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

Geographical description

The study site is included in the province of Almería (South East Spain,)between coordinates 2° 11’ 10” W and 2° 31’ 10” W; and 37° 00’ 04”,7 N and 37° 10’ 04”,7 N. The climate is arid (Mediterranean South). Rainfall is very scarce, always inferior to 300 mm per year. ETo is in a range between 1,400 – 1,500 mm/year. Although the province is not very large (8774 km2), we have within the study site two main areas where past and ongoing work of interest for the proposal is being (or has been) carried out.

Area A is located in the Sorbas-Tabernas Basin which is one of the Neogene basins of the Betic Cordilleras situated in a crustal transcurrent shear zone. It is an intra-montane depression, bounded by the Sierra de Filabres to the North and the Sierra Alhamilla to the South and at the leeward side of the Nevada and Gador ranges, all of which are over 2000 m above sea level. The altitude ranges between 200 and 400 m.a.s.l. Soils in this area are developed on carbonated Tertiary parent materials, sometimes with high amounts of gypsum, or on Quaternary parent materials including sands, conglomerates or clays of fluvial origin. Dominant soils in this area belong to the Leptosol or Regosol Reference Group, although we can find Cambisols that tend to be exploited for olive cultivation. These soils are loamy to sandy loam in texture, with basic pH, low organic matter and nutrients content and shallow depth. We find soils with high amounts of soluble salts more soluble than gypsum. The stratigraphic series, the Tortonian-age Chozas formation that gave rise to the Tabernas badlands, is about 150-m thick and includes mudstone and some calcareous sandstone. The mudstone has been identified as calcareous and gypsiferous predominantly composed of 80% silt grains with the following mineralogical composition: muscovite 35%, paragonite 10%, minerals with a main peak at 1.4 nm (mainly chlorite and a small amount of smectite) 3%, quartz 9%, calcite 20% to 35%, dolomite 2% to 5% and gypsum 5% to 20%. 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. Soils are mainly calcaric Regosols developed on a wide variety of carbonated parent materials, in different topographic positions with slopes ranging between 0% and 40%. These soils present basic pH, with loamy or coarser textures, low organic matter and nutrients content and shallow depth, except for the very scarce calcaric Fluvisols found as spots in the “Ramblas” around the study zone. We can also find soils affected by salts as a consequence of the xeric moisture regimen of the area.

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
 Stone fruit orchards sited in Agua Amarga at bloom.

Cropping systems

Tree crops orchards of different species planted at varied densities can be found in the study area, being perhaps the most representative, olives (Area A) and almond and stone fruits (Area B). In Area A (Tabernas) we found conventional and also some organic olive orchards with a tree density labelled as intensive for this crop (200-300 trees/ha; density considered low instead for many other fruit trees). Modern new super high density orchards (1500-2500 trees/ha) with mechanized harvesting using adapted grape harvesters are in development in the area. In intensive orchards olive trees are vase trained while in super high density orchards usually central-leader training systems are used. In Area B, the most interesting new development is focused on intensive (600-800 trees/ha) very large orchards of low chilling stone fruits (peaches, nectarines, apricots, plums). Trees are commonly trained in a vase shape, with 4-5 main scaffolds where productive wood is formed (Figure 2). 

Non-tillage and weed control with herbicides or reduced tillage is usually applied in most modern olive and stone fruit orchards in the study site. Most of these orchards are drip irrigated. Conventional fertilizers are normally used, mainly N (several applications per year) and K. Conventional or chemical control of pest and diseases is normally used. Main pests and disease in olive orchards are olive fruit fly, prays, black scale, peacock spot, and verticillium wilt. Verticillium has no cure since no effective control on this soil fungus is available. Excessive irrigation and runoff contribute to the dispersion of this lethal disease. Temporal cover crops can be used instead of conventional tillage for soil improvement and for reducing erosion. Nonetheless, the very scarce rainfall in the area makes difficult for growers to adopt this management technique. In intensive stone fruit orchards of Area B the control of weed is achieved also by herbicides and reduced tillage in areas where infiltration problems occurs, and where gullies of certain depth appear. High soil compaction can also be a problem and is commonly resolved by owners by tillage. Watering is performed by drip irrigation too. Water needs are determined according to an estimation of crop evapotranspiration using climate data from nearby weather stations. Standard fertilization common in the area includes 110, 65 and 160 kg ha-1 year-1 of N, P2O5 and K2O, respectively. Deficiencies in microelements are solved by foliar fertilization. Biological and cultural methods are first used to control pests and diseases. When really needed, chemical control is also achieved, switching active ingredients. Main pests in stone fruit crops are aphids, tripses, mites and San Jose scale. Main diseases are powdery mildew, leaf curl and Phytophthora.

