HortBase, a global electronic information system to support horticultural decisions in classroom, distance education, lifelong learning, and Extension, incorporates three innovative concepts: 1) Three-dimensional team creation of individual electronic information files (subject, communications, and information science authors collaborating from start to finish to create the file). Team-creation respects, utilizes, and develops professional strengths and resources of each team member. 2) Nationwide, or even worldwide, distribution of the workload and costs of creation, review, revision, and distribution of the individual electronic information files rather than redundant individual efforts and expenditures, enables us to do more as a group and to specialize individually. 3) National peer review by each file creator's professional society (ASHS, ACE, and ASIS respectively) enhances information quality, continued professional development of the authors, and wider acceptance and use of the information. Capabilities of electronic information systems facilitate, indeed require, this new approach to information development and delivery. For additional information, http://forages.css.orst.edu/HortBase/.
J. L. Green and A. K. Green
M.S. Albahou and J.L. Green
Incidence of blossom-end rot (BER) of tomato is known to increase with increasing salinity in hydroponics and field tomato crops due to osmotic stress and imbalanced ionic ratio in the media solution. The present investigation evaluated salinity effects on the occurrence of BER of tomato in a completely closed root environment known as the closed insulated pallet system (CIPS). The CIPS is a continuous sub-irrigation capillary system with water moving from reservoir to rootzone in response to plant uptake and loss through transpiration and growth. In CIPS, fertilizer reserve is placed at the top surface of the root matrix, so fertilizer ions move downward by diffusion. Various tomato genotypes were seeded directly into CIPS in Spring. The experiment was terminated at a 100-day growing period. The incidence of BER was calculated as percent affected fruits. Salinity treatments consisted of five concentrations ranging from 0 to 10 g/L NaCl. One salinity treatment was 1 g/L CaCl2. In CIPS, the salt gradient created by uptake of saline water had lowest concentration at the top of root compartment where fertilizer was placed. Therefore, there was minimal ionic interactions between fertilizer ions and ions from the saline water. The uptake of water and plant growth decreased with increasing salinity concentration. The addition of Ca in the sub-irrigation water had no effect on the occurrence of BER. The incidence of BER correlated negatively with salinity level and plant growth in the CIPS.
M.S. Albahou and J.L. Green
The use of the halophyte Suaeda salsa as a salt absorber in saline soils has been exploited as an attempt to increase crop productivity in marginal saline soils. The shoot and root salt contents of this halophyte has been documented to reach up to 27% and 12% of dry weights. The sodium salinity stress of the growth media [peat:vermiculite (1:1 by volume)] may be alleviated by planting the Suaeda with tomato plant in the same root pouch of a completely closed root environment, referred to as the closed insulated pallet system (CIPS). The CIPS is a continuous sub-irrigation capillary system with water moving from reservoir to rootzone in response to plant uptake. In CIPS, fertilizer reserve is placed at the top surface of the root matrix, so fertilizer ions move downward by diffusion. The objective of the present research was to utilize the Suaeda salsa as a bio-desalinator, so salinity of the growth media is reduced, thus reducing the salt uptake by the tomato cv. `Pik Red'. Two salinity levels (control and 4 g/L NaCl in the sub-irrigation water) were imposed on tomato plants or tomato grown with Suaeda in the same pouch. Sodium contents were reduced 56.4% and 37.1% in the growth media and tomato foliage, respectively, in the presence of the halophyte during a 110-day growing period. Likewise, the electrical conductivity of the growth media was reduced by 31.1% with Suaeda companionship. The Suaeda had accumulated salts up to 4.1 mg/g dry weight tissues. The results seem promising; however, growth and yield of tomato plants grown with the halophyte were significantly decreased, probably due to competition for nitrogen and/or light. Research is underway for development of the CIPS to better accomodate crop companionship.
M.S. Albahou and J.L. Green
It has been shown that container medium volume affects plant growth and development in conventional production methods. The objective of this study was to investigate the effect of media volume on the growth and yield of the determinate tomato genotype `Pik Red' in the closed, insulated pallet system (CIPS). The CIPS contains media pouches with wicks extended down into a water reservoir. Three root media volumes were investigated: 3, 6, and 9 L (3L, 6L, and 9L). The root media were placed in pouches that varied in diameter but had constant depth. The surface area of the wicks in contact with the bottom of all pouch sizes remained constant at 110 cm2. It was hypothesized that increasing the volume of root media would allow sufficient water replenishment during the dark period to meet the plant's need the next day, and thus allow greater growth and fruit yield. Daily water uptake for each individual plant was measured by the principle of atmospheric pressure and water replacement technique. Media volume had no significant effect on water uptake during early stage of plant growth. After 45 days after planting (DAP), water uptake and plant growth were less in 3L media volume. Water uptake was similar in the 6L and 9L treatments between 45–60 DAP. Total water uptake from day 60 to 125 was greatest in the 9L, intermediate for 6L, and least in the 3L treatments. The water uptake from 1–60 DAP was reflected in the fresh shoot weight, and the water uptake was reflected in the fruit weight. Average fruit sizes and the total fruit weights for the 3L were 67.7% and 60.4% those of the 9L treatment, respectively. The 6L treatment fruit yield and fruit size were intermediate between the 3L and 9L.
