Credible Sources

References

1M.L. Vitosh, J.W. Johnson, D.B Mengel. 1914. Tri-State Recommendations for Corn, Soybeans, Wheat & Alfalfa. Accessed July 2015. Retrieved from: https://www.extension.purdue.edu/extmedia/AY/AY-9-32.pdf.

2Office of the Indiana State Chemist. 2013. OISC Category 14 - Agricultural Fertilizer Applicator Rules. Accessed July 2015. Retrieved from: http://www.oisc.purdue.edu/f`ertilizer/pdf/fert_use_rules_and_faq.pdf.