Strategies for Nitrogen Fertilization of Winter Wheat Using Ammonium Stabilized Fertilizers. 1. Interaction Between Fertilization Systems, Climatic Conditions and Soils

Stabilisierter Ammonium-Stickstoff wird im Boden verzögert nitrifiziert und verlangt einen differenzierten Einsatz im Vergleich zu herkömmlichen N-Düngern. Ausgehend von einem N-Düngesystem mit bis zu vier Teilgaben wurden die Auswirkungen unterschiedlicher N-Verteilungsmuster und N-Formen auf Ertrag und Qualität von Winterweizen untersucht. Geprüft wurden Ammonsulfatsalpeter (ASS) mit dem Stabilisator 3,4-Dimethylpyrazolphosphat (DMPP). Folgende Ergebnisse wurden in den Jahren 1999 bis 2003 erzielt: 1. Die Weizenbestände haben die N-Menge von 180 kg N ha–1 in einer Gabe als stabilisiertes ASS ohne deutliche Lagerschäden vertragen. Das Ertragsniveau des Standardsystems wurde jedoch um 1,8 dt ha–1 verfehlt. 2. Die kombinierte Anwendung von Kalkammonsalpeter mit 60 kg N ha–1 zu Vegetationsbeginn gefolgt von stabilisiertem ASS mit 120 kg N ha–1 zum Schossen führte zu einem signifikanten Mehrertrag von 3,3 dt ha–1. Über die Versuchsdauer von fünf Jahren war dieses Düngesystem relativ ertragsstabil. 3. Düngesysteme mit stabilisiertem ASS haben die Risiken der Witterung maßgeblich vermindert, zeigten aber in Abhängigkeit von Witterung und Bodenqualität eine differenzierte Reaktion: (a.) Das schosser-betonte N-Düngesystem war bei Niederschlägen unter 100 mm in den Monaten Mai/Juni anderen N-Düngesystemen überlegen. Je weniger Niederschläge in dieser Zeitspanne fielen, desto höher war die positive Ertragsreaktion. (b.) Je geringer die Ackerzahl eines Bodens war, desto größer war der Einfluss eines Düngesystems mit stabilisiertem Stickstoff. Auf Böden mit hoher Ackerzahl wurden die Effekte unterschiedlicher N-Düngesysteme und die Einflüsse der Niederschläge nahezu ausgeglichen.The retarded nitrification of stabilized ammonium fertilizer requires a fertilization system different from standard application. Refering to a conventional system with a split of three to four nitrogen rates, new systems have been developed by using ammonium sulphate nitrate (ASN) with the nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP). Field trials, which were conducted on typical agricultural soils in the years 1999 to 2003, brought following results: 1. After application of 180 kg N ha–1 as stabilized ASN in one rate no serious damage by lodging has been observed. The yield response was only 0.18 t ha–1 below the conventional system with four applications. 2. The combined application of calcium ammonium nitrate fertilizer with 60 kg N ha–1 at the beginning of vegetation followed by stabilized ASN with 120 kg N ha–1 at GS 30/32 led to a positive yield response of 0.33 t ha–1. Over a period of five years the yield response was very constant. 3. Fertilizing sytems using stabilized N fertilizer decreased the risks of dry weather conditions. The reaction of winter wheat could be shown as a function of weather in spring and fertility of soil: (a.) The high rate of stabilized ASN (120 kg N ha–1) at the growth stage of stem elongation led to a positive yield response, when the precipitation in May and June was less than100 mm. The less the precipitation was, the higher was the positive yield response of winter wheat. (b.) The lower the yield potential of a soil the higher was yield response of winter wheat to fertilization systems using stabilized ammonium. Soils with high fertility based on higher field water capacity equalize different nearly fertilization systems and the influence of weather conditions

Strategies for Nitrogen Fertilization of Winter Wheat Using Ammonium Stabilized Fertilizers. 2. Effects on Yield Components and Grain Quality

