IRRIGATION AND GROUND COVER MANAGEMENT EFFECT ON SOIL-TEMPERATURE IN A MATURE PEACH ORCHARD

The purpose of this study was to assess the effect of two irrigation ( trickle vs. no irrigation) and two ground cover treatments (temporary cover vs. permanent sod) on soil temperature in a mature peach [Prunus persica (L.) Batsch] orchard on Fox sand. The soil temperatures at th e surface, 5, 10 and 20 cm depths were monitored continuously all-year during 1987 and 1988. Irrigation reduced the fluctuations in soil tem perature during summer and winter. The average daily soil temperature in nonirrigated plots during the summer was as high as 34-degrees-C at the soil surface and 28-degrees-C at the 20-cm depth, while correspon ding temperatures in irrigated plots were 28 and 26-degrees-C, respect ively. The average daily soil temperature in nonirrigated plots withou t snow cover during the winter was -12-degrees-C at the soil surface a nd -5-degrees-C at the 20-cm depth, while corresponding temperatures i n irrigated plots were -6 and -1-degrees-C, respectively. The effect o f irrigation on soil temperature was greatly diminished by snow cover. The soil temperatures at all depths remained around 0 to -2-degrees-C for both nonirrigated and irrigated plots under snow cover, even when the minimum air temperature dropped to -15-degrees-C. The permanent s od cover provided some protection against cold although this effect wa s masked by snow cover. In the summer, the permanent sod cover reduced average daily soil temperature by 1.5 and 1-degrees-C at the 10 and 2 0 cm depths.