Evaluation and improvement of N fertilization strategies in the wheat/maize double-cropping system of the North China Plain

The North China Plain (NCP) is the main production area of cereal crops in China. The intensification of agricultural systems and the increased use of chemical N fertilizers are contributing to environmental pollution. One of the objectives of this thesis was to apply an Nmin based approach for the calculation of N application rates to a previously over-fertilized farmers field of the NCP and to evaluate the potential of reducing N inputs while maintaining the grain yield of a summer-maize/winter-wheat double-cropping system; and to evaluate fertilizer strategies, aiming to reduce N inputs and loss. Using an Nmin based approach for the calculation of fertilizer application rates, a reduction of fertilizer input by up to 50% compared to farmers practice (550 kg N ha-1 a-1) is possible without negatively affecting the grain yield of a wheat / maize double cropping system. The extreme re-supply of N during the summer-vegetation periods of maize in the first two experimental seasons resulted in high yields of the control treatment (CK: 2009: 5.7 and 2010: 5.9 Mg ha-1), which did not significantly differ from the fertilized treatments. This resulted in a reduced recovery efficiency of N (REN: 0.09 kg kg-1 0.30 kg kg-1). According to the results of this field experiment there was no agronomic justification for the application of fertilizer N. The grain yield of maize of the control treatment finally decreased in the third vegetation period of summer-maize. While maintaining the yield level, the optimized application of N increased REN (0.37 0.58 kg kg-1) significantly compared to farmers practice (0.21 kg kg-1) in this final vegetation period of maize. Wheat, in contrast to maize, is dependent on the application of fertilizer N for yield formation. In both vegetation periods of wheat, REN of the reduced treatments (0.34 1.0 kg kg-1) was significantly higher compared to FP (0.26 and 0.27 kg kg-1). The highest cumulated (5 vegetation periods) agronomic efficiency of N, as well as cumulated grain yield of the wheat/maize double-cropping system was observed when ammoniumsulphate-nitrate was applied in combination with the nitrification inhibitor 3,4-dimethylpyrazolephosphate (ASNDMPP: AEN: 19 kg kg-1, yield: 35 Mg ha-1) and according to crop N demand and residual soil mineral N. The highest REN was observed when urea ammonium nitrate was applied in a shallow, banded depot (UANDEP: 40 kg kg-1). The results of this field experiment further show that the N surplus (fertilized N - grain N) as well as the N balance (N Input - N output) after harvest are significantly lower when an optimized approach to fertilizer application is followed. The over-application of N for an optimized application of urea or ASNDMPP (Surplus: -25kg to 98 kg N ha-1; Balance: -36 to 102 kg N ha-1) was significantly reduced compared to current farmers practice (Surplus: 156kg to 187 kg N ha-1; Balance: 56 to 262 kg N ha-1). This leads to lower residual N in the soil horizon from 0 - 90 cm in the reduced treatments (113 kg N ha-1 at end of experiment) compared to FP (293 kg N ha-1). The results of this experiment indicate that N contained in the residues of maize is available only to the subsequent summer-crop and may sufficiently supply N for the yield formation of maize. Should the over-application of N be effectively reduced in the cropping systems of the NCP it is therefore necessary to take the N mineralization potential of soils into account. Based on the results of this field experiment and others, a crop-soil interface model (HERMES) was calibrated and validated to the conditions of the NCP. Finally, this research observed the effect of wheat straw and the urease inhibitor (UI) N-(n-buthyl) thiophosphoric triamide (nBPT) on the turnover of urea, as well as the loss of ammonia and nitrous oxide from an alkaline soil of the NCP. UI inhibit or reduce the appearance of ammonia after the application of urea and almost completely prevent the loss of N as ammonia (urea: 12 14% loss). nBPT effectively reduces the rate of urea hydrolysis but does not down-regulate the process enough to completely inhibit nitrification, thereby maintaining the availability of N from urea for plants. Further, the addition of wheat straw prolongs the appearance of ammonium after the application of urea while the appearance of nitrate is reduced. Wheat straw may therefore either act as a stimulant of hydrolysis or as an inhibitor of nitrification. The addition of urea increases soil respiration and the emission of N2O drastically, possibly acting as a C and N source for microbial organisms and causing a priming effect on microbial activity in soils. This effect was increased further when wheat straw as well as urea were added to soil. nBPT, in contrast, prevents a significant increase in CO2-respiration and N2O-emission. The urease inhibitor may therefore generally restrict microbial activity or shift nitrification/denitrification