Nitrogen is one of the most important nutrients in barley cultivation. Excessive leaching of nitrogen through the soil is also a major contributor to groundwater pollution. Many factors and calculations are required to balance the environmental concerns of excess nitrogen with the need for sufficient nitrogen to achieve the crop's maximum potential yield. Extensive research has been conducted to find the correct levels of nitrogen application by universities and private organizations. Despite all this research there are still human decisions and divergent opinions between professionals and laboratories that make this decision complex. Nitrogen is the basis for growing a barley crop that will produce a sufficient yield. Applying fertilizer to your crop requires careful and necessary steps that will help determine the amount needed. Therefore, in the first step, when determining nitrogen needs for the next growing year, it is important to find out how much nitrogen is left in the soil from the previous growing year. This process requires a test on a soil sample, which will provide test results that show what type of nutrients are still left in the soil. “Second step, nitrogen is mineralized from the soil and made available for plant growth during the following growing season. The problem is, there is no test for this, so, in southern Idaho, farmers use an estimate of about forty-five pounds an acre” (Robertson and Stark). Step three: When following crops such as sugar beets, potatoes and onions, which have rapid residue decomposition, farmers should not use additional recommendations, for nitrogen, to break down residues from the previous crop. However, if they have a crop that produces mature grain residue, which has low tissue nitrogen levels, farmers have to apply... half the paper... to try to calculate the exact amount. While these issues cause confusion in scientific studies, farmers have still found other options for applying the acceptable amount of nitrogen needed for crop growth. Works Cited “Barley Nutrition.” www.agric.wa.gov.an. March 2007. Web. December 4, 2013. Mahler, Robert and Stephen Guy. “Spring barley”. www.cals.uidaho.edu/edcomm. July 2007.Web. November 22, 2013.Mahler, Robert. “Idaho Fertilizer of Spring Barley Guide.” www.cals.uidaho.edu. Web.August 2007. December 5, 2013.Robertson, Larry and Jeffery Stark. “Idaho Spring Barley Production Guide.” University of Idaho. www.cals.idaho.edu/edcomm/. Network. August 2013. December 3, 2013. Windes, Juliet, Kelly Olsen, and Don Obert. "Guidelines for barley production". University of Idaho. Barley.idaho.gov. Network. December 2013. 2 December 2013.