In einer Versuchsserie von 1999 bis 2003 wurde der Einsatz von stabilisiertem Stickstoff bei unterschiedlicher Verteilung geprüft. Ausgehend von dem konventionellen N-Düngesystem mit bis zu vier Teilgaben wurden beim Einsatz von stabilisiertem Ammonsulfatsalpeter (ASS) jeweils zwei N-Gaben zu Vegetationsbeginn bzw. zum Schossen zusammengelegt. Der Winterweizen reagierte positiv auf ein System mit einer geringen Andüngung von bis 60 kg N ha-1 als Kalkammonsalpeter (KAS), gefolgt von einer schosser-betonten N-Gabe von ca. 120 kg N ha-1 als stabilisierter ASS. Folgende Ergebnisse wurden erzielt: 1. Der Mehrertrag von 3,3 dt ha-1 gegenüber der Standarddüngung ergab sich aus einem höheren Kornansatz von etwa drei Körnern pro Ähre. Bestandesdichte und TKG wiesen keine signifikanten Unterschiede in den Düngungsvarianten auf. 2. Der Rohproteingehalt wurde durch das Vorziehen der Spätdüngung auf das Schossen (ES 30/32) nicht negativ beeinflusst. Er lag auf gleichem Niveau wie nach dem Standard-Düngesystem, konnte aber durch eine zusätzliche N-Gabe von 40 kg N ha-1 zum ES 49 um 0,8%-Punkte angehoben werden. 3. Das schosser-betonte N-System mit stabilisiertem Stickstoff führte im Vergleich zum konventionellen Düngesystem zu einer erhöhten N-Konzentration im Aufwuchs während der Schossphase und zu einer Vergrößerung der Fläche des Fahnenblattes um 12%.From 1999 to 2003 field trials have been conducted at different sites in Germany in order to develop a fertilization system with stabilized ammonium sulphate nitrate (ASN) compared to a standard application with ammonium nitrate containing fertilizers (CAN). The tested N stabilizer was the nitrification inhibitor 3, 4-dimethylpyrazole phosphate. The yield response of winter wheat to a combined application of 60 kg N ha-1 as CAN at beginning of vegetation in spring and 120 kg N ha-1 as stabilized ASN at growth stage 30/32 was positive. Following effects were found: 1. The yield increase of 0.33 t ha-1 derived from a better grain set by nearly 3 grains per ear. Ear density and thousand kernel weight were not affected by the fertilization systems. 2. The content of crude protein has not been altered by the different distribution of fertilizer nitrogen. An additional N application of 40 kg N ha-1 at growth stage 49 applied after 60+120 kg N ha-1, however, led to a significantly higher crude protein content (+0.8% absolute). 3. The application of 120 kg N ha-1 as ASN stabilized nitrogen at growth stage 30/32 induced a higher N concentration in green shoots during stem elongation and 12% larger area of flag leaf

Palaeogenomic analysis of black rat (Rattus rattus) reveals multiple European introductions associated with human economic history

The distribution of the black rat (Rattus rattus) has been heavily influenced by its association with humans. The dispersal history of this non-native commensal rodent across Europe, however, remains poorly understood, and different introductions may have occurred during the Roman and medieval periods. Here, in order to reconstruct the population history of European black rats, we generated a de novo genome assembly of the black rat, 67 ancient black rat mitogenomes and 36 ancient nuclear genomes from sites spanning the 1st-17th centuries CE in Europe and North Africa. Analyses of mitochondrial DNA confirm that black rats were introduced into the Mediterranean and Europe from Southwest Asia. Genomic analyses of the ancient rats reveal a population turnover in temperate Europe between the 6th and 10th centuries CE, coincident with an archaeologically attested decline in the black rat population. The near disappearance and re-emergence of black rats in Europe may have been the result of the breakdown of the Roman Empire, the First Plague Pandemic, and/or post-Roman climatic cooling.Competing Interest StatementThe authors have declared no competing interest.- Results and Discussion -- The demographic history of Rattus rattus and its closely related species -- A global phylogeography of the black rat based on mitochondrial DNA -- Ancient genomes reveal the relationships of European black rats over space and time - Discussion - Method

Effect of combining urea fertilizer with P and K fertilizers on the efficacy of urease inhibitors under different storage conditions.

Purpose Urease inhibitors provide a simple solution to mitigate ammonia loss from fertilized soil. Consumption of bulk blend fertilizers and compound fertilizers were increased in recent year and its enhanced efficiency and stabilized techniques were urgently required. However, it is essentially unknown if and how the efficacy of urease inhibitors is influenced by the inclusion of phosphorus (P) and potassium (K) fertilizers with urea. Materials and methods A laboratory study was therefore conducted to assess the impact of P and K (bulk blend scenario: combing urea with di-ammonium phosphate (DAP); compound fertilizer scenario: nitrogen (N)-P-K proportion as 16-16-16 (CN16) or 32-0-6 (CN32)) and additionally the impact of fertilizer storage duration and temperature on the efficacy of two different urease inhibitors NBPT and Limus® in reducing ammonia volatilization following application to soil. Results and discussion Both urease inhibitors significantly reduced ammonia loss from urea regardless of storage temperature and time. However, mixed storage of urea and DAP with urease inhibitors significantly decreased the efficacy of NBPT and Limus® in reducing ammonia loss. Ammonia loss increased exponentially with DAP addition rate and with storage time of the mixture. Storage at a higher temperature (30 °C compared with 20 °C) also reduced the efficacy of the inhibitors. Adding magnesium sulfate (MgSO4) to urea plus Limus® significantly mitigated the negative effect of DAP mixed storage on the efficacy of Limus® regardless of storage temperature and time. The urease inhibitors did not significantly reduce ammonia loss from CN16, but were effective for reducing ammonia loss from CN32. Conclusions The efficacy of urease inhibitors was compromised by P fertilizer. Urease inhibitor inclusion in the production of CN32, urea, and its blends (DAP + MgSO4) are recommended as an effective means of reducing the environmental cost causing by intensive agricultural production