ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Microbiological processes in soil organic phosphorus transformations in conventional and biological cropping systems (1996)

Oberson, A. ; Besson, J. M. ; Maire, N. ; [et al.]

Springer

Biology and fertility of soils 21 (1996), S. 138-148

add to mindlist on the mindlist

Details

ISSN: 1432-0789

Keywords: Organic soil P ; Acid phosphatase activity ; Soil microbial biomass ; Organic C mineralization ; Temporal fluctuations ; Farming systems ; P turnover

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract We studied microbiological processes in organic P transformations in soils cultivated with conventional and biological farming systems during the 13th and 14th year of different cropping systems. The treatments included control, biodynamic, bioorganic, and conventional plots and a mineral fertilization treatment. Different P fractions were investigated using a sequential fractionation method. Labile organic P, extracted by 0.5 M NaHCO3, was not affected by the farming systems. However, residual organic P remaining in the soil at the end of the sequential fractionation procedure showed that the biodynamic treatment, in particular, led to a modification of the composition of organic P. Labile organic P, organic P extractable in 0.1 M NaOH, and total residual P all showed temporal fluctuations. As total residual P consists of more than 70% organic P, it can be assumed that residual organic P contributed to these variations. This result indicates that chemically resistant organic P participates in short-term accumulation and mineralization processes. All biological soil parameters tested in this study showed significant temporal fluctuations, mainly attributed to differences in climatic conditions between years, but possibly also related to the growth cycle of the crop. The higher values of the biological soil parameters in the biodynamic and bioorganic treatments were explained by the greater importance of manure and the different plant protection strategies. The level of phosphatase activity and mineralization of organic C indicated a higher turnover of organic substrates, and thus of organic P, in the biodynamic and bioorganic treatments. Biological parameters were shown to be critical for assessing the significance of organic P in the soil P turnover.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00335925

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

Microbiological processes in soil organic phosphorus transformations in conventional and biological cropping systems (1996)

Oberson, A. ; Besson, J. M. ; Maire, N. ; [et al.]

Springer

Biology and fertility of soils 21 (1996), S. 138-148

add to mindlist on the mindlist

Details

ISSN: 1432-0789

Keywords: Key words Organic soil P ; Acid phosphatase activity ; Soil microbial biomass ; Organic C mineralization ; Temporal fluctuations ; Farming systems ; P turnover

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract We studied microbiological processes in organic P transformations in soils cultivated with conventional and biological farming systems during the 13th and 14th year of different cropping systems. The treatments included control, biodynamic, bioorganic, and conventional plots and a mineral fertilization treatment. Different P fractions were investigated using a sequential fractionation method. Labile organic P, extracted by 0.5 M NaHCO3, was not affected by the farming systems. However, residual organic P remaining in the soil at the end of the sequential fractionation procedure showed that the biodynamic treatment, in particular, led to a modification of the composition of organic P. Labile organic P, organic P extractable in 0.1 M NaOH, and total residual P all showed temporal fluctuations. As total residual P consists of more than 70% organic P, it can be assumed that residual organic P contributed to these variations. This result indicates that chemically resistant organic P participates in short-term accumulation and mineralization processes. All biological soil parameters tested in this study showed significant temporal fluctuations, mainly attributed to differences in climatic conditions between years, but possibly also related to the growth cycle of the crop. The higher values of the biological soil parameters in the biodynamic and bioorganic treatments were explained by the greater importance of manure and the different plant protection strategies. The level of phosphatase activity and mineralization of organic C indicated a higher turnover of organic substrates, and thus of organic P, in the biodynamic and bioorganic treatments. Biological parameters were shown to be critical for assessing the significance of organic P in the soil P turnover.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00335925

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Soil phosphorus dynamics in cropping systems managed according to conventional and biological agricultural methods (1993)

Oberson, A. ; Fardeau, J. C. ; Besson, J. M. ; [et al.]

Springer

Biology and fertility of soils 16 (1993), S. 111-117

add to mindlist on the mindlist

Details

ISSN: 1432-0789

Keywords: Available P ; Isotopic exchange kinetics ; Organic soil P ; Acid phosphatase activity ; Soil microbial biomass ; Farming systems

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The effects of conventional and biological farming systems on soil P dynamics were studied by measuring some microbiological parameters after 13 years of different cropping systems. The treatments included control, biodynamic, bio-organic, and conventional plots and a mineral fertilizer treatment. The farming systems differed mainly in the form and quantity of nutrients applied and in the plant protection strategies. The results of a sequential fractionation procedure showed that irrespective of the form of P applied, neither 0.5 M NaHCO inf3 sup- nor 0.1 M NaOH-extractable organic P, but only the inorganic fractions, were affected. The residual organic P, not extracted by NaHCO3 or NaOH was increased in the biodynamic and bio-organic plots. The soil microbial biomass (ATP content) and the activity of acid phosphatase were also higher in both biologically managed systems. These results were attributed to the higher quantity of organic C and organic P applied in these systems, but also to the absence of or severe reduction in chemical plant protection. The relationship between acid soil phosphatase and residual organic P was interpreted as an indication that this fraction might be involved in short-term transformations. The measurement of the intensity, quantity, and capacity factors of available soil P using the 32P isotopic exchange kinetic method showed that P could not be the factor limiting crop yield in the biological farming systems. The kinetic parameters describing the ability of P ions to leave the soil solid phase, deduced from isotopic exchange, were significantly higher for the biodynamic treatment than for all other treatments. This result, showing a modification of chemical bonds between P ions and the soil matrix, was explained by the higher Ca and organic matter contents in this system.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00369411

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Isotope methods for assessing plant available phosphorus in acid tropical soils (2003)

Bühler, S. ; Oberson, A. ; Sinaj, S. ; [et al.]

