Organic conservation tillage – evidence from more than 15 years of research

In Europe, the plough is a common machine for soil tillage. Its history is dating back to the early days of agriculture and hence its use is deeply rooted in European culture. With ongoing heavier machines, larger fields and less landscape diversity, ploughing contributed to large-scale soil degradation. The bare soil surface is prone to erosion; the risk of soil fertility decrease is high. Long-term sustainability of current ploughing practices is therefore questioned. In organic farming, ploughing is seen as an important tool for weed control, ley termination and incorporation of organic material. Yet, also organic farming practices can still be improved. The aim was therefore to replace ploughing by less intensive tillage methods and to monitor changes in soil quality and yield performance. At FiBL, research started roughly in 2000 with both scientific and practice oriented trials and collaborations

Geerdet - wie kommt der Ackerbau wieder in Balance?

Der Klimawandel hat viele seiten. Der Ruf nach Anpassung durch Anbau hitze- und trockenheitsresistenter Pflanzen ist die eine. Der Blick auf die Verursacher ist eine andere. Die biodynamische Landwirtschaft ist besonders klimafreundlich

Enhanced soil quality with reduced tillage and solid manures in organic farming - a synthesis of 15 years

Demands upon the sustainability of farming are increasing in step with climate change and diversity loss. Organic farming offers a viable approach. To further improve organic management, three strategies with potential to enhance soil quality are being tested in a long-term trial since 2002 on a clay loam in temperate Switzerland: reduced tillage vs. ploughing, solid vs. liquid manures and biodynamic preparations. A synthesis of 15 years reveals an increase in topsoil organic carbon (SOC, +25%), microbial biomass (+32%) and activity (+34%) and a shift in microbial communities with conversion from ploughing to reduced tillage. Soils under reduced tillage are more stratified in SOC and nutrients. Additional application of composted manure has increased SOC by 6% compared to pure slurry application, with little impact on soil microbes. Biodynamic preparations have had a minor impact on soil quality. Fertilisation and biodynamic preparations did not affect yields. Both higher and lower yields were harvested in the reduced tillage system in relation to ploughing. The main yield determinants were N supply and higher weed infestation under reduced tillage. Continuously reduced tillage in organic farming has been proven to enhance soil quality at this site, while also presenting more challenges in management

Erratum to “Geometrical and mechanical properties of four species of northern European brown macroalgae”[Coast. Eng. 84 (2014) 73–80]

© 2016 This erratum concerns Eq. (1) used in Paul et al. [3] which is the same as Eq. (1) in Paul and Henry [4]. A three-point bending test with clamped ends was performed on macroalga blade samples. As suggested in Fig. 1, this mechanical test was considered by Paul et al. [3] as equivalent to a cantilever with one fixed end and one free end, with a span s/2, bending under half the load recorded during a three-point bending test. Following the classic static, or Euler, beam theory (see e.g. Gere and Goodno [2]), the flexural rigidity of such a free-hanging cantilever is given by where according to Paul et al. [3], s is the distance between clamped ends of the sample, P the applied force and h the resulting maximal vertical deflection. However, it was a conceptual error to assume equivalency of a three-point bending test with clamped ends and a free-hanging cantilever with half the load. This note aims to correct this conceptual error and clarify the formulation of the flexural rigidity for different set-ups using the basic principles of Euler beam theory. Correct formulation of the flexural rigidity The flexural rigidity of a beam fixed at both ends with a concentrated load in its center can also be derived from the classic static beam theory, and is often found in beam design manuals such as [1]. Consider a clamped beam loaded at its center with a point force P (Fig. 2), the correct formulation of the flexural rigidity J for such a set-up is: Consequences for the work of Paul et al. [3] and Paul and Henry [4] It will be noted that Eqs. (1) and (2) differ by a factor 4. As a consequence, the flexural rigidities and Young's tangent moduli obtained for macroalga blade samples by Paul et al. [3] (Tables 1 & 2, Fig.5 and throughout the text) and Paul and Henry [4] (Table 1 and throughout the text) should be divided by 4. Although absolute values are impacted by this error, relative values are not and so the discussion of results and the scientific conclusions of both Paul et al. [3] and Paul and Henry [4] are not affected and are still valid. To prevent similar error in futur works, Fig. 3 gives a reminder of three common set-up use to characterise the bending properties of a beam, and details the correct formulations to compute the flexural rigidity of these different tests. These results can readily be derived from Euler's beam theory

