Test Plots (IMAGE) Penn State Caption The research was conducted at Penn State's Russell E. Larson Agricultural Research Center on 12 hydrologically isolated research plots. Half the plots received manure injection; half had manure applied by broadcasting it on the surface. Credit Jack Watson Research Group / Penn State Usage Restrictions Non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.