Main authors: Lúcia Barão and Gottlieb Basch
Editor: Jane Brandt
Source document: Barão, L. and Basch, G. (2017) Selection of sites for testing "soil improving" measures. iSQAPER Project Milestone 6.1 26 pp

 

In »Effect of management practices on soil quality in case study sites we describe how, across all 14 iSQAPER case study sites, we selected 132 sets of paired control and AMP plots in which either single or combinations of agricultural management practices were being used and we measured their impact on soil quality by making visual soil assessments.

Here we describe how we selected a sub-set of those 132 pairs as experimental sites in which we to looked at in more detail at those impacts in two field campaigns.


Contents table
1. Characterization of experimental sites using innovative AMPs
2. Criteria for selection of experimental sites

1. Characterization of experimental sites using innovative AMPs

The iSQAPER case study sites were asked to identify and collect information from farms located in their study area with plots where innovative agricultural management practices (AMPs) are being used by the farmers. In order to get a representative sample, the study sites were asked to apply the following criteria in their selection:

  1. include the 2 main different farming systems of the study area;
  2. include at least 2 different soil types in their climatic region;
  3. include at least 3 different AMPs (or combinations of AMPs).

Also, control plots for every innovative AMP plot were identified by the study sites. Control plots are plots with the same soil type, farming system and similar in every other way, except for the presence of the innovative AMP.

Farming systems

The case study sites were requested to identify plots with one of these three farming systems:

  1. arable land,
  2. permanent crops and
  3. pastures

and to select plots representative of the two main dominant farming systems of the study area.

The details of types of farming system within these three broad categories were based on the list described in »Farming system classification in the iSQAPER project. Minor changes were introduced to face the real conditions identified by the study sites during their selection (Table 1).

Table 1 Farming systems classification used during the identification of farms/plots with innovative AMP’s

Farming system
1. Arable Land  1.1 Non-irrigated arable Land

1.1.1 Cereals
1.1.2 Maize
1.1.3 Legumes
1.1.4 Oil crops
1.1.5 Fodder crops
1.1.6 Root crop
1.1.7 Fallow
1.1.8 Flowers, fruits and vegetables

1.2 Permanently irrigated arable Land  1.2.1 Cereals
1.2.2 Maize
1.2.3 Legumes  
1.2.4 Oil crops 
1.2.5 Fodder crops 
1.2.6 Root crop
1.2.7 Fallow 
1.2.8 Flowers, fruits and vegetables 
2. Permanent crops 2.1 Vineyards
2.2 Fruit trees and berry plantation
2.3 Oil groves
 
3. Pastures 3.1 Extensive 
3.2 Intensive
 

Pedo-climatic zones

The distribution of case study sites (CSSs) covers 6 climatic zones in Europe and 2 in China (Table 2).

Table 2. CSSs per climatic zone in Europe and China.

Europe     China
Atlantic Mediterranean temperate Mediterranean semi-arid Southern Sub-Continental Northern Sub-Continental Boreal to Sub-Boreal Central Asia Tropical Zone Middle Temperate Zone

Netherlands (CSS1)

France (CSS2)

Portugal (CSS3)

Greece (CSS5)

Spain (CSS4) 

Slovenia (CSS6)

Hungary (CSS7) 

Romania (CSS8)

Poland (CSS9) 

Estonia (CSS10) 

Qiyang (CSS11)

Suining (CSS12)

Gongzhuling (CSS14)

The major pedoclimatic zones were defined by Tóth et al. (2016) and embody the soil processes that prevail at these climatic regions.

A total of 8 climatic groups were defined in Europe (»Pedoclimatic zones of Europe) (Figure 1) :

  • Boreal to Sub-Boreal (CZ1), Atlantic (CZ2), Sub-oceanic (CZ3) Northern sub-continental (CZ4), Mediterranean semi-arid (CZ5), Southern sub-continental, (CZ6), Mediterranean (temperate and sub-oceanic) (CZ7) and Temperate mountainous (CZ8).

For China, a total of 10 climatic groups were defined (»Pedoclimatic zones of China) (Figure 2):

  • Tropical zone; Southern Asia tropical zone; Central Asia tropical zone; Northern Asia tropical zone; Warm temperate zone; Plateau temperate zone; Plateau artic zone; Plateau sub-arctic zone; Middle temperate zone; Cold temperate zone.

