, saving water, labor, electricity, and fertilizer. Estimates of the required irrigation amount can be based on plant and environmental factors. Plant size affects water use because it affects plants’ transpirational surface area ( Ray and Sinclair, 1998
When determining whether landscaping is sustainable, we should consider environmental, financial and human factors. Environmental factors include: 1) the capacity of the landscape to damage or heal the system within which it is placed, 2) the environmental effects of the cultural techniques and products used in the installation and maintenance of that landscape, and 3) the ability of that landscape to endure without environmentally damaging inputs. Financial factors include: 1) the cost of the landscape compared to the economic return in terms of increased property values, 2) ability to attract and hold industry in a neighborhood, and 3) user fees paid by people attracted to an area by the landscaping. Human factors include: 1) the effects of the landscape on mood, employee retention, health and 2) activity of the individuals who interact with the environment. The ideal landscape would be sustainable in all three of these areas, meaning that there is more benefit than cost environmentally, financially and humanly.
When determining whether landscaping is sustainable, we should consider environmental, financial, and human factors. Environmental factors include the capacity of the landscape to damage or heal the system in which it is placed, the environmental effects of the cultural techniques and products used to install and maintain the landscape, and the ability of that landscape to endure without environmentally damaging inputs. Financial factors include the cost of the landscape compared to the economic return in terms of increased property values, the ability to attract and hold industry in the neighborhood, and user fees paid by people attracted to an area by the landscaping. Human factors include the effects on the landscape on mood, employee retention, and health and activity of the individuals who interact with the environment. The ideal landscape would be sustainable in all three of these areas, meaning there is more benefit than cost environmentally, financially, and humanly.
problem is observed more frequently in inland areas than in coastal ranches that have cooler, overcast weather, suggesting that environmental conditions are likely factors in the development of T3B. During periods of T3B occurrence, economic losses can be
Cracking of carrot (Daucus carota L.) roots during harvest and handling is a serious problem for the commercial industry, particularly for `cut and peeled' products. Thirty commercial fields of cv. `Sugar Snax' in California were surveyed over the period 2000-03. Soil texture was determined, and soil and crop nutrient status, air temperature and soil moisture were monitored. In 10 fields the effect of excessive N fertilization was investigated; 90-180 kg·ha-1 N was sidedressed in addition to the growers' N regime. At one site a comparison of 10 cultivars was conducted to determine the root cracking sensitivity of commercial cultivars suitable for the cut and peeled market. In all fields roots were hand harvested, with undamaged roots 18-24 mm in diameter selected for study. Roots were cooled to 5 °C and subjected to an impact test to rate cracking sensitivity. Fields varied widely in root cracking sensitivity, with 4% to76% of roots cracked in the impact test. Cracking sensitivity was positively correlated with the % silt and clay in soil, and with air temperature in the final month of growth. Irrigation management had no consistent effect on cracking sensitivity. N application in excess of the growers' N regime did not increase carrot yield, but increased root cracking sensitivity by an average of 30%. Root cracking varied among cultivars from 10% to 49%. However, when the periderm was peeled from roots before impact testing, incidence of cracking declined to 2% or less in all cultivars. Periderm strength or flexibility is apparently the dominant factor in carrot cracking sensitivity, and environmental and management variables that affect cracking sensitivity must do so by affecting the periderm structure.
Abstract
Low temperature is the most important environmental factor promoting flower initiation in Pelargonium domesticum Bailey, but 1 of 3 cultivars tested had little or no requirement for low temperature and flowered even when grown at greenhouse night temperatures of 21°C (70°F). High light flux can partially substitute for the low temperature requirement for flowering. At a constant temperature of 15.5°C, long days increased the total number of inflorescences and their rate of development as compared to short day control plants.
