SUPPLEMENTARY IRRIGATION AND MULCH BENEFIT THE ESTABLISHMENT OF HERITAGE PRIMOCANE-FRUITING RASPBERRY

Field experiments including supplementary trickle irrigation (IR), IRT -76 plastic film (PF), and straw mulch (STR) treatments were conducted during 1993 and 1994 to determine the influence of root-zone temperat ure and soil moisture status on carbon assimilation and dry mass distr ibution, and soil and plant nutrient content, during the establishment of Rubus idaeus L. 'Heritage' primocane-fruiting raspberries. The IR, PF, and STR treatments were reapplied after the 1993 establishment ye ar to examine their effects on an established, hedgerow planting. Phys ical environment, vegetative and reproductive data were collected. PF increased root and shoot mass, total flower number, and total berries harvested. Maximum leaf net photosynthetic (Pn) rates were observed un der cool air temperatures and root-zone temperature of 25 degrees C. F ield Pn measurements indicated that there was no seasonal decline in P n, Mulch treatments however, were not beneficial to the established (i .e., 2-year-old) hedgerow planting. The root system of the 2-year-old planting was largely confined to an area within the foliage wall and a lso at a greater depth from the mulch treatments. Therefore, beneficia l effects of mulch management on the growth and development of raspber ries may be limited to the establishment year.