Annual Bloom-time Phosphorus Fertigation Affects Soil Phosphorus, Apple Tree Phosphorus Nutrition, Yield, and Fruit Quality

Abstract

<jats:p>A randomized, complete block, split-plot experimental design with six replicates was established and maintained annually for the first five fruiting seasons (1999 to 2003) in a high-density apple [<jats:italic>Malus sylvestris</jats:italic> (L) Mill var. domestica (Borkh.) Mansf] orchard on M.9 rootstock planted in Apr. 1998. Main plot treatments involved eight different nutrient regimes, each containing three tree subplots of each of five different cultivars (Ambrosia, Cameo, Fuji, Gala, and Silken). This report compares a +phosphorus (P) treatment, involving annual fertigation at bloom time of 20 g P/tree as ammonium polyphosphate (10N–15P–0K), to a −P treatment. Both treatments also received nitrogen, potassium, and boron nutrients through fertigation. Drip fertigation of P increased 2 M KCl-extractable P to 0.4-m depth within 0.5-m distance of the drippers. Leaf and fruit P concentrations were consistently increased by the +P treatment with few differences among cultivars. P-fertigated trees also had a 20% increase in cumulative yield overall cultivars during the first five fruiting seasons. Standard fruit quality measurements, including fruit size, soluble solids concentration, titratable acidity, and red coloration were unaffected by P application. However, reductions in incidence of water core at harvest, increased resistance to browning, and elevated antioxidant content of harvested fruit measured in some years imply a role for P in apple membrane stability. The cumulative results indicate that applications of 20 g P as ammonium polyphosphate annually at bloom would be advantageous for apples receiving adequate fertigated applications of nitrogen, potassium, and boron. Best apple performance was associated with leaf P concentrations above 2.2 mg·g<jats:sup>−1</jats:sup> dry weight and fruit P concentrations between 100 and 120 mg·kg<jats:sup>−1</jats:sup> dry weight.</jats:p>

Nitrogen Fertigation Concentration and Timing of Application Affect Nitrogen Nutrition, Yield, Firmness, and Color of Apples Grown at High Density

“…Eight rows were required for each block with 16 rows required to encompass the six replicate blocks. Two of the fertigation treatments involved the presence or absence of annual P for which results have previously been described (Neilsen et al, 2008). Pertinent to this report was a factorial combination of six fertigation treatments involving two N rates and three N timings.…”

The Effect of Deficit Irrigation and Crop Load on Leaf and Fruit Nutrition of Fertigated ‘Ambrosia’/‘M.9’ Apple

“…In contrast, it might be argued that excessive P applications were made during the study. However, the susceptibility of P to precipitation within the soil (Neilsen et al, 1993;O'Neil et al, 1979) and documented benefits of large P applications at bloom (Neilsen et al, 2008) support maintenance of these P application rates. However, reductions in the B and N application rates may have been possible.…”

Physicochemical characteristics of unripe and ripe banana ‘FHIA 18’ submitted to phosphorus fertilizer over three production cycles

“…Over the two first production cycles, the firmness of ripe fruits presented average values of 1.37 and 1.57 N, respectively ( Figure 4); but also, no evidence of P fertilizer effect, probably due to the absence of this effect on the percentage of dry matter in the fruits. Research evaluating the influence of P fertilizer on the firmness of some fruits also indicated the lack of response to P (Neilsen, Neilsen, & Toivonen, 2008;Medeiros, Andrade, Pereira, Mendonça, & Fonseca, 2014;A. C. Silva et al, 2016).…”