Browsing by Subject "Ernteertrag"

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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.
Crop yield and fate of nitrogen fertilizer in maize-based soil conservation systems in Western Thailand
(2021) Wongleecharoen, Chalermchart; Cadisch, Georg
The increase in food demand and land scarcity in high-potential lowland areas have forced cropping intensification with a transformation of land use from subsistence to permanent agriculture in remote hillside in Southeast Asia. This change and inappropriate land use are the prime cause of soil degradation by erosion, which have negatively affected the agricultural systems productivity and sustainability in Thailand. Therefore, vulnerable land in sloping terrain is classified as unsuitable for continuous production of arable crops unless conservation measures are introduced to stabilize the landscape. Even though conservation practices can stabilize sloping land, farmers have not been widely adopted the measures due to various constraints, such as crop area loss and crop-tree competition. To improve land use management, a two-year study (2010-2011) was conducted at the Queen Sirikit research station (13°28’N, 99°16’E), Ratchaburi Province, Thailand, on a hillside with a slope of around 20%. The treatments consisted of (T1) maize (Zea mays L.) mono-crop under tillage and fertilization, (T2) maize intercropped with chili (Capsicum annuum L.) under tillage and fertilization, (T3) maize intercropped with chili, application of minimum tillage plus Jack bean (Canavalia ensiformis (L.) DC) relay cropping and fertilizer application, (T4) maize intercropped with chili, application of minimum tillage with Jack bean relay cropping and fertilizer application plus perennial hedges of Leucaena leucocephala (Lam.) de Wit, (T5) as T3 but without fertilization, and (T6) as T4 but without fertilization. There was an additional plot of chili sole cropping to calculate the land equivalent ratio (LER). The first part of the study evaluated yield performance and nitrogen use efficiency (NUE) of crops using the 15N isotope technique under diverse fertilized cropping systems during the first year. Maize grain yields were lower in T2 (3.1 Mg ha-1), T3 (2.6 Mg ha-1) and T4 (3.3 Mg ha-1) than in the control (T1) (6.7 Mg ha-1). The total returns from maize and chili yields were 1,914, 5,129, 3,829, 3,900, 3,494, and 2,976 USD ha-1, for T1, T2, T3, T4, T5 and T6, respectively. Higher economic returns in mixed crop systems, by selling both maize and chilies, compensated for the maize area loss by intercropping. Maize 15NUE was highest in T2 (53.5%), being significantly higher than in T1 (47.0%), T3 (45.5%), and T4 (45.7%). Overall system’s NUE in T2 (56.8%) was comparable to T1 (53.8%) and T4 (54.5%) but significantly lower in T3 (48.6%). Minimum tillage and hedgerows (despite their positive filter effect) did not increase NUE but adversely affected maize growth during the establishment phase. The second part of the study examined nitrogen fertilizers fate and quantified partial nitrogen budgets at plot level over two cropping seasons for various maize-based cropping systems with or without fertilizer application. Overall plant uptake of fertilizer 15N applied to maize was 48.6-56.8% over the first season, while residual fertilizer 15N recovery of plants was only 2.3-4.9% over the subsequent season. The quantity of applied labelled N remaining in the soil at the end of season 1 and season 2 was 6.2-28.1% and 7.7-28.6%, respectively. Thus, 60.0-76.0% in season 1 and 12.7-31.3% in season 2 of the applied fertilizer 15N were accounted for within the plant-soil system. Consequently, 24.0-40.0% and 12.9-16.1% of labelled fertilizer N were not accounted for at the end of season 1 and season 2, respectively. The derived N balance over two years revealed severe soil N depletion under T1 (-202 kg N ha-1), T5 (-86 kg N ha-1) and T6 (-48 kg N ha-1), and a slightly negative N budget under T2 (-5 kg N ha-1). In contrast, T3 (87 kg N ha-1) and T4 (62 kg N ha-1) had positive N balances. The increase of N input via additional N fertilizer applied to chili and symbiotic N2 fixation of legumes, and the reduction of N losses by soil erosion and unaccounted fertilizer N (probably lost via leaching, volatilization and denitrification) were the main factors of the positive N balances under maize-chili intercropping systems with conservation measures and fertilization (T3 and T4). Maize yield decline under T1, T2, T5 and T6 in season 2 was related to negative N balances, while maize yield increase under T3 and T4 was related to positive N balances. However, maize-chili intercropping with fertilization had some advantage (LER > 1.0) relative to sole species cropping. Moreover, total returns from crop yields in season 2 of all maize-chili intercroppings (1,378-1,818 USD ha-1) were higher than chili sole cropping (1,321 USD ha-1), which pointed to its crucial role in decreasing production risk by reducing yield loss by pests and diseases observed in chili plants. The third part of the study used combined data of stable isotope discrimination and electrical resistivity tomography (ERT) to improve understanding of competition at the crop-soil-hedge interface. Hedges significantly reduced maize grain yield and aboveground biomass in rows close to hedgerows. ERT revealed water depletion was stronger in T1 than in T4 and T6, confirming time domain reflectometry (TDR) and leaf area data. In T4, water depletion was higher in maize rows close to the hedge than rows distant to hedges and maize grain δ13C was significantly less negative in rows close to the hedge ( 10.33‰) compared to distant ones ( 10.64‰). Lack of N increased grain δ13C in T6 ( 9.32‰, p ≤ 0.001). Both methods were negatively correlated with each other (r= 0.66, p ≤ 0.001). Combining ERT with grain δ13C and %N allowed identifying that maize growth close to hedges was limited by N and not by water supply. In conclusion, the results suggested a significant positive interaction between mineral N fertilizer, intercropping systems and soil conservation measures in maintaining or improving crop yields and N balances in Thailand’s hillside agriculture. Simultaneously, combining ERT imaging and 13C isotopic discrimination approaches improved the understanding of spatial-temporal competition patterns at the hedge-soil-crop interface and pointed out that competition in maize-based hedgerow systems was driven by nitrogen rather than water limitation. Therefore, sustainable agriculture might be achieved if farmers in Thailand combine soil conservation measures with appropriate and targeted N fertilizer use.
