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  • 1
    Language: English
    In: Nutrient Cycling in Agroecosystems, 2011, Vol.91(3), pp.327-337
    Description: The nitrogen (N) use efficiency of field vegetable production systems needs to be increased in order to, reduce the detrimental effects of N losses on other ecosystems, save on production costs, and meet the limits set by the German government concerning N balance surpluses. Winter catch crops (CCs) have been shown to be a useful tool for reducing N losses in many agricultural production systems. This study was designed to test the effects of different CCs: rye ( Secale cereale L.), fodder radish ( Raphanus sativus L. var. oleiformis Pers.), bunch onion ( Allium cepa L.), and sudangrass ( Sorghum sudanense Stapf), planted at different sowing dates (early, late), on the N balance of 2-year vegetable crop rotation systems. The crop rotations started with a cauliflower ( Brassica oleracea L. var. botrytis L.) crop, which was fertilized with N in a conventional manner. The experiments took place at three different sites in Germany. Results revealed that the average N balance surplus, when taking into consideration, fertilization, soil mineral N, and aboveground plant biomass N, was 217 kg N ha −1 in the control treatments without a CC. This high value was mainly a consequence of large quantities of crop N and soil mineral N remaining after the harvest of the cauliflower. In spite of these high N surpluses, the application of CC only reduced the N balance surplus, on average across all sites and experiments, by 13 kg N ha −1 , when compared to the control treatments. The type of CC and the sowing date had only minor effects on the N balance. The findings of this study suggest that for many sites the application of CCs does not solve the problem of high N balance surpluses in intensive field vegetable production systems.
    Keywords: Catch crop ; Crop rotation ; Vegetable production ; Nitrogen losses ; Leaching ; Nitrogen balance
    ISSN: 1385-1314
    E-ISSN: 1573-0867
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  • 2
    Language: English
    In: Biology and Fertility of Soils, 2010, Vol.46(2), pp.159-167
    Description: One of the challenges in organic farming systems is to match nitrogen (N) mineralization from organic fertilizers and crop demand for N. The mineralization rate of organic N is mainly determined by the chemical composition of the organic matter being decomposed and the activity of the soil microflora. It has been shown that long-term organic fertilization can affect soil microbial biomass (MB), the microbial community structure, and the activity of enzymes involved in the decomposition of organic matter, but whether this has an impact on short-term N mineralization from recently applied organic substances is not yet clear. Here, we sampled soils from a long-term field experiment, which had either not been fertilized, or fertilized with 30 or 60 t ha −1 year −1 of farmyard manure (FYM) since 1989. These soil samples were used in a 10-week pot experiment with or without addition of FYM before starting (recent fertilization). At the start and end of this experiment, soil MB, microbial basal respiration, total plant N, and mineral soil N content were measured, and a simplified N balance was calculated. Although the different treatments used in the long-term experiment induced significant differences in soil MB, as well as total soil C and N contents, the total N mineralization from FYM was not significantly affected by soil fertilization history. The amount of N released from FYM and not immobilized by soil microflora was about twice as high in the soil that had been fertilized with 60 t ha −1 year −1 of FYM as compared with the non-fertilized soil ( p  〈 0.05).
    Keywords: Decomposition ; Microbial biomass ; Organic fertilization ; Soil adaptation
    ISSN: 0178-2762
    E-ISSN: 1432-0789
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  • 3
    Language: English
    In: Soil Science Society of America journal, 2012, Vol.76(4), pp.1290-1300
    Description: Long-term use of organic soil amendments, compared with unamended or mineral fertilized soils, can change soil organic matter content, microbial biomass content, the microbial community structure, and the activity of enzymes involved in organic matter decomposition. It is not clear, however, whether long-term use of organic amendments, by means of these changes, leads to modified decomposition rates of newly added organic amendments. Therefore, this study was used to test the hypothesis that amendment history has an influence only on the decomposition of recalcitrant organic amendments and not on less recalcitrant organic amendments. Soils used for experimentation were taken from a field experiment where contrasting organic amendment regimes of farmyard manure, pine (Pinus sylvestris L.) bark, vegetable crop residues, and an unamended control had been applied for 35 yr. In a full factorial, laboratory-based incubation experiment, each soil was treated with each of these amendments and net C and N mineralization and microbial biomass C contents were monitored during a 147-d period. Collected data were then used to estimate gross turnover rates of newly added amendments with a modeling approach based on the soil organic matter module of the Daisy model. The modeling results suggested that the turnover of farmyard manure and pine bark, not however of crop residues, should be simulated in consideration of an amendment history effect. In contrast, the results of the ANOVA indicated that amendment history had an insignificant effect on net C and N mineralization from recently applied amendment. We concluded that the effects of amendment history on gross turnover rates of recently added organic amendments may depend on the type of amendment but that these effects on net C and N mineralization are minor in magnitude and hence irrelevant to N fertilization practice. ; p. 1290-1300.
