Biogaserzeugung im viehlosen Betrieb: Effekte auf Stickstoffmanagement, Erträge und Qualität

In organic farming systems without livestock some problems arise concerning the nitrogen management: On the one hand, there is a lack of transportable nitrogen fertilisers, on the other hand there is a potential for high losses with the usual management. The biological N2 fixation is decreased, when clover grass is mulched. If the biomass of intercrops and clover grass gets mineralised in autumn, it can be leached in winter. In the trial referred to here, the impact of fermentation of biomass on some agricultural parameters like yield etc. are investigated within a crop-rotation of clover grass, potatoes, winter wheat, peas, winter wheat and summer wheat with undersown clover grass. Intercrops are sown after winter wheat and peas. In the control variant the coupled products (clover grass, straw and intercrops) are left on the field as mulch. In the biogas system this material is harvested for digesting. The remaining products are used as fertilisers. There are liquid products which were used to fertilise the winter wheat and solid ones, which were used for fertilizing potatoes and summer wheat. This system allows a higher efficiency of the nitrogen management: The yield and the content of raw protein in winter wheat increased. The solid material did not mineralise as fast as necessary. It would be better to add this material to the intercrops

Eigenschaften von Mischungen mit perennierenden Leguminosen und Gräsern aus dem Anbau in alternierenden Reihen unter Einbeziehung einer Hochzuckergras-Sorte

Three different perennial legume species (Lotus corniculatus, Medicago sativa, Trifolium pratense) were cultivated in alternate drills with one of three different grasses each. L. corniculatus is known to be rich in tannins, which are supposed to have positive effects on protein digestion of ruminants and methane emissions. One of the grass components was a Lolium perenne cultivar (cv. Aberavon) with increased concentrations of water-soluble carbohydrates (wsc). The influence of this grass variety on forage characteristics in mixtures was tested compared to other grasses (Lolium perenne cv. Gladio and Lolium multiflorum cv. Ligrande). Dry matter yield of different mixtures was determined and concentration of wsc in herbage before ensiling was analysed. Digestibility of organic matter (DOM) in silages was determined encymatically. Aberavon had higher contents of wsc compared to other grasses but there were no differences in DOM of silages caused by the grass cultivar. Mixtures containing Aberavon yielded less dry matter than other grasses. Dry matter yields of mixtures with L. corniculatus were similar or slightly inferior to the yield of the mixtures with M. sativa or T. pratense. Digestibility of silages including L. corniculatus was similar to M. sativa variants and even superior to T. pratense mixtures in single cases

Biogaserzeugungspotential aus Gülle und Koppelprodukten in viehhaltenden und viehlosen Betriebssystemen des ökologischen Landbaus

In two agricultural systems with and without animal husbandry the potential to produce renewable energy by digesting slurry and organic residues to biogas were assessed. In comparison to some other methods of energy production by biomass biogas production has the advantage of keeping the nutrients of the substrates within the agricultural system. They can be used as fertilisers. In the investigated system with milk production (0,8 cows ha-1, 8 crops, among them 4 cereals, peas, potatoes and 2 clover grasses with catch crops after winter cereals and peas (see DEUKER et al. 2005), it is possible not only to ferment slurry, but also catch crops and straw of peas and cereals. The methan production potential by digesting only slurry is the equivalent of around 327 l diesel fuel ha-1. By digesting a well developed catch crop it is possible to harvest the equivalent of around 750 l diesel fuel per ha.-1 sown with such crops. Related to the whole system with 4 catch crops within 8 fields it is possible just by including catch crops in the fermentation process with slurry to duplicate the methan harvest of the digesting plant to around 700 l diesel fuel ha-1 a-1. By utilisation of biomass like the straw of peas and other residues it is possible to generate the equivalent of approx. 450 l diesel fuel ha-1. Total biogas production potential by including all fermentable biomass is the equivalent of approx. 1150 l diesel fuel per each ha and year. Usually one third of this energy is necessary to temperate the digester, one third can be converted to electricity and one third can be used to heat buildings in the neighbourhood of the fermentation plant. In a typical stockless organic agricultural system composed of six crops (clover gras, potatoes, winter wheat, peas, winter wheat and summer wheat with undersown clover grass, with catch crops after winter wheat and peas, see STINNER et al. 2005) biomass of clover grass and catch crops will normally be left on the field and incorporated in the soil. By fermentation of clover grass there is a biogas production potential of around the equivalent of 3300 to 4700 l diesel fuel ha-1 a-1. Digesting catch crops allows a methan yield of ca. 650 to 700 l diesel fuel ha-1, digestion of other residues like straw other 1250 to 1350 l diesel ha-1. The total energy production potential of the whole crop rotation system is the equivalent of around 1700 to 1800 l diesel per ha and year. Removal of crop residues is coupled with removal of substantial quantities of nitrogen, reducing the residual mineralisable nitrogen amounts on fields at the end of the vegetation period and the risk of nitrate leaching

Auswirkung der Fermentation biogener Rückstände in Biogasanlagen auf Flächenproduktivität und Umweltverträglichkeit im Ökologischen Landbau – Pflanzenbauliche, ökonomische und ökologische Gesamtbewertung im Rahmen typischer Fruchtfolgen viehhaltender und viehloser ökologisch wirtschaftender Betriebe

