EN    EN EN 
 
EN    EN  COMMISSION OF THE E UROPEAN COMMUNITIES 
Brussels, 21.4.2009 
SEC(2009) 449 
COMMISSION STAFF WORKING DOCUMENT 
 
accompanying the  
COMMUNICATION FROM THE CO MMISSION TO THE EUROPEAN 
PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL 
COMMITTEE AND THE COMMI TTEE OF THE REGIONS 
 
Towards a better targeting of the aid to farmers in areas with natural handicaps 
 
TECHNICAL ANNEX  
 
 
Technical details for po ssible common criteria  
 
  
{COM(2009) 161 final} 
{SEC(2009) 450} {SEC(2009) 451} 
 
EN 2   EN COMMISSION STAFF WORKING DOCUMENT 
Technical Annex 
Technical details for possible common criteria  
1. INTRODUCTION  
Soil, climate and terrain are the major determinan ts of the suitability of land for agricultural 
use. Every crop type has a set of  requirements with regards to soil and climate. To yield a 
harvest, a crop needs sufficient physical stability, sufficient bu t not too much heat and photo-
synthetically active radiation, oxygen, water and nut rients, in the absence of toxic substances 
or damaging impacts from storms or pests. 
To keep the delimitation of areas affected by natural handicaps to ag riculture simple, robust 
and transparent, a restricted selection of elemen tary soil, climate and terrain characteristics is 
made. These are judged to be most pertinent fo r distinguishing land according to its suitability 
for generic agricultural activity. The interaction of the selected land characteristics on the 
growth of crops is accounted for by one addition al characteristic, the soil moisture balance.  
There is a range of land quality assessment methods  developed on the International and 
European level. Different methods have been constructed for different  purposes and therefore 
the process and analysis are different. 
A number of approaches were studied; a cons ensus was reached amongst experts and the JRC 
based on a set of requirements and recomme ndations that the UN Food and Agriculture 
Organisation (FAO) method the 'Problem Land A pproach' was the best st arting point. It is a 
straightforward and simple approach for identif ying broad types of agricultural problem soils 
and limitations in climate. The approach identifie s soil types with common characteristics that 
frequently dominate agricultura l land. Therefore a simple cla ssification system for identifying 
areas suffering from natural handicaps has b een developed, by the JRC in conjunction with 
experts, for the Europe Union. 
The reasons for choosing a modified "Problem La nd approach" rather than  a more elaborated 
Land Quality approach can be explained by the obj ectives pursued i.e. to identify areas with 
constraints to agriculture and not to identi fy all necessary conditions to reach optimal 
production for each kind of crop. Each criterion is distinct from the others in terms of impact 
and threshold. However all the individual criteria indicate at the specific threshold mentioned 
the point at which agricultural production is se verely handicapped. This means that it is 
possible to compare the handicap of one criteri on against another unrel ated criterion.Hence 
the delimitation of areas is transparent and comparable across the whole of the Community regardless of which criterion is  used in differing locations. 
2. L
EVEL OF DELIMITATION  
The amount and density of data and the seman tic detail available fr om point observations 
determine the spatial and semantic resolution of the results that can be obtained when 
mapping the area according to the criteria. The le vel of semantic resolu tion of the resulting 
mapping has a large effect on the ar ea of land classified, due to the differing data sets and the 
 
