Corn

Experiments at the North Willamette Experiment Station in 1979 and 1980 indicated that, for N applied as ammonium nitrate at 160 pounds N/acre, sweet corn yields were increased by delaying application of most of the N until the corn was 10 to 12 inches tall. These experiments were at fairly high levels of early season irrigation, and the lower yields when all N was applied at planting may have been caused by leaching of nitrate-N out of the root zone. In a trial in 1984, however, splitting the N application did not increase yield with ammonium nitrate as N source.

Energy input comparisons between tillage systems; evaluation of the value of legumes as part of a cover crop mixture used in strip-till sweet corn production; evaluation of the nitrogen contribution of legume-based cover crops to organic vegetable production.

Introduction

Introduction

The rationale for this trial was similar to that of the previously described broccoli and sweet corn experiments. Sweet corn is planted at smaller populations and wider row spacings than is broccoli and may be less effective at taking up applied N. The purpose of this trial was to determine if yield of sweet corn would be affected by placement or source of N fertilizer at several rates of applied N.

Methods

Research report from OSU's North Willamette Agricultural Research and Extension Center

Delbert Hemphill
OSU Dept of Horticulture, NWREC

Introduction

Introduction

Introduction

This grower trial was undertaken to determine whether residual nitrate and ammonium levels in grower fields were similar to those found in our experiments at NWREC. The data should be useful in indicating which of the major processed vegetable crops leave significant quantities of residual mineral N in the soil at harvest and the extent to which grower cultural practices, particularly fertilizer application, influence the amount of residual N that is available for leaching by heavy winter rainfall.

Methods

Introduction

The justification for this trial is similar to that for cauliflower, reported earlier. A sweet corn trial in 1992 indicated that source and placement of nitrogen fertilizer had little effect on yield or quality of sweet corn. Rates of nitrogen application greater than 60 pounds per acre resulted in accumulation of significant amounts of nitrate-N in the soil. The purpose of these trials was to confirm 1992 results and to determine if yield of sweet corn would be affected by source or timing of application of nitrogen fertilizer.

Methods

Introduction

Introduction