Nutrient Losses in Runoff from Conventional and No‐Till Corn Watersheds

Abstract

Abstract A study was initiated to determine the quantity of nutrients and sediment in runoff from conventional and no‐till corn ( Zea mays L.) watersheds. Runoff was collected with H‐type flumes and Coshocton wheels. Parameters measured in runoff included NH 4 + ‐N, NO 3 − ‐N, total N, ortho‐PO 4 , total soluble P, total P, suspended sediment, and soluble solids. There was a significant difference in total runoff between the conventional and no‐till watersheds. Over nine times more runoff originated from the conventional‐till watershed when compared with the no‐till watershed in 1982. A large difference between the two watersheds in suspended sediment content was also observed. Yearly sediment losses of 370 and 9 kg ha −1 from the conventional and no‐till watersheds, respectively, were found for 1982. There was also a significant difference in the loss of soluble solids between the two watersheds. For 1982, there was over a 29‐fold greater loss of soluble solids from the conventional‐till watershed than from the no‐till watershed. Losses of NH 4 + ‐N, NO 3 − ‐N, and total N from each watershed were very low, although large differences were observed between the two watersheds. In 1980, 271, 638, and 1199 g ha −1 of NH 4 + ‐N, NO 3 − ‐N, and total N, respectively, were lost from the conventional‐till watershed, while 2, 47, and 87 g ha −1 , respectively, of the above parameters were lost from the no‐till watershed. The loss of all forms of P from each watershed was also very small. During 1982, 161 g ha −1 of total P were lost from the conventional‐till watershed while only 8 g ha −1 were lost from the no‐till watershed. The loss of ortho‐PO 4 and total soluble P was not significantly different between the two tillage treatments.