EN 3   EN percentage of area that would need to be constr ained for the whole area to then be classified 
as handicapped. 
To accurately asses the areas constrained by natu ral handicaps it is im portant to map at an 
adequate administrative level, with the sp atial and semantic resolution capturing the 
characteristics of the agricultura l land in the area at the territorial level LAU2 or as close as 
possible to LAU2. Currently most delimited areas are based on the LAU2 level. This level is the most appropriate for mapping an area and the continuation of this administrative level will 
allow for a certain degree of continuity.  
An area is considered affected by significant natu ral handicaps if a large part of the utilised 
agricultural area (UAA) in the area, at least 66%, meets at least one  of the criteria listed in the 
table at the threshold value indicated.  
The thresholds should be considered as a minimu m level of handicap to be met for classifying 
an area as constrained, Member States would have the possibility  to be more restrictive with 
the threshold level if this is justified by national circumstances.  
The indicators used for fine tuning should be valid for the life time of a programme. 
Member States should explai n the methodology and parameters used in the general mapping 
and the fine tuning process. 
The criteria indicated in the table below and the associated critical limits or threshold values 
can be used for European conditions to disc riminate land presenting severe limitations for 
agricultural production on the basis that soil and climate data of sufficient spatial and 
semantic detail are available.  
 
EN 4   EN 3. COMMON BIOPHYSICAL CRITERIA  
The table below lists the common soil, climate and terrain criteria for classifying land 
according to its suitability for generic agricult ural activity, as well as the threshold values 
indicating agricultural areas with seve re natural handicap to agriculture.  
CRITERION  
 DEFINITION  
 THRESHOLD  
CLIMATE   
Length of Growing Period (number of 
days) defined by number of days with daily 
average temperature > 5°C (LGP t5) OR ≤ 180 days OR 
 Low 
Temperature  Thermal-time sum (degree-days) for 
Growing Period defined by accumulated 
daily average temperature > 5°C. ≤ 1500 degree-days 
Heat Stress  Number and length of continuous periods 
(number of days) within the growing period for which daily maximum temperature (Tmax) exceeds the threshold. One or more periods of at least 10 
consecutive days with daily Tmax > 35°C 
SOIL  
Drainage  Areas which are water logged for 
significant duration of the year (lack of gaseous oxygen in soil for root growth or land not accessible for tillage). Poorly drained soil 
> 15% of topsoil volume is coarse 
material OR 
Unsorted, coarse or medium sand, loamy coarse sand OR 
Heavy clay (>60% clay) OR  
Organic OR 
Vertisol, clay, silty clay or sandy clay with vertic properties OR Texture and Stoniness  Relative abundance of clay, silt, sand, 
organic matter (weight %) and coarse 
material (volumetric %) fractions in top soil 
material. 
Rock outcrop, boulder within 15 cm 
of the surface  
Rooting depth  Depth (cm) from soil surface to coherent 
hard rock or hard pan. < 30 cm 
Salinity: > 4 deci-Siemens per 
meter (dS/m) OR Chemical properties  Presence of salts, exchangeable sodium and 
gypsum (toxicity) in the topsoil. 
Sodicity: > 6 Exchangeable Sodium 
 
EN 5   EN Percentage (ESP) OR 
Gypsum: > 15% 
SOIL AND CLIMATE  
Soil Moisture 
Balance Number of days within growing period as 
defined by temperature > 5°C (LGP t5), for 
which the amount of precipitation and water available in the soil profile exceeds half of potential evapotranspiration.  ≤ 90 days 
TERRAIN  
Slope Change of elevation with respect to 
planimetric distance (%). > 15% 
 
The section below provides a more detailed defi nition and justification for each criterion, as 
well as the indications for its applic ation within the simulation exercise. 
4. DETAILS FOR EACH CRITERION  
Criterion 1: Low Temperature  Definition 
Low temperature is defined as  the condition in which crop pe rformance or survival is 
compromised by temperatures during the growi ng period which are insufficient for optimal 
growth and development of plants. 
In the context of areas affected by natura l handicaps for agricultu re in Europe, low 
temperature is considered a characteristic of land for which thermal-time accumulation during the growing period is insufficient for plan ts to complete the production cycle.  
Agricultural Impact  
Low temperatures limit crop growth and de velopment through the impact on important 
physiological processes such as photosynthesis and leaf appear ance. Land in which thermal-
time accumulation systematically is not sufficien t for crops to complete the production cycle 
is unfavourable for agriculture.  
Negligible growth occurs for most agricultural crops at temperatures below 5
oC. When crops 
are grown under lower than adeq uate temperatures, yields can be reduced by various 
mechanisms including: limited lig ht interception (e.g. due to slow leaf area expansion), 
inefficient conversion of inter cepted light into  biomass (i.e. reduced photosynthesis rates), or 
direct damage to plant tissues caused by early or late frosts 
 
