Tamás Kismányoky

Effect of mineral and organic fertilization on crop yield, nitrogen uptake, carbon and nitrogen balances, as well as soil organic carbon content and dynamics: results from 20 European long-term field experiments of the twenty-first century

Assembled results from 20 European long-term experiments (LTE), mainly from the first decade of the twenty-first century, are presented. The included LTEs from 17 sites are the responsibility of institutional members of the International Working Group of Long-term Experiments in the IUSS. Between the sites, average annual temperatures differ between 8.1 and 15.3°C, annual precipitation between 450 and 1400 mm, and soil clay contents between 3 and 31%. On average of 350 yield comparisons, combined mineral and organic fertilization resulted in a 6% yield benefit compared with mineral fertilization alone; in the case of winter wheat, the smallest effect was 3%, the largest effect, seen with potatoes, was 9%. All unfertilized treatments are depleted in soil organic carbon (SOC), varying between 0.36 and 2.06% SOC. The differences in SOC in unfertilized plots compared with the respective plots with combined mineral (NPK) and organic (10 t ha−1 farmyard manure) fertilization range between 0.11 and 0.72%, with an average of 0.3% (corresponding to ∼15 t ha−1). Consequently, the use of arable soils for carbon sequestration is limited and of low relevance and merely depleted soils can temporarily accumulate carbon up to their optimum C content.

Humus und Klimaänderung - Ergebnisse aus 15 langjährigen Dauerfeldversuchen

Zusammenfassung Die Quantifizierung des Einflusses von Klimaänderungen auf den Humusgehalt des Bodens ist von großer wirtschaftlicher und wissenschaftlicher Bedeutung. Eine Möglichkeit dieser Quantifizierung besteht in der Auswertung von Dauerfeldversuchen mit der kontinuierlichen Bestimmung des Kohlenstoff- und Stickstoffgehaltes von Böden über einen Zeitraum von mehreren Jahrzehnten unter Wahrung des Ceteris-Paribus-Prinzips. Für die vorliegende Arbeit wurden die Ergebnisse von insgesamt 15 Dauerfeldversuchen an zehn verschiedenen Standorten mit rund 150 unterschiedlichen Düngungsvarianten ausgewertet. Die Versuchsdauer lag mit einer Ausnahme zwischen 40 und 110 Jahren. Die Corg-Daten konnten nahezu lückenlos über einen Zeitraum von jeweils 20 Jahren einbezogen werden. Die Nt-Gehalte wurden in sechs Versuchen berücksichtigt. Die Ergebnisse zeigen, dass bei allen Prüfgliedern mit kombinierter organisch-mineralischer Düngung in der Größenordnung, wie sie der “guten fachlichen Praxis“ oder auch der Humusbilanzmethode entspricht, keine Verringerung der Corg-Gehalte eingetreten ist. In einigen Fällen waren signifikante Erhöhungen zu verzeichnen. In 11 von 15 Versuchen war auch ohne Düngung oder mit ausschließlicher Mineraldüngung keine Reduzierung und somit keine klimabedingte Verringerung der Humusgehalte im Untersuchungszeitraum nachweisbar. Stattdessen wurde in einigen Fällen eine signifikante Erhöhung gefunden. Auch bei den Nt-Gehalten war in keinem Fall eine signifikante Verringerung festzustellen. Umfangreiche Großzahlanalysen und Dauerfeldversuchsauswertungen anderer Autoren bestätigen uneingeschränkt die Ergebnisse.

Effect of mineral and organic fertilization on soil organic carbon content as well as on grain production of cereals in the IOSDV (ILTE) long-term field experiment, Keszthely, Hungary

The study was conducted in the international mineral and organic nitrogen fertilization trial (IOSDV) located in Keszthely in the western part of Hungary. The soil class of the study site was Ramann-type brown forest soil (Eutric Cambisol). The factors of the experiment are the increasing rate of mineral N fertilization and the complementary application of different forms of organic fertilizers in a three-course crop rotation (maize, winter wheat and winter barley) set up in 1983. The organic carbon content of the soil (Corg%) definitely increased after application of organic manure (OM), similarly to the average yield of the cultivated crops. After application of OM the increase in Corg content was 0.20%, and after straw + complementary N application it was 0.12%, compared with plots without organic manures. Mineral N fertilizer did not significantly influence the Corg content in soil over this period. Depending on the type of crop, the specific year and the N content of the soil, the combined application of mineral fertilizers and organic manures resulted in a 12–17% increase in crop yield, in general, whereas at maximum yields the increase accounted for 5–10%.