processes towards the emission of N2.Die Nordchinesische Tiefebene (NCP) ist Chinas Hauptanbaugebaut für Getreide. Die Intensivierung der Landwirtschaft und der steigende Einsatz chemischer Düngemittel tragen wesentlich zur Umweltverschmutzung in China bei. Ein Ziel dieser Arbeit war es, ein Nmin-basiertes System zur Ermittlung des Düngebedarfs in einer typischen Weizen / Mais Doppelfruchtfolge der NCP anzuwenden. Hierbei sollte das Potential zur Verringerung der Stickstoff (N-)Einträge bei gleichzeitigem Beibehalt der Ertragserwartungen abgewägt werden. Außerdem wurden Strategien, die eine Verringerung sowohl der N-Einträge als auch Verluste zum Ziel haben, mit der gängigen landwirtschaftlichen Praxis (FP) in Hinsicht auf N-Einträge, Ertrag und N-Nutzungseffizienz verglichen. Hierzu wurde über 2.5 Jahre ( 3 * Mais; 2 * Weizen) ein Feldversuch in einem ehemals überdüngten Feld der NCP durchgeführt. Die Anwendung eines Nmin-basierten Systems zur N-Bedarfsermittlung lässt im Vergleich zur gängigen landwirtschaftlichen Praxis eine Verringerung des N-Düngeaufwands um 50% zu, ohne den Ertrag der Weizen / Mais Doppelfruchtfolge zu verringern. Eine extrem hohe Remineralisation von N führte in den ersten zwei Anbauperioden von Mais zu hohen Erträgen der Kontrollbehandlung (CK: 2009: 5.7 und 2010: 5.9 Mg ha-1). Diese Erträge unterschieden sich nicht signifikant von den gedüngten Behandlungen des Versuchs. Aus diesem Grund wurde in den gedüngten Varianten eine sehr geringe N Wiederfindungseffizienz (REN: 0.09 kg kg-1 0.30 kg kg-1) ermittelt. Aus agronomischer Sicht war eine N-Gabe in den ersten zwei Anbauperioden von Mais nicht notwendig. Erst in der dritten Anbauperiode von Mais wurde ein Ertragseinbruch der Kontrollbehandlung beobachtet. Die optimierte N-Düngung führte im Vergleich zu FP (0.21 kg kg-1) zu signifikant höheren N-Nutzungseffizienzen (0.37 0.58 kg kg-1). Im Gegensatz zu Mais ist Winterweizen zur Ertragsentwicklung auf eine N-Gabe angewiesen. Der Nmin-basierte Ansatz zur Ermittlung des Düngebedarfs führte im Vergleich zu FP (0.26 and 0.27 kg kg-1) zu einer signifikant gesteigerten N Wiederfindungseffizienz (0.34 1.0 kg kg-1). Die Ermittlung der kumulierten Erträge und agronomischen Nutzungseffizienz zeigte, dass eine optimierte N-Gabe mit Ammonsulfatsalpeter (ASN) in Verbindung mit dem Nitrifikationshemmstoff 3,4-dimethylpyrazolephosphate (DMPP) mittelfristig die höchsten Erträge sowie agronomische N Effizienz aufwies (ASNDMPP: AEN: 19 kg kg-1, Ertag: 35 Mg ha-1). Die höchste Wiederfindungseffizienz wurde bei einer Depotdüngung mit Ammoniumnitrat-Harnstofflösung ermittelt (UANDEP REN: 0.40 kg kg-1). Die optimierte N-Düngung verringert die N Bilanz nach der Ernte. Die optimierte Düngung von Harnstoff oder ASNDMPP führte zu signifikant verringerten N Bilanzen (-36 to 102 kg N ha-1) im Vergleich zu FP (56 to 262 kg N ha-1). Hierdurch verringerte sich die Überschuss an N im Boden (Urea und ASNDMPP: 113 kg N ha-1 ; FP: 293 kg N ha-1; Versuchsende). N Mineralisation findet hauptsächlich in der Vegetationsperiode von Mais im Sommer statt. Die Ergebnisse dieses Feldversuchs weisen darauf hin, dass N in den Ernterückständen von Mais nicht der dazwischen angebauten Weizenkultur, sondern erst der folgenden Maisfrucht zur Verfügung steht. Die N Mineralisationsrate reicht hier für die Ertragsbildung von Mais aus. Um die Überdüngung mit N effektiv zu verringern, ist es somit notwendig das Mineralisationspotential überdüngter Böden zuverlässig zu bestimmen. Auf Grundlage der Ergebnisse von diesem und weiteren in der NCP durchgeführten Feldversuchen wurde das Boden-Pflanze Interaktionsmodel HERMES am ZALF Müncheberg kalibriert und validiert. In einem Laborversuch wurde der Einfluss von Weizenstroh und dem Urease-Inhibitor (UI) N-(n-buthyl) thiophosphortriamid (nBPT) auf die Umsetzung von Harnstoff, sowie die gasförmigen Emissionen von Kohlenstoffdioxid (CO2), Lachgas (N2O) und Ammoniak (NH3) untersucht. nBPT verringert die Umsetzung von Harnstoff zu Ammonium (NH4+) stark und verhindert fast vollständig NH3 Verluste über einen Zeitraum von 2 Wochen (Harnstoff: 12 14% Verlust). Die Umsetzung des Harnstoff wird hierbei nicht so sehr verlangsamt als dass die Nitrifikationsrate beeinflusst wird. Dadurch ist die Verfügbarkeit von N für Pflanzen gewährleistet. Weiterhin verlängert Weizenstroh das Auftreten von NH4+ und verringert das Auftreten von Nitrat (NO3-). Es könnte somit entweder die Hydrolyse des Harnstoff stimulieren oder als Nitrifikationsinhibtor (NI) agieren. Harnstoff steigerte die Bodenrespiration und Emission von N2O. Unter Zugabe von Weizenstroh kam es zu einer Interaktion der Haupteffekte des Versuchs und einer um Faktor 5 gesteigert N2O-Emission. Die Ergebnisse weisen darauf hin, dass Harnstoff als C und N Quelle für Mikroben fungiert und die mikrobielle Aktivität antreibt. NBPT verhinderte jedoch diesen Interaktionseffekt. Somit verhindert nBPT entweder das Priming der mikrobiellen Aktivität oder es verschiebt die Nitrifikations/Denitrifikationsprozesse zum Verlust von N als N2

