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Browsing by Subject "Bodenbearbeitung"

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Die Auswirkungen einer einmalig variierten Bodenbearbeitung auf Ertragsbildung, Verunkrautung und Bodennitratgehalt unter ökologischen Produktionsbedingungen
(2007) Häberle, Annette; Claupein, Wilhelm
Although organic farming is a very non-polluting kind of agriculture, nitrate leachate losses can also be found under this management. Restrictions in organic fertilization have the purpose to keep the nitrate leachate with soil tillage and crop rotation on a low level. Due to this aim field experiments were conducted to investigate the short-term effect of timing and method of cultivation after the harvest of legumes and crops with high-N crop residues on N mineralization, nitrate leaching, crop growth, diseases and weeds in wheat crops. The study was designed to compare the effects of the ?Schutz- und Ausgleichsverordnung? (SchALVO) in Baden-Württemberg and tillage strategies which are normally used in practice, like reduced and conventional tillage in autumn and to compare different times of conventional tillage in winter and spring in three different areas of Baden-Württemberg with typically soil types. The areas were located in the Main-Tauber-Kreis with soils from Keuper and shell lime, in the Gäu-Region with soils from löss and the Schwäbische Alb with soils of limestone. Especially organic farms use, for the admancement of yield und for the regulation of weed population, a timely and increased requirement of soil tillage. In the results of October 2002 till summer 2005 there was no significant influence of timing and method of cultivation, for example reduced tillage in autumn or tillage in winter or spring, on the productivity of organic farms. In the most cases the conditions on the experimental fields were very good resulting of a low weed density and a good farming management. On fields with a high density of perennial weeds the risk of multiplication of weed population persists even after a short-term variation of tillage. There were only a few, not significant differences in the development of wheat growth because of different soil tillage. The most differences were seen between the growth of winter wheat and summer wheat. The yield of summer wheat was not significantly lower than the yield of winter wheat. Summer wheat reached nearly the same yield potential with higher amounts of crude protein. Especially in areas with strong winters and low N-input the yield of summer wheat was higher than the yield of winter wheat. Because of a second peak of mineralization in spring there was a better adaptation of NO3-release to the growth of summer wheat after soil tillage in November, December and February. Because of the better utilization of soil-N from summer wheat the lower yield potential in comparison to winter wheat was relativised in the most areas. With regard to N mineralization a time displacement of soil tillage in winter or spring didnt reduce the N-mineralization before winter in all cases. But in this time displaced treatments there was a second peak in N-mineralization additional to the first peak in autumn. Short-term practice of reduced soil tillage did not reduce N-release in the field experiments. Altogether a time displaced soil tillage in winter or spring could be, based on the experiments, a practical alternative for N-conservation through winter with regard to N-mineralization as well as with regard to corn yield. With the cultivation of a fast-growing catch crop farmers could reach an additional reduction of mineralised N amount over winter. In the farming practice a well timed sowing of catch crops is not always possible, like it is shown in the experiments, but it should be kept in mind for N conservation.
