Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions - Towards a better targeting of the aid to farmers in areas with natural handicaps - Technical annex - Technical details for possible common criteria {COM(2009) 161 final} {SEC(2009) 450} {SEC(2009) 451}
Date: 2009-04-21
Institutions: European Commission
Subjects: agricultural area with environmental restrictions, aid to agriculture, hill farming, mountain region, regional farm policy

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COMMISSION OF THE EUROPEAN COMMUNITIES 

Brussels, 21.4.2009 
SEC(2009) 449 

COMMISSION STAFF WORKING DOCUMENT 

accompanying the 

COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN 
PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL 
COMMITTEE AND THE COMMITTEE OF THE REGIONS 

Towards a better targeting of the aid to farmers in areas with natural handicaps 

TECHNICAL ANNEX 

Technical details for possible common criteria  

{COM(2009) 161 final} 
{SEC(2009) 450} 
{SEC(2009) 451} 

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COMMISSION STAFF WORKING DOCUMENT 
Technical Annex 

Technical details for possible common criteria 

1. 

INTRODUCTION 

Soil, climate and terrain are the major determinants 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 but not too much heat and photo-
synthetically active radiation, oxygen, water and nutrients, in the absence of toxic substances 
or damaging impacts from storms or pests. 

To keep the delimitation of areas affected by natural handicaps to agriculture simple, robust 
and transparent, a restricted selection of elementary soil, climate and terrain characteristics is 
made. These are judged to be most pertinent for 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 additional 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 consensus was reached amongst experts and the JRC 
based  on  a  set  of  requirements  and  recommendations  that  the  UN  Food  and  Agriculture 
Organisation (FAO) method the 'Problem Land Approach' was the best starting point. It is a 
straightforward and simple approach for identifying broad types of agricultural problem soils 
and limitations in climate. The approach identifies soil types with common characteristics that 
frequently dominate agricultural land. Therefore a simple classification system for identifying 
areas  suffering  from  natural  handicaps  has  been  developed,  by  the  JRC  in  conjunction  with 
experts, for the Europe Union. 

The reasons for choosing a modified "Problem Land approach" rather than a more elaborated 
Land Quality approach can be explained by the objectives pursued i.e. to identify areas with 
constraints  to  agriculture  and  not  to  identify  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  severely  handicapped.  This  means  that  it  is 
possible  to  compare  the  handicap  of one  criterion  against  another  unrelated  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. 

LEVEL OF DELIMITATION 

The  amount  and  density  of  data  and  the  semantic  detail  available  from  point  observations 
determine  the  spatial  and  semantic  resolution  of  the  results  that  can  be  obtained  when 
mapping  the  area  according  to  the  criteria.  The  level  of  semantic  resolution  of  the  resulting 
mapping has a large effect on the area of land classified, due to the differing data sets and the 

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percentage of area that would need to be constrained for the whole area to then be classified 
as handicapped. 

To  accurately  asses  the  areas  constrained  by  natural  handicaps  it  is  important  to  map  at  an 
adequate  administrative  level,  with  the  spatial  and  semantic  resolution  capturing  the 
characteristics of the agricultural 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 natural 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 minimum 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 explain 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  discriminate  land  presenting  severe  limitations  for 
agricultural  production  on  the  basis  that  soil  and  climate  data  of  sufficient  spatial  and 
semantic detail are available.  

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3. 

COMMON BIOPHYSICAL CRITERIA 

The  table  below  lists  the  common  soil,  climate  and  terrain  criteria  for  classifying  land 
according  to  its  suitability  for  generic  agricultural  activity,  as  well  as  the  threshold  values 
indicating agricultural areas with severe natural handicap to agriculture.  

CRITERION 

DEFINITION 

THRESHOLD  

CLIMATE 

Low 
Temperature 

Heat Stress 

SOIL 

Drainage 

Texture  and 
Stoniness 

Length  of  Growing  Period  (number  of 
days) defined by number of days with daily 
average temperature > 5°C (LGPt5) OR 

≤ 180 days OR 

sum 

Thermal-time 
for 
Growing  Period  defined  by  accumulated 
daily average temperature > 5°C. 

(degree-days) 

≤ 1500 degree-days 

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 

Areas  which  are  water 
for 
significant  duration  of  the  year  (lack  of 
gaseous  oxygen  in  soil  for  root  growth  or 
land not accessible for tillage). 

logged 

Relative  abundance  of  clay,  silt,  sand, 
organic  matter  (weight  %)  and  coarse 
material (volumetric %) fractions in top soil 
material. 

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 

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 

Chemical 
properties  

Presence of salts, exchangeable sodium and 
gypsum (toxicity) in the topsoil. 