EN 6   EN Threshold 
Temperature thresholds and thermal requireme nts for plant development vary among crop 
species and cultivars. For European conditions , thermal-time sum (TS) requirements can be 
used as a reference to delimit thresholds for the development of agricultural crops. 
Severely  limiting low temperature is said to occur if TS 5 is lower than or equal 1500oCd or if 
LGP  t5 is lower than or equal than 180 days.  
Assessment 
To assess low temperature as a land characteri stic, the concepts of thermal-time sums (TS b, 
degree days, oCd) or length of temperature growing period (LGP t, days) can be used. 
a) The length of the temp erature growing period (LGP t5), i.e. the number of days with daily 
average temperatures (T avg) above 5oC is calculated for each year. The LGP t5 characterizes the 
days in which temperatures are conducive to crop growth. 
b) Thermal-time sums above a base temperature (T b) of 5oC, are calculated for each year by 
accumulating the difference between daily T avg and T b.  
Calculated values of LGP t5 or TS b are compared with reference thresholds for severe limiting 
conditions. Finally, the number  of years with limiting conditions is counted. If limiting 
conditions occur in more than 20% of the years of  the whole time series, the land is classified 
as constrained.  
A time series of daily meteorol ogical data preferably over 30 (or more) recent years is 
required to assess the probability of exceedance. 
Criterion 2: Heat Stress 
Definition 
Heat stress is defined as the condition in which crop performan ce or survival is compromised 
by periods of exposure to high temperatures. 
In the context of areas affected by natural handicap s for agriculture in Europe, heat stress is a 
characteristic of land which is subjected to one or more periods of continuous days within the 
growing period, for which maximum daily temperature (Tmax) exceeds 35oC. 
Agricultural Impact  
Episodes of high temperature, par ticularly during critical plant development stages drastically 
reduce yields of field crops. Th e thermal-sensitive period us ually spans from one to two 
weeks around flowering. 
Exposure to short episodes of high temperatur e during this thermal-sensitive period reduces 
the set of fruits and grains and limits grain fi lling. Possible impacts include a reduction in the 
number of flowers, number of pollens, pollen tube growth, polle n release, pollen viability and 
flower fertility. 
 
EN 7   EN Threshold 
Thresholds for heat stress have been iden tified for common crops. These thresholds are 
different among crops and also va ry within species. Yield loss is usually severe above 35oC, 
while the magnitude of damage increases with  the period of exposure, increasing at higher 
temperatures until complete damage is observed at above 40-45oC, near lethal temperatures. 
Severely  limiting heat stress is said to occur wh en “one or more periods of at least 10 
consecutive days with daily maximum temperatures above 35oC” are observed.  
Assessment 
To assess heat stress, maximum temperature as a land characteristic (T max, oC) can be used. 
The consecutive days with daily maximum temperature above 35 degrees should be 
accounted for in each year. Finally, the number of years with limiting condition (one or more periods of at least 10 consecutive days with daily maximum temperatures above 35
oC) is 
counted. If limiting conditions occur in more than  20% of the years of the whole time series, 
the land is classified  as constrained.  
A time series of daily meteorological data preferably over 30 (or more) recent years is 
required to assess the probability of exceedance. 
Criterion 3: Drainage 
Definition 
Soil drainage refers to the maintenance of th e gaseous phase in soil pores by removal (or non-
addition) of water. A so il has internal drainage, i.e. the facility for removing excess water by 
gravity, and external drainage, i.e. the amount of water removed (or not added) by its position 
in the landscape with respect to contri buting overland areas (runoff) or groundwater.  
Agricultural Impact  
Poor drainage reduces the space for the gaseous phase, in particular gaseous oxygen, in the 
rooting zone. It increases the incidence and seve rity of soil-borne pat hogens and makes tillage 
impossible. 
Threshold 
The thresholds identify land areas that are waterlogged for significa nt periods during the 
normal growing season and thus affect normal fa rming operations or crop yields. It identifies 
soils on which farming operations for adapted crops are possible, but with severe yield reductions due to late planting or poor tillage , crop damage by transient anoxic conditions or 
plant pathogens resulting from poor drainage. 
Soil drainage is said to be severely  limiting if with regard to drainage the soil is classified as 
poorly or very poorly drained. 
Assessment 
Different methods for the assessment of this criterion are possible. Most map classification 
systems and soil maps worldwide include water-regime related criteria.  
 