Acidification of Soils in Long‐Term Field Experiments

Abstract As a consequence of intensive soil management and land use and environmental effects, soil properties can change remarkably. It is especially true for acid soils because of combined effect of pollution (heavy metals, depleting the soil buffering capacity, excess of nitrates, atmospheric deposition). Small‐plot fertilization trials were initiated in 1967 to evaluate changes of soil acidity (pH) and the other environmental effects in the unfertilized and in the different fertilizer‐treated plots during the long‐term experimental years under controlled conditions. In the National Long‐Term Field Experimental Network, four of the soil types have an acid chemical reaction. Small‐plot trials were established with 4‐yr crop rotations of wheat‐maize‐maize‐wheat biculture. The NPK rates in the first 20 yr were 0, 50, 100, 150, and 200 kg N; 0, 50, 100, and 150 kg P2O5; and 0 and 100 kg K2O ha−1 yr−1. From the 21st yr on, the fertilizer rates increased up to 0, 100, 150, 200, and 250 kg N; 0, 60, 120, and 180 kg P2O5; 0, 100, and 150 kg K2Owheat; and 0, 200, and 250 kg K2Omaize ha−1 yr−1. The pHKCI in 1967, 1987, and 1999 in the 20‐cm layers in the control plots was as follows: site Bicsérd, Mollisol loam: 6.40, 5.60, and 5.04; site Karcag, Mollisol clay loam: 5.70, 4.73, and 4.62; site Kompolt, Mollisol clay loam: 5.20, 4.16, and 4.22; site Putnok, Alfisol clay loam: 5.70, 4.48, and 4.62, respectively. Three of the soil (Karcag, Kompolt, and Putnok) lime were applied (lime rate 8.0 t ha−1), limestone 80% calcium carbonate in 1987. In the four replications of each fertilization treatments, two plots were limed and two plots remained unlimed. After the 32nd yr, acidity and the exchange capacity of the soils were investigated in the control plots and in two fertilized plots. After liming (20th yr) the pH of soils increased for 1–4 yr after which pH decreased again. Between the yr 20–32, the limed plots kept the same acidity level as it was in the 12th yr. It is typical on all of the soils that the soil acidification is also occurring on the zero NPK plots probably because of leaching and plant uptake of basic cations and possibly because of environmental pollution.

Effect of mineral and organic fertilization on soil fertility as well as on the biomass production and N utilization of winter wheat (Triticum aestivum L.) in a long-term cereal crop rotation experiment (IOSDV)

In this trial the effect of mineral and organic fertilization was investigated on the biomass production (grain and straw), N balance, N uptake of winter wheat and some indices of N utilization (N harvest index %, N use efficiency, agronomic efficiency, apparent recovery efficiency) as well as soil fertility in a long-term field experiment. The bifactorial cereal crop rotation (w. wheat, w. barley, maize) trial was set up in 1984 in Keszthely, Hungary, as a part of the international mineral and organic nitrogen fertilization trial network (IOSDV). The statistical significance of the experimental factors (increasing rates of N fertilizer and organic fertilization) was tested by analysis of regression and variance. As a result of the experimental treatments it can be concluded that the increasing rate of N fertilization as well as the additional organic fertilizers influenced the biomass production and N uptake of winter wheat or soil fertility. The Corg content of soil increased significantly with the incorporation of both farmyard manure and straw. Thus, straw as a byproduct should be recycled into the soil mainly if there is no animal husbandry in the farm to preserve the C balance.

Effect of Organic Matter Recycling in Long‐Term Fertilization Trials and Model Pot Experiments

Abstract Sustainable agriculture implies the use of biological resources. Farmyard manuring (FYM) and ploughing in plant residues have an important role in maintaining soil fertility. Our aim was to study the effect of various combinations of organic and mineral N‐fertilizers on the Corg content of the soil, grain yield, dry matter production, and N uptake of barley. A model pot experiment was set up with spring barley. Large pots were filled with 46 kg sandy loam soil originating from the plots of the “International Long‐term Experiments for Investigating the Effect of Organic and Inorganic Fertilisers,” Keszthely, Hungary. The field experiment, which was set up in 1983, contains three crop rotations with winter wheat, winter barley, and maize. Treatments: 1) inorganic fertilizers only with increasing N doses (N); 2) FYM in every 3rd yr+N; 3) stalk, straw, or green manure+N. Yield results gained in the field experiment with winter barley were also evaluated. In the 18th yr of the experiment, FYM+N resulted in significantly higher Corg content than with treatments 1 and 3. Grain yields in the field trial were the lowest in treatments without organic matter recycling. In the pot experiment, dry matter production and N uptake of the grains and vegetative plant parts were significantly higher in treatments with FYM+N. Our results clearly prove the advantage of FYM combined with mineral fertilization over the other treatments.

