Subsurface drip irrigation has been increasingly employed for the production of specific vegetables, such as onion ( Allium cepa ) and processing tomato ( Solanum lycopersicum ) ( Ayars et al., 2015 ; Enciso et al., 2007 ; Leskovar et al., 2004
Michael Maurer* and Justin Weeaks
Throughout much of the Southwestern United States, poor quality water and limited water resources require innovative methods to conserve water. No research to date has indicated whether seeded bermudagrass Cynodon dactylon can be established by using subsurface drip irrigation (SDI). In 2001 (Expt. I) and 2002 (Expt. II), seeded bermudagrass was evaluated for establishment using SDI. Treatments consisted of emitters and tubing spaced at 30, 46, and 61 cm. The control treatment consisted of pop-up sprinklers. Salinity accumulation is a concern when irrigating turfgrass in areas of poor water quality and low annual rainfall. Salinity accumulation was visible at the soil surface during establishment in 2001, but turfgrass showed no visible signs of stress due to salinity. In 2002, substantial rainfall reduced salinity accumulation during establishment as salinity was not present on the soil surface. Salinity accumulation was greater in most months at the 0-15 cm depth in both years compared to the 15-30 cm depth. Full turfgrass coverage (≥90%) for the control plots in 2001 was about 8.5 weeks and the SDI treatments had complete coverage in 10 weeks. Turfgrass coverage for all treatments in 2002 was 9 weeks. Expt. II had a slightly faster establishment rate due to greater rainfall and different soil characteristics than that of Expt. I. Root count and depth of roots for both years showed roots to 61 cm depth in all treatments. A general trend of higher salinity accumulation at the midpoint between tubing was seen in Expts. I and II. However, after significant rainfall salinity levels returned to concentrations comparable to initial soil salinity concentrations in both years. This research documents the ability to successfully establish seeded bermudagrass using SDI.
Clinton C. Shock, Erik B. G. Feibert, and Lamont D. Saunders
Onion (Allium cepa L.) production in the Treasure Valley of eastern Oregon and southwestern Idaho has been based on furrow irrigation with 318 kg·ha-1 N fertilizer and average yields of 70 Mg·ha-1, but these practices have been implicated in nitrate contamination of groundwater. Drip irrigation, introduced in the early 1990s, has several advantages, including reduced leaching losses. Since onion plant populations and N fertilizer rates can affect economic returns, studies were conducted in 1999, 2000, and 2001 to determine optimum plant populations and N fertilizer rates for subsurface drip-irrigated onion. Long-day onion (`Vision') was subjected to a combination of seven nitrogen fertilization rates (0 to 336 kg·ha-1 in 56-kg increments applied between late May and early July) and four plant populations (185, 250, 300, and 370 thousand plants/ha). Onion was grown on silt loam in two double rows spaced 0.56 m apart on 1.1 m beds with a drip tape buried 13 cm deep in the bed center. Soil water potential was maintained nearly constant at -20 kPa by automated irrigations based on soil water potential measurements at a 0.2-m depth. Onion bulbs were evaluated for yield and grade after 70 days of storage. Onion yield and grade were highly responsive to plant population. Onion marketable yield increased, and bulb diameter decreased with increasing plant population. Within the range of plant populations tested, gross returns were not always responsive to plant population. Returns were increased by the increase in marketable yield obtained with higher plant population, but higher plant population also reduced the production of the largest sized bulbs which had the highest value per weight. Onion yielded 95 Mg·ha-1 with no applied N fertilizer, averaged over plant populations and years. Onion yield and grade were not responsive to N fertilizer rate or interaction of N fertilizer rate with plant population. Preplant soil available N, N mineralization, and N in irrigation water all contributed N to the crop. Onion N uptake did not increase with increasing N fertilizer rate.
Blaine R. Hanson, Donald M. May, and Larry J. Schwankl
The effect on crop yield of drip-irrigation frequencies of two irrigations per day (2/d), one irrigation per day (1/d), two irrigations per week (2/week), and one irrigation per week (1/week) was investigated for lettuce (Lactuca sativa), pepper (Capsicum annuum), and onion (Allium cepa) grown on sandy loam and processing tomato (Lycopersicon esculentum) grown on silt loam during experiments conducted during 1994 to 1997. All treatments of a particular crop received the same amount of irrigation water per week. Results showed that the 1/week frequency should be avoided for the shallow rooted crops in sandy soil. Irrigation frequency had little effect on yield of tomato, a relatively deep-rooted crop. These results suggest that drip irrigation frequencies of 1/d or 2/week are appropriate in medium to fine texture soils for the soil and climate of the project site. There was no yield benefit of multiple irrigations per day.
