Main authors: Abdallah Alaoui, Ursula Gämperli Krauer, Tatenda Lemann, Vincent Roth, Gudrun Schwilch & iSQAPER Case Study Site teams
iSQAPERiS editor: Jane Brandt
Source documents: 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
Alaoui, A., Schwilch, G. (2019) Database of currently applied and promising agricultural management practices. iSQAPER Project Deliverable 5.3, 14 pp

 

The impact of promising agricultural management practices (AMPs) on soil quality was assessed using a Visual Soil Assessment (VSA) tool (e.g. Shepherd, 2000) in a total of 138 pairs of plots/farms spread across 14 study site areas, with10 located in Europe and 4 in China. The full description of the study site areas, the establishment of promising AMPs as well as the criteria used to select these 138 pair of farms/plots within each study site is provided in »Identification of experimental sites in which to measure impact of AMPs and Barão et al. (2019).


Contents table
1. Paired AMP/control experimental plots in the iSQAPER study sites
2. Impact of AMPs on soil quality
3. Analysis of AMPs using WOCAT framework
4. Comments on results and further research

1. Paired AMP/control experimental plots in the iSQAPER study sites

Each pair of expeimental plots includes a farm/plot where a new, promising AMP has been used for at least the last 3 years (plot-AMP) and a farm/plot where the corresponding conventional practice has been used for the last 3 years (plot-control).

The 138 pair of farms/plots include a myriad of promising AMPs and combinations in use by farmers and represent the promising management choices undertaken locally. The majority of the evaluated pairs of plots/farms were on arable land with fewer pairs addressing management practices in pasture and permanent farming systems (Table 1).

Table 1. Tested AMPs at case study sites

Promising AMP tested  Farming System Total plots/farms 
Arable Pasture Permanent
No-till 4   6 10
Min-till 8   2 10
Permanent soil cover / Removing less vegetation cover   3   3
Cover crops 3   1 4
Residue maintenance / Mulching 7   1 8
Cross-slope measure 1   2 3
Measures against compaction 2      2
Leguminous crop  5      5
Green manure / Integrated soil fertility management 2     2
Manuring & composting 12     12
Crop rotation / Control or change of species composition 12   1 13
Integrated pest and disease management incl. organic agriculture 3   4 7
Water diversion and drainage     1 1
Irrigation management 4     4
Major change in timing of activities 1     1
Area closure / rotational grazing   3   3
Change of land use practices / intensity level 2 8   10
Total single promising AMP tested 66 14 18 98
Crop rotation / Control or change of species composition; Integrated pest and disease management incl. organic agriculture 1     1
Integrated pest and disease management incl. organic agriculture; Major change in timing of activities 1     1
Leguminous crop; Residue maintenance / Mulching     1 1
Manuring & composting; Crop rotation / Control or change of species composition 1     1
Manuring & composting; Integrated pest and disease management incl. organic agriculture     1 1
Manuring & composting; Change of land use practices / intensity level   1   1
Manuring & composting; Crop rotation / Control or change of species composition 1     1
Manuring & composting; Cross-slope measure     1 1
Manuring & composting; Integrated pest and disease management incl. organic agriculture 1     1
Min-till ; Crop rotation / Control or change of species composition 1     1
Min-till; Crop rotation / Control or change of species composition 1     1
Min-till; Irrigation management     1 1
Min-till; Manuring & composting 1   2 3
Min-till; Residue maintenance / Mulching 1     1
No-till ; Crop rotation / Control or change of species composition 1     1
No-till; Residue maintenance / Mulching 1     1
Permanent soil cover / Removing less vegetation cover; Leguminous crop     1 1
Permanent soil cover / Removing less vegetation cover; Manuring & composting 1 2   3
Residue maintenance / Mulching; Irrigation management 1     1
Total combination of 2 promising AMP tested 13 3 7 23
Green manure / Integrated soil fertility management; Integrated pest and disease management incl. organic agriculture; Irrigation Management 1     1
Manuring & composting; Crop rotation / Control or change of species composition; Irrigation management 1     1
Min-till; Cover crops; Green manure / Integrated soil fertility management     1 1
Min-till; Manuring & composting; Crop rotation / Control or change of species composition 1     1
Min-till; Permanent soil cover / Removing less vegetation cover; Manuring & composting     1 1
Permanent soil cover / Removing less vegetation cover; Manuring & composting; Residue maintenance / Mulching     1 1
Total combination of 3 promising AMP tested 3 0 3 6
Manuring & composting; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; measures against compaction 1     1
Min-till; Cover crops; Green manure / Integrated soil fertility management; Integrated pest and disease management incl. organic agriculture     1 1
Min-till; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; Measures against compaction 1     1
Total combination of 4 promising AMP tested 3 0 1 3
Cover crops; Green manure / Integrated soil fertility management; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; Measures against compaction 1     1
Min-till; Leguminous crops; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; Measures against compaction 1     1
Min-till; Manuring & composting; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; Measures against compaction 1      
Total combination of 5 promising AMP tested 3 0 0 3
Min-till; Manuring & composting; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; Cross-slope measure; Measures against compaction 1     1
Min-till; Manuring & composting; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; measures against compaction; Measures against compaction 1     1
Total combination of 6 promising AMP tested 2 0 0 2
Min-till; Leguminous crops; Manuring & composting; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; Measures against compaction; Water diversion and drainage 1     1
Min-till; Permanent soil cover / Removing less vegetation cover; Leguminous crops; Manuring & composting; Residue maintenance / Mulching; Crop rotation / Control or change of species composition; Measures against compaction 2     2
Total combination of 7 promising AMP tested 3 0 0 3

