standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
standard deviation within 20km radius
flag for data quality, higher values poorer accuracy
Dummy==1 where imputed values used for: "noaddprop", "gelic", "petric", "vertic"
Dummy==1 where imputed values used for: "clayheavy", "claylight", "clayloam", "loam", "loamysand", "sand", "sandyclay", "sandyclayloam", "sandyloam", "siltloam", "siltyclay", "siltyclayloam"
Dummy==1 where imputed values used for: "issoil", "t_texture", "drainage", "awc_class", "t_gravel", "t_sand", "t_silt", "t_clay", "t_usda_tex_class", "t_ref_bulk_density", "t_bulk_density", "t_oc", "t_ph_h2o", "t_cec_clay", "t_cec_soil", "t_bs", "t_teb", "t_caco3", "t_caso4", "t_esp", "t_ece", "s_gravel", "s_sand", "s_silt", "s_clay", "s_usda_tex_class", "s_ref_bulk_density", "s_bulk_density", "s_oc", "s_ph_h2o", "s_cec_clay", "s_cec_soil", "s_bs", "s_teb", "s_caco3", "s_caso4", "s_esp", "s_ece","su_symbol", "su_value"
Bulk density is inversely related to porosity.
Bulk density is inversely related to porosity.
Organic Carbon is together with pH, the best simple indicator of the health status of the soil. Moderate to high amounts of organic carbon are associated with fertile soils with a good structure.
Low values are acidic; high values alkaline. Best soils for most crops lie in 5.5 to 7.2 range.
The total nutrient fixing capacity of a soil is well expressed by its Cation Exchange Capacity. Soils with low CEC have little resilience and can not build up stores of nutrients.
The total nutrient fixing capacity of a soil is well expressed by its Cation Exchange Capacity. Soils with low CEC have little resilience and can not build up stores of nutrients.
The base saturation measures the sum of exchangeable cations (nutrients) Na, Ca, Mg and K as a percentage of the overall exchange capacity of the soil (including the same cations plus H and Al). The value often shows a near linear correlation with pH.
Total exchangeable bases stand for the sum of exchangeable cations in a soil: sodium (Na), calcium (Ca), magnesium (Mg) and Potassium (K).
Low levels of calcium carbonate enhance soil structure and are generally beneficial for crop production but at higher concentrations they may induce iron deficiency and when cemented limit the water storage capacity of soils.
Up to 2 percent gypsum in the soil favours plant growth, between 2 and 25 percent has little or no adverse effect if in powdery form, but more than 25 percent can cause substantial reduction in yields.
Exchangeable sodium percentage has been used to indicate levels of sodium in soils. It is calculated as the ratio of Na in the CEC (or sum of cations) ESP= Na*100/CECsoil
Salt content of a soil can be roughly estimated from the Electrical Conductivity of the soil (EC, expressed in dS m-1). Crops vary considerably in their resistance and response to salt in soils. Some crops will suffer at values as little as 2 dS m-1 (Spinach) others can stand up to 16 dS m-1 (Date palm).
Bulk density is inversely related to porosity.
Bulk density is inversely related to porosity.
Organic Carbon is together with pH, the best simple indicator of the health status of the soil. Moderate to high amounts of organic carbon are associated with fertile soils with a good structure.
Low values are acidic; high values alkaline. Best soils for most crops lie in 5.5 to 7.2 range.
The total nutrient fixing capacity of a soil is well expressed by its Cation Exchange Capacity. Soils with low CEC have little resilience and can not build up stores of nutrients.
The total nutrient fixing capacity of a soil is well expressed by its Cation Exchange Capacity. Soils with low CEC have little resilience and can not build up stores of nutrients.
The base saturation measures the sum of exchangeable cations (nutrients) Na, Ca, Mg and K as a percentage of the overall exchange capacity of the soil (including the same cations plus H and Al). The value often shows a near linear correlation with pH.
Total exchangeable bases stand for the sum of exchangeable cations in a soil: sodium (Na), calcium (Ca), magnesium (Mg) and Potassium (K).
Low levels of calcium carbonate enhance soil structure and are generally beneficial for crop production but at higher concentrations they may induce iron deficiency and when cemented limit the water storage capacity of soils.
Up to 2 percent gypsum in the soil favours plant growth, between 2 and 25 percent has little or no adverse effect if in powdery form, but more than 25 percent can cause substantial reduction in yields.
Exchangeable sodium percentage has been used to indicate levels of sodium in soils. It is calculated as the ratio of Na in the CEC (or sum of cations) ESP= Na*100/CECsoil
Salt content of a soil can be roughly estimated from the Electrical Conductivity of the soil (EC, expressed in dS m-1). Crops vary considerably in their resistance and response to salt in soils. Some crops will suffer at values as little as 2 dS m-1 (Spinach) others can stand up to 16 dS m-1 (Date palm).
