Tea time for soils : decomposition experiments in Swedish long-term field trials
Abstract Soils represent a large carbon pool, with almost twice the amount contained in living plant biomass and the atmosphere combined. Consequently, soil has a significant impact on the global C cycle and it is suggested that soil organic C (SOC) sequestration is one of the most cost-effective...
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| Format: | H2 |
| Language: | Inglés Swedish |
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SLU/Dept. of Ecology
2017
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| _version_ | 1855571632948510720 |
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| author | Åkesson, Olle |
| author_browse | Åkesson, Olle |
| author_facet | Åkesson, Olle |
| author_sort | Åkesson, Olle |
| collection | Epsilon Archive for Student Projects |
| description | Abstract
Soils represent a large carbon pool, with almost twice the amount contained in living plant biomass and the atmosphere combined. Consequently, soil has a significant impact on the global C cycle and it is suggested that soil organic C (SOC) sequestration is one of the most cost-effective alternatives to counteract climate change.
The literature was reviewed regarding the influence of abiotic and biotic factors on SOC dynamics, and how SOC stocks vary with management practices and cropping systems. I also screened the literature for different meth-odologies to study carbon and litter decomposition. I decided to use the Tea bag index (TBI) approach. The TBI uses two types of commercially available tea bags, and characterizes decomposition dynamics in terms of two parameters, the decomposition rate (k) and stabilization factor (S).
I hypothesized that the TBI would be sensitive enough to quantify the impact of common agricultural practices on litter decomposition under a wide range of pedo-climatic conditions. I selected treatments from 13 long-term field trials that allowed me to compare: perennial forage versus annual crops (N = 4), fertilized versus unfertilized fields (N = 6) and different tillage practices (N = 3).
The results showed that the two TBI parameters were sensitive to both management practices and cropping systems. Fertilized plots showed higher stabilization (S) than unfertilized plots, but there were no differences on decomposition rates (k). The effect of different tillage practices on k and S were variable across sites and treatments, although ploughing tended to result in lower decomposition rates, compared to direct drilling or shallow cultivation treatments. The TBI was most sensitive when comparing perennial forage versus annual cropping systems, where the measurements for forage generally indicated higher S values and lower k values. The results also showed that climate, through precipitation and air temperature, had a large impact on stabilization (R2 = 0.33), while its effect on decomposition rates was limited. The decomposition rates were found to be significantly affected by soil properties such as clay content (R2 = 0.13) and soil C/N-ratios (R2 = 0.19). It can be concluded that the TBI approach is a useful tool to characterize decompo-sition dynamics and to identify climate-smart agricultural management practicies under different pedo-climatic conditions. |
| format | H2 |
| id | RepoSLU10068 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2017 |
| publishDateSort | 2017 |
| publisher | SLU/Dept. of Ecology |
| publisherStr | SLU/Dept. of Ecology |
| record_format | eprints |
| spelling | RepoSLU100682018-09-26T12:23:31Z Tea time for soils : decomposition experiments in Swedish long-term field trials Åkesson, Olle Tea Bag Index SOC SOC dynamics stabilization decomposition Abstract Soils represent a large carbon pool, with almost twice the amount contained in living plant biomass and the atmosphere combined. Consequently, soil has a significant impact on the global C cycle and it is suggested that soil organic C (SOC) sequestration is one of the most cost-effective alternatives to counteract climate change. The literature was reviewed regarding the influence of abiotic and biotic factors on SOC dynamics, and how SOC stocks vary with management practices and cropping systems. I also screened the literature for different meth-odologies to study carbon and litter decomposition. I decided to use the Tea bag index (TBI) approach. The TBI uses two types of commercially available tea bags, and characterizes decomposition dynamics in terms of two parameters, the decomposition rate (k) and stabilization factor (S). I hypothesized that the TBI would be sensitive enough to quantify the impact of common agricultural practices on litter decomposition under a wide range of pedo-climatic