed that low‐dosage root zone application of organic biochar‐based fertilizers caused substantial yield increases in rather fertile silt loam soils compared with traditional organic fertilization and to mineral NPK or NPK‐biochar fertilization. This can be explained by the nutrient carrier effect of biochar, causing a slow nutrient release behaviour, more balanced nutrient fluxes and reduced nutrient losses, especially when liquid organic nutrients are used for the biochar enrichment. The results open up new pathways for optimizing organic farming and improving on‐farm nutrient cycling. Copyright © 2017 John Wiley & Sons, Ltd.     

Seasonal Dynamics of Mineral Nitrogen in the 10th and 30th Years of a Long‐Term Field Experiment in Hungary

Abstract

Long‐term field experiments are the most suitable tools for determining the optimal nutrient‐supplying technologies that contribute to sustainable agriculture. Under certain environmental conditions (low precipitation, deep groundwater table, negative water balance), part of the applied nitrogen (N) can be found in the soil profile for a longer period and provide N nutrition for crops. A long‐term field experiment has been running at Nagyhörcsök in Hungary since 1973. The nitrogen–phosphorus–potassium (NPK) application rates follow the overall nutrient‐supplying categories (weak, medium, adequate, excessive) by the main nutrients and their combinations. The seasonal dynamics of exchangeable NH₄ and NO₃ were followed in 1983 and 2003. From certain treatments, two parallel average samples (20–20 subsamples were mixed to get average composite samples by plots) were collected 19 times from March through November from three soil layers. There was no difference in NH₄‐N between years, and its seasonal fluctuation was slight in both years, whereas there was an increase in NO₃‐N in accordance with the applied N rates. No significant difference occurred in the NO₃‐N of the N₀P₀K₀ and the N₁P₁K₁ treatments during both years. A significantly higher NO₃‐N content was observed in the higher rate nutrient treatments. Both soil N forms were higher in 1983 than in 2003. Based on the experimental results, the fate and behavior of the surplus N in the soil can be characterized and the residual amount can be taken into account during the calculation of the N‐fertilization demand of arable crops in relation to the N‐fertilizer advisory system.     

Hydraulic properties of Eucalyptus grandis in response to nitrate and phosphate deficiency and sudden changes in their availability

Some herbaceous plant species have been shown to dynamically alter the hydraulic properties of their roots in response to sudden changes in the concentrations of mobile nutrients. These hydraulic adaptations effectively allow plants to ‘chase' mobile nutrients across the rhizosphere. Trees, on the other hand, could mitigate effects of heterogeneous, dynamic soil environments with extensive root systems as such systems would effectively equalize nutrient availability. In addition, large dendritic root systems would reduce the effectiveness of rapid, localized, physiological hydraulic changes as these local changes might cancel each other at lower‐order root junctions. Thus, the aim of this study was to determine if trees (Eucalyptus grandis) employ short‐term (minutes to hours), physiological hydraulic changes or rely on long‐term (days), growth‐based hydraulic acclimations to enhance mobile nutrient uptake. We used two nutrients, nitrogen (N) and phosphorus (P), that are characterized by contrasting soil mobility: N being mobile and P immobile. Transpiration, whole‐plant hydraulic resistance (liquid phase), and the hydraulic resistance of single roots of E. grandis plants grown in high and low N combined with high and low P availability were measured. In general, plants grown with high N availability had lower whole‐plant hydraulic resistance than plants grown with low N availability. When N or P were in short supply, a sudden addition of N or P did not change either single‐root or whole‐plant hydraulic resistance at a given leaf water potential. However, addition of N reduced the transpiration rate, thus, enhancing plant water status, suggesting that E. grandis behavior prioritizes water conservation over N uptake in short‐term. Prolonged exposure to low nutrient availability resulted in high overall hydraulic resistance further suggesting prioritization of water conservation over N gain.     

