Assessment of Vegetation Response to Drought in Nebraska Using Terra-MODIS Land Surface Temperature and Normalized Difference Vegetation Index

GIScience & Remote SensingGIScience & Remote Sensing, Volume 48, Number 3 / July-September 2011

Sharmistha Swain, Brian D. Wardlow, Sunil Narumalani, Tsegaye Tadesse, and Karin Callahan

“Eight-day composite Terra-MODIS cumulative LST and NDVI timeseries data were used to analyze the responses of crop and grassland cover types to drought in Nebraska. Four hundred ninety 1 km pixels that included irrigated and non-irrigated corn and soybeans and three grassland cover types were selected across the state of Nebraska. Statistical analyses revealed that the majority of the land cover pixels experienced significantly higher daytime and nighttime LSTs and lower NDVI during the drought-year growing season (p < 0.01). Among the land cover types analyzed, grassland experienced the highest increase in daytime LST and decrease in NDVI.”

Application of GIS for Determination of Groundwater Quality Suitable in Crops Influenced by Irrigation Water in the Damghan Region of Iran

International Journal of the Physical SciencesInternational Journal of the Physical Sciences, Vol. 6(4), pp. 843-854, 18 February, 2011

Shahram Ashraf, Hossein Afshar, and Abdol Ghaffar Ebadi

“In order to evaluate the quality of groundwater in Damghan plain for irrigation purposes, 199 surveyed wells with GPS data used to produce the map. The features that generally had considered for evaluation of the suitable quality of groundwater for irrigation are salinity, water infiltration rate, and specific ion toxicity. The SAR , ions Ca2+,Mg2+, Na+, K+, CO3 2-, HCO3- – , SO4 2- , Cl-, electrical conductivity (EC), total dissolved solids (TDS), pH were analyze as the evaluation indexes. The EC map indicates the presence of about 0.04% of the study area; groundwater lie in good range (none degree of restriction on use) 61.38% slight to moderate and 38.58% severe for irrigation purposes. The suitable zones for ECw are in the central and northwestern and portion of south of the study area (61.42%). The quality of groundwater for the sodium hazard on infiltration is in 98.9% of study area none degree of restriction on use and in 0.6% slight to moderate and 0.5% severe.

Spatial distribution of ECw(μs cm-1) for crops

Spatial distribution of ECw(μs cm-1) for crops

“The suitable zones for infiltration have no degree of restriction on use in majority of the study area. The maps result of crops yield potential as influenced by irrigation water salinity (ECw) indicates that crops barley>wheat > Alfalfa respectively have yield potential more against ECW in study area (99.42,92.3 and 0.23%). The results of thematic maps of sodiumw, choloridw were overlaid with maps of sodiumplant, choloridplant showed that the crops yield potential of barley and wheat. Alfalfa in all the study area is 100%.”