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Granular matrix sensors (GMS) represent an alternative technology for measuring soil water to schedule irrigation. When GMS were tested by drying them to measure changes in electrical resistance with decreasing water content, their resistance response to drying in air in an oven was similar (t = −0.87, 134 df) to that for drying in a field soil, with a response curve that suggested GMS could be used to measure soil water potential (Ψ). Granular matrix sensor meter readings were compared with tensiometer, neutron probe, and gravimetric measurements of soil water in the root zone of potato (Solanum tuberosum L. cv. Russet Burbank) grown in silt loam. Measurements with GMS were closely related to soil water potential measurements and to soil water measured gravimetrically or by neutron probe. Meter model 30KTC, as supplied by the manufacturer, when calibrated against tensiometers, had a linear response represented by the equation y = −6.44 − 0.738 x, where y = Ψ J kg−1), and x = 30KTC meter reading (dimensionless units) of GMS, with r2 = 0.89. Granular matrix sensors were used to monitor transitory soil water stress treatments in an experiment to determine potato response to water stress.

Sugar beet (Beta vulgaris) varieties were evaluated for disease resistance to curly top to establish if disease ratings made in inoculated nurseries correlated with disease ratings and yield in sugar beet crops exposed to natural disease outbreaks. Cultivars were planted both in inoculated curly top nurseries in Kimberly, ID, and in commercial cultivar trials in irrigated fields near Ontario, OR and Nampa, ID. Plants were evaluated for curly top using a rating scale of 0 (no symptoms) to 9 (dead). Moderate disease pressure in the Ontario (mean rating = 3.8) and Nampa (mean rating = 4.1) fields resulted in significant differences for disease rating, root yield, sugar content, and estimated recoverable sugar among cultivars. Disease ratings from both commercial fields were positively correlated (r = 0.91 and 0.82, P < 0.0001) with ratings from the inoculated nurseries. In commercial fields, root yield was negatively related to disease rating (r2 = 0.47 and 0.39, P ≤ 0.0004). For each unit increase in disease rating (increasing susceptibility), root yield decreased 5.76 to 6.93 t/ha. Thus, curly top nurseries reliably predict curly top resistant cultivars for commercial cultivation.

Potential new onion (Allium cepa L.) cultivars for commercial production in eastern Oregon and southwestern Idaho are evaluated annually in yield trials conducted at the Malheur Experiment Station, Oregon State University, Ontario, Ore. Bulb yield and market grade were determined in field trials for 63 yellow onion cultivars and lines in 1996 and for 49 cultivars and lines in 1997. Marketable yield out of storage in January ranged from 478 to 1131 cwt/acre (54 to 127 Mg·ha-1) in 1996, and from 383 to 912 cwt/acre (43 to 102 Mg·ha-1) in 1997. Marketable yields of `9003C', `Seville', `El Charro', `Sunre 1430', `El Padre', `Golden Security', `Bravo', and `X 202' were greater than 1000 cwt/acre (112 Mg·ha-1) in 1996. In 1997, marketable yields of `Seville', `Bravo', `Quest', `T-433', `9003C', `Goldstar', `Superstar', `RNX-10020', `Vision', and `Sweet Perfection' were greater than 850 cwt/acre (95 Mg·ha-1). Of the 30 cultivars evaluated both years, the average marketable yields of `Seville', 9003C, `Bravo', `Quest', and `Sweet Perfection' were among the highest. Many others showed potential for high yields and merit further evaluation. In both years, most bulbs of all selections graded jumbo [3 to 4 inch (7.6 to 10.2 cm) diameter] and colossal [>4 inch (10.2 cm) diameter], and only a few cultivars had more than 2% medium-size [2.25 to 3 inch (5.7 to 7.6 cm) diameter] bulbs. Infection by neck rot (Botrytis allii Munn.) and plate rot [Fusarium oxysporum f. sp. cepa (H. N. Hans.) W.C. Snyder & H.N. Hans.] during storage was more severe in 1996 than in 1997, but in general, most cultivars showed relatively low levels of these diseases in both years. Averaged across all cultivars, bolting was evident in less than 1% of bulbs in both years.

Portable plot sprinklers were developed that allowed individual plots to be irrigated independently of other plots. Each plot sprinkler consisted of three rotary‐pendulum, square‐pattern sprinkler heads mounted on a PVC pipe frame. Plot sprinkler water output was 0.9 m3 h−l, on an area 4.6 m wide by 13.7 m long, with Cu = 80%, when operated at 86 kPa. Plot sprinklers were used to apply irrigation treatments In a randomized block design to evaluate potato (Solanum tuberosum L. ‘Russet Burbank’) tuber quality response to six levels of transitory drought stress during early tuber bulking. Yield of U.S. Number One tubers decreased and yield of U.S. Number Two tubers increased with increasing severity of transitory drought stress. Plot sprinklers allow irrigation of plots in an experiment at different frequencies or durations.