Willamette Valley

This trial is the fourth in a series of winter cauliflower variety trials dating from 1978. Previous trials have established that best quality is obtained with varieties that mature in April or May in average years. Very early varieties are less hardy, often fail to produce sufficiently large frames to support large heads, and may suffer frost damage to the curd. Several varieties maturing in late May and June have good yield potential but poor curd quality. This trial focused on mid-maturity varieties to determine those with the best combination of yield and quality.

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

Delbert Hemphill
OSU Dept of Horticulture, NWREC

Introduction

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

Delbert Hemphill
OSU Dept of Horticulture, NWREC

Mary Powelson
OSU Dept of Botany and Plant Pathology

Introduction

The objective of this project was to evaluate the effect of plant spacing and nitrogen rate on yield and disease incidence in broccoli.

Methods

Control of virus-vectoring insects, particularly aphids, is essential in production of potatoes for seed to exclude viruses such as potato virus Y, leaf roll, and net necrosis. Seed production fields are heavily treated with insecticides to prevent virus transmission, but control is often inadequate. Floating row covers may protect plants from attack by insect vectors, reducing the need for insecticides. Row covers might also increase yield through their effect on air and soil temperatures around the plants.

Crop protection with floating row covers interferes with tillage or other means of weed control. Therefore, herbicides or ground mulch are the likely means of weed control under covers. A successful weed control program depends on understanding the environmental and physiological interactions between the herbicide and other components of the cropping system. Results in 1983 with bunching onions (N. S. Mansour) indicated that paraquat residues on row covers might injure the subsequently emerging crop.

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

Delbert Hemphill and Bob Mcreynolds
OSU Dept of Horticulture, NWREC

Fertilizer trials with overwintered onions at the North Willamette Station indicated a strong yield increase with application of lime, an increase with gypsum (calcium sulfate), and higher yields with ammonium sulfate rather than other N sources. The yield response to gypsum and ammonium sulfate indicated that when soil pH, N, P, and K are optimal, S may be the limiting element in onion production.

Overwintered onions in the Willamette Valley are seeded in early September for harvest the following spring. Strong growth in the spring is essential for producing high value jumbo bulbs. However, air and soil temperatures in the spring are less than optimal, possibly limiting response to fertilizers.

Storage onions in western Oregon have been grown almost exclusively on lake bottom soils which are high in organic matter (more than 10%). Recently, production of onions on mineral or "upland" soils with low organic content and N availability has increased rapidly and now equals production on the organic soils. Response of onions to nitrogen rate and to applications of phosphorus and potassium on the mineral soils is not well understood.