Research paperFoliar nutritive fluids affect generative potential of apples: Multilocation DOP indexing and PCA studies under dry temperate agro-climatic conditions of north-west Himalaya

- Nutrient dynamics of foliar nutrient fluids on phenological and pomological traits of apples in dry temperate ecosystem was carried out.
- DOP indexing showed foliar supplementation with the investigated preparation resulted in an increase in N, P, K and Mg concentration in the leaves.
- 'Oregon Spur' apple exhibited better balanced nutritional values compared to 'Royal Delicious' apple.
- PCA studies on phenological and pomological traits were also worked out.

Multilocation trials were established to evaluate the conjoint effects of foliar nutrient fluids supplemented along with soil NPK fertilizers on generative potential of apples in dry temperate ecosystem of north-west Himalaya. The principal objective of selecting three site locations was to ascertain any interaction between variety and climate. Trial procedure included conjoint tree fertilization of foliar nutritive fluids of NPK-water soluble fertilizers (WSF, 0.5% solution as foliar spray) supplemented at different growth stages viz., NPK-19:19:19 (at an interval of 15 days from foliage sprouting stage), NPK-13:00:45 (KNO3, at an interval of 15 days from pink bud stage) and NPK-00:00:50 (K2SO4, at an interval of 15 days from walnut-fruit development stage) either 3 or 2 times based upon WSF version along with 5 levels of NPK soil fertilization. Different factor levels included the schedule in RCBD factorial matrix as T1: 100% of the blanket Recommended dose of fertilizers (RDF, NPK-70:35:70) + foliar WSF, T2: 87.5% RDF+ foliar WSF, T3: 75% RDF+ foliar WSF, T4: 62.5% RDF+ foliar WSF, T5: 50% RDF+ foliar WSF, and T6: Control (NPK-RDF soil fertilizers+ water spray). Foliar fertilization with T4 significantly affected phenological and pomological traits as well as leaf nutrients concentration. According to DOP and ΣDOP indexes, the excessive leaf N, P, K and Mg, and the deficiency of Ca, and micronutrient concentrations was noticed. DOP indexing showed that foliar supplementation with the investigated preparation resulted in an increase in N, P, K and Mg concentration in the leaves. 'Oregon Spur' apples exhibited better balanced nutritional values as compared to 'Royal Delicious', confirmed the better adaptation of 'Spur' apples to acidic soils associated with tree vigourness than 'Delicious' apples. Principal component analysis (PCA) also worked out the differences induced at various fertilizer treatments. It is concluded that foliar WSF supplemented along with 62.5% of RDF of soil NPK fertilizers at foliage sprouting, flowering and fruit set stage at 15 days' interval resulted in better cropping behavior and fruit yield compared to traditional soil fertilization in dry temperate ecosystem.