Study Site Trials

The SICS selected for trialling in this Study Site are described below: 

Country General Treatment Category Study Site Trials
Sweden Sub soil loosening, tillage

1. Sub soil loosening - Sub soiling loosening; Sub soiling loosening with straw pellets; Normal mouldboard ploughing - control


Study Site poster 2018 (download)

 

 SICS 1:  Sub-soil loosening with straw pellets

 

 Subsoiler2400x300  Trialestablishment400x533    Sweden amendment  
         

 

 Key findings

  • Subsoiling affected only a few centimeters of the upper subsoil layer below the topsoil
  • There were distinct stripes in the subsoil but 38-45% of the upper subsoil layer was affected • Straw incorporation during subsoiling did not result in mixing with loosened subsoil
  • Rooting characteristics were improved by subsoiling
  • The impact of subsoiling on yields of cereals and sugar beets was not significant. However, considering that only subsoil stripes may affect yields, recalculations indicated a positive impact of stripes on yields

 

Geographical description

The Orup site is located in the county Skåne in Southern Sweden. Precipitation varies between 500 and 1000 mm per year. Mean temperature is around 0 °C in January and 16 °C in July.  On the site, the subsoil is compacted (density between 1.7 and 1.9 kg L-1). The soil is a silty sand and the compaction is most likely from the time the ground was formed, i.e.it has a natural origin. The harvests for this site have remained much lower than at the other soil fertility experiments, approx. 30-40% lower.  In spring 2011, an inventory was made in Orup with regard to root growth in the subsoil. The results show the same results as in previous studies in the 1990s: the roots of the crop are restricted to the topsoil and no roots grow below 30 cm depth. A structural improvement through liming is limited at Orup due to a low clay content (about 10%).  In lighter soils such as this, a structural improvement can be achieved primarily through the supply of organic matter. Therefore, the experiment investigates the possibility of improving soil structure through the supply of organic material in combination with mechanical subsoil loosening. The supply of organic material is made in the form of straw pellets that are blown into the ground.

Cropping systems

Different cropping intensities from no fertilization to high fertilization rates are applied at the Orup site. Both treatments with and without animal manure are run. Rates of manure are in relation to yields provided by the cropping system. The site is treated according to conventional agricultural practices of the region.

LocationMap 
 The map of Skåne showing the Orup study site

 

Types of crops
Two 4-year rotations are applied:
- crop rotation with livestock: barley, ley, winter wheat and sugar beets
- crop rotation without livestock: barley, oil seed rape, winter wheat and sugar beet.

Management of soil, water, nutrients and pests
Soil tillage includes yearly mouldboard ploughing, cultivation, fertilization, manuring, chemical weed and pest treatment. Crops are rain-fed and no catch crops to combat N leaching are grown.

Soil improving cropping system and techniques currently used
Measures include crop rotation, use of animal manure, no removal of crop residues in non-manured plots, and
regular lime application.

 Study Site Trials

 The SICS selected for trialling in the Study Site are described below:

Country General Treatment Category Study Site Trials
Greece Cover crops, tillage, crop change

1. Soil erosion rate assessment - No till in organic olive orchards; Conventional till (15-20 cm) in organic olive orchards; Conversion from orange orchard to avocado; Conventional orange orchard; Cover crop (vetch) in organic vineyards; Bare soil in organic vineyards


Study Site poster 2018 (download)

 OrangeGrove

    Greece experiment factsheet Avocado Final front coverRead this fact sheet in Greek here  

 Avacado

  Conversion from orange orchards to avocado

   
       

 

 Key findings

  • The biological health and condition of the avocado plot were inferior to the orange tree plots according to the earthworm density experiment.
  • Water and solute movement, as well as soil aeration, were positive for both cultivations, as identified by the top and bottom soil bulk density experiments.
  • High content of soil organic carbon concentration was measured at both plots. Orange orchards presented reduced soil organic carbon compared to avocado trees, during the 3-year monitoring, probably due to higher inputs.
  • The level of weed infestation was 10% less in the avocados field compared to the orange trees field.
  • Electric conductivity values indicate high salinity levels in both plots. Even higher values were observed for avocado trees.

 

 Olives1     Greece experiment factsheet olives FINAL front coverRead this fact sheet in Greek here  

 Olives tilled

 No-till and conventional till in organic olive orchards

   

 

 Key findings

  • Intensified tillage contributed significantly to increased soil erosion and affected the rooting system of the crop, causing exposed tree roots.
  • The biological health and condition of the no-till plots were clearly better compared to the tilled plots.
  • Apart from tillage, irrigation also increases soil erosion since irrigated trees are less resilient to water stress due to shallow roots.
  • High content of soil organic carbon concentration was measured at both plots.
  • Water and solute movement, as well as soil aeration, are appropriate even in the case of no-till.