Meta-analysis of nutrient budgets in organic farms across Europe

Nutrient supply to organic farms is a highly discussed topic in Europe, due to the restricted availability of external fertilizer resources and the use of contentious inputs. To optimize the flow of nutrients throughout the organic farming system, it is firstly necessary to obtain valid data on the nutrient status of organic farms. Nutrient budgets are a valid tool to investigate the nutrient demand or surplus of a system. However, there is currently no comprehensive overview of nutrient budgets of European organic farms. We therefore carried out a meta-analysis on 56 individual studies that reported either farm-gate or soil-surface budgets. The analysis showed an imbalance between nutrients, a general surplus of nitrogen (45 kg N ha-1 year-1 [95%-confidence interval (CI): 30, 61]), magnesium (16 kg Mg ha-1 year-1 [-9, 40]) and sulphur (45 kg S ha-1 year-1 [-29, 118]), a balanced phosphorus budget (0 kg P ha-1 year-1 [-2,2]), and a deficit for potassium (-12 kg K ha-1 year-1 [-21, -3]). We observed large differences between farms that could be partly explained by farm type and budgeting method. Arable and mixed farms showed lower nitrogen, phosphor, magnesium and sulphur budgets than dairy/beef farms or even vegetable farms, while all farm types besides dairy/ beef farms showed deficits for K budgets. Further, farm-gate budget studies yielded higher budgets than soil surface budgets. Variations between studied countries could also be detected, but the coverage and comparability is low due to differences in studied farm types and budgeting method

