Soil organic matter of a sandy soil influenced by agronomy and climate

Long term field experiments are being conducted at Humboldt University of Berlin (Germany) to obtain information regarding sustainable management of arable land with sandy soils. In Thyrow, a location in the south of Berlin with silty and sandy soil (85 % sand, 12 % silt, 3 % clay, 0.5 % Corg, pH 5.5) several experiments have been carried out since 1937. They include the study of the long-term effects of the agronomic factors of: crop rotation; organic fertilization; mineral fertilization and irrigation on soil and crops. The results of annual Corg measurements make it possible to describe the influence of agronomic management and climate on the development of soil organic matter (SOM). The following ranking of agronomic factors was observed from greatest to lowest influence: Organic fertilization > crop rotation > mineral N-fertilization > irrigation. Organic fertilization with Farm Yard Manure (FYM) increases the content of Organic Carbon by 53 % compared with the control. A crop rotation consisting of cereals only leads to 34 % higher carbon contents than crop rotations including cereals and maize or potatoes respectively. Mineral nitrogen fertilization increases the Corg content from between 19 to 32 % but only a minor effect of 2 to 8 % was detected with irrigation treatments. At the Nutrient Deficiency Experiment Thyrow, contents of SOM have been analysed since 1965. In general, the results show a decreasing level of SOM contents with all treatments of fertilization. Over a period of 40 years the organic carbon content lost 10 to 13 % while the average air temperature rose by 1.2 °C

Comparing the reliability of maize variety data from on-farm trials and experimental stations

Sortenempfehlungen basieren in der Regel auf regionalspezifischen Exaktversuchen. Dabei können die Wechselwirkungen zwischen Sorte und Umwelt sowie zwischen Sorte und Management zu steigenden Problemen bei der Sortenwahl führen. Eine ergänzende Möglichkeit sind daher dezentralisierte Sortenversuche in Landwirtschaftsbetrieben. Für die direkte Sortenwahl bieten diese On-Farm-Versuche eine hohe Praxisrelevanz, da die tatsächlichen Einflussgrößen im Betrieb getreuer abgebildet werden können, als es Exaktversuche vermögen, wenn sie nur an wenigen, zum Teil eingeschränkt repräsentativen Standorten durchgeführt werden. Andererseits ist die Aussagefähigkeit von On-Farm-Versuchen häufig durch Störgrößen und fehlende Feldwiederholungen begrenzt. Anhand von Maissortenversuchen mit sechs verschiedenen Sorten wurden auf vier Brandenburger Landwirtschaftsbetrieben sowie auf zwei Versuchsstationen die Sortenleistung in On-Farm- und Exaktversuchen auf Sandböden geprüft. An jedem Standort wurde die Varianz der Sortenrankings über die Jahre genutzt, um Informationen über die Konsistenz der Sortenleistung an jedem der Standorte zu gewinnen. Für den Trockenmasse-Ertrag zeigten die On-Farm-Versuche sowohl die höchste, als auch die niedrigste Konsistenz der Rankings. Einige Qualitätsparameter, wie die Nichtfaser-Kohlenhydrate (NFC) und der Stärkegehalt, zeigten in den On-Farm-Versuchen eine bessere Konsistenz des Sortenrankings über die Jahre als in beiden Exaktversuchen. Dies legt nahe, dass On-Farm-Versuche das Potenzial haben, die regionale Leistungsprüfung von Sorten zu unterstützen. DOI: 10.5073/JfK.2014.11.03, https://doi.org/10.5073/JfK.2014.11.03While current variety recommendations are based on replicated small-plot trials in a specific region for which the trial is thought to be representative, genotype × envi­ronment interactions, genotype × management interactions, and increasing weather fluctuations make it increasingly difficult to predict which variety will be best in a given environment. An additional approach is therefore to decentralize variety trials and place them on working farms. However, although on-farm trials offer potentially more relevance for direct variety selection on site, they are also likely to be subject to more noise and trial entries can often not be fully replicated. To evaluate the relative merit of on-farm trials vs. fully replicated trials conducted at experimental stations, we tested 6 maize varieties at four farms and at two stations in a region dominated by sandy soils. The variance of variety rankings over the years within each site was used as proxy to evaluate the consistency of variety information gained at each location. For dry matter yield, on-farm trials showed both the highest and the lowest consistency of variety ranking, with the consistency being intermediate at the experimental stations. For some quality parameters, namely non-fibre carbohydrate and starch content, the majority of on-farm trials showed more consistent variety ranking over the years than the more consistent of the two replicated trials. This suggests that in terms of year-on-year reliability of maize yield and quality, on-farm trials may have the potential to complement replicated variety trials. For both types of trials, however, there is also scope for decreasing technical sources of variation. DOI: 10.5073/JfK.2014.11.03, https://doi.org/10.5073/JfK.2014.11.0