High content of salts of Tabernas area soil is a common cause of yield reduction. Excessive N fertilization contributes to this problem, increasing also the sensitivity to pests and diseases and crop costs. Scarce water resources and regulation limitation due to the protection of environment in orchards sited in the Natural Park Cabo de Gata-Nijar might reduce yield, and increase costs for stone fruit trees. Flower and fruit thinning represent the most important cost. Excessive watering has been occasionally linked with damages caused by soil fungus (Phytopthora in this case) suggesting an improvement can be achieved. Excessive nitrogen application also leads to higher damages caused soil and airborne fungi. An adequate control of nitrogen level avoids some yield losses and improves fruit quality and enhances postharvest.

External factors and drivers

Current UE strategies of agricultural and rural development policies contribute to put in action help lines for rural areas of the study site through the Program LIFE and FEADER Regulation. UE objectives include the implementation of different tools in the period 2014-2020 to support the adoption of beneficial practices for the
conservation of climate and environment (the so called greening EU strategies). Among potential beneficiaries of those help lines we find organic farmers and growers of permanent crops such as olive and fruit trees. Special attention will be given too to farms totally or partially located in areas included in EU Directive 92/43, relative to natural habitats conservation, Directive 2000/60, linked to actions in the field of water protection, and Directive 2009/147, relative to the protection of wild birds.

Other Programs and Normative are established. At national level we should mention Red Natura 2000 plan that will implement the help lines established in 1305/2013 and 1306/2013 Regulations. In Andalusia, through the Program for Rural Development, these areas may find tools to sustain the economy of those areas. Two different types of actions and helplines deserve mentioning: modernisation of agricultural exploitations and animal husbandries, and Preservation of the nature and landscape in agricultural exploitations. Organic production of food in Andalusia is reinforced by regional normatives (besides Commission Regulation (EC) No 889/2008) aiming to supervise production and labelling of organic products.

Regarding societal drivers we must recognise that the characteristics of the crops of the study site confer to them of a multifunctional character due to their localization (often within and/or in the limits of natural areas protected by law). In these systems, excellent products very much appreciated by customers are being produced. Further development of agriculture in the area is extremely important since it represents the main economic activity and the first source of income for the families. This development is also essential since might be of help allowing fixing rural population to the site. Maintaining profitable agriculture in the area diminishes the risk of fire and help minimizing erosion when sustainable practices in the farms are achieved. The concept of multi-functionality for the agrarian systems represents the recognition of the capacity of rural areas to create an aggregate of goods and services of different kinds: economic, but also social and environmental.

The multi-functionality of the services provided by rural can be studied under two complementary orientations: the establishment of the list of goods and services being produced, and the demand that the society makes of them trying to identify the preferences of the Society. Combining both orientations, offer and demand, an integral analysis can be performed to orientate tools and instruments of intervention within EU agricultural politic in order to maximize the social welfare derived from the agricultural activities in the study site.

Climate change may contribute to the aridity of the zone; higher frequency of extreme episodes of rainfall and drought would make more vulnerable the environment, increasing erosion, already a very serious problem in the badlands of Tabernas. Global warming could make more difficult to satisfy chilling requirements of the crops, most of them with reduced need of winter chilling, however. Displacement of crop phenology to earlier bloom could increase the risks of frost, although warm winters in the study site suggests seldom occurrence of damages. Increasing temperatures during winter and spring will accelerate fruit ripening and harvest with positive effects on prices and profitability.