scholarly journals 689 PB 239 SOIL WATER POTENTIAL IRRIGATION CRITERIA FOR ONION PRODUCTION

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 531e-531
Author(s):  
Erik B. G. Feibert ◽  
Clint C. Shock ◽  
Monty Saunders
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Furrow Irrigation ◽  
Silt Loam ◽  
Yield And Quality ◽  
Water Potentials ◽  
Granular Matrix ◽  
Irrigation Treatments

Onions were grown with different soil water potentials as irrigation criteria to determine the soil water potential at which optimum onion yield and quality occurs. Furrow irrigation treatments in 1992 and 1993 consisted of six soil water potential thresholds (-12.5 to -100 kPa). Soil water potential in the first foot of soil was measured by granular matrix sensors (Watermark Model 200SS, Irrometer Co., Riverside, CA) that had been previously calibrated to tensiometers on the same silt loam series. Both years, yield and market grade based on bulb size (more jumbo and colossal onions) increased with wetter treatments. In 1993, a relatively cool year, onion grade peaked at -37.5 kPa due to a significant increase in rot during storage following the wetter treatments. These results suggest the importance of using moisture criteria to schedule irrigations for onions.

NITROGEN TRANSFORMATIONS NEAR UREA IN SOIL WITH DIFFERENT WATER POTENTIALS

1988 ◽  
Vol 68 (3) ◽  
pp. 569-576 ◽  
Author(s):  
YADVINDER SINGH ◽  
E. G. BEAUCHAMP
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Incubation Period ◽  
Relative Rate ◽  
Soil Water Potential ◽  
Nitrification Inhibitor ◽  
Silt Loam ◽  
Nitrogen Transformations ◽  
Water Potentials ◽  
Initial Soil

Two laboratory incubation experiments were conducted to determine the effect of initial soil water potential on the transformation of urea in large granules to nitrite and nitrate. In the first experiment two soils varying in initial soil water potentials (− 70 and − 140 kPa) were incubated with 2 g urea granules with and without a nitrification inhibitor (dicyandiamide) at 15 °C for 35 d. Only a trace of [Formula: see text] accumulated in a Brookston clay (pH 6.0) during the transformation of urea in 2 g granules. Accumulation of [Formula: see text] was also small (4–6 μg N g−1) in Conestogo silt loam (pH 7.6). Incorporation of dicyandiamide (DCD) into the urea granule at 50 g kg−1 urea significantly reduced the accumulation of [Formula: see text] in this soil. The relative rate of nitrification in the absence of DCD at −140 kPa water potential was 63.5% of that at −70 kPa (average of two soils). DCD reduced the nitrification of urea in 2 g granules by 85% during the 35-d period. In the second experiment a uniform layer of 2 g urea was placed in the center of 20-cm-long cores of Conestogo silt loam with three initial water potentials (−35, −60 and −120 kPa) and the soil was incubated at 15 °C for 45 d. The rate of urea hydrolysis was lowest at −120 kPa and greatest at −35 kPa. Soil pH in the vicinity of the urea layer increased from 7.6 to 9.1 and [Formula: see text] concentration was greater than 3000 μg g−1 soil. There were no significant differences in pH or [Formula: see text] concentration with the three soil water potential treatments at the 10th day of the incubation period. But, in the latter part of the incubation period, pH and [Formula: see text] concentration decreased with increasing soil water potential due to a higher rate of nitrification. Diffusion of various N species including [Formula: see text] was probably greater with the highest water potential treatment. Only small quantities of [Formula: see text] accumulated during nitrification of urea – N. Nitrification of urea increased with increasing water potential. After 35 d of incubation, 19.3, 15.4 and 8.9% of the applied urea had apparently nitrified at −35, −60 and −120 kPa, respectively. Nitrifier activity was completely inhibited in the 0- to 2-cm zone near the urea layer for 35 days. Nitrifier activity increased from an initial level of 8.5 to 73 μg [Formula: see text] in the 3- to 7-cm zone over the 35-d period. Nitrifier activity also increased with increasing soil water potential. Key words: Urea transformation, nitrification, water potential, large granules, nitrifier activity, [Formula: see text] production

scholarly journals Onion Response to Water Stress

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 837D-837
Author(s):  
Clinton C. Shock ◽  
Erik B.G. Feibert ◽  
Lamont D. Saunders
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Marketable Yield ◽  
Water Deficits ◽  
Yield And Quality ◽  
Highly Sensitive ◽  
Granular Matrix ◽  
Response To Water