Fengyun Zhao, Junli Sun, Songlin Yu, Huaifeng Liu, and Kun Yu
transplanting. Fig. 1. Experimental design. ( 1 ) Water pump. ( 2 ) Main tube. ( 3 ) Filter. ( 4 ) Aeration system for subsurface drip irrigation (SDI) with tanks. ( 5 ) Water meter. ( 6 ) Switch. ( 7 ) Branch pipe of SDI with tanks. The experiment was conducted
Clinton C. Shock, Erik B.G. Feibert, Alicia Riveira, and Lamont D. Saunders
soil volume would be more likely to reach the root plate of all bulbs, initiating new root growth and enhancing yield. In this study, furrow-irrigated onion was just as productive as subsurface drip-irrigated onion. The lower yield expected using furrow
C. J. Phene, R.B. Hutmacher, and K.R. Davis
Processing tomato is an important crop in California, where ≈ 100,000 ha is grown annually. In the past, processing tomatoes have been irrigated mostly by sprinkler and furrow irrigation, although several tests have been conducted with drip irrigation, and a few growers are using subsurface drip irrigation. Yields of tomato have been shown to be sensitive to water management when the amount of irrigation water closely matches plant water use. Tomatoes have been identified as susceptible to drought stress and waterlogging at both ends of the furrow irrigation cycle. Subsurface drip irrigation is a relatively new method in which drip irrigation laterals are buried permanently 20 to 60 cm below the soil surface. This method has provided the control and uniformity of water and fertilizer distribution necessary to maximize the yield of processing tomatoes. A computerized control system maintains nearly constant soil water and nutrient concentration in the root zone by irrigating and fertilizing frequently, thus avoiding small water and nutrient stresses, especially during the critical period between first and peak bloom. During the maturation and ripening stage, irrigation and nutrient concentrations can be adjusted to increase soluble solids and to adjust the maturation rate to coincide with the harvest schedule. Maximum yield levels can be obtained when nearly all the fertilizers (N, P, and K) are injected precisely in time and space through the drip irrigation system to meet the crop nutrient requirement. Water-use efficiency (WUE), defined as the ratio of yield: unit of water used by the plant, can be maximized by using this precise irrigation and fertilization technique. Yields >200 t·ha-1 of red tomatoes were achieved in large field plot research, and commercial yields of 150 t·ha-1 were achieved in large-scale field applications with a lesser degree of control. Therefore, we predict that with further fine-tuning, commercial yields of 200 tons of processing tomatoes/ha could be achieved using a subsurface drip irrigation system with accurate water and fertility management.
Clinton C. Shock, Erik B.G. Feibert, and Lamont D. Saunders
Long-day onion (Allium cepa L. `Vision') was subjected to five soil water potential (SWP) treatments (–10, –20, –30, –50, and –70 kPa) using subsurface drip irrigation in 1997 and 1998. Onions were grown on 1.1-m beds with two double rows spaced 0.56 m apart and a drip tape buried 13 cm deep in the bed center. Soil water potential was maintained at the five levels by automated, high-frequency irrigations based on SWP measurements at 0.2-m depth. Onions were evaluated for yield and grade after 70 days of storage. In 1997, total and colossal (bulb diameter ≥102 mm) yield increased with increasing SWP, but marketable yield was highest at a calculated –21 kPa because of greater decomposition in storage in wetter treatments. In 1998 total, marketable, and colossal-grade onion yield increased with increasing SWP. Onion profits were highest with a calculated SWP of –17 kPa in 1997, and at the wettest level tested in 1998. Storage decomposition was not affected by SWP in 1998. Maintenance of SWP at –10 and –20 kPa required, respectively, 912 and 691 mm of water in 1997 and 935 and 589 mm of water in 1998. Onion crop evapotranspiration from emergence to the last irrigation totaled 681 mm in 1997 and 716 mm in 1998.
Clinton C. Shock, Erik B.G. Feibert, Alicia Rivera, Lamont D. Saunders, Nancy Shaw, and Francis F. Kilkenny
forbs are not well adapted to row crop production practices. Supplemental water can be provided by sprinkler or furrow irrigation systems, but these irrigation systems risk encouraging weeds and fungal pathogens. Subsurface drip irrigation can reduce
Bernd Leinauer, Matteo Serena, and Devesh Singh
placed 30 cm apart from each other and pressure compensating emitters delivered water at a rate of 2 L·h −1 . Subsurface drip irrigation was chosen because of the site's wind exposure that historically resulted in poor irrigation coverage from sprinkler