Search Results
Abstract
Broccoli (Brassica olerica L. var. italica) and corn (Zea mays L.) N-treated adjacent plots had essentially the same initial Ν content. Extractable inorganic Ν to a depth of 60 cm (N at 28 to 48 kg·ha-1) was considerably less than the Ν taken up into the total above-ground parts of the crop (N at 118 to 157 kg·ha-1); thus, both crops depended on mineralization of soil Ν for their growth. Although broccoli and corn had the same total demand for Ν as shown by total uptake, only broccoli responded to Ν application. Since corn required Ν over a longer period of time (116 days) than broccoli (90 days), the net mineralization rate of soil Ν [0.8 to 1.0 kg·ha-1 (per day)] matched approximately the average Ν uptake rate over the whole season [1.1 to 1.2 kg·ha-1 (per day)] in the corn trial. Net Ν mineralization rate [-0.1 to 1.4 kg·ha-1 (per day)] tended to be less than the average Ν uptake rate by broccoli (1.3 to 3.1 kg·ha-1 (per day)], resulting in the response to Ν applied. Slightly more downward movement of inorganic Ν occurred in the 1982 than in the 1979 broccoli trial. This coincided with slightly higher precipitation in 1982 particularly late in the growing season. By using path coefficient analyses, it was found that several plant variables were consistently correlated with horticultural yield, but the nature of the relationship was not consistent from year to year, suggesting that slightly different mechanisms contributed to the yield effect each year but that the net result was similar.
Abstract
A single harvest method using horticultural maturity rating data was tested in 2 years of Ν application field trials with broccoli. Using analysis of variance with the maturity data as covariates, it was possible to evaluate how broccoli yield response to Ν was influenced through the effect of Ν on maturity. This single harvest method simplified field operations and facilitated interpretation of Ν uptake data. Nitrogen treatments did not significantly alter maturity of broccoli in either year. Broccoli yield increased with up to 250 kg·ha–1 of Ν in both years. Sweet corn, which was grown adjacent to the broccoli in the first year, did not respond to similar applications. Nitrogen did not preferentially increase vegetative growth of broccoli, but in one year increased head yield. Nitrogen accumulated in the head of broccoli. The corn crop accumulated extra Ν in the vegetation and this was assumed to be luxury uptake. The difference in response to Ν of corn and broccoli was assumed to be the result of a difference in Ν use or uptake efficiency rather than overall demand, since the total above-ground uptake by corn and broccoli was quite similar.
Abstract
The nectars of several apple (Malus domestica Borkh.), apricot (Prunus armeniaca L.), crab apple (M. baccata L. and M. floribunda Seib.), peach (Prunus persica L.), pear (Pyrus malus L.), and sweet cherry (Prunus avium L.) cultivars were analyzed for sugar contents. ‘Skaha’ apricot was significantly higher in fructose, glucose, and sucrose than ‘Wenatchee Moorpark’ or ‘Tilton’. ‘Lambert’ sweet cherry was significantly higher in these sugars than ‘Van’ or ‘Stella’. Sugar levels were higher in ‘Bartlett’ and ‘Spartlett’ than ‘Anjou’. ‘McIntosh’ and ‘Red Delicious’ nectars were higher in the individual sugars than ‘Golden Delicious’. An appreciable range of values was found among the crab apples but the sugar content in some were comparable to those of apple.
Abstract
Newly opened flowers of 4 parthenocarpic tomato (Lycopersicon esculentum Mill.) genotypes, PSET-1 (pat-2), ‘Severianin (pat-2), RP 75/59, and Stock 2524 (pat), and 3 nonparthenocarpic genotypes, ‘Walter’, ‘Flora-Dade’, and ‘Homestead 24’, were excised and placed on nutrient media. The ovaries of the parthenocarpic genotypes increased in diameter and weight to a much greater extent than the ovaries of the nonparthenocarpic genotypes during a 6-day period at 25°C. In other comparisons, the parthenocarpic genotypes had larger ovaries than the nonparthenocarpic genotypes after 2, 4, 6, 12, 18, and 24 days. The ovaries of buds excised 1 and 3 days before anthesis and at anthesis from PSET-1 and ‘Severianin’ were larger after 6 days than those excised from ‘Walter’ and ‘Flora-Dade’.
Greenhouse-grown `Bison' and `Doria' peppers (Capsicum annuum L.) were harvested when mature green (MG) (>95% surface green) or ripe (>95% of surface red or yellow). Both cultivars responded similarly to temperature and neither exhibited chilling injury (CI), as indicated by surface pitting, after storage at 13C for 1 or 2 weeks. Ripe peppers showed no CI when held at 1C for 1 or 2 weeks, while MG peppers exhibited CI after these treatments. Exposing MG peppers to 1C for 3 days caused CI and stimulated C2H4 (12.3x) and CO2 production (2.5x). In contrast, a similar exposure of ripe peppers did not cause CI but stimulated C2H4 (6.5x) and CO2 production (1.4x). It seems that CO2 and C2H4 production was stimulated by exposure to 1C, not necessarily by CI development. Our data question the physiological significance of elevated CO2 and C2H4 production in CI development. The observed tolerance of ripe peppers to 1C suggests that ripe greenhouse-grown peppers can be stored at temperatures lower than those currently recommended for bell peppers.
