Soil quality variables in organically and conventionally cultivated field sites
Introduction
Alternative agricultural practices such as organic farming have been initiated mainly since 1990. There is growing evidence that organic systems exhibit an improved soil quality characterized by higher biological activity than conventional ones (Drinkwater et al., 1995, Droogers and Bouma, 1996). In organic systems, plant production depends almost exclusively on nutrient transformations in soils, since only limited amounts of permitted fertilizers are used. Because nutrient transformations are primarily controlled by microbes, an active soil microflora and a considerable pool of accessible nutrients are very important to the smooth functioning of organic systems.
The evaluation of soil quality is quite complex and requires the consideration of physical, chemical and biological variables (Wander and Bollero, 1999), since the different variables exhibit disproportional behavior when the land use changes (Bending et al., 2004). Specifically, enzyme activities have been suggested as good early indicators of changes in soil properties because of their relationship to soil microflora, the easiness of measurement and their rapid response to changes in soil management (Dick, 1994). Moreover, the substrate utilization patterns of the soil microbial communities are known to be sensitive to management practices (Marx et al., 2001) while their functional diversity could provide information on the resilience of these communities to stress.
Most frequently comparisons of soil quality are made between tillage and no tillage systems (Aon and Colaneri, 2001, Carpenter-Boggs et al., 2003). A factor usually neglected in this studies is how the duration of organic management (e.g. the time since the organic cultivation begun) affects soil properties (Werner, 1997), although it is known that soil functioning changes only after some years of organic farming (Drinkwater et al., 1995). Soil function in organic systems is based upon organic matter decomposition. From this point of view they can be comparable to hedgerow systems, which constitute islands of natural vegetation between cultivated areas. Although it is expected that the nearby to hedgerows land use exert a strong impact on their dynamics, only in a few studies was the soil quality of cultivated areas (organic and conventional) compared with that of their neighboring hedgerows (Aude et al., 2003).
With the above considerations, this study aims at answering questions relating to the application of organic management. Specifically, the addressed issues were (a) which of the tested soil variables could be used as indicators reflecting differences in soil quality between organically and conventionally managed asparagus fields, (b) how the duration of organic management affects soil variables, (c) is soil quality in organic fields comparable to that in hedgerow systems (d) does the type of management affect the soil variables of the nearby hedgerows.
Section snippets
Study area
The study area is located in Kria Vrisi of the Pella prefecture, 75 km west of Thessaloniki, Greece. The parent rock consists of Alluvial deposits (Holocene) (IGME, 1983). The mean pH (H2O) value of the study area was about 8, while the increasing order of soil electrical conductivity was organic areas<conventional area< hedgerows (Table 1). All cultivated areas were planted by Asparagus officinalis (L.) plants. The organic areas were nearby to each other consisting a continuous field area
Chemical and biological variables
In Table 2 the average values of soil chemical variables are given. ANOVA showed that the concentrations of organic C, organic N and extractable P differed significantly among the sampling areas, while differences in the inorganic N (NH4 and NO3) concentrations were not significant. From comparisons between the organic fields, we found that O2 exhibited the lowest amounts of organic C, organic N and extractable P, while no differences were recorded among the rest of the organic areas. The
Chemical and biological variables
Based on soil chemical and biological variables, sampling areas were discriminated clearly consisting three different groups: the organically managed areas, the conventionally cultivated area and the hedgerows. Of the six variables that contributed significantly to the discrimination, MBC and MBN were of highly importance. The rest significant variables related to N transformation and to fungal biomass. Higher amounts of MBC and MBN characterized the organic systems (OF) and the conventional
Acknowledgements
This research was supported by the Greek General Secretariat for Research and Technology and the European Union under the program PENED-2001 with Grant# 01EΔ431. We are special grateful to R.G. Joergensen who offered expert assistance on ergosterol determination and J.M. Halley for his contribution to the linguistic corrections of the text.
References (41)
- et al.
Temporal and spatial evolution of enzymatic activities and physico-chemical properties in an agricultural soil
Applied Soil Ecology
(2001) - et al.