Six soil water potential irrigation criteria (–12.5 to –100 kPa) were examined to determine levels for maximum onion yield and quality. Soil water potential at 0.2-m depth was measured by tensiometers and granular matrix sensors (Watermark Model 20055, Irrometer Co., Riverside, Calif.). Onions are highly sensitive to small soil water deficits. The crop needs frequent irrigations to maintain small negative soil water potentials for maximum yields. In each of 3 years, yield and bulb size increased with wetter treatments. In 1994, a relatively warm year, onion yield and bulb size were maximized at –12.5 kPa. In 1993, a relatively cool year, onion marketable yield peaked at –37.5 kPa due to a significant increase in rot during storage following the wetter treatments.

scholarly journals A Comparison of Onion Production Under Sprinkler, Subsurface Drip, and Furrow Irrigation

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 839A-839
Author(s):  
Erik B.G. Feibert ◽  
Clinton C. Shock ◽  
Lamont D. Saunders
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Drip Irrigation ◽  
Soil Water Potential ◽  
Sprinkler Irrigation ◽  
Furrow Irrigation ◽  
Crop Evapotranspiration ◽  
Granular Matrix ◽  
Subsurface Drip

Onion yield and grade were compared under sprinkler, subsurface drip, and furrow irrigation in 1992, 1993, and 1994. Furrow-irrigated onions were planted on two double rows on 1.12-m-wide beds at 352,000 seeds/ha. Sprinkler- and drip-irrigated onions were planted in nine single rows on a 2.24-m-wide bed at 432,100 seeds/acre. Drip plots had three drip lines buried 0.10 m deep in each 2.24-m bed. Soil water potential at 0.2-m depth was measured by tensiometers and granular matrix sensors (Watermark Model 200SS, Irrometer Co., Riverside, Calif.). Furrow irrigations were started when the soil water potential at the 0.2-m depth reached –25 kPa. Drip-irrigated onions had soil water potential at the 0.2-m depth kept wetter than –25 kPa by daily replacement of crop evapotranspiration (Etc). Sprinkler irrigations were started when the accumulated Etc reached 25 mm. Sprinkler irrigation resulted in significantly higher onion yield than furrow irrigation in 1993 and 1994. Sprinkler irrigation resulted in higher marketable onion yield than furrow irrigation in 1993. Drip irrigation resulted in significantly higher onion yield than furrow irrigation every year. Drip irrigation resulted in higher marketable onion yield than furrow irrigation in 1992 and 1994. Marketable onion yield was reduced in 1993 due to rot during storage.

scholarly journals Onion Yield and Quality Affected by Soil Water Potential as Irrigation Threshold

HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1188-1191 ◽  
Author(s):  
C.C. Shock ◽  
E.B.G. Feibert ◽  
L.D. Saunders
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Allium Cepa ◽  
Total Yield ◽  
Soil Water Potential ◽  
Silt Loam ◽  
Marketable Yield ◽  
Yield And Quality

Onion (Allium cepa L., `Great Scott') was grown on silt loam soils and submitted to four irrigation thresholds (-25, -50, -75, and -100 kPa) in 1992 and six irrigation thresholds (-12.5, -25, -37.5, -50, -75, and -100 kPa) in 1993 and 1994. Irrigation thresholds (soil water potential measured at 0.2-m depth) were used as criteria to initiate furrow irrigations. Onions were evaluated for yield and grade after 70 days of storage. In 1992 and 1994, total yield, marketable yield, and profit increased with increasing irrigation threshold. In 1993, total yield increased with increasing irrigation threshold, but marketable yield and profit were maximized by a calculated threshold of -27 kPa due to a substantial increase of decomposition during storage with increasing threshold.