Salinity:  >  4  deci-Siemens  per 
meter (dS/m) OR 

Sodicity: > 6 Exchangeable Sodium 

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Percentage (ESP) OR 

Gypsum: > 15% 

SOIL AND CLIMATE 

Soil  Moisture 
Balance 

TERRAIN  

Slope 

Number  of  days  within  growing  period  as 
defined  by  temperature  >  5°C  (LGPt5),  for 
which  the  amount  of  precipitation  and 
water  available  in  the  soil  profile  exceeds 
half of potential evapotranspiration.  

≤ 90 days 

Change  of  elevation  with 
planimetric distance (%). 

respect 

to 

> 15% 

The section below provides a more detailed definition and justification for each criterion, as 
well as the indications for its application within the simulation exercise. 

4. 

DETAILS FOR EACH CRITERION 

Criterion 1: Low Temperature  

Definition 

Low  temperature  is  defined  as  the  condition  in  which  crop  performance  or  survival  is 
compromised  by  temperatures  during  the  growing  period  which  are  insufficient  for  optimal 
growth and development of plants. 

In  the  context  of  areas  affected  by  natural  handicaps  for  agriculture  in  Europe,  low 
temperature is considered a characteristic of land for which thermal-time accumulation during 
the growing period is insufficient for plants to complete the production cycle.  

Agricultural Impact  

Low  temperatures  limit  crop  growth  and  development  through  the  impact  on  important 
physiological processes such as photosynthesis and leaf appearance. Land in which thermal-
time accumulation systematically is not sufficient for crops to complete the production cycle 
is unfavourable for agriculture.  

Negligible growth occurs for most agricultural crops at temperatures below 5oC. When crops 
are  grown  under  lower  than  adequate  temperatures,  yields  can  be  reduced  by  various 
mechanisms  including:  limited  light  interception  (e.g.  due  to  slow  leaf  area  expansion), 
inefficient conversion of intercepted light into biomass (i.e. reduced photosynthesis rates), or 
direct damage to plant tissues caused by early or late frosts 

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Threshold 

Temperature  thresholds  and  thermal  requirements  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 TS5 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 characteristic, the concepts of  thermal-time sums  (TSb, 
degree days, oCd) or length of temperature growing period (LGPt, days) can be used. 

a) The length of the temperature growing period (LGPt5), i.e. the number of days with daily 
average temperatures (Tavg) above 5oC is calculated for each year. The LGPt5 characterizes the 
days in which temperatures are conducive to crop growth. 

b) Thermal-time sums above a base temperature (Tb) of 5oC, are calculated for each year by 
accumulating the difference between daily Tavg and Tb.  

Calculated values of LGPt5 or TSb 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  meteorological  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 performance or survival is compromised 
by periods of exposure to high temperatures. 

In the context of areas affected by natural handicaps 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, particularly during critical plant development stages drastically 
reduce  yields  of  field  crops.  The  thermal-sensitive  period  usually  spans  from  one  to  two 
weeks around flowering. 

Exposure  to  short  episodes  of  high  temperature during this thermal-sensitive period reduces 
the set of fruits and grains and limits grain filling. Possible impacts include a reduction in the 
number of flowers, number of pollens, pollen tube growth, pollen release, pollen viability and 
flower fertility. 

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Threshold 

Thresholds  for  heat  stress  have  been  identified  for  common  crops.  These  thresholds  are 
different among crops and also vary 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  when  “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 (Tmax,  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  35oC)  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 the gaseous phase in soil pores by removal (or non-
addition) of water. A soil 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 contributing 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 severity of soil-borne pathogens and makes tillage 
impossible. 

Threshold 

The  thresholds  identify  land  areas  that  are  waterlogged  for  significant  periods  during  the 
normal growing season and thus affect normal farming 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.  

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It  is  recommended  that  Member  States  identify  the  most  suitable  drainage/wetness 
representation in the national dataset that corresponds to the drainage 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 better drained than without the installed 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  proportions  of  different-sized  soil  particles  in  the 
bulk soil. It is more correctly called the particle-size 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-holding capacity and nutrient supply. Texture affects 
workability  (ease  of  tillage),  water  infiltration,  runoff,  and  water  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  require  intensive  soil 
conservation practices. 

Soils  with  a  texture  of  coarse  fragments  directly  reduce  the  volume  of  soil  exploitable  by 
roots,  thus  reducing  water-holding  capacity  and  nutrient  supply.  Sufficiently  large  coarse 
fragments prevent tillage, and even smaller coarse fragments wear tillage implements.  

An  important  aspect  of  “texture”  is  the  physical  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  contents,  leaving  only  a  small  window  for 
conventional tillage. Shrinking and swelling during 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 fragments (> 2 mm) of any kind in topsoil or 

(ii) average texture class of rooting zone is 

(a) 

unsorted, coarse or medium sand, loamy coarse sand or 

(b) 

heavy clay (> 60% clay) or 

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(iii) organic soil as defined with organic matter (>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 their 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 micrometers. National systems may use different 
limits but it is possible to harmonise 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 designated on the basis of this criterion, those 
areas  where,  on  average,  significant  additional  costs  and  income  foregone  for  agricultural 
production in relation to the natural handicap are not observed. 