Organic Manure Increases Carbon Sequestration Far beyond the “4 per 1000 Initiative” Goal on a Sandy Soil in the Thyrow Long-Term Field Experiment DIV.2

Carbon sequestration has been proposed as a way to mitigate the impact of CO2 on the climate. At the COP21, the ‘4 per 1000 Soils for Food Security and Climate’ initiative was launched with the goal to increase global soil organic carbon (SOC) stocks by 4‰ per year. The Thyrow long-term field experiment DIV.2 was chosen to determine the feasibility of this 4 per 1000 goal under the dry and sandy conditions in Eastern Germany. The effects of different fertilizing regimes on SOC contents and winter rye yields were investigated. Winter rye is a representative crop for the region and grown as a monoculture in the experiment. The 4 per 1000 goal was achieved in all treatments including the unfertilized control, although ploughing takes place and straw is removed every year. The highest carbon sequestration of up to 0.5 t ha−1 a−1 was provided by a combination of mineral and manure fertilization. In three out of four years, no yield difference was observed between mineral-only fertilization (120 kg ha−1 N) and a combination of mineral and organic N (97.4 kg ha−1 plant available N) fertilization. Yields increased over the years in the treatment with pure organic N and decreased in all other treatments.Peer Reviewe

Risk efficiency of irrigation to cereals in northeast Germany with respect to nitrogen fertilizer

The potential role of irrigation of cereals as a response to climate change is under debate. Especially under temperate continental conditions empirical evidence of crop yield response to irrigation in interaction with nitrogen fertilizer supply is rare. Besides mean yield effects, irrigation reduces yield variance, which may be an incentive for farmers to use irrigation. This paper investigates the risk-efficiency of irrigation in cereal production in a temperate continental climate, based on data from a long term field experiment on a sandy soil. Irrigation and no irrigation of winter rye (Secale cereale) and winter barley (Hordeum vulgare) were investigated in three different nitrogen (N) fertilizer levels. Crop yield response data (1995–2010) to irrigation and N fertilizer were used to calculate net returns, certainty equivalents (CE) for different levels of risk aversion and the conditional value at risk (CVaR) as a downside risk indicator in two price scenarios. The scenarios were calculated with a total cost and a partial budget approach. Irrigation was found to be profit-maximizing in all partial budget calculations, which sometimes required higher N input to be profit-maximizing. Irrigation and N fertilizer reduction were identified as risk mitigation strategies, even though their impact was limited. Irrigation reduced the downside risk only in the partial budget calculations. The analysis based on the CE did not show improved risk efficiency with irrigated management options. In contrast, reduced fertilizer input proved to be risk efficient at specific levels of risk aversion. The price expectations of winter rye and winter barley had a much higher impact on the ranking of the management options than risk aversion based on the crop yield variances. At low crop prices for all levels of risk aversion, irrigation of winter barley and winter rye was only economically justified if fixed costs for irrigation were not taken into account. At high crop prices, irrigation of winter barley was also justified based on the total cost calculation. However, this advantage was only given at a very low level of risk aversion. With increasing levels of risk aversion irrigation was not efficient based on the CE in the total cost accounting scenario. In conclusion, irrigation of cereals can contribute to downside risk mitigation and increased profits, if fixed costs for irrigation are covered. However, this conclusion holds only when irrigation is combined with an increased N intensity. If total costs need to be accounted for, irrigation in cereals is not an appropriate risk reduction strategy and a reduction of N input is more effective

Feldversuche zur Wirkung von Spinosad-, Neem- und B.t.t.- Präparaten auf die Regulierung des Kartoffelkäfers (Leptinotarsa decemlineata Say)

The Colorado potato beetle (CPB) is one of the most important pests on potatoes (Solanum tuberosum). In many areas, preventive measures are not sufficient enoughto prevent the damage caused by the CPB. Therefore insecticides such as neem and Bacillus thuringiensis v. tenebrionis (B.t.t.) have an important role in organic potato production in Germany. The new insecticide Spinosad was added to Council Regulations (EEC) No. 2092/91 on organic production in 2008. It is now possible to use Spinosad in organic agriculture in the EU. The active ingredient of Spinosad is obtained from the bacterium Saccharopolyspora spinosa through fermentation. Field studies compared three treatments to control CPB in 2008. 1: single Spinosad treatment (24 g/ha active ingredient (a.i.)) 2: first treatment B.t.t. (60 g/ha (a.i.)), second treatment (+4d) B.t.t. (100 g/ha a.i.) 3: first treatment neem (25 g/ha a.i.), second treatment (+4d) B.t.t. (100 g/ha a.i.). There was an average of 27 larvae per plant before the treatments. All treatments displayed nearly the same significant degree of effectiveness (78 % - 82 %) with regards to the damaged leaf area 25 days after treatment in comparison to the untreated control. The increment of the Spinosad treatment to untreated control was significant with more than 103 dt/ha