Application of the Bray–Mitscherlich Equation Approach for Economically and Environmentally Sound Fertilization of Field Crops in Hungary

Abstract

A database was compiled from the results of Hungarian long‐term N, P, and K fertilization field trials published between 1960 and 2000. Database correlations were described between the soil organic matter (SOM) content of PK (N control) plots and the responses of winter wheat and corn to N application; between the soil P test (ammonium lactate, AL) values of NK (P control) plots and the responses of wheat and corn to P application; and between the soil K test (ammonium lactate, AL) values of NP (K control) plots and the responses of wheat and corn to K application, using the Bray–Mitscherlich equation approach. The nutrient responses were expressed as both relative yields and surpluses. The database also made it possible to investigate how the responses of winter wheat and corn to N, P, and K fertilization were affected by the available nutrient contents, soil texture, pH, and carbonate status, soil type, and nutrient supply category of the control plots. Based on the correlations established in the database, new, more accurate soil N, P, and K supply categories were elaborated, providing opportunities for cost saving and environmentally sound fertilizaton of Hungarian crops.     

Soil test reporting a nutrient index system

Abstract

An index system of reporting soil test results is suggested which is not confounded with the requirements of a particular crop but is based on each laboratory's evaluation of the test results in relation to the predicted relative sufficiency of each element in a fertile soil. It is suggested that soil test—fertilizer rate correlation adjustments begin after the fact rather than in a precursory manner to influence the results reported. A 0–100 index is proposed as a self explanatory measure and correlated with general crop response as follows: 0–15, nutrient deficiencies visible; 16–50, nutrient deficiencies obscured but plant response probable; 51–100, adequate nutrients available for most crops; 100+, amounts available in excess of present needs.     

Nutrient status of apple orchards in Canterbury,New Zealand. 1. Levels in soil,leaves and fruit and the prevalence of storage disorders

Abstract

The nutrient status (N, P, K, Ca, Mg, K, Fe, Mn, Zn and Cu) of 26 Cox's Orange Pippin and 20 Braeburn apple orchard sites in the Canterbury region of New Zealand was evaluated by soil, leaf and fruit analysis. Concentrations of available nutrients in soils ranged widely but those in leaves and fruit were generally confined to a relatively narrow range. Concentrations of leaf N were high in the study area, as were levels of extractable soil P, and it is suggested that reductions in fertilizer additions of these nutrients would generally be appropriate.

Soil, leaf and fruit nutrient contents were generally not well correlated with one another. The only highly significant correlations (P≤0.001) were between leaf and fruit Ca for Cox's and soil and fruit Mg for Braeburn. The poor correlations were attributed to the empirical nature of soil tests, the presence of large nutrient reserves within the tree framework and the effects of cultural and environmental factors on nutrient uptake and translocation by the trees.

The storage disorders bitter pit and senescent breakdown in Cox's and lenticel blotch pit in Braeburn were observed in apples harvested from some of the study sites. Such disorders were generally associated with low concentrations of Ca (≤.2.5 mg/100 g) in samples of cortical plugs taken from fruit at harvest.     

Productivity increase in Northern Austria Norway spruce forests due to changes in nitrogen cycling and climate

We investigated the long‐term temporal trend in growth rate, soil chemical status, and nutrient content of needles of two Norway spruce (Picea abies) stands in the Bohemian Massif, Austria. The aim was to quantify changes in the site productivity over the last four decades as a consequence of the enriching effect of N deposition, rising CO₂ levels in the atmosphere, and changes in forest‐management practices. We used the data records of control plots from forest‐amelioration experiments that have been monitored for more than four decades. Both stands showed increased growth rates and a large deviation from the growth pattern of earlier applicable yield tables. The nutrient levels in the foliage remained unchanged and neither suggested luxury consumption nor nutrient imbalances. Results from soil chemistry analysis were inconclusive in respect of changes in soil conditions: an enrichment of the mineral soil with N and a decrease in the C : N ratio. Changes were confined to the uppermost part of the soil profile. Our data support the hypothesis that the sites are in a steady process of aggradation and that site productivity is rising.