M.S. Albahou and J.L. Green
When using the closed, insulated pallet system (CIPS), it is desired to apply the fertilizers once at the beginning of planting and last through harvest. When doing so, the electrical conductivity (EC) of the root environment needs to be at a reasonable level. Therefore, the objective of this experiment was to determine the effect of fertilizer conserver placement and increasing rate on the EC of the growth media. When delivering nutrients in such a manner, the fertilizer ions have limited surface area in contact with the root growth media that limits ion diffusion rate. Five fertilization rates, 15, 45, 60, 75, and 105 g per 1.5-L media pouch, were tested in a completely randomized arrangement. In each pouch, two fertilizer conservers were placed in the center of the lower half of media, each containing a different source of fertilizer. Tomato cv. `Pik Red' was used to test the growth response to treatment. At day 100, the ECs of the middle 5 cm stratum of the growth media for the 15–75 g treatments were not significantly different from each other. Their ECs ranged from 2.52 to 4.51 dS/m. However, middle layer in the 105g treatment was 12.97 dS/m, while EC for the layer immediately below it was 1.18 dS/m. Because there were no differences in shoot and fruit weights among all fertilization treatments, compensation nutrient uptake and water uptake specialization may have occurred in the high salinity and lower salinity, respectively. The data illustrate that delivery of nutrients in small conservers is a feasible approach for the CIPS. Only small amounts of fertilizer are required for a 100-day tomato crop grown in CIPS.
Grant J. Klein and Robert L. Green
Turfgrass management best management practices (BMPs) encompass a wide variety of activities, including fertilization, irrigation, mowing, pest control, and soil management. Little attention is given to determining just how effective information regarding BMPs is being assimilated and used by professional turfgrass managers. The objectives of this study were to assess the current perception and implementation of selected turfgrass BMPs and to determine whether or not those perceptions and implementations differed 1) between turfgrass advisors and managers and 2) between general and sports turfgrass managers. Professionals from the turfgrass industry, with an average of 13 years of experience and largely comprised of decision-makers (88%), were surveyed at the University of California, Riverside, Turfgrass Research Conference and Field Day in Fall 1998 and 1999. Turfgrass managers, especially sports turfgrass managers, were found to be the most committed to implementing the BMPs in the survey. Overall, survey respondents considered BMPs to be important and not highly difficult to implement. Limitations to the adoption of BMPs were a lack of financial backing, employee education, and necessary time—all of which could be remedied with a sufficient commitment of resources by the turfgrass industry.
J. L. Green, J. Matylonek, A. Duncan, and E. Liss
HortBase, a global electronic information system for classroom, distance education, lifelong learning and Extension, incorporates three innovative concepts: 1) Three-dimensional team-creation of the electronic information files (subject, communications, and information science authors working together from start to finish to create the file). Team-creation respects, uses, and develops the professional strengths of each of the three team members. 2) National peer review by each file creator's professional society (ASHS, ACE, and ASIS, respectively) not only enhances information quality and continued professional development of the authors, but also creates wider acceptance and use of the information. 3) Nationwide, or even worldwide, distribution of the workload and costs of creation, review, revision, and distribution of the electronic information, rather than individual efforts-expenditures within each state, will minimize redundancy and will enable us to do more as a group and to specialize individually. Capabilities of electronic information systems facilitate, indeed require, this new approach to information development and delivery.
R.L. Green, J.B. Beard, and M.J. Oprisko
Root hairs contributed variously to total root length, ranging from a low of 1% for `Emerald' zoysiagrass (Zoysia japonica Steud. x Z. tenuifolia Willd. ex Trin) and 5% for `Georgia Common' centipedegrass [Eremochloa ophiuroides (Munro.) Hack], to a high of 95% and 89% for `Texturf 10' and `FB 119' bermudagrasses [Cynodon dactylon (L.) Pers.], respectively. Genotypes ranking highest for root lengths with root hairs also ranked highest for root lengths without root hairs and for number of main roots per plant. In terms of root lengths with root hairs, first-order lateral roots contributed more to total root length than root lengths of either main roots or second-order lateral roots for all nine genotypes. Number and length of root hairs arising from either main or lateral roots were not significantly affected by their relative distance from the cap of the main root. `Texturf 10' and `FB 119' bermudagrasses ranked highest for root and root-hair extent.
R.L. Green, J.B. Beard, and D.M. Casnoff
The objectives of this investigation were to determine the stomatal frequencies of 12 perennial cool-season turfgrasses, encompassing nine species, and their associated evapotranspiration (ET) rates under nonlimiting soil moisture and controlled environmental conditions. Significant differences in stomatal density were found among the 12 cool-season turfgrasses on both the abaxial (P > F = 0.0008) and adaxial (P > F = 0.0009) leaf surfaces. Significant differences (P > F = 0.0007) in ET rates also were found among the 12 cool-season turfgrasses. The Kentucky bluegrass (Pea pratensis L.) cultivars exhibited the highest ET rates, while the fine-leafed fescues (Festuca rubra and longifolia L.) exhibited the lowest rates, except for `Big Horn' sheep fescue (Festuca ovina L.), which exhibited an intermediate ET rate. No significant correlation was found between ET rate and either adaxial or abaxial stomatal density. It was concluded that, under nonlimiting soil moisture conditions, stomatal density was not reliably associated with ET rate.