Fresh Market Vegetable Production

Post-harvest Mineral Nitrogen Status in Grower Fields (1994)

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

Effect of Nitrogen Rate, Source, Placement, and Timing on Sweet Corn Yield and Nitrogen Uptake (1994)

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

Effect of Nutri-Phite P Foliar Fertilizer on Onions and Broccoli (1996)

Introduction

Phosphorus pollution of the Willamette River and its tributaries is a problem affecting agriculture in western Oregon. Many of our soils are high in available (soluble) P, as measured by the tests commonly used to determine plant-availability of P. Consequently, many streams have background levels of P that are conducive to algal blooms and poor water quality for fisheries and recreational use. Agriculture may also contribute to P pollution of streams through the use of large amounts of phosphate fertilizers and is under pressure to reduce P applications.