2. Impact of AMPs on soil quality

The results (Table 2) show that of the 138 sets of paired plots,

  • 104 pairs (combined 75.4%, Europe 73.2%, China 84.6%) show that the AMPs had a positive impact on soil quality,
  • 20 pairs (combined 14.5%, Europe 17%, China 3.8%) show difference in soil quality,
  • and the remaining 14 plots (combined 10.1%, Europe 9.8%, China 11.5%) show a negative effect.

Table 2. Summary of the impact of the implementation of the selected AMPs on soil quality in Europe and China.

Impact Total plots (138) Plots in Europe (112)  Plots in China (26) 
  Absolute value (%) Absolute value (%) Absolute value (%)
Positive 104 75.4 82 73.2  22 84.6
No effect  20 14.5 19 17.0 1 3.8
Negative 14 10.1 11 9.8 3 11.5

In Europe, the AMPs that had a positive impact soil quality (Fig. 2A) were

  • “crop rotation /control or change of species composition”,
  • “manure and composting”,
  • “minimum tillage” and
  • “no-till”

For China, the AMPs had a positive impact on soil quality  (Fig. 2B) were

  • “residue maintenance / mulching”,
  • “manure and composting”,
  • “integrated pest and disease management”,
  • “green manure / integrated soil fertility” and
  • "irrigation management”

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Figure 2a Europe
D52 fig02b
Figure 2b China

When considering only the most common soil types that that occur at least 10 times across all study sites (Antrosol, Fluvisols, Cambisols, Regosols, Calcisols, Luvisols, and Podzols), AMPs with positive impacts on soil quality are implemented mostly in Podzols (100%), Calcisols (91%) Regosols (84.6%), Antrosols (71.4%), Luvisols (70.6%), Cambisols (62.5%), and finally Fluvisols (58%) (Table 3).