 D61 fig01
Figure 1
D61 fig02
Figure 2

The case study sites selected plots in the most commonly occurring soil types in their areas. In Europe, the most common soils are Cambisols which are found in all climatic regions except in the Boreal to Sub-Boreal. Chernozems are found only in Northern and Southern Sub-continental regions, Regosols only in Mediterranean Temperate and Semi-arid and Histosols are found only in Boreal to Sub-Boreal (Figure 3, data from »Pedoclimatic zones of Europe).

MS6.1 fig03
Figure 3

Innovative AMPs and soil threats

Based on WOCAT database (www.wocat.net), 18 promising AMPs with potential to improve soil quality were selected, taking into accound the most frequently used practices by farmers nowadays to face their current problems (Schwilch et al., 2011) (see also »Experimental framework). 

These 18 innovative AMPs can be grouped into 5 different management strategies:

  1. Soil management
  2. Nutrient management
  3. Water management
  4. Pest management and
  5. Crop management and land use change

Table 3 includes a brief description of the AMPs, expected impacts/ecological benefits of using them and the main soil threat targeted, ranked by order of relevance (where 1 is considered the most relevant).

  • Erosion,
  • Soil organic matter (SOM) decline,
  • Compaction,
  • Poor structure,
  • Poor water holding capacity,
  • Nitrate leaching,
  • Soil-borne pests and diseases
  • Salinization

Additionally, each case study site ranked the soil threats in their local area (**see also »Soil threats). The idea is to link, at a later stage, the impact of a given AMP on soil quality and the major soil threats affecting the area.

Table 3. 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 Main soil threat targeted
Soil management
1 No tillage (no-till) A system where crops are planted into the soil without primary tillage 
  • Reduces decomposition of OM rates leading to its increase in soil, enhances cycling of nutrients, enhances soil structure and increases water infiltration.
  • Improves soil biological life including disease and weed suppression.
  1. SOM decline
  2. Erosion
  3. Poor soil structure
2 Minimum tillage (min-till) Tillage operation with: a) reduced tillage depth; b) strip tillage; c) mulch tillage; or or a combination thereof
  • Reduces decomposition of OM rates leading to its increase in soil, enhances cycling of nutrients, enhances soil structure and increases water infiltration.
  • Improves soil biological life including disease and weed suppression.
  1. Erosion
  2. SOM decline
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)
  • Improves infiltration and retention of soil moisture resulting in less severe, less prolonged crop water stress and increases availability of plant nutrients.
  • Provides source of food and habitat for diverse soil life: created channels for air and water, biological tillage and substrate for biological activity through the recycling of organic matter and plant nutrients.
  • Increases humus formation.
  • Reduces the impact of rain drops on soil surface resulting in reduced crusting and surface sealing.
  • Reduces runoff and erosion.
  • Reduces wind erosion.
  • Increases soil regeneration.
  • Mitigates temperature variations on and in the soil.
  • Improves the conditions for the development of roots and seedling growth.
  1. Erosion
  2. SOM decline
  3. Poor water holding capacity
4 Cover crops
  1. Cover cropping: planting close-growing crops (usually annual legumes),
  2. Relay cropping: specific form of mixed cropping / intercropping in which a second crop is planted into an established stand of a main crop. The second crop develops fully after the main crop is harvested. Better crop cover: selecting crops with higher ground cover, increasing plant density, etc.
  1. Protects soil, between perennials or in the period between seasons for annual crops. N-fixation in case of leguminous crops.
  2. Continuously covered soil. Reduces the insect/mite pest populations because of the diversity of the crops grown. Reduces the plant diseases. Reduces hillside erosion and protected topsoil, especially the contour strip cropping. Attracts more beneficial insects, especially when flowering crops are included in the cropping system.
  3. Protects soil against the impacts of raindrops or wind and keeps soil shaded; and increases moisture content.
  1. SOM decline
  2. Poor soil structure
  3. Erosion
  4. Nitrate leaching
  5. Soil-borne pests and diseases
5 Residue maintenance / Mulching Maintaining crops residues or spreading of organic (or other) materials on the soil surface.
  • Reduces sheet and rill erosion.
  • Reduces wind erosion.
  • Maintains or improves soil organic matter content.
  • Conserves soil moisture.
  • Provides food and escapes cover for wildlife.
  1. Erosion
  2. SOM decline
  3. Poor soil structure
  4. Poor water holding capacity
  5. Compaction
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).
  1. Erosion
7 Measures against compaction
  1. Breaking compacted soil: e.g. deep ripping, subsoiling (hard pans); Digging the soil up to twice as deep as normally.
  2. Growing deep rooted plants in the rotation such as: annual alfalfa, beet, sunflower, okra, flax, turnip.
  3. Controlled traffic farming: is a system which confines all machinery loads to the least possible area of permanent traffic lanes
  4. Soil compaction models (considering tire size, inflation pressure, weather and soil conditions) to predict allowable wheel load and soil compaction maps to show how soil compaction varies at different locations and depths across the field
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)
  1. Compaction
  2. Poor soil structure
  3. Poor water holding capacity
Nutrient management
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.
  • Provides soil with nitrogen and additional nitrogen from chemical fertilizers can be reduced. (See also cover crop and green manure)
  1. Nitrate leaching
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.
  • Increases organic matter content, thereby improving fertility and reducing erodibility. In case of leguminous green manure, tilling it back into the soil allows exploiting the high levels of captured atmospheric nitrogen found in the roots.
  1. SOM decline
10 Manuring (a) / composting (b)
  1. Manure is organic matter, mostly derived from animal feces (except in the case of green manure, which can be used as organic fertilizer in agriculture).
  2. Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming.
  1. Contributes to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that are trapped by bacteria in the soil.
  2. Improves soil fertility through nutrient content and availability, soil structure and microbiological activity; impacts plant growth and health directly and indirectly.
  1. SOM decline
  2. Poor soil structure
Pest management
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.

