|Main authors:||Abdallah Alaoui, Ursula Gämperli Krauer, Tatenda Lemann, Vincent Roth, Gudrun Schwilch & iSQAPER Study Site teams|
|iSQAPERiS editor:||Jane Brandt|
Alaoui, A., Gämperli Krauer, U., Lemann, T., Roth, V., Schwilch, G. & iSQAPER Case Study Site teams (2018) Soil quality inventory of case study sites. iSQAPER Project Deliverable 5.2, 23 pp
|1. iSQAPER study sites|
|2. Pedo-climatic zones|
|3. Farming systems|
|4. Agricultural management practices|
|5. Soil quality indicators|
The impacts of agricultural management practices (AMPs) on soil quality were measured in 14 case study sites, including 10 located in Europe and 4 in China, representative of the major pedo-climatic zones (Figure 1) (see also »Pedoclimatic zones of Europe and »Pedoclimatic zones of China). The case study sites represent wide agricultural management activities and were chosen because they include promising AMPs that have been shown to improve soil quality (Table 1).
In Europe, the 10 study areas covered 6 out of the 8 climatic zones:
- Boreal to sub-Boreal (14 plots),
- Northern sub-Continental (5 plots),
- Southern Sub-Continental (49 plots),
- Atlantic (7 plots),
- Mediterranean Temperate (31 plots) and
- Mediterranean semi-arid (6 plots).
In China, climate variability is higher and only 3 out of 10 climatic areas were investigated:
- Central Tropical Asia (14 plots),
- Warm Temperate and
- Middle (6 plots) Temperate zone (6 plots).
The classification of the farming systems used in this study was according to CORINE land cover assessment (European Environment Agency, 2006) and consist of 3 classes; Arable land, permanent crops, fodder crops, root crops, and pastures (see »Farming system classification in the iSQAPER project).
Based on WOCAT database (www.wocat.net), 18 promising AMPs with potential to improve soil quality were selected (Schwilch et al., 2011) (Table 1). Each case study identified at least 3 out of the 18 selected APMs (or combinations thereof). The selection of these AMPs was performed based on the following criteria:
- management practice implemented for at least 3 years;
- at least in 2 different soil types; and
- at least in 2 different first level Farming Systems (arable, permanent, grazing).
For mixed farming systems, the study site teams were asked to consider the existence of two different farming systems on the same farm, in case it includes both arable cropping and pastures. Additionally, for each AMP plot, the study site teams had to identify 3 related control plots. The idea is to compare the soil quality on a plot where management practices have changed 3 or more years ago with that on a control plot where practices did not change. Both control and AMP plots were located in the same pedo-climatic zone and having comparable soil conditions. In total, 138 sets of paired plots (138 plots with promising AMPs and 138 controls) were considered, with 112 plots located in Europe and 26 in China.
Table 1. Promising AMPs considered, description, expected impacts/ecological benefits and the corresponding main soil threat targeted by its use (WOCAT, (Schwilch et al., 2011))
|AMP list||AMP description||Expected impacts / Ecological benefits||Example of practice described in WOCAT|
|1 - No-till||A system where crops are planted into the soil without primary tillage||
|2 - Min-till||Tillage operation with: a) reduced tillage depth; b) strip tillage; c) mulch tillage; or or a combination thereof||
|3 - Permanent soil cover / Removing less vegetation cover||Avoiding a bare or sparsely covered soil exposed to weather conditions (rain, wind, radiation, etc) by ensuring a permanent cover (at least 30% of the soil surface) throughout the year, e.g. through cutting less grass, leaving a volunteer crop or crop residues, etc. (see also cover crops and residue maintenance / mulching)||
||»Permanent grassland on peaty and eroded soils [Estonia]|
|4 - Cover crops||
|5 - Residue maintenance / Mulching||Maintaining crops residues or spreading of organic (or other) materials on the soil surface.||
|6 - Cross-slope measure||Structural measure along the contour to break slope lengths, such as terraces, bunds, grass strip, trashlines, contour tillage||Reduces surface runoff and erosion (increase infiltration capacity).||»Soil erosion control by ridges [Greece]|
|7 - Measures against compaction||
||a-b) Looses soil to improve drainage, infiltration, aeration and rooting characteristics, and brings nutrients up from deep below
c-d) Minimizes soil damage and preserves soil function in terms of water infiltration, drainage and greenhouse gas mitigation, and (d) provides useful information for decision making process for site-specific applications such as variable deep tillage to benefit from increased timeliness (and reduced management costs)
|8 - Leguminous crop||A leguminous crop is a plant in the family Fabaceae (or Leguminosae) that is grown agriculturally, primarily for their grain seed called pulse, for livestock forage and silage, and as soil-enhancing green manure. Well-known legumes include alfalfa, clover, peas, beans, lentils, lupins, mesquite, carob, soybeans, peanuts, and tamarind.||
|9 - Green manure / Integrated soil fertility management||Green manure is a crop grown to be incorporated into the ground, while the more general term ‘integrated soil fertility management’ refers to a mix of organic and inorganic materials, used with close attention to context-specific timing and placing of the inputs in order to maximize the agronomic efficiency.||
|10 - Manuring (a) / composting (b)||
|11 - Crop rotation (a) / Control or change of species composition (b)||Practice of alternating the annual crops grown on a specific field in a planned pattern or sequence in successive crop years so that crops of the same species or family are not grown repeatedly on the same field Diversify species in rotation systems or grasslands.||
a) Reduces risk of pest and weed infestations.
