Effect of fertigation with nitrogen and foliar application of some nutrients on growth, yield and apple fruit mineral composition

Utjecaj folijarne aplikacije nekih hraniva, sa ili bez fertirigacije s dušikom, u uspredbi s klasičnom gnojidbom s dušikom, na vegetativni rast, rodnost, te sadržaj mineralnih elemenata u plodovima, istraživan je sa sortom Golden Delicious, cijepljenom na podlozi M9, tijekom 2000-2002. Istraživanja su obavljena u dva subpokusa: u prvom počevši s dvogodišnjim, a u drugom s trogodišnjim voćkama. U obadva pokusa voćke su uzgajane kao super vreteno (razmak sadnje 3.2 x 0.7m). Rezultati istraživanja ukazuju na veće značenje opterećenja rodom, a relativno mali učinak folijarne gnojidbe na rast, rodnost i sadržaj mineralnih elemenata u plodovima u godinama ulaska u produktivnu dob. Kada su stabla bila prikladno opterećena rodom, sadržaj i odnosi N/Ca, K/Ca i (Mg + K)/Ca bili su u granicama koje omogućuju uspješno čuvanje u hladnjači. Nasuprot tomu, u stabala s niskim opterećenjem, niti primjena folijarne gnojidbe nije pridonijela poboljšanju sadržaja mineralnih elmenata i plodovi su bili neprikladni za duže čuvanje u hladnjači.The effect of foliar application of some nutrients and fertigation in comparison with broadcast nitrogen fertilization on growth, yield and mineral fruit composition of young apple ‘Golden Delicious’, grafted on M9 rootstock was investigated in years 2000-2002. Two orchard experiments were established, one with 2-year and the other with 3-year old trees, grown at a spacing of 3.2 x 0.7 m and trained to super spindle. The results showed low beneficial effect of applied treatments, and relatively high effect of crop load on growth, yield and fruit mineral content. Ratios of N/Ca, K/Ca and (Mg + K)/Ca in fruits indicated good storage quality as related to normal crop load. Contrary to that, when treatments were applied on trees with inadequate crop load, no beneficial effect occurred and fruits showed low storage life. This result illustrates the important balance between vegetative growth and fruit load that occurs during tree establishment