No abstract

The yield-plant density relationships of 5 bush snap bean cultivars and the effect of rate of N application on the yield-density relationship of a single cultivar were studied in 2 separate experiments. Responses were described by the equation W-θ = α + βρ where W is the pod weight per plant, ρ is the plant population density, and θ, α and β are constants. The θ, α and β values were tested for significant differences among the cultivars and levels of N. In experiment 1, θ = 0.836 was acceptable for all 5 cultivars and in experiment 2, θ = 0.897 was acceptable for the 3 rates of N. Values of θ were similar to those found for bush snap beans by other researchers. Significant differences existed among both α and β values of the cultivars. In the N experiment, α was constant but values of β differed significantly and were inversely related to the level of N. Optimum plant density was dependent on the cultivar and increased with the level of N.

Experiments were conducted to evaluate the effect of dolomitic lime rate and application method on substrate pH, creeping woodsorrel (Oxalis corniculata) establishment in containers, and growth of azalea (Rhododendron ‘Rosebud’) and pieris (Pieris japonica ‘Claventine’). In Experiments 1 and 2, pulverized dolomitic limestone was incorporated at 0, 6, 12, 24, or 47 kg/m3 (0, 10, 20, 40, or 80 lbs/yd3). Containers were overseeded with twenty seeds of creeping woodsorrel. Substrate pH was measured with a pour-through technique. Substrate pH increased linearly and quadratically with increasing lime rate. Creeping woodsorrel shoot fresh weight was negatively correlated to substrate pH (r = −0.67, p = 0.0001). Creeping woodsorrel germinated and established poorly in substrates with pH higher than 6.7, with commercially acceptable control (>90%) occurring in containers with pH higher than 8.4 and 7.5 in Experiments 1 and 2, respectively. In Experiments 3 and 4, containers were topdressed with a uniform layer of pulverized or pelletized dolomitic limestone at 0, 5, 10, 20, or 40 g (0, 0.18, 0.35, 0.71 or 1.14 oz) per container. Substrate pH was measured in 2.5 cm (1 in) layers from the top to the bottom of the container using a modified saturated media extraction procedure. At each lime rate, pH was higher on the substrate surface than lower layers when topdressed with pulverized compared to pelletized lime. Across all lime types and rates, pH was lower in the 2.5 to 5.1 cm (1 to 2 in) layer compared to the surface layer which indicates that the most significant pH effect occurs on the surface. Topdressing containers with 40 g (1.41 oz.) of pulverized lime provided acceptable creeping woodsorrel control (>90%). In Experiment 5, incorporating the same lime rates used in Experiments 3 and 4 caused chlorosis and in some cases growth reduction in azalea and pieris while topdressed lime caused no change in growth or foliar color by 125 days after potting.

Reception of photoperiodic stimuli and control of flowering of ‘Oregon 2065’ bush bean (Phaseolus vulgaris L.) by the primary and first trifoliate leaves was studied. One or both of these leaves were given short days (9 hr, SD) or long days (9 hr + 7 hr photoperiod extension, LD). All other leaves were removed. Plants flowered if either primary or trifoliate leaves received SD. The SD or LD treatment to a particular leaf had its greatest effect on flowering at the node of that leaf. Inflorescences with flower buds larger than 2.5 mm developed at primary and at first trifoliate nodes if either set of leaves received SD, but, if one received LD, bud abscission occurred before anthesis at the node of the LD leaf.