Table 3. Impacts of agricultural management practices (AMPs) on soil quality in the most investigated soil types

Soil types Positive impacts (%) No effects & Negative impact (%) Total number of soil types considered (-)
Antroposol  71.4  28.6 14
Fluvisol  58  42 19
Cambisol 62.5 37.5 32
Regosol 84.6 15.4 13
Calcisol 91 9 11
Luvisol 70.6 29.4 17
Podzol 100 0 10

Within these common soils, AMPs with negative and no effect on soil quality are implemented mostly in Cambisols (37.5 %), Fluvisols (42 %) and Luvisols (29.4 %). The non-detectable effect of the promising practices on soil quality are due to type of tillage management, soil type and fertility that mask the effect of management practices on soil. Furthermore, the timing of the assessment may be an important parameter. VSA methodology should be performed in the middle of growing period of a certain crop or crop type. Certain soils, such as Fluvisols, are so fertile that only small differences in harvest time, tillage or crop type can cause changes in scores. Some types of management (min tillage) can explain the low number of earthworms present throughout soil profile due to the fact that organic matter is not ploughed deeper into the soil.

Results show that the most sensitive variables to soil quality are those describing soil structure, such as soil structure and consistency, soil porosity, aggregate stability reflected by the slaking test, and soil colour, followed by soil compaction indicated by the presence of a cultivation pan (Fig. 3). Taking into account some criteria regarding the assessment (e.g., friendly use, sensitivity to different soil types) and the feedback from the study site teams, the indicators selected for the evaluation of the impact of the AMPs on soil quality appear to be appropriate for soils of all study sites except for very fertile soils (Fig. 3).

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Figure 3a: Europe
D52 fig03b
Figure 3b: China

In Europe, the variables selected by the farmers to evaluate soil quality are generally in accordance with researchers’ selection, but with fewer interests on soil colour, biodiversity and infiltration rate (Fig. 4). Similar opinion was also observed in China, except for biodiversity which was not selected by the farmers. Figure 5 shows that the three main variables selected by the farmers for the evaluation of soil quality are related to soil structure, namely soil porosity (5), soil structure and consistency (6), and soil slaking test (7), respectively).

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Figure 4
D52 fig05
Figure 5

It is worth mentioning that the variables describing biodiversity (earthworm numbers) and the infiltration rate provide similar results in the study sites in Europe. This observation can be explained by the fact that biopores, representing only 0.23–2.00% of the total soil volume, may account for about 74–100% of the total water flux (Alaoui and Helbling, 2006). Their volume reduction due to compaction may significantly reduce vertical infiltration and thus increase surface runoff (e.g., Gerke, 2006; Hendrickx and Flury, 2001). Decreasing infiltration due to soil compaction is due to flow connectivity breaks between the top-few centimetres and the underlying macropores (Jégou et al., 2002). Similar results regarding the variables describing soil structure cannot be drawn for the case of China, probably because of the restricted number of investigated sites (26 in China against 112 in Europe) and a wider range of pedo-climatic zones in Europe than in China.

3. Analysis of AMPs using WOCAT framework

Using the standardized WOCAT framework for documentation and evaluation of Sustainable Land Management (SLM) technologies, between 1 and 5 Agricultural Management Practices (AMP) per study site were recorded (with some exceptions of Chinese study sites). The WOCAT framework enabled the study sites to describe the details of land management practices, to show the costs of implementation and maintenance, and to provide a comprehensive list of on- and off-site impacts. In general, one WOCAT technology usually includes a single AMP, but of the 31 technologies documented 4 included more than one AMP. For esample the technology “Annual green manure with Phacelia tanacetifolia in southern Spain” contains AMP Nr. 9 “Crop rotation / Control or change of species composition” and AMP Nr. 12 “Integrated pest and disease management incl. organic agriculture.

Most documented WOCAT technologies are related to the AMPs “No-till” (19%), “Manuring & composting” (17%), “Integrated pest and disease management including organic agriculture” and “Min-till” (14% each). Eight of the AMPs have not been recorded with WOCAT (see Figure 6).