b) Introduces desired / new species, reduces invasive species, controls burning, residue burning.
|12 - Integrated pest and disease management incl. organic agriculture||Appropriate measures that discourage the development of pest populations and keep pesticides and other interventions to reduce or minimize risks to human health and the environment.||
|13 - Water diversion and drainage||A graded channel with a supportive ridge or bank on the lower side. It is constructed across a slope to intercept surface runoff and convey it safely to an outlet or waterway||
|14 - Irrigation management||Controlled water supply and drainage: mixed rainfed – irrigated; full irrigation; drip irrigation||
|15 - Major change in timing of activities||Adaptation of the timing of land preparation, planting, cutting of vegetation according weather and climatic conditions, vegetation growth, etc.||
|16 - Layout change according to natural and human environment/needs||eg exclusion of natural waterways and hazardous areas, separation of grazing types; increase of landscape diversity.||
|17 - Area closure / rotational grazing||Complete or temporal stop of use to support restoration||
|18 - Change of land use practices / intensity level||eg change from grazing to cutting (for stall feeding), from continuous cropping to managed fallow, from random (open access) to controlled access (grazing land), from herding to fencing, adjusting stocking rates.||
In order to assess the impact of AMPs on soil quality, 11 soil quality variables based on a visual soil assessment methodology were selected based on extensive literature review (e.g. Shepherd, 2000) (Table 2). For each variable, clear and precise instructions were compiled in a manual. A newly developed inﬁltrometer was used to easily assess the soil inﬁltration capacity in the ﬁeld and to investigate hydrodynamic ﬂow processes (Alaoui et al., 2018).
Table 2. List of the variables used to assess soil quality.
Indicators 1 and 2 provide general information, 3 to 8 are derived from visual soil assessment (VSA) methodology, and 9 to 11 are based on measurements.
|Nº||Soil quality indicator||Soil threats addressed|
|1||Susceptibility to Wind and Water Erosion||Erosion|
|2||Surface ponding (under cropping)||Soil compaction|
|3||Presence of a cultivation pan||Subsoil compaction|
|4||Soil Colour||OM decline|
|5||Soil porosity||Soil compaction|
|6||Soil structure and consistency||Soil compaction|
|7||Soil slaking test (soil stability)||Erosion|
|8||Biodiversity (earthworm density)||Biodiversity decline|
|10||Infiltration rate / Penetration resistance||Soil compaction|
|11||Labile organic carbon||Organic carbon decline|
It is worth mentioning that the indicators selected to evaluate soil quality are mainly related to soil structure (3 – 8 and 10) since they are based on »Visual soil and plant quality assessment (VSA). In this article, soil quality concerns mainly soil structure.
A quantitative investigation of soil quality in terms of physical, chemical and biological is given in »Impact of promising land managment practices.
For the evaluation of soil quality, a qualitative score was established for the 11 variables according to 3 conditions: good, moderate, and bad, illustrated with standardized photos serving as references. The improvement in soil quality was checked through the comparison between the AMP plot and the control.
- Where at least a single variable shows a better soil quality score in a plot with AMP (compared with the control), a soil quality improvement was considered.
- If better scores were shown in the control, the impact of AMP was considered negative.
- If the scores were similar, the AMP was assumed to have no impact.
The inventory and the scoring of soil quality were done together with land users, for all study sites under the constraints of carrying out the assessment of the paired AMP plot – control to insure comparable soil conditions. The farmers were requested to express their own opinion with regard to the variables that have meaning for soil quality within the list we proposed (Table 2). We then compared their variables with the ones that have been shown to improve soil quality in all study sites.
Note: For full references to papers quoted in this article see