Effect of drip and sprinkle irrigation on yield and quality of five tomato cultivars in southwestern Ontario

1995 ◽  
Vol 75 (1) ◽  
pp. 225-230 ◽  
Author(s):  
C. S. Tan
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Soluble Solids ◽  
Moisture Regime ◽  
Yield And Quality ◽  
Tomato Cultivars ◽  
Irrigation Treatments ◽  
Sprinkle Irrigation

The purpose of this study was to assess yield and quality of tomato (Lycopersicon esculentum Mill.) in response to drip (DI) and sprinkle irrigation (SI) in southwestern Ontario. Three irrigation treatments, DI, SI and no irrigation (NI) and five tomato cultivars, FM6203, H2653, H722, OH7814 and PUR812, grown on a Fox sandy loam soil, were evaluated during four growing seasons between 1986 and 1989. Both DI and SI increased the marketable tomato yield in 3 of 4 yr. In general, DI resulted in higher tomato yields than SI, but this was only statistically significant in 1 yr. Sprinkle irrigation out performed drip irrigation in one hot, dry year in 1988. Throughout the 4 yr, OH7814 was consistently high yielding, H2653 was consistently low yielding and FM6203, H722 and PUR812 performed more consistently than the other cultivars. In wet years, yield differences due to cultivar treatments were greater than those due to irrigation treatments, while in dry years, yield differences due to both irrigation and cultivar treatments were highly significant. Soluble solids and total solids were decreased by DI and SI. The DI produced the most uniform soil moisture regime, followed by SI. The NI plots had the greatest degree of water stress, as indicated by the low soil water potential, low stomatal conductance and elevated crop canopy temperature. Key words:Lycopersicon esculentum, yield, soil water potential

Soil Water Potential and Bromacil Uptake by Wheat

Weed Science ◽  
1975 ◽  
Vol 23 (2) ◽  
pp. 127-130 ◽  
Author(s):  
J. D. Schreiber ◽  
V. V. Volk ◽  
L. Boersma
Keyword(s):  
Triticum Aestivum ◽  
Water Potential ◽  
Soil Water ◽  
Transpiration Rate ◽  
Soil Water Potential ◽  
Dry Weight ◽  
Silt Loam ◽  
High Concentration ◽  
Water Potentials ◽  
Application Rates

The uptake of14C labeled bromacil [5-bromo-3-sec-butyl-6-methyluracil] by wheat plants (Triticum aestivumL. ‘Gaines’) grown in a Woodburn silt loam was studied at soil water potentials of −0.35 and −2.50 bars, and in solutions containing 2.0 and 4.5μg/ml bromacil. Transpiration rate, shoot and root dry weight, and bromacil content were measured as a function of time. Bromacil uptake into the root and foliar portions of the wheat plants increased with time. At the low bromacil concentration, 70%, and at the high concentration, 42%, more bromacil was taken up by the plant at the higher soil water potential. Uptake of bromacil increased concurrently with increased transpiration of water. The bromacil concentration in the transpiration stream was greater at the −0.35 bar than at the −2.50 bar soil water potential at both bromacil application rates. Transpiration rates of the plants treated with bromacil were nearly the same after a 40-hr exposure at both soil water potentials. The rate of bromacil uptake and accumulation may be influenced by the effect of soil water potential on the apoplastic movement of water and solutes in the roots.

scholarly journals `Ben Lear' and `Stevens' Cranberry Root and Shoot Growth Response to Soil Water Potential

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 795-798 ◽  
Author(s):  
Dana L. Baumann ◽  
Beth Ann Workmaster ◽  
Kevin R. Kosola
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Area ◽  
Growth Rates ◽  
Soil Water Potential ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Water Potentials ◽  
Whole Plant

Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.