Vegetation diversity of conventional and organic hedgerows in Denmark
Agriculture, Ecosystems and Environment
(2003) - et al.
Linkages between plant litter diversity, soil microbial biomass and ecosystem function in temperate grasslands
Soil Biology & Biochemistry
(1999) - et al.
Interactions between crop residue and soil organic matter quality and the functional diversity of soil microbial communities
Soil Biology & Biochemistry
(2002) - et al.
Microbial and biochemical soil quality indicators and their potential for differentiating areas under contrasting agricultural management regimes
Soil Biology & Biochemistry
(2004) - et al.
Measurement of microbial biomass phosphorus in soil
Soil Biology & Biochemistry
(1982) - et al.
Chloroform fumigation and the release of soil nitrogen: a rapid direct extraction method to measure microbial biomass nitrogen in soil
Soil Biology & Biochemistry
(1985) - et al.
Soil microbial properties under permanent grass, conventional tillage, and no-till management in South Dakota
Soil & Tillage Research
(2003) - et al.
Functional and molecular responses of soil microbial communities under differing soil management practices
Soil & Biochemistry
(2004) - et al.
Annual dynamics of phosphatase activities in an evergreen oak litter: influence of biotic and abiotic factors
Soil Biology & Biochemistry
(2004)
Amidohydrolases in soils as affected by cropping systems
Applied Soil Ecology
Long-term changes in soil fertility in organic arable farming systems in England, with particular reference to phosphorus and potassium
Agriculture, Ecosystems and Environment
Assessing shifts in microbial community structure across a range of grasslands of differing management intensity using CLPP, PLFA and community DNA techniques
Applied Soil Ecology
Influence of phosphate fertilization on fungal alkaline phosphatase and succinate dehydrogonase activities in arbuscular mycorrhiza of soybean and pineapple
Agriculture, Ecosystems and Environment
The effects of biocidal treatments on metabolism in soil
Soil Biology & Biochemistry
Aggregate stability and soil microbial processes in a soil with different cultivation
Geoderma
Developing weed -suppressive soils through improved soil quality management
Soil & Tillage Research
Why and how we should study field boundary diversity in an agrarian landscape context
Agriculture, Ecosystems and Environment
A microplate fluorimetric assay for the study of enzyme diversity in soils
Soil Biology & Biochemistry
Measurements of microbial biomass C and N in grassland soils by fumigation–incubation procedures: influence of inoculum size and the control
Soil Biology & Biochemistry
Cited by (85)
The use of trophic status indicator as a tool to assess the potential of birch-afforested soils to provide ecosystem services
2023, Agriculture, Ecosystems and EnvironmentSoil microbiological properties in livestock corrals: An additional new line of evidence to identify livestock dung
2021, Journal of Archaeological Science: ReportsThe role of hedgerows in soil functioning within agricultural landscapes
2019, Agriculture, Ecosystems and EnvironmentCitation Excerpt :Thomas and Abbott (2018) found a 25–63% reduction in NO3 leaching downslope of arable fields in western France as a result of oak hedges, with strong seasonal effects on near-surface NO3 dynamics. Monokrousos et al., (2006) studied a hedgerow site in Greece where extractable phosphorus (P) was lower and electrical conductivity higher than in adjacent arable fields. Van Vooren et al., (2017) derived a statistical model, based on an analysis of 60 published studies in temperate regions, suggesting that the SOC stock below hedgerows compared to adjacent fields was 22% greater, and 6% greater in the field margins next to hedgerows compared to arable fields.
Soil fumigation with ammonium bicarbonate or metam sodium under high temperature alleviates continuous cropping-induced Fusarium wilt in watermelon
2019, Scientia HorticulturaeCitation Excerpt :Therefore, AB + HT and MS + HT improved the nutrient levels of soil, especially AB + HT. In organic systems, nutrient cycling in soils is controlled by both microbes and soil enzymes (Monokrousos et al., 2006). The density of soil bacteria remained almost unaffected by HT treatment alone, but was significantly increased by AB + HT and especially MS + HT (Fig. 5a).