 

 

Vineyard

 

 Greece experiment factsheet Vineyard Final front cover

Read this fact sheet in Greek here

 

Vineyard covercrops

Bare soil and cover crop in an organic vineyard

   

 

 Key findings

  • Cover crops led to significantly less soil erosion.
  • Soil aggregate stability test resulted in good soil stability and resistance to erosion for both plots, however, for the vetch applied plot, slaking effect was slightly less observed, indicating better structure maintenance.
  • The biological health and condition of the vetch cover plots were clearly better compared to the no vetch.
  • High content of soil organic carbon concentration was measured at both plots.
  • Water and solute movement as well as soil aeration was slightly improved where cover crops were grown.

 

Geographical description

Crete is the largest of the Greek islands, and the 5th largest in the Mediterranean, with a total area of 8,265 km2. While retaining its own local cultural traits, the island shapes a significant part of the cultural heritage of Greece, but also contributes 5% of the national Gross Domestic Product (GDP), with agriculture and tourism as its main industries.

Map
Spatial distribution of soil erosion on the Island of Crete.

 

Pedo-climatic zone
Crete’s climate is classified as dry sub-humid (Csa according to Köppen and Geiger, Mediterranean South). About 53% of the annual precipitation occurs in the winter, 23% during autumn, 20% during spring while there is negligible rainfall during summer (Koutroulis and Tsanis, 2010). Annual rainfall ranges from 300 to 700 mm from east to west in the low areas along the coast, and from 700 to 1000 mm in the plains of the mainland, while in the mountainous areas it reaches up to 2000 mm. The annual water balance breaks down to 68-76% evapotranspiration, 14-17% infiltration and 10-15% runoff. Soils are mainly Calcisol.

Cropping systems

Cropping intensity
Almost 40% of the island is cultivated at various intensities depending on desired end product quality and intended market: e.g. olive trees can be non-irrigated (traditional/household use) or irrigated (modern/intense), vineyards may be conventional or organic, etc.

Types of crop
Agriculture is an important source of income, contributing to Crete’s GDP by 13%. Olive is the most important crop, cultivated on all soils and terrain slopes up to altitudes of about 900 m. Specifically for Chania, agricultural land is divided in 5 main crop categories: grapes 3%, trees 90% (olive trees 70%, other trees 20%), vegetables 2%, and other crops 5%.

Management of soil, water, nutrients and pests
Irrigation types on the island vary depending on crops and local water availability (e.g. olive trees are either regularly irrigated or not irrigated at all, orange groves are often waterlogged and vineyards are often drip-irrigated). Fertilisation also varies (chemicals vs animal manure). Due to high ownership fragmentation and rough topography, management is seldom large scale, and crop picking is almost always traditional and labour intensive using minimal mechanical equipment.

Study Site Trials

The SICS selected for trialling in this Study Site are described below:

General Treatment Category Study Site Trials
Soil-imrpving crops, Crop rotations,

1. Bico da Barca - Organic rice in rotation with perennial lucerne - Conventional rice monoculture (Control); Organic rice in rotation with perennial Lucerne (2 years of rice + 2 years of Lucerne)

Cover crops

2. Loreto – Conventional grain corn in succession with legumes winter cover - Conventional grain corn with Forage Pea as a cover crop in winter; Conventional grain corn with Red Clover as a cover crop in winter; Conventional grain corn with Yellow Lupine as a cover crop in winter; Conventional grain corn with Balansa Clover as a cover crop in winter; Conventional grain corn with Arrowleaf Clover as a cover crop in winter; Conventional grain corn with no cover crop in winter (fallow- control)

Fertilisation/amendments

3. São Silvestre - Conventional grain corn fertilized by urban sludge - Grain corn receiving urban sludge fertilization; Grain corn receiving conventional mineral fertilization (control)

 

Study Site poster 2018 EGU 2019 Study Site poster (download)

 

SICS 1 :- Rotation system - Bico da Barca – Organic Rice in rotation with perennial lucerne (two years of rice + 2 years of Lucerne)

 

     SICS1a  

 

Portugal rotation factsheet EN AK 2021.08.08 FINAL frontcover

Read this fact sheet in Portuguese here

 

SICS1b

SICS1c  

 

Key findings

  • SICS improves soil fertility in terms of soil organic matter content
  • SICS using the Nitrogen biological fixation avoid any mineral nitrogen fertilization and is a very conservative technic in term of nutrient leaching and groundwater pollution.
  • SICS does not increase weed burdens, thus leaving corn yields unaffected. Blind seeding and rotation with perennial lucerneare efficient techniques in terms of weed control, with a significant seed bank reduction.

 

SICS 2 :- Succession system - Loreto - Principal crop (grain corn ) integrated in a succession of legumes (clover, pea, trefoil….) used as green manure.