Einfluss der Bearbeitungsintensität beim Umbruch von Luzerne-Kleegras auf die Stickstoffmineralisation zur Folgefrucht Winterweizen im organischen Landbau
(2003) Wald, Fabian; Claupein, Wilhelm
In the crop rotation of organic farming grass-legume mixtures play an important role due to the legumes´ ability to assimilate N. Ploughing-in of established grass-legume mixtures results in releasing the assimilated N by mineralisation of organic matter. In practice the mineralisation can only be controlled by means of soil cultivation. The aim of the present study is to analyse the relations between different intensities of soil cultivation and N-mineralisation. The data were used to test the simulation model CANDY. The field experiment of each 0.1 ha was set up at three sites in two different locations, which were cultivated from 1999 to 2001: Hohenheim (with trials 610 and 611) and Kleinhohenheim (with trial 660). In the beginning all sites had a three-year old grass-clover-alfalfa mixture, which was ploughed-in for trial 610 and 660 in the late summer of 1999 and in the year 2000 for trial 611. The factor soil tillage was varied in three stages as follows: RT+RT+plough: double rototill cultivation (RT, 10 cm deep) in intervals of approx. 2 weeks, followed by ploughing (plough, 25 cm deep); RT+plough: single rototill cultivation, followed by ploughing (depths as mentioned above); Plough: ploughing without any preceding cultivation (depth 25 cm). After uniform seedbed preparation with a rotary harrow, wheat was sown on all trial sites in autumn, and in trials 610 and 660 it was followed by oat in 2001. Nitrogen content in the soil was determined by repeated sampling at a depths of 0-10, 10-20, 20-30, 30-60 and 60-90 cm. Monitoring boxes were installed in 1 m depth in an undisturbed soil body from September 2000 until April 2001 to record nitrate leaching. Ploughing-in of the grass-clover-alfalfa by means of rototiller cultivation (treatments RT+RT+plough and RT+plough) was followed by a significant increase of mineralisation, which in case of the plough treatment was less pronounced. In this case the date of cultivation, 6 weeks after the rototilling, may have had an influence. Nmin-contents in autumn 1999 were higher after RT+RT+plough than after RT+plough. It has to be taken into consideration that there was a time gap between both treatments of 9 days. But also in the following year (611), when both treatments were cultivated the same date, there was a significant, slight difference of the Nmin values depending on the treatment. Nitrate leaching was only measured in trial 611. Quantities of 86, 84 and 64 kg N/ha were observed in treatments RT+RT+plough, RT+plough and plough, respectively during winter. Due to high Nmin-contents in autumn, for the rototill treatments higher nitrate losses can be assumed compared to the plough treatment for both years of experiment. Depending on the location, nitrogen uptake and yields of wheat turned out to be different. In Kleinhohenheim they were lower in treatments RT+RT+plough and RT+plough than in the plough treatment. It was the other way round in Hohenheim on a higher production level. Due to strong hail impact, this relation between the treatments was not to be proved in trial 611. Oat was the second crop. In this case no effects of intensity of soil cultivation on nitrogen uptake and yield could be observed between treatments and locations. The CANDY model was used for simulating the results of trials 610 and 611. First, the model seemed to be inadequate because it could not model the N-dynamic after soil cultivation. Adding fictitious organic material to the system helped to overcome this problem and then, on average, the N-dynamic model fit was satisfying. An estimate to overcome the general insufficient fit of the model could be mineralisation of parts of the physically protected organic matter (SOS), which is already implemented in the model, right at the moment of cultivation. Data of soil moisture of trial 611 served to calibrate the model successfully. With amended soil parameters the model was then easily applied to the corresponding data of trial 610. In contrast, CANDY did not predict well the nitrate leaching - possibly because the model did not consider preferential flow.
Entwicklung der Zufriedenheit der Landmaschinenhändler mit den Herstellern
(2015) Becker, Tilman; Semenenko, Ksenia
Bereits im April/Mai 2006 und im April/Mai 2008 wurde die Zufriedenheit der Landmaschinenhändler mit ihren Herstellern im Rahmen einer schriftlichen Befragung abgefragt. Eine Online-Befragung erfolgte dann im April/Mai 2015. Insgesamt nahmen 160 Händler an der Befragung teil. Wie 2006 und 2008 wurde auch 2015 die Bewertung der Händler zu fünf unterschiedlichen Kategorien abgefragt: - Traktoren - Mähdrescher - Futtererntetechnik - Bodenbearbeitung und Saat - Technik für Pflanzenschutz und Düngung. Abgefragt wurden z.B.: - Gesamtzufriedenheit mit jeweiligem Hauptlieferanten - Zufriedenheit mit einzelnen Marketingmaßnahmen im Detail Die Marketingmaßnahmen umfassen z.B. die Bereiche: - Produktprogramm - Zukunft der Lieferanten im Wettbewerb - Beziehung zu Lieferanten. Die Gesamtzufriedenheit setzt sich aus der Zufriedenheit in den einzelnen Bereichen zusammen. Um die Bedeutung einzelner Bereiche für die Gesamtzufriedenheit zu bewerten, wurde der Korrelationskoeffizient zwischen der Gesamtzufriedenheit und dem jeweiligen Bereich berechnet. Zusammenfassend kann man einen zumindest leichten Anstieg bei der Gesamtzufriedenheit feststellen. Lediglich in der Produktgruppe der Mähdrescher kam es zu einer insgesamt schlechteren Bewertung als 2006. Bezogen auf alle Beurteilungen konnte die Futtererntetechnik wie schon in den Vorjahren am besten abschneiden.
