Fruit Growing Research (Jan 2012)
INFLUENCE OF CHEMICAL FERTILIZATION ON STRAWBERRY FRUIT PROPERTIES
Abstract
The worldwide trend of plantations fertilization imposed a new concept in this field. On one hand, it was abandoned the idea of using large amounts of fertilizer to force the obtaining of high yields, and on the other hand, increasingly require more and more application of organic and unpolluted fertilizers. In practice, the nutritional control of strawberry is very difficult, because a large number of factors influence the absorption and availability of nutrients through mechanisms that are not fully understood. Aim is to establish concrete measures for improving crop technology by applying optimum dose of fertilizers, leading to increased productivity and fruit quality of strawberry culture. The research was conducted during 2009-2010, in a two-way experience. It was located at the Research Institute for Fruit Growing Pitesti. Experimental factors were: A - cultivars: a1 – ‘Onebor’, a2 – ‘Real’, a3 – ‘Elsanta’, a4 – ‘Mira’, a5 – ‘Alba’, a6 – ‘Premial’; B – Fertilizer with 6 graduations: b1 - unfertilized, and for graduations b2 - b6 were applied mixtures ofthe below fertilizers the amounts becoming increasingly larger, thus: b2 - 6.4 kg / ha / week, b3 - 14.3 kg / ha / week, b4 - 21.4 kg / ha / week, b5 - 28.5 kg / ha / week and b6 - 35.8 kg / ha / week. The fertilizers applied were: Polyfeed (N19: P19: K19), K nitrate (N12: P0: K43: Mg2) and Magnesia (N11: P0: K0: Mg15). Mixtures were applied at 2 weeks intervals, as follows: 1 April to 15 May (flowering), 2 applications, containing macroelements N: P: K: Mg 14:6,3:20,7:5,7 g / 100 g mixed fertilizers, May 15-June 15 (in the picking period), 2 applications of N: P: K: Mg 10,2:6,3:13,5:2,83g/100 g blend fertilizer and August 1 to September 15 (2 applications) with N: P: K: Mg 12,2:6,3:20,7:31,6 g/100 g mixed fertilizers. Following determinations were made: average weight of fruit (g) by weighing a sample of 250 fruits, fruit soluble dry matter (%), refractive, total acidity (g of Malic acid/100 g fresh matter) iodometric method. Experimental treatments have led to differences in the acidity of the fruit. Thus, the analysis of fertilizer doses on the chemical components of the fruits of the six studied cultivars, we concluded that V5 and V6 treatments had a positive influence on pH of the fruits of ‘Premial’ cv. (3.460), ‘Elsanta’ (3.400) and ‘Mira’ (3.460). Treatments induced also, highest average fruit weight in variety ‘Mira’ (45,025 g), weight varies as compared to the control (32.795 g) and from other experimental versions of the same variety. Average dose of fertilizer belonging V4 and V5 variants showed the highest values of fruit dry matter content of the variety ‘Premial’ (65.55%), respectively (7.570%), higher values the witness variant and other variants analyzed