EN 8   EN It is recommended that Member States id entify the most suitable drainage/wetness 
representation in the nationa l dataset that co rresponds to the dr ainage criteria. 
Fine tuning the area delimitation  based on the 'Drainage' criterion 
In many areas of Europe with natural drainage problems, soils have been  artificially drained. 
If these drainage systems are permanent and functioning, the drained soil units should be 
evaluated as if they were be tter drained than without the in stalled drainage systems.  
Member States should remove from the areas designated, on the basis of this criterion, those 
areas where restricted agricultural production in  relation to the natural handicap is not 
observed because artificial drainage  systems improved the water regime.  
Criterion 4: Soil Texture and Stoniness 
Definition 
The texture of a soil refers to the relative pr oportions of different-sized soil particles in the 
bulk soil. It is more correctly called the particle-si ze distribution. Conventionally it is divided 
into two parts: coarse fragments > 2 mm effective diameter, and the fine soil.  
Agricultural Impact  
Soil texture is directly related to water-holdi ng capacity and nutrient supply. Texture affects 
workability (ease of tillage), water infiltration, runoff, and wa ter movement within the soil 
(both down and up). 
Silt and very fine sand fraction is associated with a high susceptibility to accelerated water 
and wind erosion. Soils with high proportions of these fractions re quire intensive soil 
conservation practices. 
Soils with a texture of coarse fragments dir ectly reduce the volume of soil exploitable by 
roots, thus reducing water-holding capacity a nd nutrient supply. Suffic iently large coarse 
fragments prevent tillage, and even smaller coarse fragments wear tillage implements.  
An important aspect of “texture” is the physi cal reaction of the soil  to wetting and drying. 
Vertic properties severely limit tillage options, the soil changes from hard and dry to plastic 
and sticky over a narrow range of water c ontents, leaving only a small window for 
conventional tillage. Shrinking and swelling duri ng the growing season can also damage plant 
roots. 
Threshold 
Soil texture is said to be severely limiting if any of the following condition are present:  
(i) more than 15 % volume of coarse fragme nts (> 2 mm) of any kind in topsoil or 
(ii) average texture clas s of rooting zone is 
(a) unsorted, coarse or medium sand, loamy coarse sand or 
(b) heavy clay (> 60% clay) or 
 