Genotypische Variation der Überdauerungsneigung von transgenem und konventionell gezüchtetem Raps und Möglichkeiten der Beeinflussung durch Bodenbearbeitung als Beitrag zur Sicherheitsforschung bei transgenen Kulturpflanzen
(2004) Gruber, Sabine; Claupein, Wilhelm
High losses during harvesting of oilseed rape in combination with secondary dormancy of the seeds can result in a large soil seed bank which may persist for several years. Volunteers emerging from this seed bank cannot be controlled completely, particularly when they develop in another rapeseed population. In addition to well known agricultural problems, the risk of temporal and spatial gene dispersal by persistent seeds and volunteers gets more significant. With regard to genetically modified (GM) cultivars, seed dormancy and persistence of oilseed rape volunteers have to be reconsidered. The aim of the current study was to investigate the chances for a reduction of seed persistence and gene dispersal by growing specific genotypes and by the implementation of appropriate tillage operations. Four publications describe and discuss experiments in the laboratory and the field on the aspects ?genotype? and ?soil tillage?. One central point was the characterisation of the genotypic variation of secondary dormancy and seed persistence in GM (herbicide tolerant) and conventionally bred oilseed rape. A gradual approach towards field conditions was performed by three experiments. The first experiment examined potential seed persistence by artificial induction of secondary dormancy in the laboratory. The second experiment was a burial of seeds in the soil for six months on a field. The third experiment examined persistence of seeds actually lost during harvest and exposed afterwards to different tillage operations in a field experiment. All three experiments showed a high genotypic variability in seed dormancy and persistence. In the laboratory the level of secondary dormancy of conventional cultivars was a total of 3?76% and of the GM cultivars 1?31%. The number of persistent seeds in the burial experiment was 7?90% in the conventional and 12?79% in the GM assortment. Seeds from the seed rain of the four conventionally bred cultivars in the field experiment persisted in the soil from 0?11% over six months. A significant, positive correlation was found between the laboratory results for cultivars from two crop years as well as between the results from laboratory and burial experiments. This is an indication for a genetic background of seed dormancy and persistence of oilseed rape. It has been demonstrated that a laboratory method for induction of secondary dormancy can describe differences of seed persistence in the field. This result gives a chance for screening new cultivars in the laboratory to identify desired, low persistent genotypes. The other focus of the study was the effect of various tillage treatments on seed persistence and seedling recruitment in the field. Four differently intensive tillage operations incorporated the seeds of two near-isogenic cultivars at different times and soil depths, or left the soil untilled. Winter wheat was sown as following crop in all treatments whereby no weed control was performed. The highest number of seeds generally entered the soil seed bank when seeds were incorporated into the soil by stubble tillage immediately. After six months 1?14% of the initial seed input was found again in the soil in these treatments, and in one isolated case about 28%. Delaying the stubble breaking, the soil seed bank was 0?3%. Leaving the seeds undisturbed on the soil surface until direct drilling resulted in a soil seed bank of 0?17%. Therefore, the first tillage operation after harvest of oilseed rape should be performed with some time delay to avoid large soil seed banks. Soil inversion by a mouldboard plough shifted the majority of seeds into deep soil horizons from where a successful germination was restricted. In contrast, primary tillage by a rigid tine cultivator or zero tillage mainly distributed the seeds within the upper soil layer. Thus the number of flowering volunteers in the first spring was highest in these treatments, with a maximum of one volunteer m-2. Gene dispersal from oilseed rape volunteers to other rape crops and feral relatives was possible because their flowering periods overlapped. The volunteers were able to produce viable seeds, despite high levels of damage by pests and diseases. Overall, a high genotypic variability was found for seed persistence of oilseed rape. Tillage operations, particularly the time of stubble tillage, can also influence seed persistence and the occurrence of volunteers. Combined with a thorough knowledge of the processes involved, the selection of low persistent genotypes and adequate tillage operations offer chances to limit or even to avoid undesired gene dispersal from oilseed rape volunteers, and to make gene dispersal a predictable factor.
