Search Results

You are looking at 1 - 10 of 19 items for

  • Author or Editor: H. J. Mack x
Clear All Modify Search
Author:

Abstract

Yield and size grades of table beets (Beta vulgaris L.) as affected by row spacings of 60, 45, 30, and 15 cm, fertilizer rates and harvest dates were determined in 4 field experiments. Total yields were significantly lower from 15 cm rows than from the conventional 60 cm row spacing. Highest yields of small roots, 25-51 mm diame-ter, were produced from narrow rows. Delaying harvest increased total and weighted yields. Fertilizer rates were varied in 3 experiments, and increasing the fertilizer rate increased total yields in 2 experiments. Concentration of N in leaves was decreased as row spacings were decreased in 2 experiments but P concentration in leaves was highest in 15 cm rows. Leaf concentration of N was highest at the highest fertilizer rate but K concentration was lowest. Concentrations of other elements in leaves were not consistently affected by row spacings or fertilizer rates.

Open Access
Author:

Abstract

There were no significant fertilizer x plant-density interactions affecting yields or leaf nutrient concentrations of snap beans (Phaseolus vulgaris L.) in 5 field experiments. Higher rates of fertilizer application produced significantly higher yields of pods than did lower rates in 2 experiments. At higher plant densities (15.2- to 30.5-cm rows, 43 to 65 plants/m2) yields were 20% to 38% higher than at lower plant densities (91.4-cm rows, 22 to 29 plants/m2). Average yield increase at higher densities was 29%. Crop economic values followed similar trends. At higher plant densities, average N, K, Ca, and Mg concentrations in leaves at early bloom were lower than at lower densities. Higher fertilizer rates tended to increase N concentration in leaves but had no consistent effects on P, K, Ca, and Mg.

Open Access
Author:

Abstract

Sweet corn yields increased 35 to 55% as plant population increased from about 4,900 to 21,000 plants per ha under irrigated conditions. Ear wt was 10 to 15% less at the higher populations. Greatest difference in yield usually occurred as row spacing was reduced from 90 to 30 cm. Row spacing affected yield less than population. Some of the highest yields were from 30 × 30 cm spacings in equilateral triangles. Triangular spacing as close as 20 × 20 cm (46,000 plants per ha) produced smaller ears, more culls and lower yields. There were no significant interactions of fertilizer rates and populations on yield; however, minimum fertilizer rates were as high or higher than most commercial applications. Yields of ‘Jubilee’ were more favorably affected by narrow row spacings and higher populations than ‘Golden Cross Bantam’.

Open Access
Author:

Abstract

Total root yields as well as roots <25 and 25-38 mm diameter, were increased in carrot (Daucus carota cv Red Cored Chantenay), as row spacings were decreased from 60 to 15 cm in 2 field experiments. Different within-row seeding rates did not have a significant impact on total yields, but affected yields of various size grades.

Open Access
Authors: and

Abstract

The percentage set of blossoms and number and weight of pods of bush snap beans, Phaseolus vulgaris L. were reduced when plants were subjected to high maximum temperatures during bloom. Yields were reduced 0 to 65% in greenhouse and field tests. Perforated plastic-covered cages in the field produced maximum temperatures of 83 to 101°F while maximum temperatures for checks averaged 74 to 89°. High temperatures decreased carbohydrates in leaves, starch more than sugars, when compared to checks.

Open Access

Abstract

Anatomical and morphological studies were made on ‘Gallatin 50’ and ‘Oregon 58’ bush snap beans. The first leaf primordium was observed 3 to 4 days after planting. Four or 5 leaf primordia were formed in spiral phyllotaxy with plastochrons lasting 1 day or less. The first floral primordium occurred in the axil of the uppermost leaf 7 to 9 days after planting. Floral parts became discernible 5 days later.

