Forecasting of N fertilizer requirements for sweet potatoes

Forecasting of N fertilizer requirements for sweet potatoes

1985

A:PS

Nitrogen treatments (0-134 kg N/ha) were applied on a sandy boam over 11 growing seasons to establish critical soil and tissue N levels, and to evaluate the effects of seasonal precipitation on annual variability in response of `Painter` and `Centennial` sweet potatoes [Ipomoea batatas (L.) Lam.] to applied N. Critical concentrations of soil NO3-N at 29 days after transplanting (DAT) and laminal N at 72 DAT were detrmined to be 37 ug N/g soil and 5% (dry weight), respectively. Correlation between soil NO3-N at 29 DAT and leaf N at 72 DAT was highly significant. Multiple regression analyses predicted a quadratic relationship between root yield and applied N and predicted a yield maximum at 88 kg N/ha. Inclusion of annual precipitation during the fallow season (1 Oct.-31 May) in the N model significantly improved the prediction of response to applied N. Fallow season precipitation provided an index of N carry-over in sandy loam soils and could be used to improve estimates of N fertilizer requirements for sweet potatoes. [AS]

v.110(3):358-361, AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE, JOURNAL

Research > Published Articles