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Figure 6
D52 fig07
Figure 7

Looking at the implementation of the new AMPs reported with WOCAT (Figure 7), it can be seen that almost 60% of all technologies where introduced through the innovation of the land users while only roughly one quarter were introduced during the experiment. The main purpose of the reported technologies are to reduce, prevent, or restore land degradation (23%) followed by the motivation to improve production (18%), to create beneficial economic impact (17%) and to preserve or improve biodiversity (16%). Off-site oriented purposes such as reduce risk of disaster (2%) protect watershed and downstream areas (2%) were hardly mentioned. This is also reflected in Figure 8 where it can be seen that only a few off-site impacts of the AMPs were reported by the study site teams, compared to on-site impacts.

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Figure 8
D52 fig09
Figure 9

An on-site impact is the impact of a new implemented technology in the area or on the plot where the practice is applied. WOCAT differentiates between socio-economic, socio-cultural, and ecological impacts. Over all case studies, it appears clearly that socio-cultural impacts, such as “SLM knowledge” and “food security” have been increases through the implementation of new practices. In general the newly documented technologies also have positive ecological impacts with some exceptions in “soil loss”, “water quality” and “soil compaction”. Most negative impacts are observed or expected in “workload”, “expenses”, and “crop production”, which are all socio-economic impacts and mainly related to the AMP Nr. 12 (integrated pest and disease management incl. organic agriculture). The other most frequently documented AMPs, Nr 1 (no-till), Nr. 2 (min-till) and Nr. 7 (manuring / composting), have all mainly positive socio-economic, socio-cultural, and ecological impacts (see Figure 9).

On the other hand, impacts can also be off-site and affect adjacent areas further downstream with “groundwater pollution” or “damages on infrastructure and fields” (see Figure 8). However, the AMPs implemented recently have all negligible or positive off-site impacts. Especially through reducing “groundwater pollution” and “damages on infrastructure and fields” through reduced surface runoff and soil erosion.

In summary, the following outcomes can be reported.

  • Ten different AMPs have been documented using WOCAT database that are parts of 31 Technologies and 2 Approaches.
  • The documented technologies have mainly positive socio-economic, socio-cultural, and ecological impacts with a few exceptions.
  • Most negative impacts are observed in “workload”, “expenses”, and “crop production” and mainly related to the AMP Nr. 12 which is including organic agriculture.
  • The study site teams reported few off-site impacts. The off-site impacts are rather negligible or positive with regard to socio-economic, socio-cultural and ecological dimensions.

4. Comments on results and further research

The positive impact of the promising agricultural management practices (AMPs) on soil quality was demonstrated in the majority of the case study sites. However, only 71% of the plots have a single AMP and the remaining ones contain a combination of AMPs. Thus, it is difficult to examine the impact of a single AMP on soil quality but rather the impact of a combination of AMPs on soil quality.

The non-detectable effect of the promising practices on soil quality can be attributed to the type of tillage management, soil type and fertility (Cambisols and Fluvisols) that mask the effect of management practices on soil. The time of year chosen for the assessment may have also played a part. Particularly for the fertile soils, it was difficult to distinguish between the plot with AMPs and the control and the timing of the assessment may be an important parameter influencing the scores of evaluation. Therefore, VSA methodology should be performed in the middle of growing period of a certain crop rotation and/or crop type and repeated several times per year.

In addition, soil threats were only partially covered with our indicators, for example nutrient decline was excluded. In this study, score of soil quality was done in a qualitative way. A quantitative approach is taken in »Impact of promising land managment practices. Additional evaluations based on laboratory and field measurements including physical, chemical, and biological aspects are were made in some sites to validate our findings. Plant indicators (e.g., size and development of the root system, crop yield, root diseases, weed infestation) were considered in the following seasons to check the quality of the information collected by soil indicators with the aim of providing sound data on soil quality and its improvement through promising management practices across Europe and China.

 


Note: For full references to papers quoted in this article see

» References

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