Open Access
Authors: and

Field experiments were conducted in 1986 through 1988 to evaluate the effects of rates and timing of ethephon application on growth, yield, and lodging of `Jubilee' sweet corn (Zea mays L.). As a comparison, hand-topping was performed 10 days after early silking to simulate the commercial practice of mechanical topping to reduce lodging. Ethephon reduced plant height by 12% to 26%, with timing of application determining location of internode length reductions. There was greater reduction of ear height by ethephon applied at tassel elongation (TE) than at 1 and 2 weeks later. Effects of ethephon on husked yield varied from an 8% increase in yield to an 18% decrease, depending on rate, timing, and season. Topping reduced yield in one of the four experiments. Ear length was reduced by ethephon at 0.28 kg·ha-1 in two of the four experiments. A helicopter fly-over resulted in 66% of topped plants lodging, compared to 87% of untreated plants. Lodging of plants that received an ethephon application of 0.28 kg·ha-1 at TE averaged 51% for Expts. 2, 3, and 4. The amount of lodging tended to be least in those ethephon treatments with the largest reduction `in plant or ear height. Chemical names used: 2-chloroethyl phosphonic acid (ethephon).

Free access
Authors: and

Abstract

Broccoli cultivars differed greatly in their tendency for premature heading and total loss from this factor and from culls. Per cent premature heads was increased by the use of large transplant sizes in the 9 cultivars studied; total loss was generally, but less, affected in the same way. Significant interactions were found between varieties and plant size in both premature heading and total loss. Transplanting date affected premature heading and total loss in one of the 2 years it was considered. Nitrogen levels, included in one experiment, did not cause significant effects.

Open Access

Abstract

Calcium (Ca) level of leaves sampled in mid- or late summer was closely related to peel Ca levels of mature apples (Malus pumila Mill. cv. Baldwin). Ca content of fruit was directly related to fruit yield of the tree, cycling with biennial bearing. In 1971 bitter pit incidence could be predicted from either leaf or peel Ca; internal breakdown and decay were less predictable. In 1972 leaf Ca and peel Ca averaged, respectively, 27 and 17% higher than in 1971, accompanying increased yield. Little bitter pit, internal breakdown, or decay occurred, even at Ca levels correlated with high incidence rates the previous year. We concluded that Ca must be only 1 among several factors regulating these occurrences.

Open Access

Abstract

Yields of snap bean pods were increased by irrigation and plant density in 4 field experiments. Highest yields were obtained with the −0.6 bar soil water potential regime which represented removal of 40-45 percent of the available soil water at 30 cm depth. Yields were lowest with the −2.5 bars soil water potential which represented 65-70 percent water removal. An average of 60 percent more water applied to the −0.6 bar than the −2.5 bars treatment increased yields approximately 54 percent. Yields were usually intermediate with the −1.0 bar soil water potential representing 50-55 percent available soil water removal. Two cultivars were used in 2 of the experiments and responded differently to irrigation. Yield of ‘Oregon 1604’ was higher than that of ‘Galamor’ with −0.6 bar soil water potential but was lower than ‘Galamor’ with −2.5 bars. Yield of ‘Oregon 1604’ averaged 27 percent higher in square arrangement than in 91 cm rows and the increase was greater for the high than for the low population density when compared in 1 experiment. Yield was 20 percent higher for high density of 43.0 plants/m2 than for low density of 21.5 plants/m2. Yields of 2 cultivars in 2 experiments averaged 67 percent higher in high density (40-57 plants/m2) than in low density (20-33 plants/m2) plantings. There were no consistent irrigation × density interactions. Usually there was a more rapid depletion of soil water for high density than for low density. Fiber in canned sieve size 5 pods was higher in ‘Oregon 1604’ at −2.5 bars soil water potential than for ‘Galamor’, but at the −0.6 bar soil water potential regime, the amount of fiber was similar in the 2 cultivars. Percent of pod weight attributed to seed and percent fiber were usually highest at −2.5 soil water potential.

Open Access