Land Preparation Methods and Soil Quality of a Vertisol Area in the Central Highlands of Ethiopia
(2005) Jijo, Teklu Erkossa; Stahr, Karl
The industrialization of agriculture led to societal concerns for environmental protection and food quality in developed countries. On the other hand, the need for increased agricultural productivity to address the persistent poverty and food insecurity in developing countries is intensified. Thus, improved management systems to meet the double objectives of increased productivity and sustained environmental quality are increasingly required. The assessment of soil quality and productivity are among the means of monitoring the various management systems to achieve the goals. Among the interrelated definitions formulated for soil quality, a committee established by Soil Science Society of America for the same purpose defined it as the capacity of soil to function within natural and managed ecosystem boundaries to sustain plant and animal productivity, maintain or enhance soil, water and air quality and support human health and habitation. The central idea in most of the definitions is the capacity of the soil to function. The capacity of a soil to function depends on its inherent properties derived from its genesis and the dynamic properties resulting from the prevailing management systems. Most of the hitherto soil quality assessments considered agricultural production as the major management goal. As this study was conducted in the highlands of Ethiopia where food security remains a basic challenge, the primary management goal could not be different. Shortage and fragmentation of land driven by population pressure have become issues of concern in the area. With a continually dwindling national land-holding average of only one ha per household, farmers struggle to produce enough to feed their families. Since the possibility of expanding agricultural land is limited, increased production is realistic only from higher productivity per unit land per unit time. Covering about 8 million ha, Vertisols are among the high potential soils, where significant increase in productivity is likely. However, their productivity is constrained by their physical and hydrological properties, manifested by their hardness when dry and their stickiness when wet, impeding land preparation. The traditional management systems led neither to increased productivity nor to enhanced soil quality. Thus, the need for alternative technologies is paramount. Despite a concerted effort during the last two decades to develop improved technologies for the soils, land preparation for agricultural productivity and sustaiability remains a major challenge. In addition to technical difficulties associated with their nature and deep-rooted poverty and illiteracy, lack of farmers? participation is believed to have hampered the development and adoption of robust technologies. The challenge facing the soil management research in Ethiopia is thus double fold: development of technologies that swiftly increase agricultural production and ensure judicious use of the land resources. Farmers are the ultimate decision makers on their plots, at least in Ethiopia, often irrespective of the consequences of their decisions. Simple technologies are required to manipulate their decisions in favour of the desired goals. This requires development of technologies that fit into their aspiration, tradition and socio-cultural values with their participation in the generation and evaluation of the technologies. This study was to identify alternative land preparation methods for increased productivity and economic profitability, while maintaining or enhancing the soil quality of the Vertisols. The hypothesis tested was that the alternative land preparation methods improve soil productivity and maintain or enhance soil quality. Three alternatives, Broad Bed and Furrow (BBF), Green Manure (GM) and