Northwest and Allee Research and Demonstration Farm
Excess sediment and phosphorus (P) impair many Iowa water resources and the Gulf of Mexico. Most of the sediment and P originate from agricultural fields and stream banks. Previous research on P loss with surface runoff in Northwest Iowa was based on rainfall simulations. This technique provides useful information about dissolved P loss but poorly estimates the long-term differences and total P loss from fields. Therefore, a long-term study based on large plots and natural precipitation was conducted at the ISU Northwest Research and Demonstration Farm from 2007 until 2012. The objectives were to study effects of corn and soybean production, tillage, and fertilizer or manure P management systems on yield and both soil and P loss with surface runoff.
Iowa State University
Mallarino, Antonio P.; Haq, Mazhar Ul; Helmers, Matthew J.; Sievers, Joshua L.; and Rusk, Ryan, "Effects of Tillage and Phosphorus Source onLong-term Phosphorus Runoff Loss and Crop Yield" (2013). Iowa State Research Farm Progress Reports. 1968.