EN 9   EN (iii) organic soil as defined with organic matte r (>30%) of more than 40 cm either extending 
down from the surface or taken cumulatively  within the upper 80 cm of the soil or 
(iv) texture class of clay, silty clay, or sandy clay with vertic properties or; 
(v) any proportion of rock outcrops, boulders (largest dimension above or equal to 60 cm) 
within 15 cm of the surface. 
Assessment 
Coarse fragments (> 2 mm) are described by thei r abundance (volume %), size, shape, state of 
weathering, and nature. Fine earth (<2 mm) is  defined by the relative proportion (by weight) 
of sand, silt and clay as determined in the laboratory. The upper limits used here correspond to the FAO norms and are 2000, 63 and 2 microm eters. National systems may use different 
limits but it is possible to harmoni se data using transfer functions. 
It is recommended that Member States identify  the most suitable texture representation and 
information on vertic features and organic soils in the national dataset that correspond to the 
texture criteria. 
Fine tuning the area delimitation based on  the 'Soil Texture and Stoniness' criterion 
Member States should remove from the areas de signated on the basis of  this criterion, those 
areas where, on average, significant additiona l costs and income foregone for agricultural 
production in relation to the na tural handicap are not observed. 
The types of production indicators th at seems appropriate for ensuring that those areas that are 
initially identified as suffering from a natura l handicap are in reality constrained by that 
handicap are; 
• average yields for arable crops represen ting the predominant crop in the area or 
• livestock density or tree density in case of permanent crops or 
• result indicator (standard gro ss margin) for a production type 
– The average yield is close to the physical produ ctivity of an area and is not influenced by 
market trends, it is considered the most adapted criterion for arable area s, but could also be 
used for permanent crops.  
– The average stocking density is adapted to areas where livestock breeding is the main 
activity or  
– where orchards or groves of trees  is the main agricultural system 
– The standard gross margin (SGM) can be considered as an indicator of the average 
profitability potential of agriculture in an area. The regional average SGM per hectare in 
comparison to a national average could therefor e be used to exclude from LFA those areas 
where for example soils are poor but agricultur e is sufficiently profitable compared to a 
national average, even when the yield per hectare is low (e.g. vineyards). 
 
EN 10   EN Member States should fix a ceiling expressed by  a percentage of the national average of the 
yield or density or SGM for th e indicators. Member States ca n exclude mountain areas from 
the national average, since thes e could significantly lower the average. Member States could 
also, if more applicable, use a regional average as a reference. 
Member States can choose alternative or additional national or regionally specific indicators 
to use for the fine-tuning, while ensuring that the general principle of the Regulation and Strategic objectives of the interven tion mechanism are complied with. 
Criterion 5: Rooting Depth 
Definition 
Rooting depth is the maximum depth from the soil surface to where most of the plant roots 
can extend. It is defined by th e effective soil depth above a ny barrier to root extension, 
excluding impediments to root extension as such compact (massive) structure. 
Agricultural Impact  
Roots grow into the soil to pr ovide a physical anchor for the plant, and to extract soil-bound 
water and nutrients. For annual grain crops and grasses, the anchoring function does not 
require great depth; .the  first 10 cm or so provide enough st ability. However, water is rapidly 
exhausted from shallow depths by the growing plant.  
Rooting depth is generally constr ained by coherent hard rock or hardpans (dense soil layers). 
Physical limitations to rooting depth are also im pediments to normal tillage, such that if plant 
roots cannot grow easily, it is  unlikely that the plough can cut easily into the soil. 
Threshold 
Severe
 physical rooting depth: < 30 cm  
Assessment 
During routine field survey, rooting depth is  typically assessed by augering. The observed 
depths are then interpolated with reference to  the landscape structure to produce rooting depth 
estimates for land areas or map units. 
Fine tuning the area delimitation bas ed on the 'Rooting depth' criterion 
See the previous section 'Fine tuning the area  delimitation based on the 'Soil Texture and 
Stoniness' criterion, for fine tuning of the area delimited based on the criterion Rooting depth. 
Criterion 6.1: Chemical Properties – Salinity 
Definition 
Salinity is the presence of soluble salt in the la nd surface, in soil or rocks, or dissolved in 
water. It can be a natural process but has b een accelerated by human in tervention disturbing 
natural ecosystems. Soil salinity refers to the total amount of soluble salt in soil. 
 