THE EFFECT OF SOIL WATER POTENTIAL, TEMPERATURE AND SEEDING DEPTH ON SEEDLING EMERGENCE OF WHEAT

1979 ◽  
Vol 59 (3) ◽  
pp. 259-264 ◽  
Author(s):  
R. DE JONG ◽  
K. F. BEST
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Minimum Temperature ◽  
Seedling Emergence ◽  
Potential Temperature ◽  
Soil Water Potential ◽  
Triticum Aestivum L ◽  
Planting Dates ◽  
Water Potentials ◽  
Soil Temperatures

Daily emergence counts were made on Canthatch wheat (Triticum aestivum L.) grown in five soil types, at four soil temperatures and three water potentials and planted at five different depths. Regardless of soil type, soil water potential or depth of planting, 50% emergence generally occurred within a week at 19.4 and 26.7 °C, and within 2 wk at 12.2 °C, but it took up to 6 wk at 5 °C. The heat sum required to attain 50% seedling emergence did not increase significantly with decreasing soil water potentials, but the minimum temperature for emergence dropped from 1.3 to 0.2 °C as the water potential decreased from −⅓ to −10 bar. It was suggested that the seedlings compensated for the increased water stress by lowering their minimum temperature requirements. Increasing the planting depth not only increased the heat requirement for emergence, but it also increased the variability of emergence, especially at low temperatures. Practical aspects concerning planting dates and depths were considered.

Modifying sexual expression of containerized jack pine by topping, altering soil nitrogen and water, and applying gibberellins

1994 ◽  
Vol 24 (5) ◽  
pp. 869-877 ◽  
Author(s):  
W.H. Fogal ◽  
S.J. Coleman ◽  
M.S. Wolynetz ◽  
H.O. Schooley ◽  
S.M. Lopushanski ◽  
...  
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Nitrogen ◽  
Soil Water Potential ◽  
Jack Pine ◽  
Sexual Expression ◽  
Growth Responses ◽  
Tree Crown ◽  
N Supply ◽  
Water Potentials

The numbers of seed strobili and pollen strobilus clusters and the extent of branch terminal growth were determined on 6-year-old containerized jack pine (Pinusbanksiana Lamb.) trees following modification of the soil nitrogen (N) supply (NH4NO3 at 3, 100, or 300 mg N/L; NO3− at 100 mg N/L; or NH4+ at 100 mg N/L in a nutrient solution), soil water supply (soil water potentials above −20 kPa compared with potentials near −70 kPa), and tree crown size (intact trees outside polythene shelters and lightly versus severely topped trees under polythene shelters). These factors were tested with or without biweekly foliar applications of spray solutions containing 400 mg/L of GA4/7. Intact trees outside polythene shelters did not display sexual or growth responses to N or GA4/7 treatments. Seed strobilus production on topped trees under shelters was not influenced by the level of topping or N supply, but it was depressed by low soil moisture potentials and stimulated by GA4/7 with high or low soil water potentials. Pollen strobilus production was depressed by severe topping and by low soil water potential; it was stimulated by GA4/7 on lightly topped trees but not on severely topped trees and by a low (3 mg N/L) N supply. In the year after treatment, terminal growth of a branch from the 2-year-old nodal whorl was not influenced by nitrogen supply or by light topping but it was increased by severe topping; it was increased by GA4/7 treatment if soil water potential was high but not with low water potential; it was depressed by low soil water potential.

Soil and plant resistance effects on transpirational and leaf water responses by groundnut to soil water potential

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 51 ◽  
Author(s):  
RP Samui ◽  
S Kar
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Uptake ◽  
Plant Resistance ◽  
Sandy Loam ◽  
Soil Water Potential ◽  
Leaf Water ◽  
Arachis Hypogea ◽  
Water Potentials ◽  
Soil Water Conditions

The phasic and diurnal leaf water potential (�L) and transpirational responses to soil water potential by groundnut (Arachis hypogea L.) were investigated under controlled soil water conditions in a glasshouse. Three different soil water potentials (�s) in the tensiometric ranges were maintained in a lateritic sandy loam soil (Oxisol) during the seedling (S1), branching (S2) and peg formation (S3) stages of groundnut. Measured values of �s, �L rooting density, soil capillary conductivity and transpiration rate were used to calculate the soil and plant resistances to water uptake by the plant. The soil and plant resistances to water uptake by the groundnut plant increased appreciably as the soil water potential decreased from -0.11 to -0.70 bar. Plant resistance (Rp) was two to three orders of magnitude higher than soil resistance (Rs). Rs decreased with growth of the plant, whereas Rp increased, especially at -0.7 bar �s, Decreases in transpiration at �s lower than -0.33 bar were closely associated with the increases in the plant and soil resistances, and with lower leaf water potentials.

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