  • Improves distribution of channels or biopores created by diverse roots (various forms, sizes and depths).
  • Improved distribution of water and nutrients through the soil profile.
  • Allows exploration for nutrients and water of diverse strata of the soil profile by roots of many different plant species resulting in a greater use of the available nutrients and water.
  • Increases nitrogen fixation through certain plant-soil biota symbionts and improved balance of N/P/K from both organic and mineral sources. Increases humus formation.

b) Introduces desired / new species, reduces invasive species, controls burning, residue burning.

  1. Soil-borne pests and diseases
  2. Poor water holding capacity
  3. Poor soil structure
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.
  • Emphasizes the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms.
  1. Soil-born pests and diseases
Water management
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
  • Reduces hazard towards adverse events (floods, storms,…), reduces soil waterlogging
  1. Erosion
14 Irrigation management Controlled water supply and drainage: mixed rainfed – irrigated; full irrigation; drip irrigation
  •  Improves water harvesting; increased soil moisture; reduces evaporation; improves excess water drainage; recharge of groundwater
  1. Poor water holding capacity
  2. Salinization
  3. Nitrate leaching
  4. Erosion
Crop management
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.
  • Reduced soil compaction, soil loss, improved biomass, increased biomass, increased soil OM
  1. Compaction
  2. SOM decline
  3. Erosion
  4. Nitrate leaching
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.
  •  Reduces surface runoff and erosion, increases biomass, nutrients and soil OM, controls pests and diseases
  1. Erosion
  2. SOM decline
  3. Compaction
17 Area closure / rotational grazing Complete or temporal stop of use to support restoration
  • Improves vegetative cover, reduces intensity of use, and soil compaction and erosion.
  1. SOM decline
  2. Compaction
  3. Erosion
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.
  •  Increases biomass, nutrient cycling, soil OM, improves soil cover, beneficial species (predators, earthworms, pollinators), biological pest / disease control, and increases / maintains habitat diversity. 
  • Reduces soil loss, soil crusting/sealing, soil compaction, and invasive alien species.
  1. Erosion
  2. SOM decline
  3. Soil-borne pests and diseases
  4. Compaction
  5. Poor soil structure

 


 

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