EN 11   EN Agricultural Impact  
With regard to agriculture, the c onsequences of so il salinity include: 
a) Significant losses of producti vity. With increasing soil salinit y, plants always find it more 
difficult to extract water from the soils. Most normal crop and pasture plants are not highly 
salt-tolerant and will eventually die out under saline conditions;  
b) Damaged soil structure and increasing content of toxic substances that may be limiting to 
plant growth; and  
c) More serious soil erosion, bot h by wind and by water, due to  worsening soil structure and 
reducing vegetation cover. 
Threshold 
Salinity tolerance is influenced  by plant physiology, soil, and e nvironmental factors and their 
interrelationships. 
Levels over 4 dS/m (deci Siemens per meter) severely  affect many plants. 
Dry land salinity occurs where there is removal or loss of native vegetation, and its 
replacement with crops and pastur es that have shallower roots. This results in more water 
reaching the groundwater system. The groundwater  rises to near the surface in low-lying 
areas. It carries dissolved salts from the soil a nd bedrock material through which it travels. As 
saline groundwater comes close to the soil surface (within 2m), salt enters the plant root zone. 
Even where the groundwater does not bring much salt with it, the water logging of the plant 
root zone alone, can damage or kill vegetation 
Assessment 
Soil salinity is determined by measuring the electrical conductivity of a solution extracted 
from a water-saturated soil paste. However, soil classifications systems usually allow estimating salinity from the soil name.  
Fine tuning the area delimitation based on the 'Salinity' criterion 
See the previous section 'Fine tuning the area delimitation based on the 'Soil Texture and 
Stoniness' criterion , for fine tuning of the area delimite d based on the criterion Soil Salinity.  
Criterion 6.2: Chemical Properties - Sodicity 
Definition 
Sodicity refers to the presence of a high proporti on of adsorbed sodium in the clay fraction of 
soils. In the context of naturally handicapped areas for agriculture in Europe, soil sodicity is a characteristic of land for which the proportion of adsorbed sodium in th e soil clay fraction is 
too high for plants to perform or survive.  
Agricultural Impact Soil sodicity has two main effect s on soils and i ndirectly on its 
agricultural capacity to produce. Note that the e ffects of sodicity are of ten indirect as they 
affect vital soil properties ra ther than crop growth itself. 
 
EN 12   EN Soils become prone to water logging due to th e capping effect. They are also more prone to 
erosion and particularly er osion through water runoff. 
Sodic soil runoff has a detrimental effect on wate r ways and reservoirs due to the mobilisation 
of nutrients with the soil. This  has the unintended consequences  of producing additional cost 
for cleaning the water and also an increased ri sk in producing algal blooms in water bodies 
which are a significant environmental problem. 
Threshold 
The effect of Exchangeable Sodium Percen tage (ESP) on the yield, chemical composition, 
protein and oil content a nd uptake of nutrients is Severe  when soil sodicity is at ESP > 6  
Assessment 
Sodicity is determined by m easuring the exchangeable s odium proportion of the cation 
exchange capacity or by comparing the sol uble Calcium and Magnesium in a soil solution 
(SAR – Sodium Adsorption Ratio). However, soil classifications systems usually allow 
estimating sodicity from the soil name. 
Fine tuning the area delimitation  based on the 'Sodicity' criterion 
See the previous section 'Fine tuning the area delimitation based on the 'Soil Texture and 
Stoniness' criterion , for fine tuning of the area delimited based on the criterion Sodicity.  
Criterion 6.3: Chemical Properties - Soil Gypsum Content 
Definition 
Gysiferous soils are soils that  contain sufficient quantities of gypsum (calcium sulphate 
dehydrate) to interfere with plant growth. 
Agricultural Impact Many factors affect plant growth in gypsiferous soils,  including gypsum 
content within the root zone, depth to a gypsic layer, depth to impermeable layers, crop tolerance level and gypsum solubility. Fu rthermore physical properties are often 
unfavourable, causing low water availability, sl aking of loamy top soils, piping and collapse 
of irrigation canals. In soils with gypsum, almo st all crops show deficiency of most plant 
nutrients, in particular ph osphorus and micronutrients.  
Threshold 
Gypsiferous soils present a severe
 limitation to crop producti on once the gypsum percentage 
exceeds 15%.  
Assessment 
Gypsum is determined by the differential wa ter loss method which estimates the gypsum 
percentage from the loss of water in the soil  sample between 70 and 90°C. It can also be 
estimated with gravimetric dete rminations of precipitated BaSO 4. However, soil 
classifications systems usually allow estimati ng the presence of Gyps um from the soil name. 
 