    Keywords: Crop Residues ; Organic Soils ; Nitrogen Fertilizers ; Soil Organic Matter ; Organic Matter ; Field Experimentation ; Microbial Biomass ; Enzymes ; Vegetable Crops ; Models ; Soil Amendments ; Microbial Communities ; Pinus Sylvestris ; Bark ; Mineralization ; Analysis Of Variance ; Community Structure ; Animal Manures
    ISSN: 0361-5995
    E-ISSN: 14350661
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  • 4
    Language: English
    In: Nutrient Cycling in Agroecosystems, 2016, Vol.106(2), pp.217-231
    Description: The decomposition of vegetable crop residues, e.g. from Brassica species, can cause substantial nitrous oxide (N 2 O) and ammonia (NH 3 ) emissions due to their high nutrient and water contents. One promising approach to reduce these harmful emissions is optimizing post-harvest crop residue management. So far published results on the effects of different crop residue placement techniques on N 2 O and NH 3 emissions do not give a consistent picture. One of the key issues is the diverse experimental conditions, in particular with respect to soil characteristics. Therefore, we studied the effects of cauliflower residue management, i.e. no residues (control), surface application (mulch), incorporation by mixing (mix), incorporation by ploughing (plough), on N 2 O and NH 3 emissions in a 7.5-months field study, using a unique open-air facility featuring three different soils with contrasting soil texture (loamy sand, silt loam, sandy clay loam). Cauliflower residues caused the highest N 2 O emissions after ploughing (2.3–3.4 kg N 2 O–N ha −1 , 1.5–2.2 % of residue-N), irrespective of the soil type. In contrast, ammonia emissions were only affected by the residue placement technique in loamy sand, which exhibited the highest emissions in the mulch treatment (1.9 kg NH 3 –N ha −1 , 1.2 % of residue-N). In conclusion, under the given conditions incorporating crop residues by ploughing appears to produce the highest N 2 O emissions in a range of soils, whereas surface application may primarily increase NH 3 emissions in coarse-textured soils.
    Keywords: Nitrous oxide ; Ammonia ; Vegetable crop residues ; Soil type ; Cauliflower ; Tillage
    ISSN: 1385-1314
    E-ISSN: 1573-0867
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  • 5
    In: Annals of Applied Biology, July 2019, Vol.175(1), pp.111-118
    Description: Root exudation of organic carbon (C) is generally believed to be the cause of positive effects of root activity on nitrous oxide (NO) emissions. We tested the effects of root exudation in an actual soil–plant system on NO emissions while excluding most other potential factors. The C source/sink ratio in cucumber was changed by removing fruits to increase root exudation. Root‐zone emissions of carbon dioxide (CO) and NO were monitored in complete stands of adult plants in a greenhouse. Whereas CO emissions rapidly increased as a result of fruit removal the NO emissions were completely unaffected. After cutting the shoots CO emissions decreased within 2 weeks in both the fruit removal treatment and the control to a value significantly lower than that before the start of the treatments. However, NO emissions immediately exhibited a short peak, which was significantly higher in the fruit removal treatment compared to the control. Thereafter NO emissions in both treatments remained on the same level but considerably higher than before shoot cutting. We concluded that in a well‐aerated root zone, a root exudation pulse does not necessarily increase NO emissions, because C substrates are quickly respired by microorganisms before they can support heterotrophic denitrification. The results further indicate the significance of dying/dead roots for the creation of denitrificaton hot‐spots, which likely result from providing C substrates as well as poorly aerated habitats. Plant roots have the potential to enhance NO emissions and this effect has mostly been attributed to root exudation of organic carbon. However, our study shows that a root exudation pulse by suddenly and drastically shifting the source/sink ratio in a cucumber crop does not necessarily increase NO emissions in a well‐aerated root zone but that roots and carbon allocation to the roots may become a crucial factor for post‐termination NO emissions, that is, after truncating plant shoots.