Einfluss von Anbauverfahren und Umweltfaktoren auf Ertrag, Qualität und agronomische Eigenschaften von Soja (Glycine max L. Merrill)
(2021) Sobko, Olena; Gruber, Sabine
With a crude protein content of approximately 40% and a crude fat content of approximately 20% in the seeds, soybean (Glycine max L. Merril) is one of the worlds most important crops with a wide range of uses. The high-quality soybean protein is an important component of animal feed in dairy and meat production. Soybean oil is often used in human nutrition, and with increasing vegetarian or vegan diets, protein-rich foods made from soybean are in high demand. In practical farming, soybean is a beneficial crop in crop rotations because it can fix atmospheric nitrogen through symbiosis with rhizobia, making the plant self-sufficient in nitrogen supply. Since soybean cultivation has no tradition in Germany, optimization of the cultivation technique is required. The present work is about the elaboration of efficient cultivation techniques for soybean in Germany. In three publications, based on three multi-year as well as multi-location and orthogonal field trials, the effects of sowing density and sowing system on yield, protein, and oil content as well as on agronomic properties of soybean are investigated in several varieties from different maturity groups. In addition, the effects of temperature, precipitation and solar radiation on yield, oil content, and protein content have been investigated to identify potential locations for specific production priorities. In the first publication (published in Agronomy Journal MDPI), the results from trials over two years and two locations in southern Germany with four soybean varieties of different maturity groups (00, 000) and growth types with either drill seeding (row spacing 14 cm) or precision seeding (row spacing 28 cm) are presented. To answer the question of which seeding method is more efficient, the following characteristics have been investigated, namely seed yield and yield structure, protein and oil content, LAI, plant height, height of the first pod set, lodging, and nodule numbers. The sowing system did not significantly affect the tested traits, and there was little difference in yield and qualities (seed yield: 3.6 t ha-1 DM, protein content: 40.9 % DM, oil content: 18.8 % DM for drill seeding; seed yield: 3.8 t ha-1 DM, protein content: 40.1 % DM, oil content: 19.1 % DM for precision seeding). These results are very helpful for soybean producers, because they do not need to invest in new sowing technique but can sow with sowing machines which are already available on the farm. The second publication (published in Plant, Soil and Environment) is about the effects of sowing density of soybean with four varieties of maturity groups 00 and 000. Four sowing densities (30, 50, 70, and 90 seeds m-2) were tested over two years and two locations in southern Germany. The lowest seed yield (3.2 t ha-1 DM was obtained at a sowing density of 30 seeds m-2 and the highest at 90 seeds m-2 (4.4 t ha-1 DM). The 00 varieties (3.6 t ha-1 DM) were higher yielding than the 000 varieties (3.4 t ha-1 DM). Sowing density did not affect seed quality characteristics. Plants were more susceptible to lodging with increasing sowing density. The lowest pod set was 4 cm higher at a sowing density of 90 seeds m-2 (13.4 cm) than at 30 seeds m-2 (9.4 cm). Increasing sowing density could reduce yield losses due to threshing because the height of the first pod set was increased at high sowing densities. Consequently, the optimum soybean seed rate would be between 50 and 70 seeds m-2 for 00 and 000 varieties at the tested locations and similar regions in Germany. In the third publication (published in Agronomy Journal MDPI), the influences of environmental factors on yield, protein and oil content, and protein and oil yield of soybean in Germany have been investigated. In the two-year field trials, 13 soybean varieties from maturity groups 00 and 000 were tested at several locations across Germany (four in 2016 and five in 2017). The 000 varieties were less sensitive to environmental factors compared to the 00 varieties. Regardless of maturity group, high solar radiation and appropriate precipitation tended to increase seed yields (r seed yield / solar radiation = 0.32 and r seed yield / solar radiation = 0.33). High temperatures at maturity reduced the productivity but provided slightly higher protein contents in 000 varieties (r protein content / CHU at maturity = 0.23). The locations that are not at risk for water stress would be suitable for soybean production if protein or oil yield is the primary concern. Overall, this study indicates that a sowing density of 50-70 seeds m-2 in combination with varieties of appropriate maturity groups could promote soybean cultivation in Germany. In dry locations, a lower sowing density is advisable in contrast to locations with more precipitation. Additional costs for the adaptation of technical equipment would not be incurred, because both drill seeding and precision seeding can be applied. By matching the direction of use (protein and/or oil production) of soybean to the climatic conditions of specific regions, soybeans for food and feed can be produced in Germany with sufficient traceability for quality and food safety. Climate warming offers opportunities to extend soybean production in Germany. This thesis provides results from which recommendations can be derived that are immediately applicable in agricultural practice.