Reduced Tillage (RT) with the traditional method, Ridge and Furrow (RF) were compared for 6 years, setting crop yield, economic profitability, and soil erosion and soil quality as performance indicators. This on station experiment was complemented by a participatory assessment at a small watershed scale. The objectives of the latter were identification of local soil functions, definition of soil quality concepts, and identification of soil quality indicators and evaluation of the soils for the major functions. Land preparation methods influence soil functions through their effects on soils qualities. Among the soil physical quality indicators considered, GM increased aggregate stability and reduced surface crust strength due to its increased OM content and microbial activities. While RT led to least penetration resistance, infiltration, water-holding capacity, and moisture content were less sensitive to the treatments. The chemical characteristics and plant nutrients response was not consistent indicating the need of longer time for the effects to show a clear trend. Organic carbon and MBC content of the soil increased due to RT and GM, but the increment was not proportional leading to lower microbial quotient. This indicates SOM build up with a long-term soil quality improvement. The effect on runoff was inconsistent during the first three years (1998-2000), but BBF and RT slightly increased. In 2001 and 2002, BBF drained 67% and 54 %, respectively, of the seasonal rainfall as runoff while RT routed 61% and 53%. There is a non significant tendency of increased soil and nutrient losses from BBF and RT due to the increased runoff. BBF significantly increased the grain yield of lentils by 59% (1.03 t ha-1 to 1.63 t ha-1) compared to the control. Similarly, RT resulted in the highest grain yield of wheat (1.86 t ha-1) and tef (1.34 t ha-1). Economically, BBF is the most profitable option for lentils with 65% increase in total gross margin while RT resulted in 11% and 8% increase in gross margin of wheat and tef, respectively, as compared to the control. The soil quality index was not significantly affected by the land preparation methods. Nevertheless, GM has shown a slight enhancement with the highest SQI, followed by BBF and RT. Thus, the land preparation methods are favoured in order of GM> BBF> RT> RF, for soil quality. The relative enhancement of soil quality by GM was linked mainly to its increased Corg content. The performance indicators (productivity, economic profitability, soil conservation and soil quality) are also affected differently. A matrix ranking of the effects on the indicators showed that none of treatments is superior for all the indicators. The average of the ranks (no weight attached) showed that BBF was the most favourable followed by RT. Therefore, the methods are preferred in the order of BBF> RT>GM=RF considering the overall indicators. The superiority of BBF and RT corresponds to their productivity and economic benefits. For soil quality and erosion control, GM is a favourable option. However, as its economic benefit was low, further improvement is required. In addition, lack of fast growing legumes tolerant to both shortage and excess water, failure of the short rain for planting, cost of chopping and incorporating the cover crops and the possible need of special equipment for incorporating may hinder its wider application and hence need further investigation. The success of the alternatives depends on the farmers? capacity and willingness to invest. As the issues of soil quality and land degradation are more of societal concerns than of the individual farmers, external technical and financial incentives are desirable to enhance their capacity and to initiate their interest. Institutional and policy issues influencing agriculture and natural resource management and uncertainties like variation in weather deserve judicious consideration.