    Keywords: Anaerobic Microorganisms ; Cucumis Sativus L ; Denitrification Hot‐Spots ; Dry Matter ; Root Exudation
    ISSN: 0003-4746
    E-ISSN: 1744-7348
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  • 6
    Dissertation
    Dissertation
    Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I
    Language: English
    Description: In der vorliegenden Studie wurden zwei Fragestellungen bearbeitet, die beide das Ziel verfolgen, die Stickstoff(N)-Ausnutzungseffizienz in landwirtschaftlichen Systemen zu steigern: 1) Hat die langjährige organische Düngung einen Einfluss auf den Abbau kürzlich applizierter organischer Dünger? Die Hypothese war, dass relevante Effekte nur bei schwer abbaubaren organischen Düngern auftreten während bei leicht abbaubaren organischen Düngern die Düngungshistorie keine Rolle spielt. 2) Können die hohen N-Bilanzüberschüsse im intensiven Freilandgemüsebau durch den Einsatz von Winterzwischenfrüchten (ZF) deutlich reduziert werden? Die Hypothese war, dass ZF die Bilanzüberschüsse der betrachteten zweijährigen Fruchtfolgen um mindestens 30 kg N / ha reduzieren. Die erste Hypothese wurde überprüft, indem der Abbau organischer Dünger in Böden, die sich in ihrer organischen Düngungshistorie unterschieden, gemessen wurde. Es wurden ein Topfversuch im Gewächshaus sowie ein Inkubationsversuch im Labor durchgeführt. Die Ergebnisse deuteten darauf hin, dass es Effekte der Historie auf den Abbau von Stallmist und Kiefernrinde gab, während es keine Effekte bei leicht abbaubarem Kohlmaterial gab. Daher wurde die Hypothese angenommen. Allerdings ergaben die beobachteten Effekte kein konsistentes Bild in Hinblick auf die Richtung der Effekte auf die Kohlenstoff(C)- und N-Mineralisierung und Effekte auf die Netto-N-Mineralisation waren generell sehr klein. Zur Überprüfung der zweiten Hypothese wurden an drei Standorten in Deutschland Feldversuche mit Gemüsefruchtfolgen und unterschiedlichen ZF durchgeführt. Die Ergebnisse ergaben, dass trotz der die mittleren Bilanzüberschüsse der Kontrollen (ohne ZF) von 217 kg N / ha die ZF die N-Bilanz im Mittel um nur 13 kg N / ha reduzierten. Daher wurde die Hypothese abgelehnt. Die Ergebnisse zeigten weiterhin, dass der verlustfreie Transfer der von der ZF aufgenommenen N-Menge an die Folgefrucht ein kritischer Schritt bei dieser Technik ist. The current study dealt with two questions that target potential options to increase the nitrogen (N) use efficiency of agricultural systems: 1) Does long-term organic fertilization affect the decomposition of recently added organic fertilizers? The hypothesis was that effects only occur for recalcitrant organic fertilizers while for readily decomposable organic fertilizers, the fertilization history does not play a role. 2) Can the N balance surpluses in intensive field vegetable production systems be substantially reduced by cultivation of winter catch crops (CC)? The hypothesis was that the N balance surpluses of the investigated two-year crop rotations can be reduced by more than 30 kg N / ha. The first hypothesis was tested by applying organic fertilizers to soils that only differed in organic fertilization history. A greenhouse pot experiment and a laboratory incubation experiment were conducted. The results indicated that fertilization history had effects on the decomposition of farmyard manure and pine bark, not however on the decomposition of readily decomposable cabbage material. Hence, the hypothesis was accepted in that fertilization history effects depended on the type of fertilizer. However, fertilization history effects showed no consistent trend with respect to increase or decrease in carbon (C) and N mineralization and the effects on net N mineralization were minor in magnitude. The second hypothesis was tested by performing field experiments at three sites in Germany. Vegetable crop rotations were set up, testing different types of CC. The results suggested that in spite of high N surpluses in the control treatments (no CC) of 217 kg N / ha, CC reduced the N balance surplus on average by only 13 kg N / ha. Hence, the hypothesis was rejected. The findings further indicated that the transfer of N taken up by the CC to the succeeding crop is a critical step when adopting this technique.
