ISHS Acta Horticulturae 721: V International Symposium on Mineral Nutrition of Fruit Plants
EFFECTS OF THE RATE OF NUTRIENTS BY FERTIGATION AND BROADCAST APPLICATION IN ´GALA´ AND ´FUJI´ APPLE |
| Authors: | D. Malaguti, A.D. Rombola, M. Quartieri, A. Lucchi, C. Inderst, B. Marangoni, M. Tagliavini |
| Keywords: | fruit quality, Malus, mineral nutrition, nitrate, soil solution |
| Abstract:
The addition of fertilizers to irrigation water (fertigation) might allow a synchronization of soil nutrient availability with plant nutrient demand, thus avoiding temporary nutrient deficiency even in periods on high nutrient uptake. In the present study, from 1997 to 2004, different fertilizing strategies were applied to apple trees since plot establishment to (I) compare broadcast application of N, P, K, Mg (80, 25, 100, 10 kg ha-1, respectively) to their addition by fertigation, (II) test the possibility of reducing the rates of N, P, K, Mg when supplied by fertigation and (III) assess the importance of including P and K in the fertilization program. Two apple varieties, “Gala” and “Fuji” (on M9) well suited for lowland production areas in the Po Valley (Northern Italy), but differing in vigor, alternate bearing and fruit characteristics, were planted in winter 1996/97 at 3.8 x 1.0 m spacing in an alluvial soil at the Experimental Station of the Bologna University. With fertigation, nutrients were provided daily; when broadcast, N was split into three applications and K, P and Mg in two applications. The nutrient application technique affected the availability of nutrients in the soil solution extracted by suction lysimeters. Reducing N rates resulted in lower nitrate concentration in the soil solution. Leaf N concentration and leaf chlorophyll were little affected by the application technique but decreased as a consequence of reduced N rate. Regardless of K rate supplied, fertigation increased soil and leaf K concentrations, while no effects of the application technique on soil P and Mg were recorded. The effects of treatments on vegetative and production parameters were greater for “Gala” than for “Fuji” trees. Reducing N rate by fertigation from 80 to 40 kg ha-1 depressed vegetative growth and cumulative fruit yield in “Gala”. The presence of P in the fertigation program had a slight positive effect on vegetative growth, especially after transplanting, while in “Gala” only, K supply enhanced the fruit color development. | |
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