Meta-analysis of nutrient budgets in organic farms across Europe

Nutrient supply to organic farms is a highly discussed topic in Europe, due to the restricted availability of external fertilizer resources and the use of contentious inputs. To optimize the flow of nutrients throughout the organic farming system, it is firstly necessary to obtain valid data on the nutrient status of organic farms. Nutrient budgets are a valid tool to investigate the nutrient demand or surplus of a system. However, there is currently no comprehensive overview of nutrient budgets of European organic farms. We therefore carried out a meta-analysis on 56 individual studies that reported either farm-gate or soil-surface budgets. The analysis showed an imbalance between nutrients, a general surplus of nitrogen (45 kg N ha-1 year-1 [95%-confidence interval (CI): 30, 61]), magnesium (16 kg Mg ha-1 year-1 [-9, 40]) and sulphur (45 kg S ha-1 year-1 [-29, 118]), a balanced phosphorus budget (0 kg P ha-1 year-1 [-2,2]), and a deficit for potassium (-12 kg K ha-1 year-1 [-21, -3]). We observed large differences between farms that could be partly explained by farm type and budgeting method. Arable and mixed farms showed lower nitrogen, phosphor, magnesium and sulphur budgets than dairy/beef farms or even vegetable farms, while all farm types besides dairy/ beef farms showed deficits for K budgets. Further, farm-gate budget studies yielded higher budgets than soil surface budgets. Variations between studied countries could also be detected, but the coverage and comparability is low due to differences in studied farm types and budgeting method

Farm gate nutrient budgets in organic farms – a case study in Germany

Low nutrient availability, especially of nitrogen (N) and phosphorus (P), is one of the major constraints on crop yields in organic farming. We investigated the nutrient supply to 20 organic farms in Germany. The investigation showed, that the hgher the reliance on legumes for nitrogen fertilization, the higher is the risk of negative phosphour and potassium budgets

Reliance on Biological Nitrogen Fixation Depletes Soil Phosphorus and Potassium Reserves

Limited nutrient availability is one of the major challenges in organic farming. Little is known about nutrient budgets of organic farms, the underlying factors or effects on soil fertility. We therefore assessed farm gate nutrient budgets for nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg) and sulfur (S) of 20 organic farms in Germany and analyzed their soil nutri-ent status. In average, the budgets showed a surplus of N (19 kg ha−1), K (5 kg ha−1), S (12 kg ha−1), and Mg (7 kg ha−1), and a deficit of P (−3 kg ha−1). There was, however, high variability between farms (e.g. standard deviation up to ± 36 kg N ha−1), which was mainly explained by different degrees of reliance on biological N fixation (BNF) as N source. When farms obtained more than 60% of their N input through BNF, they had deficits of P (mean −8 kg P ha−1) and K (mean −18 kg K ha−1). Nutrient status of most soils was within the ad-vised corridor, but for P, K and Mg, 10–15% of fields were lower and 45–63% were higher than advised. Extractable soil nutrient contents did not correlate with the nutrient budgets, inputs or outputs. Only extractable soil P increased with increasing P inputs and outputs. Fur-thermore, a decrease in extractable soil P was detected with a prolonged history of organic farming, indicating a risk of soil P mining in organic farming systems. In conclusion, the study revealed nutrient imbalances in organic farming and pointed to P and K scarcity as a major challenge for organic farms with high reliance on BNF in the long term