conditions. I selected treatments from 13 long-term field trials that allowed me to compare: perennial forage versus annual crops (N = 4), fertilized versus unfertilized fields (N = 6) and different tillage practices (N = 3). The results showed that the two TBI parameters were sensitive to both management practices and cropping systems. Fertilized plots showed higher stabilization (S) than unfertilized plots, but there were no differences on decomposition rates (k). The effect of different tillage practices on k and S were variable across sites and treatments, although ploughing tended to result in lower decomposition rates, compared to direct drilling or shallow cultivation treatments. The TBI was most sensitive when comparing perennial forage versus annual cropping systems, where the measurements for forage generally indicated higher S values and lower k values. The results also showed that climate, through precipitation and air temperature, had a large impact on stabilization (R2 = 0.33), while its effect on decomposition rates was limited. The decomposition rates were found to be significantly affected by soil properties such as clay content (R2 = 0.13) and soil C/N-ratios (R2 = 0.19). It can be concluded that the TBI approach is a useful tool to characterize decompo-sition dynamics and to identify climate-smart agricultural management practicies under different pedo-climatic conditions. Sammanfattning Marken är ett stort, och viktigt, kollager då det innehåller nästan dubbelt så mycket kol som atmosfären och den levande biomassan tillsammans. Därmed spelar marken också en signifikant roll i den globala kolcykeln där det organiska kolets inbindning i marken (SOC) föreslås vara ett av de mest kostnads-effektiva alternativen för att bromsa klimatförändringarna. I denna uppsats använder vi oss av Tea bag index (TBI)-metoden för att mäta kolets stabilisering och nedbrytning i ett antal svenska långliggande fältförsök. Litteraturgenomgången beskriver hur abiotiska och biotiska faktorer på-verkar det organiska kolet i marken, och hur detta påverkas av olika brukningsmetoder och odlingssystem. Den behandlar även olika metoder för att studera nedbrytningen av kol och organiskt material. Vår hypotes var att TBI skulle vara en tillräckligt känslig metod för att se skillnader i kolets dynamik i olika brukningssystem och en rad olika markförhållanden. Vi studerade behandlingar såsom odling av vall jämfört med annuella grödor (N = 4), gödslade och ogödslade fält (N = 6) och olika kultiveringsmetoder (N = 3) i totalt 13 olika långliggande svenska fältförsök. Resultaten visade att de två parametrarna S och k, erhållna från TBI, var känsliga nog för att märka skillnader i både brukningsmetoder och odlingssystem. Trenden var att stabiliseringen (S) var högre i gödslade led jämfört med ogödslade. Även om några signifikanta skillnader i nedbrytningshastigheten (k) hos dessa inte kunde upptäckas. Effekterna av olika kultiveringsmetoder var varierande både mellan de olika platserna och mellan behandlingarna, men plöjning verkade resultera i lägre nedbrytningshastighet, jämfört med direktsådd och grundare kultivering (5-7 eller 10-12 cm djup). TBI påvisade dock starkast känslighet när etablerade vallar jämfördes med annuella grödor, där resultaten indikerade att vallen genererade högre S och lägre k än motsvarande annuella gröda. Resultaten visade även att klimatet, som en funktion av lufttemperatur och nederbörd, hade stor inverkan på stabiliseringen (R2 = 0.33), medan dess effekt på nedbrytningshastigheten var begränsad. Nedbrytningshastigheten påverkades dock av jordegenskaper som lerhalt (R2 = 0.13) och C/N kvot (R2 = 0.19). Slutsatsen är att TBI-metoden är ett användbart verktyg för att karaktärisera det organiska markkolets dynamik och för att identifiera klimatsmarta brukningssystem vid olika markförhållanden. SLU/Dept. of Ecology 2017 H2 eng swe https://stud.epsilon.slu.se/10068/ |
| spellingShingle | Tea Bag Index SOC SOC dynamics stabilization decomposition Åkesson, Olle Tea time for soils : decomposition experiments in Swedish long-term field trials |
| title | Tea time for soils : decomposition experiments in Swedish long-term field trials |
| title_full | Tea time for soils : decomposition experiments in Swedish long-term field trials |
| title_fullStr | Tea time for soils : decomposition experiments in Swedish long-term field trials |
| title_full_unstemmed | Tea time for soils : decomposition experiments in Swedish long-term field trials |
| title_short | Tea time for soils : decomposition experiments in Swedish long-term field trials |
| title_sort | tea time for soils : decomposition experiments in swedish long-term field trials |
| topic | Tea Bag Index SOC SOC dynamics stabilization decomposition |