Water Quality Summary, 2009

Summary of stream water quality data collected in 2009.

Water Quality Summary, 2000-2009

Summary of stream water quality data collected from 2000 through 2009.

Water Quality Summary, 2000-2010

Summary of water quality data from stream in Iowa from 2000 through 2010.

Water Quality Summary, 2010

Summary of water quality data collected from stream in 2010.

Water Quality Summary, 2000-2011

Summary of stream water quality data collected from 2000 through 2011.

Water Quality Summary, 2011

Summary of stream water quality data for 2011.

Lake Water Quality Summary, 2000-2011

Summary of lake water quality data collected from 2000 through 2011.

Lake Water Quality Summary, 2011

Summary of lake water quality data collected in 2011.

Water Quality Summary, 2000-2012

Summary of water quality data collected from streams in Iowa from 2000 through 2012.

Water Quality Summary, 2012

Summary of stream water quality data collected in 2012.

Stream Water Quality Summary, 2013

Summary of stream water quality collected in 2013.

Stream Water Quality Summary, 2000-2013

Summary of stream water quality data collected from 2000 through 2013.

Stream Water Quality Summary, 2014

Summary of stream water quality data collected in 2014.

Stream Water Quality Summary, 2000-2014

Summary of stream water quality data collected from 2000 through 2014.

Brazilian maize genotypes sensitivity to water deficit estimated through a simple crop yield model

The objective of this work was to determine the sensitivity of maize (Zea mays) genotypes to water deficit, using a simple agrometeorological crop yield model. Crop actual yield and agronomic data of 26 genotypes were obtained from the Maize National Assays carried out in ten locations, in four Brazilian states, from 1998 to 2006. Weather information for each experimental location and period were obtained from the closest weather station. Water deficit sensitivity index (Ky) was determined using the crop yield depletion model. Genotypes can be divided into two groups according to their resistance to water deficit. Normal resistance genotypes had Ky ranging from 0.4 to 0.5 in vegetative period, 1.4 to 1.5 in flowering, 0.3 to 0.6 in fruiting, and 0.1 to 0.3 in maturing period, whereas the higher resistance genotypes had lower values, respectively 0.2-0.4, 0.7-1.2, 0.2-0.4, and 0.1-0.2. The general Ky for the total growing season was 2.15 for sensitive genotypes and 1.56 for the resistant ones. Model performance was acceptable to evaluate crop actual yield, whose average errors estimated for each genotype ranged from -5.7% to +5.8%, and whose general mean absolute error was 960 kg ha-1 (10%).