Assessing long term effects of compost fertilization on soil fertility and nitrogen mineralization rate

Background: Fertilization with organic waste compost can close the nutrient cycles between urban and rural environments. However, its effect on yield and soil fertility must be investigated. Aim: This study investigated the long-term effect of compost on soil nutrient and potentially toxic elements (PTEs) concentration, nutrient budgets, and nitrogen (N) mineralization and efficiency. Methods: After 21 years of annual compost application (100/400 kg N ha–1 year–1 [100BC/400BC]) alone and combined with mineral fertilization, soil was analyzed for pH, organic carbon (SOC), nutrient (total N and P, Nmin, extractable CAL-P, CAL-K, and Mg), and PTE (Cu, Ni, Zn) concentrations. Yields were recorded and nutrient/PTE budgets and apparent netmineralization (ANM, only 2019) were calculated. Results:Nefficiency was the highest in maize and formineral fertilization. Compost application led to lower N efficiencies, but increased ANM, SOC, pH, and soil N, and surpluses of N, P, and all PTEs. Higher PTE concentrations were only found in 400BC for Cu. Nutrient budgets correlatedwith soil nutrient concentration. A surplus of 16.1 kg P ha–1 year–1 and 19.5 kgKha–1 year–1 resulted in 1mg kg–1 increase in CAL-P and CAL-K over 21 years. Conclusion: Compost application supplies nutrients to crops with a minor risk of soilaccumulation of PTEs. However, the nutrient stoichiometry provided by compost does not match crop offtakes causing imbalances. Synchronization of compost N mineralization and plant N demand does not match and limits the yield effect. In winter wheat only 65–70% of Nmineralization occurred during the growth period

World-Wide FINGERS Network: A global approach to risk reduction and prevention of dementia

© 2020 The Authors. Alzheimer\u27s & Dementia published by Wiley Periodicals, Inc. on behalf of Alzheimer\u27s Association Reducing the risk of dementia can halt the worldwide increase of affected people. The multifactorial and heterogeneous nature of late-onset dementia, including Alzheimer\u27s disease (AD), indicates a potential impact of multidomain lifestyle interventions on risk reduction. The positive results of the landmark multidomain Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) support such an approach. The World-Wide FINGERS (WW-FINGERS), launched in 2017 and including over 25 countries, is the first global network of multidomain lifestyle intervention trials for dementia risk reduction and prevention. WW-FINGERS aims to adapt, test, and optimize the FINGER model to reduce risk across the spectrum of cognitive decline—from at-risk asymptomatic states to early symptomatic stages—in different geographical, cultural, and economic settings. WW-FINGERS aims to harmonize and adapt multidomain interventions across various countries and settings, to facilitate data sharing and analysis across studies, and to promote international joint initiatives to identify globally implementable and effective preventive strategies

Precision and accuracy of single-molecule FRET measurements - a multi-laboratory benchmark study

Single-molecule Förster resonance energy transfer (smFRET) is increasingly being used to determine distances, structures, and dynamics of biomolecules in vitro and in vivo. However, generalized protocols and FRET standards to ensure the reproducibility and accuracy of measurements of FRET efficiencies are currently lacking. Here we report the results of a comparative blind study in which 20 labs determined the FRET efficiencies (E) of several dye-labeled DNA duplexes. Using a unified, straightforward method, we obtained FRET efficiencies with s.d. between ±0.02 and ±0.05. We suggest experimental and computational procedures for converting FRET efficiencies into accurate distances, and discuss potential uncertainties in the experiment and the modeling. Our quantitative assessment of the reproducibility of intensity-based smFRET measurements and a unified correction procedure represents an important step toward the validation of distance networks, with the ultimate aim of achieving reliable structural models of biomolecular systems by smFRET-based hybrid methods

Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants