Ebb-and-flow irrigation reduced water and fertilizer use by ≈ 40% when compared to overhead hand-watering by hose in the production of Hedera helix. In contrast, water and fertilizer use were not significantly different between ebb-and-flow and drip irrigation systems in the production of Asiatic hybrid lilies. Adequate growth of Hedera helix `Baltica' was obtained with 50 mg N/liter of 20-10-20 (20N-4.4-16.6K) or 20-19-18 (20N-8.4P-14.9K). Also, good market-quality hybrid lilies were produced with 75 mg N/liter of 20-19-18 (20N-8.4P-14.9K), 16-4-12 (16N-1.8P-10K), 20-0-20 (20N-0P-16.6K), and 20-10-20 (20N-4.4P-16.6K).
E. Jay Holcomb, Silvia Gamez, David Beattie, and George C. Elliott
Tatiana Borisova and Pilar Useche
implemented by regional and local agencies, Cooperative Extension Services, and other organizations to encourage more efficient irrigation water use and residential water conservation; however, limited information exists about the effectiveness of such
Jianjun Chen, Richard C. Beeson Jr., Thomas H. Yeager, Robert H. Stamps, and Liz A. Felter
Irrigation runoff water from a containerized landscape plant production bed was blended with rainwater from green house roofs in a constructed collection basin. Water from both the collection basin and an on-site potable well were characterized and used to grow foliage and bedding plants with overhead and ebb-and-flow irrigation systems. Over a 2-year period, a total of 18 foliage and 8 bedding plant cultivars were produced with plant growth and quality quantified. Alkalinity, electrical conductivity, hardness, and concentrations of nutrients of water from both sources were well within desired levels for greenhouse crop production. Turbidity and pH were relatively high from algal growth in the collection basin. However, substrate pH, irrigated by either water source, remained between 6 and 7 throughout the production periods. All plants at the time of finishing were of marketable sizes and salable quality independent of water source. No disease incidences or growth disorders related to water sources were observed. Results suggest that captured irrigation runoff blended with rainwater can be an alternative water source for green house crop production.
C.A. Brown, D.A. Devitt, and R.L. Morris
Research was conducted to assess the response of tall fescue (Festuca arundinacea Schreb.) to water deficit conditions. Different leaching fractions (LF = drainage volume/irrigation volume) and irrigation frequencies (IF) were imposed over a 119-day summer period in Las Vegas, Nevada, followed by a 71-day recovery period. Plots of tall fescue contained 120 cm deep × 51 cm diameter draining lysimeters. Irrigations were based on an evapotranspiration (ET) feedback system to establish LFs of +0.15, 0.00, -0.15, -0.25, and -0.40. Plots were irrigated on a daily or twice per week schedule. N was applied to subplots at a rate of 0, 12.2, or 24.4 kg·ha-1 per month. As LF decreased, relative soil water in storage declined in a linear fashion (r 2 = 0.97, P = 0.001). Storage depletions for the four lowest LFs at the end of 119 days of imposed water deficits were about 15%, 40%, 60%, and 70% compared to the +0.15 LF treatment. Canopy temperature, soil matric potential (Ψm), leaf xylem water potential (ΨLX), leaf stomatal conductance (gs), clipping yield, color and cover ratings all statistically separated (P < 0.05) based on LF but not on IF. However, irrigation amount (I), ET, tissue moisture content and total Kjeldahl N (TKN) separated based on LF and IF with a significant LF by IF interaction for I (P < 0.05) and TKN (P < 0.001). An irrigation savings of 60.4 cm was realized during the 119-day water deficit period at the -0.40 LF. However, at the lower LFs, plant stress increased (all parameters) with color ratings declining below an acceptable value of 8.0. An Irrigation/Potential ET (I/ETo) threshold of 0.80 was determined for both color and cover. After a 71-day recovery period both color and cover returned to pre experimental values at the two higher N rates. Results of this experiment indicate that implementing a twice weekly irrigation strategy at a -0.15 LF on tall fescue during summer months in an arid environment would lead to savings of 37.5 cm of water while still maintaining acceptable color and cover ratings.
Virginia I. Lohr and Lenore H. Bummer
Implementing water-conserving landscapes is one action that many individuals can take to help ease the nation's water crisis, but few people seem to be exercising this option. Some horticulturists attribute this to a negative attitude toward such landscapes. Our research was designed to assess these attitudes and to see if they could be improved with information. Questionnaires were administered to people in treatment or control groups. Those in the treatment group viewed a short videotape about water issues and water-conserving landscapes. Initial attitudes in both groups were neutral or positive, not negative as predicted. Viewing the videotape was associated with significantly improved attitudes. People in the treatment group described water-conserving landscapes as less hot, more colorful, and more attractive three weeks after viewing the videotape than they had initially.
We investigated mixtures of buffalograss [Buchloë dactyloides (Nutt.) Engelm. `Texoka' and `Cody'] and fine fescue species (Festuca rubra ssp. rubra L. `Vista', F. ovina var. glauca Lam. `Minotaur', F. rubra ssp. commutata Gaud. `Jamestown II') or stream-bank wheatgrass [Agropyron riparium Scribn. & Smith `Sodar'; syn. Elymus lanceolatus (Scribn. & Smith) Gould subsp. lanceolatus] as a low-maintenance turf with low irrigation requirements and season-long green color and growth. Buffalograss plots in Logan, Utah, were overseeded with fine fescue and streambank wheatgrass at two seeding rates. Plots of fine fescue, wheatgrass, or buffalograss alone were also established. At 50% evapotranspiration (ETo) replacement, fine fescues dominated the mixtures with no differences due to seeding rates. Wheatgrass mixture plots were unacceptable in quality. Buffalograss control plots and mixtures were similar for turfgrass quality in August, and fine fescue controls and mixtures were similar in spring and fall. The mixtures performed well in the low-maintenance turf situation, but dominance of fine fescue over the buffalograss limits the potential of these specific mixtures.
David W. Burger
Comparisons were made between a commercially available, solar-activated mist control device (Weather Watcher®) and time clocks to determine their relative effectiveness, usefulness, and water-use characteristics on a greenhouse mist propagation bench. Coleus cuttings produced more roots per cutting and had greater average root lengths under Weather Watcher-controlled mist than those cuttings on a mist bench controlled by time. Paulownia cuttings produced the same number of roots under solar- or time-activated mist; however, the average root length was greater under Weather Watcher control. Mist benches controlled by the Weather Watcher used only one-third the water used by benches controlled by a time clock.
Rafael Muñoz-Carpena, Yuncong C. Li, Waldemar Klassen, and Michael D. Dukes
A low-volume/high frequency (LVHF) soil moisture-based drip irrigation system was tested on a shallow sandy soil at a commercial tomato (Lycopersicon esculentum) farm in southern Florida. Six LVHF irrigation treatments were compared with the standard commercial practice on the farm (control), where a portable pump was used for manual drip irrigation twice each week. In the six LVHF treatments the system was continuously pressurized by means of an electrical pump and a pressure tank, and controlled by an irrigation timer set to irrigate a maximum of five times per day with the irrigation time (i.e., volume) set according to historical evapotranspiration (ET) demands in the area. Two treatments were based on timer schedules, one to supply 100% of the maximum recommended crop water needs in the area based on historical ET (ET-100%), and the other to supply 150% of those needs (ET-150%). The other four treatments were created by interfacing two types of soil moisture sensors (switching tensiometers and granular matrix sensors with control modules) set at two moisture points (wet = 10 kPa, optimal = 15 kPa) in a closed control loop with the irrigation timer programmed at the ET-100% schedule. Results showed that the six LVHF treatments reduced water use while not significantly affecting tomato yields. Switching tensiometers at the 15 kPa set point performed the best (up to 73% reduction in water use when compared to the control, 50% with respect to ET-100%). The results show that water use below historical ET levels can be obtained without sacrificing yield by keeping the root zone moisture at controlled levels with the soil-moisture based system. Routine maintenance was critical for reliable operation of the switching tensiometers. Granular matrix sensor based irrigation behaved erratically, and did not improve water savings compared to ET-100%, indicating that this system was not effective under the conditions of the area due to the sensor's slow response to frequent wetting-rewetting cycles and characteristics of the interface.
Frank J. Dainello, Larry Stein, Guy Fipps, and Kenneth White
Competition for limited water supplies is increasing world wide. Especially hard hit are the irrigated crop production regions, such as the Lower Rio Grande Valley and the Winter Garden areas of south Texas. To develop production techniques for reducing supplemental water needs of vegetable crops, an ancient water harvesting technique called rainfall capture was adapted to contemporary, large scale irrigated muskmelon (Cucumis melo var. reticulatus L.) production systems. The rainfall capture system developed consisted of plastic mulched miniature water catchments located on raised seed beds. This system was compared with conventional dry land and irrigated melon production. Rainfall capture resulted in 108% average yield increase over the conventional dry land technique. When compared with conventional furrow irrigation, rainfall capture increased marketable muskmelon yield as much as 5355 lb/acre (6000 kg·ha-1). As anticipated,the drip irrigation/plastic mulch system exceeded rainfall capture in total and marketable fruit yield. The results of this study suggest that rainfall capture can reduce total supplemental water use in muskmelon production. The major benefit of the rainfall capture system is believed to be in its ability to eliminate or decrease irrigation water needed to fill the soil profile before planting.
Rolston St. Hilaire, Michael A. Arnold, Don C. Wilkerson, Dale A. Devitt, Brian H. Hurd, Bruce J. Lesikar, Virginia I. Lohr, Chris A. Martin, Garry V. McDonald, Robert L. Morris, Dennis R. Pittenger, David A. Shaw, and David F. Zoldoske
communities, only drastic measures or catastrophic events have caused water-efficient landscapes to be implemented. For example, in 1981, a court ordered the Denver Water Department to promote water conservation in outdoor landscapes ( Hagan, 1988 ). Faced