Improve Wisconsin Potato Productivity and Reduce Nitrogen Leaching
Nitrogen rate was 250 lbs N/acre. AMS/AN treatment is split application with 1/3 of total N applied at emergence as ammonium sulfate and incorporated by hilling cultivation with the remaining 2/3 applied as ammonium nitrate at tuberization and immediately watered in. Agrotain treated urea (Urea + AT) and Super U treatments were similarly split as 1/3 at emergence and 2/3 at tuberization. ESN was applied in one application at emergence and similarly incorporated by the hilling cultivation. Yield values are marketable yield and are means of three years. Leaching comparison is based on 3-yr average cumulative nitrate loading at a 3.3-ft depth. Source: Dr. M. Ruark, Univ of Wisconsin, Manuscript in preparation.
Potatoes require careful management of relatively high nitrogen (N) rates. They are a shallow-rooted crop often grown on sandy soils with potential for nitrogen (N) leaching beyond the root zone and into groundwater. ESN has repeatedly been shown to produce greater potato yields with fewer applications, reduce N leaching, and increase profits. In this Wisconsin study, one ESN application produced greater yields than all other N sources and was the most effective source in controlling leaching losses.
One ESN application produced greater yield and increased profit by $275/ acre over split application of ammonium sulfate and ammonium nitrate.
Chemical N inhibitor products produced lower yields, similar to an unfertilized control and were less profitable than the unfertilized control.
ESN reduced nitrate leaching to about 55% that of the AMS/AN split application. The next best treatment for leaching control reduced leaching by about 28% but reduced yields and profits.
Only ESN both increased yield and profits and reduced leaching.
