Potential and Limits of Pesticide Free Apple Growing by a Self-Regulating Orchard Set-Up: Project Presentation and First Experiences

Different research groups have already proven that flowering plants in orchards can enhance beneficial arthropods. Even within the tree rows different beneficial can be supported by selected plant species. In most experimental work done to stabilize the apple production system only single interaction effects were tested. However until now, no research group has quantified the additive effects of multiple measures on systembiodiversity and on the production economy. Our experiment combines all known measures of indirect pest and disease control measures in a near-to practical production model orchard without the use of any pesticide (not even organic ones). The orchard is split in 4 blocks: in two of them bio-control measures e.g. application of Granulosis Virus against codling moth (C. Pomonella) are applied; in the other two blocks no bio-control is applied. Standard commercial organic and integrated orchards with the disease-susceptible cultivar Gala in the vicinity of the model orchard are assessed by the same methods and serve as reference. Our intermediate results reveal that the self-regulating orchard developed already in the 2nd and 3rd leaf a clearly higher flora and fauna biodiversity compared to the reference orchards. The same happened in relation to the specific fruit beneficial e.g. the populations of aphid predators. In the self-regulating orchard they were capable to keep the aphid damages – in particular of the powdery apple aphid (D. plantaginea) - on trees and fruits under a commercially relevant level although the initial abundance of aphid colonies in spring was by far over the common threshold value. It is planned to continue the experiment until 2016

Vom Reisebüro zur Tourismuskritik

Der Autor des Beitrags, Bankkaufmann, Betriebswirtschaftler, viel gereist, arbeitete zuerst als Abteilungsleiter bei einem großen Reiseveranstalter, bis er als Sachbearbeiter in die Fachstelle Ferntourismus ins Zentrum für Entwicklungsbezogene Bildung (ZEB) kam. In seinem Beitrag berichtet er über diesen Wechsel; er stellt die Arbeit der Fachstelle Ferntourismus im ZEB vor und reflektiert über die Chancen als "Bildner" im Dritte-Welt-Tourismus. (DIPF/Orig.

Nitrogen Budgets and Soil Nitrogen Stocks of Organic and Conventional Cropping Systems: Trade-Off between Efficiency and Sustainability of Nitrogen Use

Organic and conventional cropping systems differ in the nature and amounts of nitrogen (N) inputs, which may affect efficiency and sustainability of N use. In the DOK (bio-Dynamic, bio-Organic, Konventionell) field experiment, organic and conventional cropping systems have been compared since 1978 at two fertilization levels. Nitrogen inputs via manure and/or mineral fertilizers, and N exports from plots with harvested products have throughout been recorded. For all treatments, N outputs with harvests have exceeded the inputs with fertilizers. Over the past years, symbiotic N2 fixation by soybean and clover grown in the trial has additionally been assessed, indicating average annual inputs of about 100 kg ha-1 yr-1 of N fixed from the atmosphere. Soil surface budgets opposing N inputs via fertilization, symbiotic fixation, seeds and deposition to N outputs via harvested products have been computed at the plot level for the duration from 1985 to 2012. The resulting balances range from negative values of about -20 kg N ha-1 yr-1 (where outputs exceed the sum of said N inputs) to surpluses of about +50 kg N ha-1 yr-1. The budget based N use efficiency (NUE; N output via harvested products divided by sum of N inputs) in the case of negative balances suggests irrationally high NUE (>100%), while positive balances are related to lower NUE for treatments with inputs exceeding outputs. Negative balances, however, indicate soil N mining, while surpluses point to a risk of N losses, and/or N accumulation in the soil. Estimation of soil N stock changes based on yearly total N concentration measurements in the topsoil layer is currently ongoing. Preliminary results suggest that soil N stocks in the topsoil decreased under all treatments more than expected from the N balance, and that positive N balances are needed to maintain topsoil N stocks. An increase in soil N concentration was observed in none of the treatments. In conclusion, the results indicate an efficiency-sustainability trade-off. Treatments with a higher NUE lose more soil stock N than those with a lower NUE. Treatments with lower NUE indicate higher N losses from the studied crop-topsoil system. Sustainable soil N management in addition to organic fertilizer inputs might at this site require reduced soil tillage. The significance of N contained in deeper soil layers, and deep rooting crops in recovering leached N should as well be investigated

Symbiotische N2 Fixierung und N–Bilanz von Soja unter Be-rücksichtigung der N-Rhizodeposition im DOK Versuch