Soil texture, soil organic carbon, soil pH, total exchangeable bases
Soil Organic carbon, Soil texture, base saturation, cation exchange capacity of soil and of clay fraction
Soil textures, bulk density, coarse fragments, vertic soil properties and soil phases affecting root penetration and soil depth and soil volume
Soil drainage and soil phases affecting soil drainage
Soil salinity, soil sodicity and soil phases influencing salt conditions
Calcium carbonate and gypsum
Soil texture, effective soil depth/volume, and soil phases constraining soil management (soil depth, rock outcrop, stoniness, gravel/concretions and hardpans)
Negative values show distance across land to coastline; Postive values show distance across water to coastline (very small islands have positive values)
data quality flag--higher numbers are less accurate
data quality flag--higher numbers are less accurate
data quality flag--higher numbers are less accurate
Sorensen, R., Zinko, U., & Seibert, J. (2006). On the calculation of the topographic wetness index: evaluation of different methods based on field observations. Hydrol. Earth Syst. Sci., 10(1), 101-112. doi:10.5194/hess-10-101-2006
data quality flag--higher numbers are less accurate
data quality flag--higher numbers are less accurate
names of categories
Topographic openess developed by Yokoyama R, Shirasawa M and Pike RJ, 2002, Visualizing topography by Openness: A new applicationof image processing to digital elevation models. Photogrammetric Engineering and Remote Sensing, 68(3): 257-265.
data quality flag--higher numbers are less accurate
data quality flag--higher numbers are less accurate
names of categories
data quality flag--higher numbers are less accurate
names of categories
data quality flag--higher numbers are less accurate
data quality flag--higher numbers are less accurate
Enhanced Vegetation Index: https://lpdaac.usgs.gov/products/modis_products_table/mod13q1
data quality flag--higher numbers are less accurate
Leaf Area Index: https://lpdaac.usgs.gov/products/modis_products_table/mod15a2
data quality flag--higher numbers are less accurate
The total amount of precipitation that falls during an average year (1960 to 1990) in units of millimeters (mm3 per year / mm2 = mm / year).
data quality flag--higher numbers are less accurate
Relative humidity is defined as the ratio of the actual vapor pressure of water vapor to the saturation vapor pressure of water, in other words how much water is in the air divided by the most water that could possibly be there.
data quality flag--higher numbers are less accurate
the volume of water running over this gridcell divided by the area of the gridcell itself (mm3 per year / mm2 over 1 yr = mm/yr)
data quality flag--higher numbers are less accurate
The amount of water removed from the surface through evaporation (due to temperature, humidity, radiation...) and through transpiration (the process by which plants move water up from their roots and out through their leaves). Evapotranspiration can be used to estimate the amount of water the local vegetation needs to remain in equilibrium with the ground water supply.
data quality flag--higher numbers are less accurate
The Growing Degree Day (GDD) is based on the fact that if temperature is too hot or cold, plant growth will slow. GDD is calculated for a range specific to a particular plant or suite of plants. Taking corn as an example, it grows with a minimum temperature of 10?C and a maximum temperature of 30?C. So if one day the maximum temperature is 21?C and the minimum temperature is 15?C, the average temperature of that day was 18?C. To determine how many GDD were in that day, simply subtract the base temperature from the average temperature (18?C-10?C) remembering that this all happened on one day. Thus for this example, there were 8 GDD accumulated by the corn during that day. Had the base temperature been 5?C, there would have been 13 GDD accumulated. Annual GDD is the average number of GDD accumulated in a particular area under normal climatic conditions. In this dataset, a base temperature of 5?C was used to compute monthly GDD and those monthly values were then totaled to yield an annual number.
data quality flag--higher numbers are less accurate
NPP is calculated by taking the gross primary productivity (the total amount of energy/mass taken in by the plant) and subtracting the plant's respiration (the total amount of energy/mass lost by the plant as it breathes).  NPP is measured in units of kg-Carbon per square meter per year, or the net amount of carbon the plants in an average square meter of the gridcell take up during an average year.
data quality flag--higher numbers are less accurate
The amount of water that would be removed from the surface by evaporation and transpiration, if the amount of water already present were not a limiting factor. In other words, the potential evapotranspiration over the Sahara desert is very large because the amount of evaporation that could take place there is huge. However, because there isn't any water there to be evaporated, the evapotranspiration that actually takes place is quite small.
data quality flag--higher numbers are less accurate
Potential vegetation is the vegetation that would exist at a given location had human forms of land use never existed. In other words, if humans weren't around, this would be an accurate description of the planet's land cover.
data quality flag--higher numbers are less accurate
names of categories
The average annual snow depth--natural log scale, range is from 10^-20mm (trace) to 10^10mm (greater than a kilometer).
data quality flag--higher numbers are less accurate
The average amount of water in the soil
data quality flag--higher numbers are less accurate
The fraction of each grid cell that is suitable to be used for agriculture. It is based on the temperature and soil conditions of each grid cell.
assignments by Doug White