 

   SICS4a  SICS4b  

 

Portugal succession factsheet EN FINAL front cover

Read this fact sheet in Portuguese here

 

 SICS4c

 SICS4d  

 

 Key findings

  • In general, all six legume cover crops showed good adaptation to Mediterranean conditions, yielding large amounts of dry biomass (up to 8 ton/ha for some clovers species). ​
  • The overall median N-P-K nutrient uptake over the 2 study years considering all the species was 176-20-172 kg/ha with clover species presenting generally the best performances.​
  • The capacity of the legume cover crops to provide green manure services enabled a general reduction of about 35% of N, 50% of P, and 100% of K supplied generally by mineral fertilizers for a grain corn production of 12t/ha.​
  • Legume cover crops effectively controlled weeds, although only in the second year of the study. Three clover species (crimson, balansa, arrowleaf) performed best in terms of weed control due to early establishment and/or high biomass production in later growth stages, and thus continuous competition with weed species.​
  • Legume cover crops incorporation into the soil leaded through the two years experiment to a slight depletion of the soil organic matter content generally more severe for the less fertile soils. However, large fluctuations in soil organic matter content in legume cover crops plots between soil sampling occasions were observed for the LCC plots, but not for the fallow control plot, reflecting important modifications in soil nutrient cycles due to incorporation of large LCC biomass with high decomposition potential.​
  • No differences were found between treatments and in term of pH, Nitrogen, available phosphorus and potassium or exchange base (K+, Mg2+,Na+,ca2+), soil compatibility, infiltration capacity, or biodiversity (earthworm).

 

SICS 3 :- Organic fertilization system - São Silvestre - Organic fertilization system from urban origin (sewage sludge)

 

   SICS3a  SICS3b  

 

Portugal urban sludge factsheet EN front cover

Read this fact sheet in Portuguese here

 

 SICS3c


SICS3d
 

 

 Key findings

  • After 3 consecutive years of urban sludge application in the agricultural field, soil fertility was significantly improved. Almost all the parameters analyses in this study show a positive impact of the urban sludge application. It improved pH, SOC content, Total Nitrogen, Available Phosphorus and Potassium, exchangeable cations (Ca2+ and K+) and also Earthworms density.​
  • Under urban sludge application, extremely high values of Phosphorus and Potassium were identified, especially Phosphorus.​
  • Under urban sludge application, any relevant increase of heavy metal concentration in the soil was identified. The concentrations maintained were much lower than the limits defined by the national law for sludge application or fertilizer application in general. 

 

Geographical description

The study areas are located in the Lower Mondego river valley, an alluvium plane situated in Central Portugal. The valley is roughly east-west oriented and 40 km long (from the Coimbra city to the estuary near Figueira da Foz) and bordered by gently sloping hills. The floodplain covers about 15.000 ha of fertile land and has traditionally been used for irrigated agriculture.

The entire valley is between 0 and 25 meters above sea level. Soils are modern alluvial soils, with a texture from silt-loam to sandy-clay-loam. The climate is Mediterranean, characterized by rainy winters and dry summers, more precisely a Csa climate under the Köppen climate classification, " Hot-summer Mediterranean climate ". The annual average temperature is 16.1ºC, with smooth variations. The annual average precipitation is 922 mm, essentially concentrated between October and March.

The Baixo Mondego valley is mainly dedicated to a monoculture of irrigated corn grain and flooding rice. The eastern part is mainly used for corn, while the western area, closer to the river mouth, is used mainly for rice.

 Map

Cropping systems

Conventional tillage is practised with various passes of heavy machinery. Disc harrow passes for straw stubble incorporation, furrow plough passes for soil inversion, chisel and rotary tiller passes to prepare seedbed.

In 1970, the hydro-agricultural exploitation project of the Mondego Valley started that affects about 12.300 ha (total irrigation perimeter). It considers the development and restructuration of the agricultural system which involves: property reparcelling, soil levelling and the creation of new irrigation and drainage systems. To date, about 6.700 ha are equipped. Irrigation is principally performed with surface furrow irrigation systems, by gravity fed. Soils are levelled and water flows passively on furrows opened between each line of maize. Compared to pressurized systems (sprinkler and drip), surface irrigation systems require lower capital investment. However, some farmers also use pivot irrigation systems.

Production is based on expensive production factors: mineral fertilizers to compensate for the important soil nutrient exportation after harvesting, pesticides for pest control problems driven by intensive monoculture.

Soil improving cropping system and techniques currently used

Concerning rice cropping systems, the DRAP-Centro is currently monitoring a long term experiment (for about 10 years) that involves a cropping system composed of organic rice in rotation with perennial lucerne (two years of rice followed by two years of lucerne). The introduction of a legume in the rotation provides an increase of the nitrogen available for rice production and is beneficial for pests and weeds control.

Concerning maize cropping systems, some farmers use organic amendments such as urban sludge, but it is a very controversial issue. A small number of farmers have introduced legumes or a mix of legumes and gramineous as cover crops during the winter, but it’s not a very common technique.

 

External drivers or factors

Institutional and political drivers

As previously stated, part of the SoilCare effort made by the Portuguese (ESAC) team will be a consequence of the implementation of the forthcoming new priorities set by the Common Agriculture Policy. In addition, the new reading made of the Water Framework Directive will imply an increase of the water price for agriculture.

Societal drivers

There is an ongoing tendency to shift from the traditional to the organic systems which is pushed by a younger and urban population fringe. This implies that the organic farming systems are gaining territory.

Bio-physical drivers

Being under a wet Mediterranean type of climate, the Portuguese study areas are affected by water shortages that occur during the vegetative growth season. The absence of proper irrigation systems and the proper water amounts for irrigation have an overwhelming effect on crop productivity.