| dc.contributor.advisor | Tonn, Bettina Dr. | |
| dc.contributor.author | Scheile, Thorsten | |
| dc.date.accessioned | 2018-09-05T05:22:37Z | |
| dc.date.available | 2018-09-05T05:22:37Z | |
| dc.date.issued | 2018-09-05 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-002E-E49E-1 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-7040 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-7040 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-7040 | |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 630 | de |
| dc.title | Effect of plant and animal functional traits on nutrient cycling in low-input pastures | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Isselstein, Johannes Prof. Dr. | |
| dc.date.examination | 2017-11-17 | |
| dc.description.abstracteng | Excrements of grazing animals play a key role for nutrient cycling in grazed grasslands. So far, most studies on nutrient cycling in pasture systems were performed using simulated excrement patches under simulated grazing conditions. Influences of both plant and animal functional traits on nutrient cycling are known for soil-to-plant-to-animal cycling steps, but relatively little is known about their effect on animal-to-soil-to-plant cycling steps. In low-input pastures excrements from grazing animals represent the main nutrient source for grassland vegetation. Plant and animal functional traits should therefore have a greater impact on nutrient cycling in these systems. For this approach the excrement patch is the functional scale at which nutrient cycling should be assessed in a grazed grassland.
In this study, I investigated grazing animal excrement patches to determine whether different plant and animal functional traits have an effect on plant biomass production, plant nutrient concentration and grazing animal selectivity under real grazing conditions in a grazing system with rotational stocking. Furthermore, I studied the medium-term effects of grazing animal excrements on the plant biomass, plant nutrient concentration and soil nutrient concentration under simulated conditions over a complete grazing season.
The experiments were performed in a semi-natural grassland, which corresponded to a moderately species-rich Lolio-Cynosuretum community. The site is located in the Solling Uplands (Germany / Lower Saxony). Two sward types were realized: a moderately species-rich (diverse) and a grass-dominated sward, achieved by selective herbicide application. In a grazing experiment, swards were rotationally grazed by cattle or sheep from spring to autumn. Excrements were marked in spring and autumn and plant biomass and vegetation height were sampled in the subsequent grazing rotation to cover both plant and animal response. Plant biomass nutrient concentration, production and grazing animal forage uptake at the excrement patches were not affected by the stocking periods, animal species and sward types in the grazing experiment. There was only a general effect of excrement patches on these factors. The results indicated an overall low response of the grassland vegetation to the excrements. Presence of urine patches increased plant biomass production as well as the nitrogen and potassium content of the forage. Dung patches increased the plant biomass potassium content and decreased the animal forage uptake. Regarding their gracing behaviour, clear differences could be seen between cattle and sheep in close vicinity to the dung patches. Cattle avoided grazing vegetation close to dung patches following both deposition in spring and in autumn and sheep only following dung deposition in spring. Furthermore, cattle preferentially grazed at urine plots of the grass-dominated swards.
A second experiment was realized with simulated grazing where excrements, derived from the grazing experiment, were applied and plant biomass was sampled according to three grazing rotations over the year. Additionally, soil nutrient status was sampled at the end of the simulated grazing season to cover the medium-term pasture response to excrements. In this simulation experiment, the excrements only affected the plant biomass production following application in spring without differences between animal species. Grass-dominated swards showed a higher production than diverse swards at plots receiving excrements. Dung patches decreased plant biomass production at the diverse swards and cattle urine patches increased plant biomass production at grass-dominated swards. Excrement nutrient concentration showed a great variability for both cattle and sheep and sampling date. The analysis of plant biomass nutrient concentration at the simulation experiment revealed a great variability of both plant biomass N and K concentration which was independent from the excrement nutrient concentration, time of excrement application and sward botanical composition. Soil nutrient status showed the greatest response to the application of excrements in spring. Cattle induced a higher soil nutrient concentration (nitrate, ammonium, potassium) than sheep. Cattle dung patches additionally increased the phosphorus concentration. Sheep dung and urine patches only affected the soil nitrate and ammonium concentration.
Our results indicate an overall low response of plant biomass parameters to the presence of grazing cattle and sheep excrements, whereby plant and animal functional traits did not alter the plant response at the excrement patch. In the low-input pasture, pasture vegetation and grazing animals showed a rather general response to the presence of excrement. The high variability found for excrement and plant biomass nutrient concentration and plant biomass production indicates the complexity of nutrient cycling in a real grazing system. At the small-scale of the excrement patch, this high variability is an important factor determining nutrient cycling. Assessing nutrient losses following excrement application and determining the nutrient use efficiency of pasture vegetation at the excrement patch scale should give more detailed information on nutrient cycling. | de |
| dc.contributor.coReferee | Wrage-Mönnig, Nicole Prof. Dr. | |
| dc.contributor.thirdReferee | Dittert, Klaus Prof. Dr. | |
| dc.subject.eng | Nutrient Cycling | de |
| dc.subject.eng | Grazing Selection | de |
| dc.subject.eng | Forage Intake | de |
| dc.subject.eng | Excreta | de |
| dc.subject.eng | Diverse Grassland | de |
| dc.subject.eng | Soil Nutrients | de |
| dc.subject.eng | Low-Input | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-002E-E49E-1-5 | |
| dc.affiliation.institute | Fakultät für Agrarwissenschaften | de |
| dc.subject.gokfull | Land- und Forstwirtschaft (PPN621302791) | de |
| dc.identifier.ppn | 1030406839 | |