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  • Author or Editor: I.R. McCann x
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Abstract

Significant interactions between irrigation and N management for total yield and for incidence of brown center or hollow heart in potatoes (Solanum tuberosum L. cv Russet Burbank) were found in field studies conducted in southeastern Idaho during 1987 and 1988. When soil water content was maintained at 80% to 90% available, 30 kg N/ha applied weekly for 3 weeks, beginning shortly after tuber initiation, resulted in a higher incidence of brown center or hollow heart than when the same total amount of N was applied pre-plant or in smaller increments over a longer period of time.

Open Access

Abstract

Regression models of potato (Solanum tuberosum L. cv. Russet Burbank) leaf water potential (ψleaf) were developed for irrigated conditions using concurrent measurements of total solar irradiance (Rs), air vapor pressure deficit (VPD), air temperature (Ta) and windspeed. Estimates of potential evaporation (Ep) also were related to ψleaf. The data were collected over a 3-year period from two locations in southern Idaho. Of the variables tested, Rs had the highest simple correlation with ψleaf (r = 0.93), although a slightly higher correlation was obtained for log-transformed values of VPD (1n VPD). Potato ψleaf was best described by the equation ψleaf = -0.3672 - 0.1959 In VPD – 0.0005 Rs, where ψleaf, VPD, and Rs are expressed in units of MPa, kPa and W·m–2, respectively. The model accounted for 95% of the variation in ψleaf for well-watered ‘Russet Burbank’ potatoes. When the model was tested on an independent data set, it estimated diurnal changes in ψleaf for several different cultivars to within ±0.1 MPa of the measured values. The relationship between ψleaf and Ep was nonlinear and was described by an exponential function. Estimates for the Ep model were nearly identical to those for the VPD Rs model when ψleaf values were below -0.3 MPa.

Open Access