The types of production indicators that seems appropriate for ensuring that those areas that are 
initially  identified  as  suffering  from  a  natural  handicap  are  in  reality  constrained  by  that 
handicap are; 

•  average yields for arable crops representing the predominant crop in the area or 

•  livestock density or tree density in case of permanent crops or 

•  result indicator (standard gross margin) for a production type 

–  The average yield is close to the physical productivity of an area and is not influenced by 
market trends, it is considered the most adapted criterion for arable areas, 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 therefore be used to exclude from LFA those areas 
where  for  example  soils  are  poor  but  agriculture  is  sufficiently  profitable  compared  to  a 
national average, even when the yield per hectare is low (e.g. vineyards). 

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Member States should fix a ceiling expressed by a percentage of the national average of the 
yield or density or SGM for the indicators. Member States can exclude mountain areas from 
the national average, since these 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 intervention 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  the  effective  soil  depth  above  any  barrier  to  root  extension, 
excluding impediments to root extension as such compact (massive) structure. 

Agricultural Impact  

Roots grow into the soil to provide 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 stability. However, water is rapidly 
exhausted from shallow depths by the growing plant.  

Rooting depth is generally constrained by coherent hard rock or hardpans (dense soil layers). 

Physical limitations to rooting depth are also impediments 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 based 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  land  surface,  in  soil  or  rocks,  or  dissolved  in 
water. It can be a natural process but has been accelerated by human intervention disturbing 
natural ecosystems. Soil salinity refers to the total amount of soluble salt in soil. 

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Agricultural Impact  

With regard to agriculture, the consequences of soil salinity include: 

a) Significant losses of productivity. With increasing soil salinity, 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, both by wind and by water, due to worsening soil structure and 
reducing vegetation cover. 

Threshold 

Salinity tolerance is influenced by plant physiology, soil, and environmental 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  pastures  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 and 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 delimited based on the criterion Soil Salinity. 

Criterion 6.2: Chemical Properties - Sodicity 

Definition 

Sodicity refers to the presence of a high proportion 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 the soil clay fraction is 
too high for plants to perform or survive. 

Agricultural  Impact  Soil  sodicity  has  two  main  effects  on  soils  and  indirectly  on  its 
agricultural  capacity  to  produce.  Note  that  the  effects  of  sodicity  are  often  indirect  as  they 
affect vital soil properties rather than crop growth itself. 

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Soils become prone to water logging due to the capping effect. They are also more prone to 
erosion and particularly erosion through water runoff. 

Sodic soil runoff has a detrimental effect on water 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 risk in producing algal blooms in water bodies 
which are a significant environmental problem. 

Threshold 

The  effect  of  Exchangeable  Sodium  Percentage  (ESP)  on  the  yield,  chemical  composition, 
protein and oil content and uptake of nutrients is Severe when soil sodicity is at ESP > 6  

Assessment 

Sodicity  is  determined  by  measuring  the  exchangeable  sodium  proportion  of  the  cation 
exchange  capacity  or  by  comparing  the  soluble  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.  Furthermore  physical  properties  are  often 
unfavourable, causing low water availability, slaking of loamy top soils, piping and collapse 
of  irrigation  canals.  In  soils  with  gypsum,  almost  all  crops  show  deficiency  of  most  plant 
nutrients, in particular phosphorus and micronutrients.  

Threshold 

Gypsiferous soils present a severe limitation to crop production once the gypsum percentage 
exceeds 15%. 

Assessment 

Gypsum  is  determined  by  the  differential  water  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  determinations  of  precipitated  BaSO4.  However,  soil 
classifications systems usually allow estimating the presence of Gypsum from the soil name. 

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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 delimited based on the criterion Soil Gypsum 
Content. 

Criterion 7: Soil Moisture Balance 

Definition 

Deficit in the soil moisture balance is defined as the condition in which crop performance or 
survival  is  compromised  by  limited  water  availability  during  the  growing  period,  which  is 
insufficient for optimal growth and development of crops. 

In the context of areas affected by natural handicaps 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.  Agricultural  production  is  seriously  impaired  if  soil  water  is 
limiting during the growing season causing adverse affects on plant growth and crop yields  

Threshold 

Short  growing  period  provides  unfavourable  conditions  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 information on the number of days when average 
temperature (Tavg) > 5oC and Actual evapotranspiration (AET) / 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 variability 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,  water  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  considered  as  favourable  areas  for  agricultural 
production 

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 a high proportion, >50% of the UAA, is irrigated. 

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Criterion 8: Slope 

Definition 

Slope is the angle the soil surface makes with the 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 the more difficult it becomes to manage the land and to grow 
crops.  In  particular  mechanisation  is  hampered  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 degradation (erosion) and land slides. 

Threshold 

Slopes  above  15%  pose  severe  problems  for  mechanized  cultivation,  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 maximum rate of change between each cell and its 
neighbours is calculated, for example the steepest downhill decent for the cell. 

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