Ertragsbildung und Konkurrenzverhalten perennierender Körnerfruchtarten in Rein- und Mischbeständen auf marginalen Standorten
(2002) Weik, Lena; Aufhammer, Walter
Cultivation of perennial grain crops in pure and mixed stands was examined as a possibility for preserving marginal arable land. The following questions were investigated: - Which dry matter and grain yield potential do these species display on marginal lands? - Are the examined species able to persist on marginal sites? - Can effects of competition be identified in mixed stands of perennial grain crops by commonly used static and dynamic parameters? - Which competitiveness do the examined species show in mixed stands compared to pure stands? In field experiments perennial species of rye (Secale cereale x S. montanum), intermediate wheatgrass (Elymus hispidus), lupine (Lupinus polyphyllus) and linseed (Linum perenne) were grown in pure and different mixed stands. Intermediate wheatgrass reached with a maximum at almost 13 t ha-1 highest dry matter yields. Grain yields were on a low level, maximum yields were obtained with 2.7 t ha-1 in pure stands of rye. Intermediate wheatgrass and lupine demonstrated the best ability for perennialism. Rye showed a satisfactory ability to persist only when grown in mixture with legumes. The persistence of linseed was very low. The relative yield total (RYT) was found to be a suitable static indicator of resource complementarity. Competitive ability was appropriately described by the competitive balance index (Cb). Regression models derived from Lotka-Volterra equations rendered a good description of dynamic growth and competition. Both grass species were in most cases stronger competitors than the companion species. The experiments showed, that using grain cop mixtures of grasses and legumes seem to be most promising for cultivation on marginal lands.
Regionalising a soil-plant model ensemble to simulate future yields under changing climatic conditions
(2023) Bendel, Daniela Silke; Streck, Thilo
Models are supportive in depicting complex processes and in predicting their effects. Climate models are applied in many areas to assess the possible consequences of climate change. Even though Global Climate Models (GCM) have now been regionalised to the national level, their resolution of down to 5x5 km2 is still rather coarse from the perspective of a plant modeller. Plant models were developed for the field scale and work spatially explicitly. This requires to make adjustments if they are applied at coarser scales. The regionalisation of plant models is reasonable and advantageous against the background of climate change and policy advice, both gaining in importance. The higher the spatial and temporal heterogeneity of a region, the greater the computational need. The (dis)aggregation of data, frequently available in differing resolutions or quality, is often unavoidable and fraught with high uncertainties. In this dissertation, we regionalised a spatially-explicit crop model ensemble to improve yield projections for winter wheat under a changing climate. This involved upscaling a crop model ensemble consisting of three crop models to the Stuttgart region, which has an area of 3,654 km2. After a thorough parameter estimation performed with a varying number of Agricultural Response Units on a high-performance computing cluster, yield projections up to the year 2100 were computed. The representative concentration pathways of the Intergovernmental Panel on Climate Change (IPCC) RCP2.6 (large reduction of CO2 emissions) and RCP8.5 (worst case scenario) served as a framework for this effort. Under both IPCC scenarios, the model ensemble predicts stable winter wheat yields up to 2100, with a moderate decrease of 5 dt/ha for RCP2.6 and a small increase of 1 dt/ha for RCP8.5. The variability within the model ensemble is particularly high for RCP8.5. Results were obtained without accounting for a potential progress in wheat breeding.
Untersuchungen zur Ertragskartierung während der Getreideernte mit dem Mähdrescher
(1997) Reitz, Peter
Die Getreideernte in den Industrieländern wird heute ausschließlich mit dem Mähdrescher durchgeführt. Durch eine gleichzeitige Ertragskartierung werden die Voraussetzungen für eine teilflächenspezifische Feldbewirtschaftung geschaffen. Aus den geokartierten Ertragsdaten lassen sich Rückschlüsse über kleinräumige Unterscheide in den Wachstumsbedingungen innerhalb eines Feldes ziehen. In der vorliegenden Arbeit werden die theoretischen Grundlagen zur Ertragskartierung und ein Verfahren zum Betrieb des Mähdreschers mit geokodierten Teilflächendaten entwickelt und untersucht. Zu deren Realisierung werden Module für die Erfassung, Übertragung, Verarbeitung und Umsetzung geokodierter Teilflächendaten benötigt.