Nitrous oxide emissions and mitigation strategies in winter oilseed rape cultivation
(2019) Kesenheimer, Katharina Anne; Müller, Torsten
After carbon dioxide and methane, nitrous oxide, is the third most important greenhouse gas in the atmosphere. Nitrous oxide contributes to the greenhouse gas effect as well as to ozone depletion. The major portion of anthropogenic N2O emissions are stimulated by the use of nitrogen fertilizers in agriculture. The main processes for N2O production in soils are nitrification and denitrification. Various environmental and management factors such as precipitation, soil type, tillage, and crop residues affect these processes. N2O emissions can occur substantially in the post-harvest period. In Germany, approximately 50 % of the annual N2O emissions can occur during winter. This exhibits the importance and necessity of annual data sets which prevent misinterpretations instigated by investigations limited to the vegetation period. Winter oilseed rape is the most important raw material for biodiesel in Germany. As of 2018, the framework of the European Renewable Energy Directive requires that the use of biofuels achieve GHG savings of at least 50 % compared to fossil fuels. Feedstock production for biodiesel contributes more than half of the total GHG emissions. To close the nutrient cycle with renewable energy, digestate from biogas plants can be used as a substitute for mineral N fertilizer permitting the reduction of GHG emissions in the production process of synthetic fertilizers. When compared to other crops, OSR has a high N demand. The low N removal by the seeds results in inefficient use of nitrogen and therefore a high N surplus in the soil which is susceptible to gaseous or leaching losses to the environment. Another potential risk for N2O losses are crop residues after harvest. The type of soil cultivation can have both positive and negative implications on N2O emissions which depend, among other things, on tillage depth, soil type and moisture. Results from studies measuring N2O emissions from different tillage systems are contradicting and site dependent. This study aims to investigate the effect of (a) N fertilization (mineral and organic), (b) nitrification inhibitors, (c) crop residues and (d) tillage on direct N2O emissions and, inter alia, yield and soil nitrogen dynamics in OSR production. N2O emissions were monitored for three years over a range of N fertilization levels at five study sites chosen so as to best represent typical winter oilseed rape production in Germany. Furthermore, the effect of the nitrification inhibitor (NI) TZ+MP (1H-1,2,4-triazole and 3- methylpyrazole) with digestate is investigated. Additional experiments for 15N labelled crop residues, nitrification inhibitor DMPP (3,4-dimethylepyrazole phosphate) with mineral fertilizer and soil tillage were implemented. A high spatial and temporal variability in N2O fluxes over all sites was observed. At each site, increased N2O fluxes were often detected after N fertilization in conjunction with rainfall events. During the first six weeks after harvest we frequently observed increased N2O fluxes following rainfall. In this postharvest period of winter oilseed rape, nitrate contents in the top soil were generally elevated. There were no considerable N2O pulses observed during thawing of frozen soil. Winters were mild without any severe frost periods in all three surveyed years which could be a reason for the generally low N2O winter fluxes observed in this study. On all examined sites, increasing N fertilization significantly enhanced N2O flux rates. Data obtained during the study were used to augment an existing model, wherefrom a new emission factor for OSR can be calculated. Assuming a quantity of 200 kg N ha-1 the global fertilizer-related emission factor derived from the exponential model was 0.6 %. This factor is within the uncertainty range of the EF1 IPCC emission factor (0.3 % – 3.0 %), but about 40 % lower than the 1 % IPCC default. The nitrification inhibitor (NI) TZ+MP combined with digestate mitigated the N2O fluxes significantly across all study sites and experimental years. As already noted in the fertilizer experiment, a high spatial and temporal variability in N2O fluxes over all sites was observed. The magnitudes of the N2O fluxes also showed similar trends. Over the entire investigation, the application of the NI significantly reduced annual N2O emission by a factor of three. During the fertilization period this mitigation effect was six times significant. This clearly emphasizes the importance of annual data sets to avoid overestimating NI effects.
Untersuchungen leistungsspezifischer Kenngrößen der Zugtiernutzung im südlichen Niger
(1991) Betker, Joachim; Kutzbach, Heinz Dieter
Im Niger wie auch in anderen Ländern verlangt die Ernährung einer ständig wachsenden Bevölkerung nachhaltige Produktionssteigerungen im landwirtschaftlichen Bereich. Die Weiterentwicklung der traditionellen Handarbeit durch die Mechanisierung von Feld- und Transportarbeiten ermöglicht durch eine Steigerung der Arbeitsproduktivität diese notwendige Erhöhung der agrarwirtschaftlichen Produktion. Zielsetzung der vorliegenden Arbeit ist es, Ansätze zu einer Optimierung der Zugtiernutzung durch die Ermittlung leistungsspezifischer Kenngrößen aufzuzeigen. Hierfür ist die Anpassung des Leistungsbedarfs der lokal eingesetzten Gerätetypen an das Leistungsvermögen der vorhandenen Zugtiere von besonderer Bedeutung.

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