Der internationale organische stickstoffdauerdüngungsversuch (IOSDV) keszthely nach 12 versuchsjahren

Der Internationale Organische Stickstoffdauerdungungsversuch wurde 1984 in Keszthely auf einer Braunerde mit 3 Stufen organischer Dungung und 5 Stufen mineralischer N‐Dungung in einer Fruchtfolge mit Mais — Winterweizen ‐ Wintergerste angelegt. Die Kornertrage im Zeitraum 1984–1995 (vier Rotationen) werden mitgeteilt. Die positive Wirkung bzw. Nachwirkung von Stallmist zeigte sich mit abnehmendem Bedarf an mineralischer N‐Dungung bei Mais und Wintergerste und mit hoherem Maximalertrag bei Winterweizen. Die Strohdungung wirkte schwacher und ergab niedrigere Ertrage bei Mais und Wintergerste als die mineralische N‐Dungung allein. Mit fortschreitender Versuchsdauer hat die Fruchtbarkeit des Bodens der organisch und mineralisch gedungten Parzellen zugenommen und wahrend dieser Zeit ist auch die Produktivitat der Nullparzellen nicht gesunken.

Effect of Long‐Term Fertilization on the Strontium Content of Soil

Abstract The total and available strontium (Sr) contents of the experimental soil in the National Long‐Term Fertilization Trials set up in 1968 in Keszthely were compared in correlation to the Sr content of the Ramann‐type brown forest soil and different long‐term P‐fertilizer treatments. The Sr uptake by lettuce was also studied. Soil samples were taken from the 0‐ to 20‐cm depth in the 32nd year of the experiment from plots given different P fertilizer treatments (0–50–100–150–200 kg P2O5 ha−1 y−1). The total and available Sr content of soils were measured using ICP‐AES. A positive linear correlation was established between the total and available Sr contents of the experimental soils. The total and available soil Sr contents were significantly higher in large dose P‐fertilizer treatments than in case of lower doses. The Sr concentration of lettuce was four to eight times greater than the available Sr content of the soil samples, and Sr accumulation was observed in lettuce leaves.

Einfluss langjähriger organischer und mineralischer N‐düngung auf gehalt an Corg und N‐verlagerung

Der Gehalt an Corg verandert sich signifikant durch die Stallmist‐ und Strohdungung, aber die mineralische N‐Dungung allein hat keine Veranderung verursacht. Hohe Eintrage durch die hochsten N‐Stufen mit Strohdungung haben Nitratanreicherung und eine Abwartsbewegung der NO3‐K.onzentrationsspitze bewirkt, die vermutlich zu einer Belastung des Grundwassers fuhren wird. Die Ergebnisse zeigen, das bei einer N‐Gabe uber ca. 150 kg/ha eine weitere N‐Ausgleichdungung fur Strohabbau uberflussig ist, sie kann zur Auswaschung fuhren. Der Stalldung hat, auch bei hoheren N‐Stufen, keine ausgepragte Nitratkonzentration im Unterboden verursacht. Der Ammonium N‐Gehalt im Bodenprofil zeigt keine wesentlichen Differenzen in Abhangigkeit von organischer und mineralischer Dungung. Die Menge Ammonium‐N ist aber bedeutend und macht etwa die Halfte des Nitrat‐N aus, ist jedoch nicht konstant.

Studying the effect of organic matter recycling combined with mineral n fertilization in long-term field and model pot experiments: Untersuchung der wirkung der rezyklierung der organischen substanz kombiniert mit mineraldüngung in dauerfeldversuchen und modellgefässversuchen

The effect of various combinations of organic and mineral N fertilizers was studied on the organic matter content of the soil, grain yield, dry matter production and N-uptake of maize. In a model experiment, large pots were filled with 55 kg sandy loam soil originating from the plots of the ‘International Long-term Experiments for Investigating the Effect of Organic and Inorganic Fertilisers’ (IOSDV), Keszthely. The field experiment, which was set up in 1983, contained three crop-rotations with maize, winter wheat and winter barley. Treatments: (1) inorganic fertilizers only with increasing N-doses (N); (2) farmyard manuring (FYM) in every third year+N; (3) stalk, straw or green manure+N. Our results clearly proved the advantage of organic matter recycling combined with mineral fertilization over treatment 1. In the fifth and sixth rotations, both types of organic matter recycling resulted in significantly higher Corg contents compared to mineral N fertilization without farmyard manuring or incorporation of crop residues. Grain yields in the field trial were the lowest in treatments without organic matter recycling. In the pot experiment, dry matter production and N accumulation in the grains and vegetative plant parts were also significantly higher in treatments where mineral fertilization was combined with organic matter recycling.