Oxford, UK : Blackwell Science Ltd

European journal of soil science 54 (2003), S. 0

add to mindlist on the mindlist

Details

ISSN: 1365-2389

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Use of isotope methods to measure the availability of phosphorus (P) in soils that are well supplied with P is well established. We have evaluated such methods for acid tropical soils with very small P contents, which are less well studied. The isotopically exchangeable P in soil suspensions (E value) and that in plant growth experiments (L value) were measured in soils that had received varying amounts of P fertilizer in two field experiments in Colombia. We determined the E values over 4–5 weeks of equilibration allowing for the kinetics of isotope exchange. The decrease in radioactivity in the soil solution at a particular time, t, divided by that at the start (rt/R) was described by three parameters (r1/R, r∞/R, and a coefficient n) derived from the time course of isotopic exchange over 100 minutes. Values of Et were calculated either from measured values of rt/R or those extrapolated until 12 weeks. Agrostis capillaris was grown on the same soils labelled with carrier-free 33P-orthophosphate ions to obtain L values. Agreement between E values derived from measured and extrapolated values of rt/R was satisfactory, but errors in n and r∞/R limited the precision with which we could estimate E values. For most soils, the P concentrations in the soil solution were greater than the detection limit of the malachite green method (0.9 µg l−1) but smaller than its quantification limit (3.6 µg l−1). In the soils with the least available P, the P content of the seed limited the determination of the L value. The E values were strongly correlated, but not identical, with the L values measured for the same time of isotopic exchange. We conclude that these approaches are not precise enough to detect in these soils the ability of a plant to access slowly exchangeable forms of P or to quantify the mineralization of organic P. However, these isotope techniques can be used to estimate the total fraction of added fertilizer P that remains available to the plants.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1365-2389.2003.00542.x

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Phosphorus status and cycling in native savanna and improved pastures on an acid low-P Colombian Oxisol (1999)

Oberson, A. ; Friesen, D.K. ; Tiessen, H. ; [et al.]

Springer

Nutrient cycling in agroecosystems 55 (1999), S. 77-88

add to mindlist on the mindlist

Details

ISSN: 1573-0867

Keywords: acid low-P soils ; improved pastures ; P budget ; P cycling ; soil P fertility

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract On acid low-phosphorus (P) Colombian Oxisols, improved pastures with acid-soil-tolerant grass and legume varieties have increased beef production by a factor of 10 to 15 with only modest P fertilizer inputs. This indicates that the efficiency of P fertilization could be greater than is commonly expected on such strongly P-sorbing soils. To understand the effect of improved pastures on P cycling and availability, we estimated P budgets, and characterized soil P by sequential fractionation, isotopic exchange and biological activity measurements on soil samples from unfertilized native savanna, and fertilized improved grass-only (Brachiaria decumbens cv. Basilisk) and grass-legume (B. decumbens + Pueraria phaseoloides, Kudzu) pastures established in 1978 on a medium-textured isohyperthermic, tropeptic haplustox. Comparison of calculated P budgets, based on inputs and exports, with total soil P contents showed that fertilization, as part of the improved pasture management, had resulted in a measurable increase of total P in the surface 0–20 cm soil layer of nearly 30 mg kg-1 or about 20% over the savanna level. Sequential soil P fractionation of different seasonal samplings indicated that grass-legume maintained higher organic and available inorganic P levels with less temporal variation than the two other types. The linkage of organic P and available P was also reflected in soil biological activity. Estimates of P in microbial biomass and phosphatase activity were significantly higher in grass-legume than grass-only and savanna. The improvement in soil P availability, as measured by solution P concentration, P sorption and exchangeable P, was much greater in grass-legume than in grass-only. With comparable fertilizer inputs and greater product exports, improved P availability in grass-legume cannot be due to differences in budgets but can be attributed to changes in the overall biological activity in the soil-plant system caused by the presence of legumes in the vegetation cover. Total C, organic P content and macrofaunal activity were all significantly higher in grass-legume soils. Greater turnover of organic litter in grass-legume may provide for steadier organic P inputs and, therefore, higher P cycling and availability.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1009813008445

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Phosphorus acquisition and cycling in crop and pasture systems in low fertility tropical soils (1997)

Friesen, D. K. ; Rao, I. M. ; Thomas, R. J. ; [et al.]

Springer

Plant and soil 196 (1997), S. 289-294

add to mindlist on the mindlist

Details

ISSN: 1573-5036

Keywords: litter decomposition ; Oxisols ; phosphorus fractionation ; root distribution ; root length ; savannas

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Soil-plant processes which enhance P acquisition and cycling in low-P Oxisols were investigated in a crop rotations and ley pasture systems experiment on the Colombian eastern plains. Comparison of rooting patterns indicated that, despite low available P at depth, there are important differences in root size and distribution among native savanna, introduced forage and crop species which affect their ability to acquire P from these soils. Differences in crop/forage residue decomposition and P release rates suggest that managing the interaction of residue with soil may help slow P fixation reactions. Despite these differences, soil P fractionation measurements indicate that applied P moves preferentially into labile inorganic P pools, and then only slowly via biomass production and microbes into organic P pools under both pastures and crop rotations.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1004226708485

Permalink