Symbiotic N2 fixation (Nfix) and N-balance was determined from organic and conven-tional grown soybean in the DOK experiment (Switzerland). Nfix was calculated i) based solely on soybean aboveground N (AGN) and ii) additionally taking into account belowground N (BGN), comprising N in physical roots and N rhizodeposition. Nfix was averagely two times higher considering AGN and BGN, ranging from 22 g N m-2 (conventional manure) to 37 g N m-2 (conventional mineral). N balances were positive in all treatments, but with 2 – 7 g N m-2 based on AGN solely comparatively small. These values were exceeded fourfold when considering BGN ranging from 13 g N m-2 (conventional manure) to 21 g N m-2 (organic and conventional mineral)

Below ground nitrogen dynamics in the sequence clover-grass maize in the DOK long term experiment

We investigated the effect of organic versus conventional cropping systems on the below ground nitrogen inputs of Trifolium pratense L., its transfer to corresponding grass and the fate in the soil organic matter in the clover-grass ley of the DOK long term experiment, Switzerland. BGN tended to be largest in conventional and organic treatments with standard fertilisation and decreased with lower fertilisation intensity. The largest amount of clover N transferred to grass was observed in the minerally fertilised conventional treatment. Clover N derived from rhizodeposition was rapidly stabilised in all treatments to clay rich fractions and thus clover N will have a relatively low direct N contribution to subsequent nonlegumes

New insights in below ground nitrogen of clover-grass mixtures

Estimates of symbiotic nitrogen fixation (SNF) of clover in mixtures usually consider only aboveground clover nitrogen (N). However, belowground inputs of clover N derived from SNF via roots and rhizodeposition and its transfer to associated grass may contribute significantly to the amount of symbiotically fixed clover N. A microplot study with a red clover ( L.)-perennial ryegrass ( L.) model mixture was conducted within zero fertilised, bio-organic and conventional field plots of the DOK (bio-Dynamic, bio-Organic, Konventionell) long-term experiment during two consecutive years

Wurzelbürtige Stickstoff- und Kohlenstoffeinträge in den Boden: Erkenntnisse aus sieben Jahren DOK Wurzelforschung

We investigated nitrogen and carbon below ground inputs of soybean, clover-grass and maize and management effects of biological and conventional systems in the DOK long term experiment. We found for soybean increasing below ground C and N inputs with decreasing fertilization intensity whereas those effects were small for clover-grass. Below ground nitrogen inputs of red clover could be estimated by above ground N multiplied with a factor of 0.5

Nitrogen budgets and soil nitrogen stocks of organic and conventional cropping systems: how reconcile efficiency and sustainability of nitrogen use?

Organic and conventional cropping systems differ in the nature and amounts of nitrogen (N) inputs, which may affect efficiency and sustainability of N use. In the DOK (bio-Dynamic, bio-Organic, Konventionell) field experiment, organic and conventional cropping systems have been compared since 1978 at two fertilization levels (with level 2 being typical for the respective system and level 1 receiving half of this dose)

Stickstoffbilanzen in biologischen und konventionellen Anbausystemen Das Effizienz-Nachhaltigkeits-Dilemma

N-balances over 35 years from the DOK trial are presented and combined with Nstock changes in DOK treatments on different fertilisation levels. Results strongly indicate an N efficiency-sustainability dilemma: DOK treatments with a high nitrogen use efficiency (NUE) lose more soil stock N than those with a lower NUE but higher N losses from the system. The biodynamic system showed little advantage in terms of soil N stocks sustainability while the solely mineral fertilised conventional treatment had highest NUE across all inputs including soil N change

The Multifunctional Challenge Of Future Agriculture – Answers From 40 Years Dok Research

"Achieving sufficient and stable crop yields with limited cropland and without excessive use of non-renewable resources under a changing climate are the multifunctional challenges of future agriculture. We compared the performance and sustainability of organic and conventional cropping systems in the DOK long-term systems comparison after 40 years of management. For the first time we present a comprehensive evaluation of the whole DOK design including the systems with reduced stocking rates. Yield, nutrient dynamic and soil quality evaluations show clearly the trade-offs between productivity and sustainability in organic as well as in conventional systems. Low input conventional systems reveal the best input-output performance but lowered soil quality; regular organic systems were most sustainable but achieved only moderate non-legume yields.