Die Effekte der Vergärung von Gülle und Nebenernteprodukten wurden auf der Ebene des gesamten landwirtschaftlichen Systems für einen viehhaltenden Gemischtbetrieb und einen viehlosen Marktfruchtbetrieb untersucht. Dabei wurden die Wirkungen der Vergärung von Gülle und Kleegras auf die Flächenproduktivität, auf die innerbetrieblichen Nährstoffflüsse, auf die Nitratauswaschungsgefahr sowie auf die Gefahr von bodenbürtigen Spurengasemissionen untersucht. Ferner wurde eine ökologische Bilanzierung der Biogasvergärung im ökologischen Landbau mittels Öko-Bilanzierung durchgeführt

Humusmenge in der Ackerkrume nach langjährig differenzierter Intensität der Grundbodenbearbeitung

The aim of the present study was to investigate the impacts of different tillage intensity on the quantity of soil organic matter in topsoils of seven long-term trials. Tillage intensity was found to affect both bulk density and Ct-contents, whereas total C quantity did not differ significantly between tillage treatments in all trials even though a high C accumulation in the reduced tillage system was visible in one trial. As for humus balancing, a consideration of tillage intensity is not supported by these results

Nanofasern als neuartige Träger für flüchtige Signalstoffe zur biotechnischen Regulierung von Schadinsekten im integrierten und ökologischen Landbau

Using nanofibers as dispensers for pheromones and kairomones in plant protection for disrupting insect chemical communication is a novel approach aiming at popularizing this technique in organic and integrated plant production. Expected advantages of the nanofibers are highly controlled spatiotemporal release rates of pheromones / kairomones, improved climatic stability, and mechanized application. Dispenser types used so far show deficiencies in one or more of these requirements. Mechanical application of pheromones is a new approach to reduce the costs of manual labour and therefore the environmentally compatible, highly specific and efficient technique of mating disruption may become an alternative to the use of synthetic pesticides in integrated pest management. The nanofibers are highly elastic, which prevents breakoff of smaller pieces, and polymers used are biocompatible. Due to the scale of nanofibers the mass input both for pheromones and for polymeric nanofibers is very low. Major environmental benefits are high control specificity, very low concentrations of residues and reduced risk of development towards insect resistance

Improvement of winter wheat baking quality in ecological cultivation by enlargement of row spacing and undersown intercrops

Under ecological crop growing conditions, considerable problems consistently arise in fulfilling the baking quality of winter wheat demanded by consumers. The “wide row” procedure shows promising potential for effectively using the nutrient supply in ecological cultivation for the production of winter wheat with high baking performance. Increasing the distance between rows of winter wheat from 12.5 cm to 50 cm proved advantageous for the indirect quality parameters sedimentation value and gluten and crude protein concentration. Either no yield decreases or low decreases only up to 10% were noted. Because of an increased tendency to erode and in order to improve of the preceding crop’s value, creation of a green zone with legumes between the rows is necessary. To prevent competition between cover and catch crops, mulching of catch crops is required

The Impact of Site and Management Factors on Humus Dynamics in Long-term Field Experiments

The impact of management and environmental site factors on quantitative and qualitative indicators of humus dynamics was investigated in eight long-term field experiments in Germany and neighbouring countries. Humus dynamics were basically influenced by environmental site conditions, but at a given site differences between farming systems could be ascerted. Mixed farming systems with farmyard manure application as a rule had a more favourable impact on humus dynamics than stockless systems. Whether an advantageous performance of humus dynamics in organic farming as compared to conventional farming will occur or not, is dependent on the respective farm types of both systems that are related to each other

Biogas in stockless organic Farming: Effects of Digestion of Clover/grass, Cover Crops and Crop Residues on Nitrogen Cycles and Crop Rotation Productivity

A common practice in stockless organic farming systems is to leave the biomass from clover/grass-ley and crop residues in the field for their residual fertility effect. No farmyard manures for transfer of nutrients within the system are available. Clover/grass-ley biomass and crop residues represents an unexploited energy potential that could be harnessed by the digestion in biogas plants for production of methane, thus replacing ruminants by the biogas digester. In field trials by implementing a whole crop rotation comprehending six crops were carried out in 2002-2005 to evaluate whether the use of N could be improved by processing biomass described above in a biogas digester and using the effluents as a fertilizer, compared to general practice. Results indicate that digestion of crop residues resulted in more efficient manuring systems, not only by the implementation of an additional “product” (power energy), but also by getting more efficient cropping systems with higher DM and N yields of most of the non-legume crops, combined with a reduction of N losses due to denitrification and a reduction of the nitrate leaching risk. The causes were a better and more evenly allocation of nutrients within the whole crop rotation, a higher N input via N2 fixation, lower N losses and probably a higher N availability of digested in comparison to the same amounts of nutrients in undigested organic manures

Effects of Biogas Digestion of Slurry, Cover Crops and Crop Residues on Nitrogen Cycles and Crop Rotation Productivity of a Mixed Organic Farming System

Manures and crop residues can be utilised for digestion, without any significant losses of nutrients. This paper presents the results of field trials about the effects of biogas digestion in a mixed organic cropping systems on nutrient cycling and yield of a whole crop rotation. Digestion of slurry affected yields and N uptake only after soil incorporation. The inclusion of crop residues for digestion increased the amounts of “mobile” manure. N uptake and yield of non-leguminous main crops increased about 10%, due to a more adapted allocation of nutrients within the whole cropping system by reallocation of N towards the crops with higher N needs. Additionally, removing the cover crops in autumn and their digestion increased the fertilizing efficiency of N, lowering the risk of leaching losses