Eco-stability of winter rye varieties under site conditions of Brandenburg

Im Mittelpunkt der Untersuchung von Winterroggensorten unter Standortbedingungen Brandenburgs standen die folgenden Fragestellungen: Bieten Hybridroggensorten im Vergleich der Sortentypen neben einer höheren Ertragsfähigkeit auch eine bessere Ökostabilität, vor allem auch unter trockenen Witterungsbedingungen? Welche Unterschiede auf Sortenebene bestehen hinsichtlich der Ökostabilität? Dazu wurden auf Basis von mehrortigen und mehrjährigen Ergebnissen aus Sortenversuchen in Brandenburg und unter Nutzung biostatistischer Parameter verschiedene Roggensorten analysiert. Die Sortenbewertung zur Ökostabilität und Ertragsleistung umfasste neben der deskriptiven Statistik und Varianzanalyse folgende Parameter: Ökovalenz, Ökoregression und Floating Checks. Zusätzlich wurden verschiedene Einflussgrößen auf die Ertragsvariabilität geschätzt und die Sortenreaktion auf unterschiedliche Witterungsbedingungen anhand der klimatischen Wasserbilanz geprüft. Abschließend erfolgte eine kurze Bewertung der verwendeten Parameter und Methoden. Die Ergebnisse der Sortenversuche zeigten, dass die Umwelt (Ort × Jahr) den stärksten Einfluss auf die Ertragsvariabilität hatte. Gegenüber der Umweltwirkung war der Sorteneinfluss geringer. Trotzdem bestanden zwischen den Sorten deutliche Unterschiede hinsichtlich der Leistungsfähigkeit, Ökostabilität und der Reaktion auf differenzierte Umweltbedingungen. Die Hybridroggensorten erwiesen sich im Vergleich der Sortentypen als deutlich ertragsfähiger und tendenziell ökostabiler, vor allem auch unter trockenen Witterungsbedingungen. Die Ergebnisse sind für die Sortenprüfung und -bewertung, die Züchtung und die landwirtschaftliche Praxis gleichermaßen bedeutsam. Sie liefern Informationen zu den umweltabhängig variierenden Eigenschaften der Sorten und bieten Unterstützung für die standortgerechte Sortenempfehlung sowie bestmögliche Sortenwahl durch Entwicklung eines Bewertungsschemas.    The main questions addressed by the present study were: Provide hybrid varieties as compared to other variety types in addition to a higher yield also an improved eco-stability, especially under dry weather conditions? Which differences in eco-stability between varieties of winter rye can be found? To answer the question results from variety trials at multiple environments of Federal State Brandenburg were used and different varieties of winter rye were analyzed according to several bio-statistical parameters. The evaluation of eco-stability and yield capacity included following parameters: Eco-valence, eco-regression and floating checks. Additionally, different impact factors on variability of yield were estimated and the reaction of varieties to different weather conditions was analyzed based on the climatic water balance. Finally a brief review of the used methods and parameters is given. The results of the different tests showed that the yield performance is determined by different environmental factors and by variety. The factor environment (site × year), which includes soil and weather throughout the course of the year, had the strongest influence on the variability of yield. The factor variety was comparatively less influential, but in special environments it can have an important influence on grain yield. There are also considerable differences between varieties with regard to the criteria eco-stability, yield capacity and their response to differentiated environmental conditions. The hybrid varieties compared to other variety types were considerably higher in yield and in tendency more stable in yield, especially also under dry weather conditions. The evaluation results are important for plant breeding as well as for the choice of site-adapted varieties in agricultural practice. They offer information to environment dependent properties of varieties and can support variety selection in breeding and official variety recommendation by using an optimized evaluation scheme.   &nbsp

