Study Site Trials

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

Country General Treatment Category Study Site Trials
Spain Cover crops, tillage, irrigation management

1. Desertification, wind erosion and organic matter decline

- Regulated vs Constant Deficit Irrigation and Minimum tillage in olive orchards;

-Regulated vs Constant Deficit Irrigation and Minimum tillage plus pruning residues added in olive orchards;

-Regulated vs Constant Deficit Irrigation and Minimum Tillage plus temporal cover crops (natural weeds and sowed) in olive orchards;

-Regulated vs standard irrigation and non-tillage (herbicide weed control) in peach orchards;

-Regulated vs standard irrigation and Non-tillage plus pruning residues added and temporal natural vegetation in peach orchards;

-Regulated vs standard irrigation and Non-tillage plus pruning residues and temporal cover crops sowed in peach orchards


Study Site poster 2018, Study Site poster Area A, 2019, Study Site poster Area B, 2019

 

 PeachOrchard   Spain aguamarga irrigation or cultivationRead this fact sheet in Spanish here  
  Peach orchard (Area B)    
 Tractor shredding pruning residuesXlowres    
Tractor shredding pruning branches    

 

Key findings

  • Although no significant results were obtained during this experiment, there were some benefits of using the SICS tested in this experiment. For example, there were higher yields in 2019 under some treatments. In 2020, however, yields were similar in 2020 regardless of treatment. This was as expected in a crop where fruit load is adjusted by hand thinning. Water savings achieved by regulated deficit irrigation (RDI) added some benefits too.
  • However, it seems that allowing the growth of weeds and/or cover crops under RDI resulted in lower profitability. In addition, these approaches may pose certain risks if weed and cover crops are not eliminated on time, including a risk of lower yields.
  • As a result of the SoilCare experiments, the owner of the experimental site has decided to increase water savings by adopting Deficit Irrigation strategies, thus reducing their water usage by 25%.

 

OliveOrchard3lowres   factsheetTabernas FinalDraft front coverRead this fact sheet in Spanish here  
 Organic olive orchard (Area A)    

 

 Key findings

  • This experiment aimed to determine if adopting regulated deficit irrigation instead of continuous deficit irrigation might increase profitability whilst improving soil quality. The rationale behind this experiment was to apply less water on the olive groves during less sensitive periods whilst increasing irrigation rates during critical phases (blooming and setting).
  • The results reject the initial hypothesis since yields were higher under CDI (Exp. 2) and fat content did not change significantly. This finding was particularly pronounced in year 1 of the study. Electric conductivity did not change in this experiment.
  • The differences among soil management treatments were small and non-significant. The content of organic matter was increased under Continuous Deficit Irrigation the first season, but not in the second. On the contrary, a trend towards higher electric conductivity was detected by using cover crops. Similar results were observed in the second experimental site (Aguamarga).
  • Contrary to what was observed in the experiment carried out under Continuous Deficit Irrigation, the use of cover crops did not lead to increased soil salinization (EC) when regulated deficit irrigation was imposed. No increase in organic matter was observed either. This was, however, likely due to the short term nature of the trial and the problems associated with having seedlings established in dry autumns-winters.

 

Geographical description

The study site is located in the province of Almería (South East Spain,). The climate is arid (Mediterranean South). Rainfall is very scarce, always less than 300 mm per year. 

Area A is located in the Sorbas-Tabernas Basin The climate is semiarid thermo-Mediterranean with an average annual temperature of 17.8ºC and an average annual rainfall of 235 mm, which is among the driest areas in Europe. The pronounced regional semiarid climate in the SE Iberian Peninsula is determined by its geographical location, in the rainfall shadow of the main Betic ranges and the proximity of northern Africa. In the autumn, rainfall is associated with incoming fronts from the Mediterranean Sea, which sometimes results in storms and torrential rains. Most rainfall events are low magnitude and low intensity. The average minimum temperature is 4.1°C in the coldest month and an average maximum of 34.7°C in the hottest month. Daily amplitudes average 13.7°C in summer. Potential evaporation is around 4 to 5 times higher than annual precipitation.

Area B is located in the Cabo de Gata Natural Park. There the climate is semiarid warm Mediterranean. The mean annual temperature oscillates around 18-19ºC, and frosts are sporadic, occurring only on isolated days. Mean annual rainfall is approximately 220 mm per year, with prolonged summer droughts, strong inter- (larger than 30%) and intra-annual variations and 9 to 12 months in which precipitation is not sufficient to compensate for potential evapotranspiration. Annual potential evapotranspiration is around 1400 mm. 

Land uses include tree and annual crops cultivation, occasionally in protected structures (greenhouses and under mesh), pasturage (especially goat herds) and recreational activities (touristic uses, beaches in Cabo de Gata, and cinema in Tabernas area). Industry development is scarce and of composed by small enterprises. The exploitation of natural resources is regulated by the current zoning plan (PORN, 2008). Agriculture is one of the main activities, covering 26% of the park area. The abandonment of some agricultural areas and simultaneous intensification in certain others (i.e., water fed agricultural systems and greenhouses) are the main causes of degradation in the park.

StudySites  Orchards
 Almería map showing study sites and EC towers
location.
 Stone fruit orchards sited in Agua Amarga at bloom.