EN 13   EN Fine tuning the area delimitation based  on the 'Soil Gypsum Content' criterion 
See the previous section 'Fine tuning the area delimitation based on the 'Soil Texture and 
Stoniness' criterion , for fine tuning of the area delim ited based on the crite rion Soil Gypsum 
Content. 
Criterion 7: Soil Moisture Balance 
Definition 
Deficit in the soil moisture balance is define d as the condition in which crop performance or 
survival is compromised by limited water ava ilability during the grow ing period, which is 
insufficient for optimal growth and development of crops. 
In the context of areas affected by natural hand icaps for agriculture in  the European Union, a 
deficit soil moisture balance is a characteristic of land for which the “number of days, within growing period as defined by temperature, for which the amount of precipitation and moisture 
available in the soil profile is not sufficient as  compared to the reference evapotranspiration, 
for plants to complete the production cycle”. 
Agricultural Impact The soil moisture balance is a critical parameter for assessing the 
potential for crop production. Agri cultural production is seriously  impaired if soil water is 
limiting during the growing season causing advers e affects on plant growth and crop yields  
Threshold 
Short growing period provides unfavourable c onditions for agriculture. On the basis of 
minimum crop cycle duration, the following critical limit has been established:  
Severe Threshold: ≤ 90 days  
Assessment  
To calculate the soil moisture balance, the in formation on the number of days when average 
temperature (T
avg) > 5oC and Actual evapotranspiration (A ET) / Potential evapotranspiration 
(PET) > 0.5, is extracted for each observation year .. According to the threshold value for the 
severe constraint, years with <= 90 non-dry days are classified as constrained. A probabilistic 
approach is applied to take account of the variab ility between years. If the handicap occurs in 
more than 20 % of the years, the land is classified as constrained.   
Fine tuning the area delimitation based on the 'Soil Moisture Balance' criterion 
It is assumed that in areas with irrigation, wa ter resources and irrigation infrastructure in 
place, no water stress occurs and that the number  of days available for crop growth is 
generously sufficient. Irrigated areas are co nsidered as favourable areas for agricultural 
production 
Member States should remove from the areas de signated on the basis of  this criterion, those 
areas where restricted agricultural production in  relation to the natural handicap is not 
observed because a high proportion, >50% of the UAA, is irrigated. 
 
EN 14   EN Criterion 8: Slope 
Definition 
Slope is the angle the soil surface makes with th e horizontal. It can be expressed in degrees or 
as a percentage (45 degrees = 100 percent).  
Agricultural Impact Slope as such has little or no direct influence on the yield of crops. 
However the steeper the slope th e more difficult it becomes to manage the land and to grow 
crops. In particular mechanisation is hamp ered while access to land and all agricultural 
operations become more time consuming. Steeper slopes are also associated with shallower 
soils in general and with a higher risk for soil degradati on (erosion) and land slides. 
Threshold 
Slopes above 15% pose severe  problems for mechanized cu ltivation, specific equipment is 
required. 
Assessment 
From neighbouring altitude data, slope can be determined by algorithms. The resulting ‘local’ 
slopes must be averaged over a larger area to be  applicable as an indicator of land suitability. 
When using a digital elevation model, the maxi mum rate of change between each cell and its 
neighbours is calculated, for example th e steepest downhill decent for the cell.