Willamette Valley

Higher yields and improved root quality are essential for processing carrot growers to remain competitive. Nitrogen fertilizer applications range from 50 to 150 pounds N/acre with most between 50 and 80 pounds. More research is needed to clarify yield response to nitrogen, especially at higher rates, and the influence of N on such root characteristics as diameter, length, splitting, and rots. The response to N should be investigated at plant densities typically used for slicing and dicing.

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.

Overwintered cauliflower trials at the North Willamette Station and by growers have usually given acceptable yields and quality. However, yields of early varieties, and particularly in cold springs, have occasionally been disappointing. Since plant nutrient uptake is limited on cold soils, these low yields may have been caused by inadequate availability of P or other elements.

Trials to evaluate the heat tolerance of cauliflower have been conducted at the North Willamette Station for several years. These trials were transplanted in late May for July harvest. The 1985 trial differed in that the varieties were transplanted in early July for late summer to early autumn harvest. As with the earlier trials, the major desired quality is the ability to withstand high temperatures without ricing or discoloration while producing a high density, moderately sized head.

Methods

The purpose of this trial was to evaluate lines of cabbage for late spring or early summer harvest. This requires planting out in early spring and many varieties will bolt under these conditions. Direct seeding is often impossible in early spring and emergence would be slow and erratic. Thus, the lines were seeded in an unheated glasshouse for later transplant. This is the second in a series of early cabbage trials.

Methods

Extremely high quality leeks are being produced on a small scale in the Willamette Valley with good yields. The crop is usually seeded in early spring, matures in autumn, and can be held through the winter for harvest the following spring. Very few varieties are grown commercially and the highest quality plants have been transplanted and grown in trench culture. The most lucrative market is the restaurant trade, which demands long, thick, blanched stems. Healthy foliage can also be used decoratively in presentation of restaurant dishes.

Introduction

Black plastic ground mulch and row covers have enhanced the growth and yield of many crops. Lily bulb production in the Pacific Northwest takes place on bare ground. The objective of this research was to study the effects of a ground mulch and a hoop-supported row cover (tunnel), as well as flower bud removal and cut flower harvest, on bulb growth and bulblet production of Asiatic lily.

Methods

Introduction

Overwintered vegetables, seeded in late summer or early autumn for harvest the following spring, are important new alternative crops in the Willamette Valley. These crops offer a source of cash flow in the spring, present the opportunity for three crops in two years, and may be less expensive to grow because of reduced needs for insecticides and irrigation. Cauliflower, onions, and spinach have shown the most promise as overwintered crops.

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

Delbert Hemphill
OSU Dept of Horticulture, NWREC

Introduction