    Keywords: Düngeverordnung ; Düngungshistorie ; Gemüsefruchtfolge ; Inkubationsversuch ; Organische Düngung ; Stickstoffausnutzungseffizienz ; Stickstoffauswaschung ; Stickstoffbilanz ; Stickstoffmineralisierung ; Stickstoffüberschuss ; Stickstoffverlust ; Umsatz Organischer Dünger ; Zwischenfrüchte ; Catch Crop ; Fertilization History ; Incubation Experiment ; Nitrogen Balance Surplus ; Nitrogen Leaching ; Nitrogen Losses ; Nitrogen Mineralization ; Nitrogen Use Efficiency ; Organic Amendment ; Organic Fertilization ; Turnover Of Organic Matter ; Vegetable Crop Rotations ; 630 Landwirtschaft ; Veterinärmedizin ; 39 Landwirtschaft ; Garten ; Zc 51600 ; Ddc:630
    Source: Networked Digital Library of Theses and Dissertations
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  • 7
    Text Resource
    Text Resource
    Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I
    Language: English
    Description: In der vorliegenden Studie wurden zwei Fragestellungen bearbeitet, die beide das Ziel verfolgen, die Stickstoff(N)-Ausnutzungseffizienz in landwirtschaftlichen Systemen zu steigern: 1) Hat die langjährige organische Düngung einen Einfluss auf den Abbau kürzlich applizierter organischer Dünger? Die Hypothese war, dass relevante Effekte nur bei schwer abbaubaren organischen Düngern auftreten während bei leicht abbaubaren organischen Düngern die Düngungshistorie keine Rolle spielt. 2) Können die hohen N-Bilanzüberschüsse im intensiven Freilandgemüsebau durch den Einsatz von Winterzwischenfrüchten (ZF) deutlich reduziert werden? Die Hypothese war, dass ZF die Bilanzüberschüsse der betrachteten zweijährigen Fruchtfolgen um mindestens 30 kg N / ha reduzieren. Die erste Hypothese wurde überprüft, indem der Abbau organischer Dünger in Böden, die sich in ihrer organischen Düngungshistorie unterschieden, gemessen wurde. Es wurden ein Topfversuch im Gewächshaus sowie ein Inkubationsversuch im Labor durchgeführt. Die Ergebnisse deuteten darauf hin, dass es Effekte der Historie auf den Abbau von Stallmist und Kiefernrinde gab, während es keine Effekte bei leicht abbaubarem Kohlmaterial gab. Daher wurde die Hypothese angenommen. Allerdings ergaben die beobachteten Effekte kein konsistentes Bild in Hinblick auf die Richtung der Effekte auf die Kohlenstoff(C)- und N-Mineralisierung und Effekte auf die Netto-N-Mineralisation waren generell sehr klein. Zur Überprüfung der zweiten Hypothese wurden an drei Standorten in Deutschland... ; The current study dealt with two questions that target potential options to increase the nitrogen (N) use efficiency of agricultural systems: 1) Does long-term organic fertilization affect the decomposition of recently added organic fertilizers? The hypothesis was that effects only occur for recalcitrant organic fertilizers while for readily decomposable organic fertilizers, the fertilization history does not play a role. 2) Can the N balance surpluses in intensive field vegetable production systems be substantially reduced by cultivation of winter catch crops (CC)? The hypothesis was that the N balance surpluses of the investigated two-year crop rotations can be reduced by more than 30 kg N / ha. The first hypothesis was tested by applying organic fertilizers to soils that only differed in organic fertilization history. A greenhouse pot experiment and a laboratory incubation experiment were conducted. The results indicated that fertilization history had effects on the decomposition of farmyard manure and pine bark, not however on the decomposition of readily decomposable cabbage material. Hence, the hypothesis was accepted in that fertilization history effects depended on the type of fertilizer. However, fertilization history effects showed no consistent trend with respect to increase or decrease in carbon (C) and N mineralization and the...
    Keywords: Düngeverordnung ; Düngungshistorie ; Gemüsefruchtfolge ; Inkubationsversuch ; Organische Düngung ; Stickstoffausnutzungseffizienz ; Stickstoffauswaschung ; Stickstoffbilanz ; Stickstoffmineralisierung ; Stickstoffüberschuss ; Stickstoffverlust ; Umsatz Organischer Dünger ; Zwischenfrüchte ; Catch Crop ; Fertilization History ; Incubation Experiment ; Nitrogen Balance Surplus ; Nitrogen Leaching ; Nitrogen Losses ; Nitrogen Mineralization ; Nitrogen Use Efficiency ; Organic Amendment ; Organic Fertilization ; Turnover Of Organic Matter ; Vegetable Crop Rotations ; Landwirtschaft, Veterinärmedizin ; Landwirtschaft, Garten ; Zc 51600
    Source: DataCite
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  • 8
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  • 9
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