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| Keller, Martina; Oberson, Astrid; Annaheim, Kathrin E.; Tamburini, Federica; Mäder, Paul; Mayer, Jochen; Frossard, Emmanuel; Bünemann, Else K.. |
| Lower P-input levels in organic than conventional farming can decrease soil total and available P, which can potentially be resupplied from soil organic P. We studied the effect of 30 y of conventional and organic farming on soil P forms, focussing especially on organic P. Soil samples (0–20 cm) were taken in a field experiment with a nonfertilized control, two organic systems receiving P inputs as animal manure, and two conventional systems receiving only mineral P or mineral P and manure. Soils were analyzed for total, inorganic, organic, and microbial P, by sequential P fractionation and by enzyme additions to alkaline soil extracts. Samples taken prior to starting the experiment were also analyzed. Average annual P balances ranged from –20 to +5 kg... |
| Tipo: Journal paper |
Palavras-chave: Soil quality; Crop husbandry. |
| Ano: 2012 |
URL: http://orgprints.org/21783/1/keller-etal-2012-JPlantNutrSoilSci-Vol175-p385-393.pdf |
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| Keller, Martina; Oberson, Astrid; Frossard, Emmanuel; Mäder, Paul; Mayer, Jochen; Bünemann, Else K.. |
| The impact of cropping systems on soil phosphorus (P) forms and P dynamics was studied. The systems were a biodynamic (DYN), a bioorganic (BIO), a conventional (CON), a stockless system (MIN) and an unfertilized control (NON). These cropping systems are part of the DOK field trial in Therwil near Basel. The systems differed in fertilization and plant protection. The P budgets over 30 years were negative except for CON and increased in the order: NON < DYN < ORG < MIN < CON. A sequential P extraction scheme was used to characterize the P forms in soil samples from 2007 and 1977 (before the start of the trial). Labile inorganic P (Pi) forms differed significantly between cropping systems. Organic P forms (Po) and stable Pi forms were not... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover; Soil; Composting and manuring. |
| Ano: 2009 |
URL: http://orgprints.org/14255/1/Keller_14255.pdf |
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