Abstract
A study was conducted to investigate environmental factors which affect leaf water potential (LWP) response of chrysanthemums (Chrysanthemum × morifolium Ramat). Meteorological parameters, including air temperature (TEMP), relative humidity (HUM), total solar radiation (RAD), and photosynthetically active radiation (PAR) were measured simultaneously as LWP determinations were made diurnally for plants grown with 5 different irrigation rates. Stepwise multiple regression analyses using the meteorological parameters as independent variables and LWP as the dependent variable showed that models developed for each irrigation rate included TEMP, HUM, and PAR as statistically significant (P = 5%) independent variables. Coefficients of determination (R2) for the models ranged from 0.83–0.87. A combined model, including irrigation rate (R) as an independent variable along with the meteorological parameters, revealed that TEMP, PAR, HUM, and R were statistically significant at P = 1% and had an R2 = 0.84. Results reveal environmental factors which must be considered in studies involving LWP measurements for chrysanthemums in order to avoid misinterpretation of data.
Seashore paspalum (Paspalum vaginatum O. Swartz) is a perennial warm-season grass that is rapidly gaining popularity for use on golf courses and athletic fields. The first seeded cultivar of seashore paspalum was recently developed. Seed from the pilot production of this cultivar harvested in Oregon during 2002 by Turf-Seeds, Inc. demonstrated a high level of apparent seed dormancy with a tetrazolium test of 91% but a germination rate of less than 5% at room temperature. This seed was used in laboratory experiments to determine the effect of a number of environmental factors on germination response in this new turf species. Treatment factors are germination media, constant and alternating (night/day) temperatures, and light. A strong and significant effect of temperature on germination was observed. Total germination was increased at higher temperatures. At the same daytime temperature, seed germination under alternating temperature was better than germination at constant temperature. The effect of light on germination was significant at 20, 25, 30, 20/35 °C in water and at 25/35 °C in 0.2% KNO3 germination media. However, the effect of light on germination in KNO3 media was not significant at 35 °C constant and 20/30 °C alternating temperatures. Alternating temperature used in conjunction with KNO3 media reduced the requirement for light. The use of 0.2% KNO3 rather than water as the germination media increased germination in most temperature and light treatments. Based on our results, maximum germination percentage was obtained when seed was germinated at 35 °C constant or 20/35 °C alternating temperature. However, when we consider field application, 25/35 °C with light is more realistic condition in field. Therefore, recommended seed germination test condition is at 25/35 °C with KNO3 treatment.
Abstract
The influence of environmental and morphological factors on chemical pinching of greenhouse azaleas with methyl esters of fatty acids (C6 - C12) was investigated. No air movement around the plants, following treatment, induced more bud necrosis than air movement; but the trends were not consistent within monthly treatments between cultivars or within a cultivar from month-to-month. Plants pre-conditioned at night/day (N/D) temp of 10/15.5°C from 1-7 days were found to have a greater response to the chemical pinching than when pre-conditioned at high temp at 26.6/32.2°C (N/D). The age of the terminal shoot influenced the response to the pinching agent. Plants with shoots 4 to 6 weeks of age were more sensitive to chemical pinching than those with 3,7, and 8 week shoots. Low relative humidity (RH 30%) and low temp (10/15.5°C, N/D) resulted in increased bud necrosis when compared with 60 and 90% RH at high temp (26.6/32.2°C, N/D).
Superficial scald development on apples is related to preharvest environmental conditions, perhaps through effects on endogenous antioxidant concentrations In 1989 we examined effects of maturity, light, and preharvest temperatures (< 10°C) on endogenous antioxidant levels in the fruit at harvest and on scald development after long-term storage in 0°C air. Cortland apple trees were sprayed with 500 ppm ethephon 1 month before normal harvest to create maturity differences. Fruit on other Cortland trees were bagged 1 month prior to harvest to reduce light interception. Samples also were harvested from other Cortland trees after exposures to different numbers of hours < 10°C, Hours < 10°C before harvest were negatively correlated to scald development. Ethephon treatment decreased scald incidence, and bagging increased it, The total lipid-soluble antioxidant activity increased with increasing hours < 10°C and with ethephon treatment, while bagging of fruit slightly decreased this antioxidant activity. To better understand the relationships between preharvest factors and antioxidant levels, individual antioxidants, including ascorbic acid, α tocopherol, anthocyanins and glutathione, are being analyzed.