Gut für den Boden, gut fürs Klima

Erste Ergebnisse eines Versuchs des Forschungsinstitut für biologischen Landbau (FiBL) zeigen, dass durch reduzierte Bodenbearbeitung im ökologischen Landbau mehr Kohlenstoff gespeichert und die Ertragssicherheit gesteigert werden kann. Voraussetzung dafür ist jedoch eine Optimierung des pfluglosen Systems

Anchor Forces on Coir-Based Artificial Seagrass Mats: Dependence on Wave Dynamics and Their Potential Use in Seagrass Restoration

Seagrasses represent an essential part of the coastal environment and are hence the target of many coastal restoration projects. Artificial seagrass (ASG) mats may facilitate seagrass growth, making them a captivating option for restoration projects. However, little is known about the forces occurring on mats deployed in marine environments and especially on how these forces are transmitted to the anchoring points. Here, we present a study of prototype biodegradable coconut-mesh mats as base layer for ASG meadows and investigate the forces that occur at the anchors. We test the performance of three mesh types under wave forcing using two different anchor configurations without ASG and subsequently test ASG mats of one mesh type under wave forcing and a 4-anchor configuration to assess the effect of the ASG on anchor loading as a function of incident orbital velocities. We found that the mat composition plays a more important role than the number of anchors in anchor load reduction. The anchor forces were 2–4 times higher at front anchors compared to rear anchors, relative to wave propagation direction, and were also considerably higher in that direction compared to the opposite direction. With ASG, the forces increased compared to the highest measured forces without ASG. The forces on the anchors were almost fully dominated by the drag on the ASG based on material properties, ASG reconfiguration and flow conditions. We derive a relation between horizontal orbital velocities and expected forcing on the anchor based on ASG properties and the corresponding area of each anchor and discuss relevant criteria for the design of ASG mats. This should help to assess the loading on anchors deployed for restoration under specific site conditions and chosen materials. Copyright © 2022 Villanueva, Paul and Schlurmann

Auswirkungen des langfristigen ökologischen Landbaus auf bodenbürtige Treibhausgasemissionen

Despite the increase in organic cropland, knowledge on the impact of organic farming on soil-derived nitrous oxide (N2O) and methane (CH4) emissions is rather limited. To improve the knowledge base, N2O and CH4 fluxes were investigated in a 571 day lasting cropping sequence in the “DOK” field trial. Two organic and two non-organic farming systems and an unfertilized control were chosen. For the whole monitoring, the two organic systems combined emitted 40% less N2O than the two non-organic ones cumulated on area-scale. Yield-scaled cumulated N2O emissions were nearly 10% lower for the organic systems combined, despite the yield gap of 27%. We found that besides N input, management induced soil quality properties drive differences in N2O emissions between farming systems as well. This supports the effort to invest in soil quality by ecological intensification not only to lower the environmental burden of agriculture but also to mitigate greenhouse gase

Beikrautsamenvorrat im Vergleich reduzierter und konventioneller Bodenbearbeitung unter Biobedingungen

Armengot L, Berner A, Blanco-Moreno J, Mäder P & Sans FX (2014) Long-term feasibility of reduced tillage in organic farming. Agron Sustain Dev 35(1): 339-346. Cooper J et al. (2016) Shallow non-inversion tillage in organic farming maintains crop yields and increases soil C stocks: a meta-analysis. Agron Sustain Dev 36: 1-20. Gruber S & Claupein W (2009) Effect of tillage intensity on weed infestation in organic farming. Soil and Tillage Research 105(1): 104-111. Montgomery DR (2007) Dirt: The Erosion of Civilizations. University of California Press, California. Moonen AC & Barberi P (2004) Size and composition of the weed seedbank after 7 years of different cover-crop-maize management systems. Weed Research 44(3): 163-177

Reduzierte Bodenbearbeitung weiterentwickeln

Gewendeter, ungeschützter Boden ist erosionsanfällig. Weltweit ging so schon ein Drittel aller Ackerflächen verloren. Eine reduzierte Bodenbearbeitung wirkt dem entgegen. Es entsteht ein reicheres Bodenleben und bei zusätzlicher Gründüngung gibt es sogar ebenso viel Ertrag wie auf konventionellen Äckern. Das System muss noch verbessert und mehr Biolandwirten nahegebracht werden