A video-imaging technique, using commercial software to process images obtained at 550 nm, was established to estimate chlorophyll content of cucumber fruit disks. The chlorophyll content of excised disks was extracted, determined, and regressed on the video-image grey level. They were linearly related. The change in grey level of the whole visible image accurately indicated the change of green color during fruit development on the vine and the loss of green color after 1 week of storage at 13C. The relationship of the chlorophyll content on grey level was quadratic for three imaging methods: 1) average grey level of the five disks; 2) average grey level of the whole cucumber image; and 3) average grey level of central one-third of the whole cucumber image. Chlorophyll content was most highly correlated to the grey level of the disks themselves (residual SD = 6.74 μg·cm-2), but this sampling technique was destructive. Both one-third of the fruit image (SD = 9.25 μg·cm-2) and the whole image (SD = 9.36 μg·cm-2) provided satisfactory precision. For simplicity, whole-fruit imaging is suitable for estimating fruit chlorophyll content and for quantifying fruit green color intensity. Potential use of this technique in product sorting and shelf life prediction of long English cucumbers is discussed.
Abstract
Results from a 4-year study indicate that flesh browning in CA-stored ‘Delicious’ apples (Malus domestica Borkh.) is a low-temperature disorder. Little or no flesh browning occurred at storage temperatures of 2°C or higher. Prestorage treatments which reduced flesh browning were dips in calcium and diphenylamine solutions, delays at 20° prior to storage, and exposure to 38°. Gibberellic acid dips had no effect on the disorder. Less flesh browning was found in a 1% CO2 than in a 1.7% CO2 atmosphere at −0.5°, but little effect was observed from CO2 concentration at a 2° storage temperature. The disorder was more prevalent with advanced maturity of the fruit. Regression analysis of variables evaluated at or before harvest showed that increased fruit size, and to a lesser extent the presence of watercore, were important factors in development of flesh browning.
Compared with more traditional sectors of U.S. agriculture, little economic information is available on the turfgrass industry, of which golf courses are an integral part. As a result, over the past 30 years individual states have conducted over 60 individual studies that describe in detail the economic importance of their industry. To date, no such information exists at the national level primarily due to the high cost of collecting primary data. To ameliorate this situation, the authors used secondary data from various sources and developed a composite of the turfgrass industry for the entire United States. This report focuses on the golf course industry in particular. Golf represents a very high value amenity use of horticultural products and services, is a major form of development, and uses large amounts of land and water. Results indicate the golf sector is the largest component of the turfgrass industry, accounting for a 44% share. The nearly 16,000 golf courses generated $33.2 billion (B) in (gross) output impacts, contributed $20.6 B in value added or net income, and generated 483,649 jobs nationwide. Economic impacts were also examined for each state, with “top 10” states highlighted. States falling in the top 10 category varied somewhat depending on the variables being examined. The exception were the top four states—Florida, California, Texas, and Illinois—that remained in the top four irrespective of variable type. In general, the top 10 states accounted for 55% to 60% of economic impacts for the entire United States while the top four alone contributed 40% of the total.
The United States environmental horticulture industry, also known as the Green Industry, is comprised of wholesale nursery and sod growers; landscape architects, designers/builders, contractors, and maintenance firms; retail garden centers, home centers, and mass merchandisers with lawn and garden departments; and marketing intermediaries such as brokers and horticultural distribution centers (re-wholesalers). Environmental horticulture is one of the fastest growing segments of the nation's agricultural economy. In spite of the magnitude and recent growth in the Green Industry, there is surprisingly little information regarding its economic impact. Thus, the objective of this study was to estimate the economic impacts of the Green Industry at the national level. Economic impacts for the U.S. Green Industry in 2002 were estimated at $147.8 billion in output, 1,964,339 jobs, $95.1 billion in value added, $64.3 billion in labor income, and $6.9 billion in indirect business taxes, with these values expressed in 2004 dollars. In addition, this study evaluated the value and role of urban forest trees (woody ornamental trees); the total output of tree production and care services was valued at $14.55 billion, which translated into $21.02 billion in total output impacts, 259,224 jobs, and $14.12 billion in value added.
Various stem-training systems were applied to greenhouse-grown `Mustang' cucumber (Cucumis sativus L.) plants at two production stages. Training systems determined the number of stems per plant, orientation of laterals, and leaf: fruit ratio. Training systems permitting high canopy light penetration resulted in darker fruit and a longer shelf life. Shelf life was positively related to rapid fruit growth in Expt. 1 but not in Expt. 2. Training systems to achieve a long shelf life of greenhouse-grown long English cucumber are described.