No abstract

Table beet (Beta vulgaris L.) seeds are characteristically slow germinating, and have a large time spread of germination. These characteristics interfere with the early establishment of a uniform, vigorous stand of seedlings in cold wet soil. This study was undertaken to determine if osmoconditioning (OC) of table beet seeds in polyethylene glycol 6000 (PEG) and MgSO4 solutions and/or other measures would improve germination and/or reduce germination time and thereby improve emergence, seedling establishment and yield. Seed balls of ‘Ruby Queen’ and ‘Cardenal’ were osmoconditioned in −1.2 and −1.18 MPa solutions of PEG and MgSO4, respectively. Treatments were performed at 15 °C for 7 days in the light. The benefits of OC were not lost by drying back the seeds. Aeration during OC followed by a 2 min rinse with water was the most effective treatment in improving germination or emergence in laboratory and growth chamber studies. In the 1980 field trial, OC in PEG improved the rate of emergence by 2 to 3 days, the stand by 40% and the root, top, and total yield by 40, 66, and 59%, respectively. In 1982, seedling emergence was biphasic. The first phase lasted 23 days and showed large differences in rate of emergence and stand between osmotically treated and untreated seeds and resembled the 1980 emergence pattern. The second phase commenced after a 30 mm rain with a resurgence of emergence in all treatments. The resurgence rate was highest in untreated seeds and this reduced the treatment differences in stand and yield. The resurgence was attributed to invigoration of the non‐germinated seed by low soil water potential (drought). Several MgSO4‐OC treatments increased the number of roots but decreased root size.

The nitrate concentrations in spinach (Spinacia oleracea L.) blades and petioles were determined for different sources and times of application of N fertilizers to a Honeoye fine sandy loam and a Lima silt loam to determine the effect of N fertilization on the concentration of nitrates in the plant parts used for consumption for food. Nitrate concentrations were determined potentiometrically, using a nitrate‐selective ion electrode, on plant samples taken at time intervals after N fertilization and at harvest stage for processing. Nitrogen fertilization substantially increased the NO3 concentrations of spinach grown in upland soils. The following observations were significant: (a) More NO3 accumulated in leaves of plants broadcast with N fertilizers before planting than if an equivalent amount of N fertilizer was supplied by sidedressing one week before harvest. (b) The N carrier was a significant factor in governing NO3 accumulation when it was applied as sidedressing.

Nitrogen fertilization may affect the yield components and quality attributes of vegetables grown for processing. The objective of this study was to determine the effects of N fertilization systems on cabbage (Brassica oleracea L. Capitata group) grown for kraut. The concentrations and contents of nitrate‐N and total N in the plants were used to determine the availability of N and uptake of N from the soil and/or fertilizer N during the growing season. Urea broadcast at 15 g N/m2 and worked into the soil preplant was compared to ammonium nitrate applied at a rate of 15 g N/m2 split into three 5 g N/m2 applications (banded at planting time plus sidedressed early plus sidedressed midseason) as fertilization systems for cabbage grown under field conditions in 1978 and 1979. The soil was a Lima silt loam (Glossoboric Hapludalf, fine loamy, mixed mesic), a productive soil derived from calcareous glacial till. Plants were spaced 4/m2. Tops of four plants grown without fertilizer N contained 12 g N/m2 at harvest. Fertilizer N applied at 15 g N/m2 increased the total N in the plant tops to 22 g N/m2. This was an increase in plant N equivalent to two‐thirds of the rate of fertilizer N applied. Cabbage plants grown without fertilizer N yielded 4 kg fresh weight/m2. Fertilizer N at 15 g N/m2, either as urea or ammonium nitrate, yielded 8 kg of heads/m2. Fertilizer N at 30 g/m2 from urea plus ammonium nitrate yielded 10 kg heads/m2. Plants grown with fertilizer N had a lower percentage of dry weight in the heads, and had higher percentages of burst heads and heads with tipburn than heads of plants grown without fertilizer N. Thus, fertilizer N increased the yield but decreased the quality of cabbage heads grown for kraut.

Cold soil interferes with early establishment of uniform, vigorous seedlings in vegetables and other crops. The aim of this work was to determine if the changes induced in carrot (Daucus carota L.) seeds during partial hydration by low osmotic potential polyethylene glycol 6000 (PEG) solution would allow early planting in cold soil and thereby improve germination, growth, and yield. Seeds of two carrot cultivars, ‘Nantes’ and ‘Perfekcja’, were treated in —8.6 bars PEG solution for 6 days at 15 C. The effects of the seed treatment were evaluated by germinating the seeds on filter paper at 10 C, in Cornell Soil Mix (peat‐lite Mix A) in a growth chamber at an alternating temperature regime of 5 and 10 C and in the field (Glossoboric Hapludalf, fine loamy, mixed mesic soil) where the average soil temperature during the first 2 weeks after field planting was 10.5 C and during the first 5 weeks 12.6 C. Seed osmoconditioning improved the emergence time, stand size, and uniformity of stand in the field and increased the total yield. The increase in fresh weight of roots in Nantes and Perfekcja from PEG treated seeds were 32 and 93% and in number of roots 37 and 100%, respectively, compared to the untreated seeds