Yield stability of winter wheat grown in Brandenburg

Im Mittelpunkt der Untersuchung von Winterweizen­sorten unter Standortbedingungen Brandenburgs stand die Fragestellung: Welche Sortenunterschiede bestehen hinsichtlich der Ökostabilität, der Leistungsfähigkeit und der Reaktion auf trockenere Witterungsbedingungen? Dazu wurden auf Basis von mehrortigen und mehr­jährigen Ergebnissen aus Sortenversuchen in Brandenburg und unter Nutzung biostatistischer Parameter verschiedene Weizensorten beurteilt. Die Bewertung zur Ökostabilität und Leistungsfähigkeit umfasste neben der deskriptiven Statistik die Parameter Ökovalenz, lineare Regressionsanalyse und Floating Checks. Weiterhin wurden verschiedene Einflussgrößen auf die Ertragsvariabilität im Rahmen einer Varianzkomponentenanalyse berechnet und die Sortenreaktion auf unterschiedliche Witterungsbedingungen anhand der klimatischen Wasserbilanz geprüft. Die Auswertung der Sortenversuche zeigte, dass die Umwelt (Ort × Jahr) den stärksten Einfluss auf die Ertragsvariabilität hatte. Im Vergleich dazu war der Sorteneinfluss deutlich geringer. Dennoch wiesen die Sorten deutliche Unterschiede hinsichtlich der Leistungsfähigkeit, Ökostabilität und der Reaktion unter differenzierten Umweltbedingungen auf. Die Ergebnisse sind für die Sortenprüfung und -bewertung, die Züchtung und die landwirtschaftliche Praxis gleichermaßen bedeutsam. Sie liefern Informationen zu den umweltabhängig variierenden Eigenschaften der Sorten und bieten Unterstützung für die standortgerechte Sortenempfehlung sowie bestmögliche Sortenwahl durch die Entwicklung eines Bewertungsschemas.    This study of winter wheat varieties grown under environmental conditions in the Brandenburg region focuses on the following question: How do winter wheat varieties differ in terms of yield stability, yield capacity and response to dry weather conditions? To answer this question, we drew on the results from variety trials carried out over a period of several years and at several different locations in the German Federal State of Brandenburg and analysed different varieties of winter wheat according to the following bio-statistical parameters: ecovalence, linear regression and floating checks. We then estimated different factors affecting yield variability and analysed the response of varieties to different weather conditions according to the climatic water balance. The study showed that environmental factors had the greatest influence on yield variability, whilst variety had a significantly smaller effect. Nevertheless, there were considerable differences between varieties with regard to yield capacity, yield stability and response to environmental conditions. The results are equally important for variety testing and evaluation and plant breeding as well as for agri­cultural practice. They provide information about the variable, environment-dependent traits of varieties and through the development of an evaluation scheme, can help breeders to select optimum varieties and make recommendations of suitable site-adapted varieties to farmers.   &nbsp

Composted biowaste digestates as fertilizers: effects on soil chemistry and plant development in a three-year field trial

In einem dreijährigen Feldversuch wurden kompostierte Gärreste aus Bioabfällen hinsichtlich ihrer pflanzenbau­lichen Einsatzmöglichkeiten und ihrer Wirkung auf boden­chemische Parameter geprüft. Zudem wurden die Auf­be­reitungsverfahren Pelletierung und Agglomeratbildung und deren Auswirkung auf die Gärprodukteigenschaften untersucht. Es wurde festgestellt, dass die unmit­telbare Düngewirkung der Produkte aufgrund der niedrigen Stickstoffverfügbarkeit gering ist. Allerdings zeigte sich nach der Anwendung eine deutliche Erhöhung der Kohlenstoffgehalte im Boden, was auf ein relevantes Humusreproduktionspotential durch derartige Gärprodukte schließen lässt. Agglomeratbildung und Pelletierung scheinen die Mineralisierung der Produkte weiter zu verlangsamen, was sich auf die Nährstofffreisetzung negativ, auf eventuelle Kohlenstoffsequenzierung jedoch positiv auswirkt. Problematisch sind speziell bei Bioabfällen hohe Gehalte an Schwermetallen und anderen Störstoffen. Die gesetzlich vorgegebenen Grenzwerte wurden in 50% der untersuchten Chargen überschritten, wobei jedoch nur max. 7% der ausgebrachten Schwermetalle im oberirdischen Pflanzenmaterial wiedergefunden wurden.In a three-year field trial, composted digestates from biowaste were tested for their potential for plant cultivation and their effect on soil chemical parameters. In addition, the preparation processes of pelleting and agglomeration and their effect on the digestate properties were investigated. It has been found that the immediate fertilising effect of the products is low due to the low nitrogen availability. However, there was a significant increase in carbon content in the soil, suggesting a relevant humus repro­duction potential from such digestate products. Agglo­merate formation and pelleting appear to further slow the mineralization of the products, negatively affect­ing nutrient release but positively impacting carbon sequenc­ing. Particularly problematic in biowaste are high levels of heavy metals and other impurities. The statutory limits were exceeded in 50% of the batches exa­mined, but only max. 7% of the discharged heavy metals were recovered in the aboveground plant material